Functions And Functions Of An Extensive Variety Of...

Functions And Functions Of An Extensive Variety Of...
Biomembranes play an essential role in regulating an extensive variety of cellular processes by
providing an active two–dimensional lipid framework within which biochemical reactions can
occur. The structure and dynamic lateral organization of these membranes selectively modulate the
activity of membrane associa¬ted proteins, such as receptors and channels.1–3 Biomembranes are
complex structures which are responsible for the entity of cytosolic organelles and cells. Besides a
structural role, membrane components play a key role in communications between the extra– and
intracellular environments, serving as messengers in signal transduction and recognition processes.
The main constituents – lipids and proteins in biological membranes stay together predominantly by
non–covalent interactions. Covalent interactions are also absent between lipids within membranes,
resulting highly dynamic properties these assemblies. Lipids are amphipathic molecules that self–
assemble into continuous double layer arrangement in aqueous environment, where polar head
groups have tendency to interact with the water while hydrophobic moieties to self–associate via
hydrophobic interactions. Although phospholipid molecular species vary greatly in eukaryotic cell
membranes, they predominantly belong to four main lipid types: Phosphatidylcholine (PC),
phosphatidylserine (PS), phosphatidyl–ethanolamine (PE) and sphingomyelin (Sph). Asymmetric
distribution of these components between extra–cellular
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Explain How The Membrane Controls What Turns Into And Out...
Cell Process Assignment
The membrane controls what passes into and out of cell. According to OpenStax College (2013),
states that the membrane allows substances to enter and leave a cell (OpenStax College, 2013). The
membrane is selectively permeable and the process by which molecules pass through the cell
membrane can be accomplished by diffusion, osmosis, facilitated transport and active transport.
Diffusion is the movement of molecules from high concentration to a region of low concentration
(OpenStax college, 2013). Osmosis is the process by which water pass through a semi–permeable
membrane. Facilitated transport, also known as facilitated diffusion is the movement of particular
molecules down a concentrated gradient. Active transport is the process in which ... Show more
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Each process plays a very important role within an organism.
There are some similarities between diffusion, osmosis, facilitated transport and active transport.
One way in which they are all similar is that they all transport substance across two different regions
to and from the cell membrane that is essential to the cell being able to sustain itself. Diffusion
transports gases, such oxygen and carbon dioxide. Osmosis transports water. Facilitated transports,
transports water, glucose and amino acids. Lastly active transport, transports ions, sugar and amino
acids. Another similarity is that diffusion, osmosis, and facilitated transports are all passive
transport. Which means that each process doesn't need energy to pass molecules through a cell.
According to OpenStax College (2013), states that it is a natural occurrence that doesn't require
energy to achieve movement (OpenStax College, 2013).
Even though there are some similarities between the different processes there are some difference.
Diffusion requires no energy to transport materials across membranes and within cells. It goes from
a

The Role Of Proteins Of Cell Membrane Transport
Discuss the role of proteins in cell membrane transport essay plan Cell membranes are surrounded
by a phospholipid bilayer that provides a semipermeable barrier for cells, separating the cytosol
from the extracellular environment. Phospholipids are ampithatic, meaning that they have a
hydrophilic head and hydrophobic tail, which causes the heads to face outwards towards the water
and the tails inwards, creating the bilayer [figure 1]. Small hydrophobic molecules such as O2 and
CO2 and small uncharged polar molecules such as H2O and ethanol can diffuse through this bilayer,
however larger molecules and ions cannot, and thus require proteins, which are polymers of amino
acids joined together by strong peptide bonds. These proteins feature throughout the membrane, and
account for around 50% of its mass [http://www.ncbi.nlm.nih.gov/books/NBK9898/] . Not only are
proteins required for transport of molecules through the membrane, but they also transport signals
and are necessary for the cell support; throughout this essay I will focus on the pivotal role they play
with regards to the transport of these molecules and signals, and what occurs when these functions
are inhibited. There are two main types of membrane transport proteins: firstly, there are channel
proteins, which are essentially pores that extend across the membrane. These pores create a
hydrophilic passage for molecules through he hydrophobic bilayer. The rate of movement through
these pores is significantly faster

Photosynthesis And Cellular Respiration
Photosynthesis and cellular respiration are two different types of processes that create energy.
Cellular Respiration is "the oxidation of glucose to produce ATP (Tortora and Derrickson, 2011, p.
1027)." This process occurs in all living organisms. In comparison, Photosynthesis is "the
conversion of sunlight into a chemical form of energy. In the cyanobacteria, the process takes place
in special thylakoid membranes, which contain chlorophyll or chlorophyll–like pigments. Among
eukaryotes, photosynthesis occurs in the chloroplasts of such organisms as diatoms, dinoflagellates
and green algae. (Pommerville, 2014, p. 185)".
Both processes have different stages to create energy. Cellular respiration has aerobic and anaerobic
processes. In the aerobic process, enzymes break down glucose in "presence of oxygen to produce
cell energy". The stages in cellular respiration include glycolysis, transition, Krebs cycle and the
electron transport system. Glycolysis occurs in the cytoplasm. During this stage, there is a
"conversion of glucose into pyruvate (Pommerville, 2014, p. 171)". In addition, "two ATP molecules
are required and the net yield is 2 pyruvates and 2 ATPs (Pommerville, 2014, p. 173)". The
transitional stage "occurs in the outer mitochondrial membrane." According to Pommerville, "Each
pyruvate is converted into an acetyl CoA as CO2 is liberated and two NADH are formed. Each
acetyl CoA combines with an oxaloacetate to form citrate (p. 174)." Unfortunately, this step did

Cell Membrane Permeability
Only uncharged, small, polar molecules, (such as water) and hydrophobic molecules, (such as
oxygen, carbon dioxide) and lipid–soluble molecules (such as hydrocarbons) can freely pass across
the membrane. All ions and large polar molecules (such as glucose) are not permeable to the
membrane.
Membrane structure
The plasma membrane maintains dynamic homeostasis by separating the internal metabolic events
of the cell from its external environment and controlling the movement of materials into and out of
the cell. The membrane is a double phospholipid membrane, also referred to as a phospholipid
bilayer, and has polar hydrophilic ("water loving") phosphate heads around the outside and non
polar hydrophobic ("water fearing") fatty acid tails on the inside of the membrane. Slight variations
in these structure of the fatty acids in the membrane alter the fluidity of the membrane.
Phospholipids with saturated fatty acid pack more tightly, because of the nature of their single
carbon bonds. This leads to a more rigid membrane. Unsaturated fatty acids, which have double
carbon bonds, limit packing and result in a more flexible membrane. Cholesterol molecules
distributed throughout the phospholipid bilayer provide some stability to the plasma membranes of
animal cells. At higher temperatures the cholesterol molecules allow the membrane to be firmer, at
lower temperatures they allow for flexibility.
Fig. 1
Proteins
The mosaic nature of the proteins scattered within the phospholipid

The Phospholipid Bilayer
1a. Explain in your own words what the underlined term above means (1).
The phospholipid bilayer is composed of two phospholipid layers in the cell membrane. The cell
membrane consists of mainly phospholipids (made up of fatty acids), which are arranged into two
layers to form the phospholipid bilayer.
1b. On page 94, the Martini and Nath (2015) text says "in each half of the bilayer, the phospholipids
lie with their hydrophilic heads at the membrane surface and their hydrophobic tails on the inside".
Explain in your own words what this means, and why the structure is this way and not the other way
around (2).
In each half of the phospholipid bilayer, the phospholipids lie with their hydrophilic heads at the
membrane surface in contact with aqueous environments on either side of the membrane; and the
phospholipids lie with their hydrophobic tails on the interior of the membrane. The structure is
formed this way and not the other way around, as the lipid tails are hydrophobic; they will not
associate with water molecules, so they must remain inside the membrane. Without the division of
water and solutes within the lipid portion of the membrane, the cell would not survive.
1c. Explain the difference between an integral protein and a peripheral protein in the cell membrane,
and give an example of each type (2).
There are two types of proteins located within the cell membrane: integral proteins and peripheral
proteins. Integral proteins are found within the

A Brief Note On Voltage Gated Sodium Channels
Abstract
Voltage gated sodium channels are fundamental players in animals physiology. By triggering the
depolarization of the lipid membrane they enable generation and propagation of the action potential.
The involvement of these channels in numerous pathological conditions makes them relevant target
for pharmaceutical intervention. Therefore, modulation of sodium conductance via small molecule
binding constitutes a promising strategy to treat a large variety of diseases. However, this approach
entails significant challenges: voltage gated sodium channels are complex nanomachines and the
details of their workings have only recently started to become clear. Here we review ¬¬– with
emphasis on the computational studies – some of the major milestones in the long–standing search
of a quantitative microscopic description of the molecular mechanism and modulation of voltage–
gated sodium channels.
Introduction: Physiological Role of Voltage Gated Sodium Channels (VGSCs)
Cells respond to stimuli from the environment by enabling the passage of ions across the plasma
membrane, a process that results in the propagation of an electrical signal. Ion channels are the key
players of this process, the membranes of excitable cells are studded with a myriad of these integral
membrane proteins, which transduce chemical and electrical stimuli into currents of charged
chemical species (Hille, 2001). Owing to their pivotal role in cell physiology, a large number of
genes encode for ion

Functions And Functions Of Eukaryotic Cell
The bodies of humans, animals, or even plants are very complex; it has infinitely many functions.
These functions are carried out by organs; all organs in the body operate in a choreograph manner
that keeps the body in a healthy state. If these functions decide to fail, life cannot be sustained. With
that said, without the body's secret ingredients the organs and the functions they carry out will cease
to exist. These secret ingredient are known as cells–the fundamental unit of life. Cells are essential
to sustaining life; ironically it is the smallest living unit in the body. It has numerous functions in
and of its self. In this paper, we will discuss some of the functions within a cell, specifically
eukaryotic cell.
Initially, let's talk about the nucleus and the functions it carries out. The nucleus is an organelle
within the cell; it is also referred to as the control center or the brain of the cell. The nucleus is
arguably the most integral function within the cell. Within the nucleus, there are numerus structures
which include, but are not limited to, nucleolus, nuclear envelope, and chromatin. First we have the
nucleolus, the nucleolus sits in the middle of the nucleus; it produces ingredients which help
produce ribosomes. Ribosomes generate proteins within the cells, and proteins are pertinent to the
basic function of the cell. Second we have the nuclear envelope (nuclear membrane), this is a
membrane that surrounds the nucleus. The envelope has an inner membrane and

Lab Report Cell Diffusion
Lab Report Introduction: Background Information The plasma membrane of a cell is like the skin of
a human. It is selectively permeable which means it selects what it wants to allow into the cell and
blocks out what it doesn't want. The cell membrane is made up of a phospholipid bilayer which
contains 75% phospholipids, about 20% cholesterol and 5% glycolipids. Phospholipids are
amphipathic which means they contain both polar and non–polar parts, these are their polar heads
and non–polar tails. The lipid bilayer is like a sandwich in which the polar heads are the bread of the
sandwich and one slice of bread faces the extracellular fluid and the other faces the cytosol. The
non–polar tails are like the contents inside of the sandwich. ... Show more content on
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It showed that if the pore of a membrane is not large enough, diffusion will not occur. However, if
the pore was large enough and diffusion subsequently occurred, the rate of diffusion was the same
even if the molecular weight cut off (pore size) was bigger. The following solutes and their simple
diffusion data will be explained in order from smallest to largest, smallest being one that was able to
fit through smaller a pore size.
NaCl was able to diffuse starting at 50 MWCO and the pore size there after did not affect the rate of
diffusion, (0.0150 mM/min) which stayed was the same. Urea was not able to diffuse until 100
MWCO and the rate of diffusion stayed the same at 0.0094 mM/min. Glucose was able to diffuse
only at a 200 MWCO and Albumin was too large to fit through any of the pore sizes and did not
diffuse.
Activity two: Simulating Facilitated Diffusion
This activity did support the hypothesis which was that the rate of diffusion increases when the
quantity of carrier proteins increases. One thing to be noted is that when the glucose concentration
was increased the rate of diffusion also increased which was not something that was expected.
However if there are not enough carrier proteins available to combine with the solute not all of the
solute will be transported/diffused down the concentration

Osmosis And Diffusion Lab Report
Molecule Properties that Allow Passive Transport Across the Membrane
There are certain properties of a solute that affects how easily it can pass through the plasma
membrane. In passive transport, all substances move from an area of high concentration to an area
or low concentration which does not cause for the use of energy, also known as adenosine
triphosphate (ATP). Diffusion and osmosis are two mechanisms of passive transport. Diffusion is
the process in which small molecules compatible with the plasma membrane can pass from the
extracellular fluid that is outside the cell to the intracellular fluid, cytoplasm inside the cell, easily
and without guidance. Molecules such as oxygen and carbon dioxide in the body pass through the
cells of ... Show more content on Helpwriting.net ...
Unlike the smaller oxygen and carbon dioxide molecules, water molecules and salt molecules are
large, polar molecules that are not lipid soluble, so they need the assistance of integral proteins.
(VanPutte, Regan, and Russo, 2017, p. 63–68) The dishwashing liquid in cup 3 parts the oil of in the
cup similar to the way integral proteins part the lipid bilayer, allowing the salt to pass through by
facilitated diffusion and the water by osmosis. Other factors such as the temperature of the
constructed lipid bilayer could have sped up or slowed down the rate of diffusion through the
bilayer. The higher the temperature of the water and oil, the easier salt would have dissolved. While
smaller molecules seep through the membrane with zero trouble, larger substances struggle and
need

The Effect Of Temperature On Membrane Permeability
The objective and the main purpose of this experiment were to determine the effects of temperature
on membrane permeability. Physical treatment on membrane permeability with its effects on the
basis of the known chemical composition of the membrane was investigated. The major result of
this experiment was the maximum membrane permeability was determined by the maximum
absorbance value. Also the membrane becomes more permeable at higher temperature, which was
the expected result considering the fact that the protein denatured at higher temperature and
phospholipid became less stable because its shape and structure changed. As figure.1 states the
result of this experiment as temperature increases, the mean absorbance value increases as well
(Reece et al., 2014).
All of phospholipid bilayers, proteins and carbohydrates together constitute the biological
membrane. Each of these members of biological membrane has separate individual task. The task of
phospholipid bilayer is to make up the cell membrane. Phospholipids are made up of two fatty acids
and long chain of hydrogen and carbon, which are, attach to glycerol head. The glycerol molecule is
also attached to phosphate group and this is the hydrophilic part of the molecule. The tail ends on
the fatty acid chain, opposite the glycerol are hydrophobic part of the molecule. The phospholipid
releases a barrier to prevent the passage from chemical and waste products. The most important
function for phospholipid is to form a

Cell Membrane Structure
1 – Describe the normal structure and functioning of cell membranes, and explain how they
compare to the membranes relating to a specific abnormality in cystic fibrosis?
All cells have a cell membrane. The structure of membranes is formed from a double layer of
phospholipids with proteins floating in it. The proteins are embedded on the surface and inside or
bridge the double layers of phospholipids. This structure is called a mosaic model. The main
function of cell membranes is to provide protection and support for the cell and they also control
what enter and exit the cell to maintain internal balance, called homeostasis. There are two types of
a membrane protein: integral proteins and peripheral proteins. The integral membrane proteins are ...
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The cystic fibrosis affects the exocrine gland, which are organs that secrete mucus. It normally
produces thin, slippery secretions such as mucus, sweat, tears and digestive juice. The organs can be
affected by cystic fibrosis are sweat glands, respiratory system, digestive system and reproductive
system.
Sweat glands: The individual who suffers from cystic fibrosis, the amount of body salts lost in the
sweat are higher than the normal people. This can cause problems during times of increased
sweating. Such as hot weather.
Respiratory system: The lining of the respiratory tract which made of tiny, hair– like cells called the
cilia. Their function is to keep the lung clean and clear from foreign substances and mucus. The
person who suffers from cystic fibrosis, the cilia can not easily remove the thick and sticky mucus
out of the air passages in the lung. The mucus clogs the air passages, causing a chronic cough and
lung infections. Repeated of lung infections can lead to damage to the lung and leading to not get
enough oxygen into the body.
Digestive system: The thick and sticky mucus blocks the pancreatic ducts and preventing the
enzymes from reaching in the small intestine to digest food. The result is incomplete digestion and
poor absorption of food

Cystic Fibrosis : An Autosomal Recessive Condition Of The...
The Disease Cystic fibrosis is an autosomal recessive condition of the secretory glands, which
affects roughly 30,000 individuals in the United States alone (Cohen & Prince, 2012, p. 509). This
chronic genetic disorder of the sweat and mucous glands affects a number of different anatomical
structures including the epithelial cells of the respiratory tract, the exocrine pancreas, and the
exocrine sweat glands. Cystic fibrosis results in the production of abnormally thick mucus which
can detrimentally affect a number of different organs throughout the body, most notably the lungs
and pancreas. With such a widespread effect on the body, cystic fibrosis is truly a multisystem
disorder.
Diagnosis and Management Cystic fibrosis can be diagnosed by a sweat test and genetic testing of
the affected individual. In the sweat chloride test, a physician rubs the patient's skin with a chemical
that induces sweating and then applies an electrode to the area which generates a small electrical
current. The sweat is then collected and analyzed. A chloride concentration of greater than 60
mEq/L is indicative of cystic fibrosis (Moskowitz, Chmiel, Sternen, Cheng, Cutting, 2008). Genetic
testing is often utilized in conjunction with the sweat test to affirm the diagnosis. Cystic fibrosis is
mainly managed through the treatment of its symptoms. Pulmonary complications of this genetic
condition such as chronic pulmonary infections are managed with oral, inhaled, or IV antibiotics,

Dn The Scientific Study Of Cells
Sex Cells: Also known as Gametes, are the sperm cells in males and the eggs cells in females. These
cells fuse in a process called fertilization , and the resulting cell (zygote) contains a mix of inherited
genes from the father and mother. Germ Cells: Germ cells are cells involved in reproduction. The
most well known examples of this type of cell are gametes. Gametes are the sperm and eggs which
come together to create a zygote which can develop into a fetus. Somatic Cells: A Somatic cell is
generally taken to mean any cell making up an organism. All cells of an organism are Somatic
except Gametes. Cytology: The scientific study of cells. This includes their structures and their
various functions. This role is generally attributed to Biologists. Extracellular Fluid: Fluid not
contained in cells but found in blood, lymph, body cavities lined with serous membrane, channels of
the brain and spinal cord, and in muscular and other body tissues.
Interstitial Fluid: A solution that bathes and surrounds the cells of multicellular animals. It is the
main component of Extracellular fluid, which also includes plasma and transcellular fluid. The
interstitial fluid is found in the interstitial spaces, also known as the tissue spaces.
Plasma Membrane: A thin, semi–permeable membrane that surrounds the cytoplasm of a cell . Its
function is to protect the integrity of the interior of the cell by allowing certain substances into the
cell, while keeping other substances out. It

Comparing The Structure And Function Of The Cell Membrane
Task 2.1 Describe the structure and function of the cell membrane
Every living cell is surrounded by a thin layer known as the cell membrane or plasma membrane,
which controls the movement of substances in to and out of the cell. This membrane is also
responsible for maintaining the ultra–structure of the cell, and keeping its internal components
together. Organelles such as the nucleus, lysosomes, the Golgi body and mitochondria are also
bound by their own individual membranes.
The molecular structure of the plasma membrane is known as the fluid mosaic model; mosaic
because of the way in which proteins are scattered around and through the membrane, and fluid
because although the phospholipid bilayer forms a firm boundary around the cell, it allows
molecules and proteins to travel through it freely. ... Show more content on Helpwriting.net ...
One end of a phospholipid is hydrophilic ("water–loving") and the other end is hydrophobic
("water–fearing"). The water–soluble hydrophilic heads form the two outer surfaces of the
membrane's bilayer. One layer is aligned on the outside of the cell toward the extracellular fluid, and
the other is aligned on the inside of the membrane, toward the intracellular fluid. The water–
insoluble hydrophobic tails are aligned inwards toward the middle of the bilayer, away from any
aqueous substances.
Within the phospholipid bilayer, many different types of proteins exist. These proteins are diverse in
shape, size and structure. Integral proteins are embedded within the bilayer, either partially or fully.
Peripheral proteins adhere to either side of the membrane's surfaces and transmembrane proteins
extend from one side of the membrane to the

Erythrocyte: Structure & Metabolism
Erythrocyte: Structure & Metabolism
หัวข้อบรรยาย 1. Red cell membrane 1. Membrane lipid 2. Membrane skeleton 3. Peripheral proteins
4. Integral proteins 2. RBC metabolism 1. Glycolytic (Embden–Meyerhof) pathway 2. Hexose
monophosphate shunt 3. Rapoport–Luebering pathway 2.4 Methemoglobin reductase pathwa 3.
Hemoglobin 3.1 Hemoglobin structure 3.2 Hemoglobin synthesis 3.3 Genetic control of hemoglobin
structure 3.4 Hemoglobin function 3.5 Hemoglobin catabolism 4. Iron metabolism
วัตถุประสงค์ของการศึกษา 1. อธิบายได้ถึงลักษณะสำคัญและส่วนประกอบของ red cell membrane ...
ฟอสโฟไลปิด ประกอบด้วย polar head และส่วนหางที่เป็น hydrocarbon (ดัดแปลงจาก
http://sun.science.wayne.edu/~bio669/Chap03.pdf)
แผ่นเยื่อชั้นนอก [pic]
แผ่นเยื่อชั้นใน
รูปที่3 แสดงการเรียงตัวของฟอสโฟไลปิด สองชั้นในเยื่อหุ้มเซลล์เม็ดเลือดแดง ฟอสโฟไลปิดทั้งสี่
ชนิด (PC, PE, PS, SM) กระจายตัวในแผ่นเยื่อชั้นในและชั้นนอกไม่เท่ากัน (ดัดแปลงจาก อานนท์ บุณ
ยะรัตเวช เม็ดเลือดแดง ใน โลหิตวิทยา 2535)
ฟอสโฟไลปิดของเยื่อหุ้มเม็ดเลือดแดงได้แก่ phosphatidyl choline (PC), phosphatidyl ethanolamine
(PE), phosphatidyl serine (PS) phosphatidylinositol (PI) และ sphingomyelin (SM) ฟอสโฟไลปิด
เหล่านี้มี คุณสมบัติที่แตกต่างกันไปขึ้นกับความเป็นประจุลบหรือการมีขั้วข
องส่วนหางที่แตกต่างกัน จากสูตรโครงสร้าง (รูปที่ 4) PS มีความเป็นประจุลบมากกว่าฟอสโฟไลปิด
PC, PE, PI คุณลักษณะนี้ทำให้โปรตีนที่เป็นส่วนประกอบของ membrane cytoskeleton ทำปฏิกิริยากับ
ประจุลบของ PS ทำให้ผนังเยื่อหุ้มเม็ดเลือดแดงมีความคงตัวมากขึ้น [pic] [pic] [pic] [pic]
รูปที่ 4 สูตรโครงสร้างของ ฟอสโฟไลปิด PC, PE, PS และ PI (ดัดแปลงจาก
http://sun.science.wayne.edu/~bio669/Chap03.pdf)
ฟอสโฟไลปิดของเยื่อหุ้มเม็ดเลือดแดงที่สำคัญมีอยู่ 4 ชนิดซึ่งอยู่ในแผ่นเยื่อชั้นนอกและชั้นใน (รูปที่

3) ในอัตราส่วนที่แตกต่างกัน (asymmetric distribution) พบว่า PS และ PE ส่วนใหญ่จะอยู่ในส่วนแผ่น
เยื่อชั้นในในขณะที่แผ่นเยื่อชั้นนอกพ
บว่ามี SM และ PC เป็นส่วนใหญ่ (ตารางที่1)
ตารางที่1 สัดส่วนของฟอสโฟไลปิดในเยื่อหุ้มเซลล์ ปริมาณSM, PC, PE และPS

Biochemistry 208.5.5
Desiree Schmitt
208.5.5
In humans/animals, the main cells that store fat for energy are adipocytes. These fat cells are found
under the skin, in the abdominal cavity and surround major organs. The fatty tissue is the body's
main means of storing energy for long periods of time. Lipids, like triglycerides are stored in the
adipocytes until ready to be used by the body for energy. Fat is broken down through metabolism in
the mitochondria of the cell. The triglycerides are broken down into glycerol and 3 fatty acids. The
glycerol can be easily converted to glyceraldehyde 3 phosphate, an intermediate of glycolysis. From
there it can go through the Krebs Cycle and electron transport chain to make ATP. The 3 fatty acids
can be broken ... Show more content on Helpwriting.net ...
Every cell membrane incorporates a fluid mosaic model. The "mosaic" of protein molecules
embedded in a lipid bilayer. It's fluid as most proteins and lipid molecules drift through it. The
membrane consists of a phospholipid bilayer embedded with various proteins. The proteins help to
get polar/hydrophilic molecules through the plasma membrane. Polar molecules have difficulty
passing thru the hydrophilic membrane. Nonpolar molecules however, easily pass thru. The proteins
can be integral proteins, meaning they go all the way through the lipid bilayer or peripheral proteins
that sit on the hydrophilic outer layer and wait for something to happen. The layers are somewhat
fluid, allowing the proteins to move across them. See diagram below.
No fat diets can actually do more harm than good. The body needs moderation of all energy
producing macronutrients; fats, carbohydrates and proteins. By not eating any fat, the body starts to
utilize the fats stored in the body, thus depleting the stores and people lose weight. However, once
those stores are gone, the good fats or HDL's, are no longer able to filter out the bad cholesterol.
This can lead to increased cholesterol levels in the blood and heart disease. A no fat diet also causes
poor vitamin absorption of the necessary fat soluble vitamins A, D, E and K. Fats transport those
vitamins from the liver to various parts of the body.
Sanders, J.

What Are The Three Postulates Of Cell Theory
LESSON 1: CELL THEORY AND ITS PARTS/ORGANELLES AND FUNCTIONS
Living and Non–living Things
All the things we see on earth are created by God Almighty. The rocks, air, soil, chemicals, plants,
trees, animals, humans among others exist on earth. But, we can classify them as living and non–
living things. Living or biotic things have life, and therefore, governed by cells which performed
roles for life to occur. These are plants, animals and humans. On the other hand, non–living or
abiotic things do not have life but they are essential to the existence of life. These are the rocks, soil
and air.
Cell and Cell Theory
The cell is a basic unit of life (Bolsover et al., 2004). It is the basic unit of plants, animals and
humans. Cells serve as the building blocks of life for example of ... Show more content on
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The union of human egg cell and sperm cell forms a new life (Lodish et al.).
Table 1. The three postulates of cell theory and its explanations.
POSTULATES EXPLANATION
Cells are the fundamental units of life Life is governed by cells, the basic unit. Life exists because of
cells. Without cells, there is no life on earth.
All organisms are composed of cells All life forms on earth are made up of cells. Microorganisms,
plants, animals, and humans are composed of cells.
All cells come from preexisting cells Cells originated from ancestral cells existing long time ago.
These cells undergo evolutionary modifications and adaptations with the physical environment.
General Cell Structures and Functions
Based on Bolsover et al. (2004), a cell has parts, structures or organelles (Table 2) that have a
respective function as a whole for life to occur (Figure 2). Generally, cells have parts such as
nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum, lysosomes and cell membrane.
Different structure has different function but working as a whole. One structure cannot make life
possible but many complex structures and functions contribute to the existence of

Eukaryotic Cell Research Paper
Eukaryotic cells use around 5% of their genes in order to synthesise lipids. There are many different
types of lipids present in membranes. Firstly, phospholipids are the most abundant type of lipid in
all biological membranes and are composed of a hydrophilic phosphate head and a hydrophobic
fatty acid tail. Some membranes also contain glycolipids, which are sugar containing lipids. In
eukaryotic membranes, but not prokaryotic membranes, cholesterol can be found, which is a lipid
and steroid. Whilst lipids do play a structural role in membranes and function in
compartmentalisation, lipids also have many functions in the cell. In this essay I will discuss how
lipids play a role in the ability of receptors to function, budding and fusion, fission, ... Show more
content on Helpwriting.net ...
Budding of a membrane domain and formation of a narrow neck are consequences of line tension
and the need to reduce the length of the energetically unfavourable domain boundary. Deformation
of the lipid molecules in opposing monolayers is present, with lipids in the outer monolayer
adopting an extended conformation, whereas those in the inner monolayer become compressed and
splayed. Thinning at the neck is driven by the formation of lipid microdomains and the
accumulation of lipids with negative spontaneous curvature in the most deformed and thinnest parts
of the neck. This decrease the barrier for transformation into a hemifission intermediate. Molecular
dynamics simulations of membrane fusion events have shown that accumulation of tilted lipids in
the contact zone results in the formation of a stable stalk like

The Cellular Level of Organization
Chapter 3: The Multiple Choice 1. a. b. c. d. e. 2. a. b. c. d. e. 3. a. b. c. d.
Cellular Level of Organization
What are the three main parts of a eukaryotic cell? Plasma membrane, organelles, cytoplasm Plasma
membrane, organelles, nucleus Plasma membrane, cytoplasm, organelles Plasma membrane,
cytoplasm, nucleus Plasma membrane, cytosol, organelles Plasma membranes consist of what three
components? Phospholipids, glycoproteins, water Proteins, cholesterol, fatty acids Cholesterol, fatty
acids, glycolipids Proteins, phospholipids, cholesterol Water, proteins, fatty acids What are the
nonpolar parts of a phospholipid? Head group Tail group Both are nonpolar Neither are nonpolar
4. This is the only polar portion of a cholesterol ... Show more content on Helpwriting.net ...
peroxisomes mitochondria proteasome ribosomes lysosomes Proteasomes Perform extracellular
digestion Perform autophagy Perform autolysis Degrade faulty cellular proteins Degrade ATP
Mitochondria move the cell generate ATP produce proteins oxidize organelles
Houston Community College Page 4
31. a. b. c. d. e. 32. a. b. c. d. e. 33. a. b. c. d. e.
Which of the following protects the contents of the nucleus? Nucleic acids nuclear membrane
nuclear centrosome cilia golgi apparatus What is the major function of a histone protein? For helix
shape Adds a charge to DNA Help organize coiling of DNA Degrade proteins Enzymatic effect This
is a long molecule of DNA that contains genes. There are 46 in each body cell. chromatin chromatid
chromosome centromere centrosome
34. This is the set of rules that, relating the base triplet sequence of DNA to the corresponding
codons of RNA, specifies a sequence of amino acids. a. gene expression b. genomics c. anticodons
d. genetic code e. protein synthesis 35. This binds to an amino acid and holds it in place on a
ribosome until it is incorporated into a protein during translation. a. mRNA b. rRNA c. tRNA d.
DNA 36. a. b. c. d. 37. a. b. c. d. e. 38. a. b. c. d. e.
Dr. D.
This portion of a DNA segment does not code for a protein. RNA Intron Exon Polyribosome This
process is division of the cytoplasm. mitosis meiosis cytokinesis cytosol centrioles During which

Eukaryotic Cells Research Paper
Eukaryotic organisms have cells that contain a nucleus. Animals, plants, fungi, and protoctista all
have eukaryotic cells. The eukaryotic cell has a plasma membrane as its external boundary like all
other cells, but it also has a variety of membranes that divide the internal space into discrete
compartments, which give them its unique feature, that enable the cell to carry out various chemical
reactions or processes in separate parts of the cell, which all form part of the same system. The
compartments in the cytoplasm are known as organelles.
The plasma membrane not only provides shape for a cell and encloses its content; its complex
design gives it a significant property which is selective permeability. This permits some molecules
and ions to pass freely through the membrane such as water, but excludes large molecules, and
charged particles such as chloride ions (Cl–) and ... Show more content on Helpwriting.net ...
This flexibility is due to the lateral movement of the hydrophobic tail knowing that cholesterol is a
component of animal cell membrane, making the membrane less fluid and less permeable to water
soluble molecules. The dual nature of the phospholipid molecule (Amphipathic nature) helps
maintain the structure of the membrane as in a bilayer. Also the attraction force between heads and
those between tails help stabilize the structure.
There are different types of protein in the bilayer. Integral proteins are hydrophobic and are
embedded in the bilayer, while the peripheral proteins are attached to the surface. Many proteins on
the outer surface are glycoprotein–that is, they have carbohydrate groups attached to them. Some of
these function as hormone binding site, others are enzymes immobilized with the active site on the
outside. Finally, there are proteins that act as a channel for passive transport to allow hydrophilic
particles across by facilitated

Taking a Look at Intracellular Fluid
Intracellular Fluid: (Located inside the cells) Fluid Contained within all of the cells of the body and
accounts for 67% of all the fluid in the body –Contains proteins and substances specific to certain
biological actions Extracellular Fluid (Plasma): Fluid Present in the blood and in the spaces
surrounding cells 20–25% is the fluid portion of the blood (Plasma) 75–80% lies around the cells
interstitial fluid Water accounts for 55–60% of body weight Maintaining differences in fluid
composition: Helps cells regulate their own activity, to accomplish certain and specific actions.
Plasma membranes separate extracellular and intracellular fluid Interstitial and plasma separated by
the wall of blood vessels Connective tissue forms extracellular matrix (ECM): Consists of a mixture
of proteins, polysaccharides, and in some cases, minerals. –Provides scaffold for cellular
attachments –Transmits info in the form of chemical messengers to cells to help regulate their
activity, migration, growth, and differentiation Proteins of the extracellular matrix consist of:
Ropelike collagen fibers and rubberband–like elastin fibers and a mixture of nonfibrous proteins
that contain carbohydrate The properties of barriers determine which substances can move between
compartments ICF <–> ISF <–> PLASMA <–> ORGANS Membrane Transport Proteins
Fundamental feature of all molecules of any substance is that they are in continuous state of
movement and vibration –Energy for this

The Lipid Bilayer And Membrane
The Lipid Bilayer is a membrane that contains protein. The lipid bilayer is a part of all cell
membrane. The structural parts provide support that marks the boundaries of the cells. It is called a
lipid bilayer because it has two layers of fat cells put in order on two sheets. Lipid Bilayer
(Phospholipid bilayer)
Assessments and Measures The Lipid Bilayer is simply a thin polar membrane made of two layers
of lipid molecules. These membranes are flat sheets that surround the cells as a barrier. Lipid bilayer
cause viruses, and living organism in the cell membranes. There also membranes that form cell
nucleus and any sub– cellular structures. The lipid bilayer keeps ions, proteins and other molecules
where they need to be. Lipid bilayer are usely waterproof towards ions which also allow cells to
keep salt in check. Amphiphilic phospholipids are usually composed in biological bilayers.
Phospholipid that have certain head groups that can change the chemistry of the bilayer. Also, just
like the head the tails of lipids can be affected by the membranes properties. At lower temperatures,
solid gel can adopt by the bilayer and transferred to a fluid state. The mechanical properties can be
affected by the way the lipid bilayer was packaged.
Biological membranes have typically many types of molecules other than the phospholipids. An
example of the animal's cholesterol with also helps strengthen the bilayer. Cholesterol also helps
control the activity of membrane proteins, because

Essay about Basic anatomy and Physiology
Exam one Study Guide: Basic Anatomy and Physiology Anatomy– the study of structure
Subdivisions: –Gross (macroscopic) – visible to the naked eye, such as surface area, regional areas
or anatomy systems –Microscopic – extremely small areas that usually need a microscope to be seen
such as cytology (the study of the shape and function of plant or animal cells) or histology ( the
study of the microscopic structure of tissue) –Developmental– compared to the evolutional study of
something such as embryology ( the study of the development of an embryo) Physiology– the study
of function at many different levels I.E. Such as the organ systems Subdivisions: –Is based on where
an organ is placed within the body ... Show more content on Helpwriting.net ...
wrist muscle in forearm) – Also some people have extra pieces in their body (i.e. nerves) – May be
asymptomatic (no problems) or symptomatic (problems) one being people having nerve problems
Body Cavities: –Dorsal: Protects nervous system –Subdivisions: Cranial (brain) & Vertebral (Spinal
Cord) –Ventral: Holds internal organs –Subdivisions: Thoracic (ribcage) & Abdominopelvic
(Abdomen and pelvis) Serous Membrane: – Double layered membrane that is separated by fluid –
Parietal: lines body walls –Visceral: lines internal organs Regions: Nine Regions: – Right
Hypochondriac Region: Organs found in this region are

Experimentation Essay
Exercise 1: Cell Transport Mechanisms and Permeability: Activity 2: Simulated Facilitated
Diffusion Lab Report Pre–lab Quiz Results You scored 100% by answering 4 out of 4 questions
correctly. 1. Molecules need a carrier protein to help them move across a membrane because You
correctly answered: d. they are lipid insoluble or they are too large. 2. Which of the following is true
of facilitated diffusion? You correctly answered: c. Movement is passive and down a concentration
gradient. 3. Examples of solutes that might require facilitated diffusion include You correctly
answered: d. all of the above. 4. Which of the following would not affect the rate of facilitated
diffusion? You correctly answered: a. the amount of intracellular ATP ... Show more content on
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You correctly answered: d. both a and b 2. For facilitated diffusion, increasing the concentration of
glucose on one side of the membrane is the same as You correctly answered: b. making the
concentration gradient steeper 3. When all of the membrane carriers are engaged, or busy, we say
they are You correctly answered: a. saturated. 4. Na+ Cl– had no effect on glucose transport because
You correctly answered: b. sodium is not required for glucose transport in the simulation.
08/30/12
page 3
Review Sheet Results 1. Explain one way in which facilitated diffusion is the same as simple
diffusion and one way in which it is different from simple diffusion. Your answer: Simple diffussion
moves molecules from an area of higher concentration to lower without an input of energy.
facilitated follows the same rule but uses protein carrier molecules to allow substance that are fat
solubles to diffuse through the cell membrane. 2. The larger value obtained when more glucose
carriers were present corresponds to an increase in the rate of glucose transport. Explain why the
rate increased. How well did the results compare with your prediction? Your answer: My prediction
was wrong the glucose transport rate would increase 3. Explain your prediction for the effect Na+
Cl– might have on glucose transport. In other words, explain why you picked the choice that you
did. How well did the results compare with your prediction? Your

Cell Membrane and Bloom S Category
Test File to accompany Life: The Science of Biology, Ninth Edition Sadava Hillis Heller
Berenbaum Chapter 6: Cell Membranes TEST FILE QUESTIONS (By Catherine Ueckert) Multiple
Choice 1. The compounds in biological membranes that form a barrier to the movement of
hydrophilic materials across the membrane are a. integral membrane proteins. b. carbohydrates. c.
lipids. d. nucleic acids. e. peripheral membrane proteins. Answer: c Textbook Reference: 6.1 What
Is the Structure of a Biological Membrane? Page: 106 Bloom's Category: 1. Remembering 2. The
plasma membrane of animals contains carbohydrates a. on the inner side of the membrane, facing
the cytosol. b. on the outer side of the membrane, protruding ... Show more content on
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Analyzing 13. When vesicles from the Golgi apparatus deliver their contents to the exterior of the
cell, they add their membranes to the existing plasma membrane. This is made possible by a. the
capacity of lipids to associate with one another. b. the fact that saturated fatty acid chains allow for
close packing of fatty acids in the bilayer. c. the great affinity cholesterol molecules in the plasma
membrane have for fatty acid tails. d. the polar proteins' affinity for fatty acids. e. the noncovalent
interactions of the anchored membrane proteins. Answer: a Textbook Reference: 6.1: What Is the
Structure of a Biological Membrane? Page: 108 Bloom's Category: 2. Understanding 14. Which of
the following is not one of the functional roles of membrane proteins? a. Allowing movement of
molecules that otherwise would be excluded by the lipid components of the membrane b.
Transferring signals from outside the cell to inside the cell c. Maintaining the shape of the cell d.
Facilitating the transport of macromolecules across the membrane e. Stabilizing the lipid bilayer
Answer: e Textbook Reference: 6.1 What Is the Structure of a Biological Membrane? Page: 108–
109 Bloom's Category: 2. Understanding 15. A protein that forms an ion channel through a
membrane is most likely to be a. a peripheral protein. b. a transmembrane protein. c. a phospholipid.
d. an enzyme. e. entirely outside the phospholipid bilayer. Answer: b Textbook Reference: 6.1

Neurone Function Essay
Membrane proteins are found in all cell membranes and it is these that determine the majority of the
membranes functions. There are often two types of membrane protein and these can be classified as
integral proteins and peripheral proteins. Integral proteins are situated in the hydrophobic interior
part of the phospholipid bilayer and can have hydrophilic channels that allow the passage of
hydrophilic substances across the membrane. Where as, peripheral proteins are not embedded in the
bilayer at all and are instead loosely bound to the surface of the membrane. Neurons are the basic
units of the nervous system and are involved in the transmission of impulses to all different parts of
the body. Membrane proteins are of great importance when it comes to considering the function of
neurones within the body, as many of the processes that occur would not be possible without the
action of proteins.
One of the key ways that membrane proteins are involved in neurone function is through the
formation of the resting potential. The resting potential is the charge difference across a cell
membrane when a neurone is at rest and not sending a signal, typically between –60 and –80
millivolts. Potassium and Sodium ions play a fundamental role in the formation of the resting
potential (Professor Sandidge/Moyle, 2012) and these ions each have a concentration gradient
across the membrane of a neuron. In the majority of neurones, the concentration of potassium is
greater inside the cell,

The Structure Of The Phospholipid Bilayer Model
In 1960, renowned biologists Gorter and Grendel made a scientific breakthrough with their
formulation of the phospholipid bilayer model, commonly referred to as the 'fluid mosaic model'.
Fifty years later, this structure remains the most valued proposed explanation of the composition of
the surface membrane, and is highly regarded throughout the scientific community. Consequently,
the general structure of the cell surface membrane is, at this point, considered highly understood.
Cell surface membranes are thought to consist largely of amphipathic molecules (Fleischer et al,
1978) held together by weaker hydrophobic interactions and components of the membrane such as
cholesterol. The term 'amphipathic' refers to molecules comprised of two ... Show more content on
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These non–polar sections are otherwise known as hydrophobic fatty acid tails, or the ceramide
(Abrahamsson and Pascher, 1977).
When analysing the fluid mosaic proposal it is important to recognise that the term 'fluid' is an
integral feature of the model. This is because the phospholipid bilayer is not rigid or designed to
keep the cells internal ultrastructure isolated from the external environment. Instead, the cell surface
membrane is a moveable apparatus intended to support the functions of the cell, e.g. transportation
of necessary solutes, waste or metabolic products, communication and movement– e.g. the
membrane of a erythrocyte gives it the ability to squeeze through capillaries (Lodish et al, 2007).
Lodish et al explained the fluidity of the model as permitting "the selective transport of material and
information" between the cell and its external environment. This is important for survival as a cell
could not survive completely independently. If the bilayer was rigid and immoveable this would
make the transportation of smaller and non–polar molecules impossible, meaning that access to ions
and nutrients was restricted.
In order to survive, cells require constant contact with external sources which are nutrient and
solute/ion rich. For example, without the transportation of ions such as sodium (Na+) and potassium
(K+) nerve cells would be unable to conduct electrical impulses. Similarly, without the ability to
release bicarbonate ions (HCO3–),

4. 2 Intracellular Binding Partners Of Podocalyxin Lab Study
1.4.2 Intracellular binding partners of podocalyxin
Two types of protein have been repeatedly shown to directly interact with the cytoplasmic domain
of PODXL, the NHERF isoforms 1 and 2 (solute carrier family 9 (Na+/H+ exchanger) member 3
regulator –1 and –2) and ezrin, a member of the ERM family (see Figure 4 (Li et al., 2002; Orlando
et al., 2001; Schmieder et al., 2004; Tan et al., 2006)). The DTHL signaling motif in the cytoplasmic
tail of PODXL is required for its interaction with the NHERF1/2 proteins via their PDZ domains (Li
et al., 2002; Tan et al., 2006). These two adaptor proteins form complexes with many different
proteins and are implicated in protein trafficking, ion transport and signaling (Donowitz et al., 2005;
Weinman, ... Show more content on Helpwriting.net ...
1.5 Ezrin – a member of the ERM family
The ERM family of proteins, consisting of ezrin, radixin and moesin form a conserved branch of the
FERM (four–point–one, ezrin, radixin, moesin) superfamily of proteins (Bretscher et al., 2002).
These proteins are closely related and best known to act as linkers between integral membrane
proteins and the and the cortical cytoskeleton, i.e. the cytoskeleton underlying the plasma
membrane, and are thus key regulators of cell morphology and polarity (Fehon et al., 2010). In fact
their amino acid sequences are strikingly similar (at least 70%), though there are certain differences
in phosphorylation sites between these proteins. For example, ezrin can be phosphorylated on
tyrosine residues that are not found in radixin or moesin (Krieg and Hunter, 1992). In addition,
ERMs show some tissue–specific expression and are reported to have many overlapping functions
and therefore a certain level of functional redundancy (Fehon et al., 2010). Ezrin is most abundantly
expressed by epithelial cells, moesin by endothelial cells and radixin by hepatocytes.
ERMs structure is characterized by a plasma membrane–associated FERM domain of approx. 300
amino acids in the N–terminus, followed by a long region with a high α–helical propensity and

The Membrane Of The Cell Membrane Essay
The cell membrane consists of eight distinctive parts that each have their own unique structure and
function. The phospholipid bilayer is an integral part of the cell membrane because it is the external
layer of the cell membrane and composes the barriers that isolate the internal cell components and
organelles from the extracellular environment. It is composed of a series of phospholipids that have
a hydrophobic region and a hydrophilic region. These regions are composed of the hydrophilic
heads and the hydrophobic tails of the phospholipids, this organization of the polar heads and
nonpolar tails allows the heads of the cell to form hydrogen bonds with water molecules while the
tails are able to avoid water. The phospholipid bilayer also has many important functions within the
cell, it gives the cell shape, provides protection, and it is selectively permeable which allows it to
only let very specific molecules pass through its surface. The phospholipid bilayer is an important
structure because it prevents harmful and unwanted molecules from entering the cell and isolates
organelles which helps to maintain the internal environmental homeostasis of the cell.
Another vital component of the cell membrane are the integral proteins. Integral proteins are
embedded within the phospholipid bilayer, these proteins are typically transmembrane proteins
which means that one end extends to the exterior of the cell while the other connects to the interior.
Integral proteins are

How Is a Cell's Membrane Suited to Its Functions?
How is a cell's membrane structure suited to its functions?
Throughout the past century, scientists have been able to conduct more research on the structure of a
cell membrane and understand its components and functions. The present agreed on model, created
in 1972 by S. J. Singer and G. Nicolson, is called the fluid mosaic model. This model depicts that
proteins (integral and peripheral) form a mosaic since they are floating in a fluid layer of
phospholipids, which makes up the components of the cell membrane (along with cholesterol). Each
of these parts of the membrane enables it to be more efficient. The purpose of a cell membrane is to
support and protect the cell, but also to control the movement of materials in and out of it. It ...
They may also use facilitated diffusion6 instead of active transport. The movement of substances
across the membrane through this protein, whether using active transport or facilitated diffusion, is
referred to as carrier mediated transport.
Unlike integral proteins, peripheral proteins do not extend into the hydrophobic region of the bilayer
but remain bound to the surface of the membrane. They are often anchored to an integral protein and
are also easier to analyze for scientists since

Small Molecule Of Voltage Gated Sodium Channels
Small Molecule Modulation of Voltage Gated Sodium Channels
Vincenzo Carnevale and Michael L. Klein
Institute for Computational Molecular Science, Department of Chemistry, Temple University,
Philadelphia, PA 19122
Abstract
Voltage gated sodium channels are fundamental players in animals physiology. By triggering the
depolarization of the lipid membrane they enable generation and propagation of the action potential.
The involvement of these channels in numerous pathological conditions makes them relevant target
for pharmaceutical intervention. Therefore, modulation of sodium conductance via small molecule
binding constitutes a promising strategy to treat a large variety of diseases. However, this approach
entails significant challenges: voltage gated sodium channels are complex nanomachines and the
details of their workings have only recently started to become clear. Here we review ¬¬– with
emphasis on the computational studies – some of the major milestones in the long–standing search
of a quantitative microscopic description of the molecular mechanism and modulation of voltage–
gated sodium channels.
Physiological Role of Voltage Gated Sodium Channels (VGSCs)
To respond to changes in the external environment, cells propagate electrical signals generated by
transient, highly controlled transmembrane ionic currents.
Responsible for this process are ion channels, ubiquitous proteins that reside in membranes of
excitable cells and convert chemical and electrical stimuli

Sbi3Ue Exam Notes
SBI3UE Examination Notes By: Gursangat Sidhu and Derek Meng Unit 1 – The Cell Unit 2 – The
Chemical Basis of Life Part 1 – Molecules of Life Part 2 – DNA Replication and Protein Synthesis
Enzymes DNA Structure DNA Replication Protein Synthesis Overview Transcription Translation
Mutations Part 3 – Cellular Respiration and Photosynthesis Unit 3 – Genetics Unit 1 – The Cell Cell
Theory: Cell theory: refers to the idea that cells are the basic unit of structure in every living thing.
It states that: ● New cells are formed from other existing cells, ● the cell is a fundamental unit of
structure, ● function and organization in all living organisms. Eukaryotic and Prokaryotic Cells 1
Prokaryotic ● ● ● ● ● ● Have pili No nucleus ... Show more content on Helpwriting.net ...
● Isotonic: Solution of equal solute concentration. ● Hypertonic: Solution with a greater
concentration than another (Hypotonic Solution). ● Hypotonic: Solution with a lesser concentration
than another (Hypertonic Solution). Unit 2 – The Chemical Basis of Life Part 1 – Molecules of Life
9 Water: Cohesion: Attract more water. Adhesion: Water attraction to surfaces. Organic
hydrophobic substances: are non–polar. Universal Solvent: dissolves most polar and ionic
substances. Transport Medium: allows for nutrients to travel through cells. Transparent: Allows for
sunlight to go through, which allows photosynthesis. High Heat Capacity: Moderate temperature in
enviroment Hydration Shell: Dipoles of water attaracted to dipoles of other substances ex) sugar.
This dissolves it. (chemestry) Energy and Thermodynamics: Energy: Ability to do work or bring
about change. Kinetic Energy: Energy of motion. Potential Energy: Stored energy ex) energy in
chemical bonds Thermodynamics: Study of heat or energy transformations. 1st Law of
Thermodynamics: Energy cannot be created or destroyed, but only converted from one form to
another. 2nd Law of Thermodynamics: Energy changes increase the entropy of the universe. The
spontaneity of a rxn depends on the change in entropy and the change in enthalpy. Gibbs Free
Energy (G): Systems tend to move from an unstable state, to a stable state. This movement can be
harnessed to do work. ∆G > 0 Endergonic Reaction – Reverse rxn is spontaneous

Type 2 Diabetes Case Study
Benjamin Stuart, 59–year–old male, is the full–time owner and manager of the Cornerstone Pub and
Bar. Previously a smoker, quit 6 months ago due to breathlessness from catching the flu. Is drinking
alcohol daily in the Pub, categorised as overweight by his GP and has recently been diagnosed with
Type 2 Diabetes due to his unhealthy lifestyle habits. After winning $23,000 on the pokies,
Benjamin wants to holiday in Thailand. It will be his first time out of Australia and he is taking his
two 25–year–old sons as well. A phospholipid bilayer is a double layered membrane made up of
phosphate heads on the outside and lipid tails on the inside, therefore giving it the name of
phospholipid bilayer. The phospholipids lie with their hydrophilic ... Show more content on
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An example of villi in the body includes the inner surface of the small intestine, their function there
is nutrient absorption which is useful to extract as much nutrients from food to store for energy
sources. Microvilli are small finger–like extensions on the outer surface of the plasma membrane of
a cell, they contain microfilaments that connect to the cell's cytoskeleton. They differ from villi as
they are microscopic and are located on the plasma membrane of cells where they increase the
surface area for absorption of extracellular materials. An example of where we would find microvilli
in the body is around the cells in the digestive tract, their function there is to increase surface area
for absorption of nutrients and materials. Large amounts of smooth endoplasmic reticulum are found
in the cells of ovaries and testes as one of the functions of smooth endoplasmic reticulum is the
synthesis of steroid hormones such as estrogen and androgen. The function that smooth endoplasmic
reticulum carries out in the reproductive cells is synthesising these steroid hormones for storage and
transport of estrogen and androgen for

What Is Mitochondria?
The body contains trillions of cells, and within one of those cells are thousands of miniscule
organelles. They provide a eukaryote with the ability of cellular respiration. Cellular respiration is
defined as: "...a set of metabolic reactions and processes that take place in the cells of organisms to
convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release
waste products". Basically these organelles produce energy, and that is what allows us to live. They
are called "mitochondria", and their processes involve very complex biomolecular procedures, all
happening on the scale of a few atoms. They can be difficult to understand but I hope to clear that
up.
Mitochondria consist of two membranes, the outermost of ... Show more content on Helpwriting.net
...
Material is brought into the matrix by electron transport chains, which are used to set up a proton
gradient between the inner and outer membrane (called the inter membrane space). These protons
accumulate to such a point in the inter membrane that they naturally flow back into the matrix. The
electron transport chains are made possible by a number of proteins studding the inner membrane,
such as the cytochrome electron shuttles. Upon reentering the matric the H+ (Hydrogen ions, which
are the carriers of the protons that were previously mentioned– no need to worry!) go through ATP
synthase, which in turn powers the synthase to phosphorylate adenosine diphosphate (ADP) to
adenosine triphosphate (ATP). Then the ATP can be used later on to be coupled with
thermodynamically unfavorable reactions which allows those chemical actions to carry one.
Thermodynamically unfavorable reactions are ones in which the energy state of the products is
higher than that of the reactant, the energy in this instance being thermodynamic (Means pertaining
to heat). Thermodynamically favorable reactions are self–sufficient and work by themselves
whereas thermodynamically unfavorable reactions do not.
The outer membrane consists of a phospholipid bilayer (Membrane that has a hydrophilic, water
repelling side, and a hydrophobic, water attracting side), spreading throughout integral proteins. The
phospholipid bilayer contains porins which allow the passage of molecules that are 10,000 Daltons
(Biochemical measure of proteins, the chemist in me likes to say atomic mass units: the two are
equivalent) or less. The permeable membrane allows for ions, water and some certain proteins to
flow freely into the membranes working

The Cell : Transport Mechanisms And Cell Permeability
The Cell: Transport Mechanisms and Cell Permeability
Hunter Dockery
Biology 2101
Derek Draper
September 15, 2016
Introduction
Cells are a highly complex entity and is both structurally and functionally the basic unit of all living
things. Cells are an important and vital part in order to sustain life. Cells are highly diverse and their
specific roles are dependent on shape and internal composition. Cells are what carry out functions to
promote life, including: reproduction, nutrient digestion, and metabolism. The cell has many
components including the nucleus, cytoplasm, many organelles, and a plasma membrane. The
nucleus contains all of the genetic material and genes, which are found in the DNA. The nucleus is
the control center of the cell as it is key for cell reproduction. The nucleus is surrounded in a
membrane called the nuclear envelope for protection and regulation of materials in and out of the
nucleus. Cytoplasm is what all of the cell contents is referred to outside of the nucleus. This includes
all the high specific metabolic machinery called organelles. A list of organelles include: Ribosomes,
endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and centrioles.
Ribosomes are free floating spherical bodies of RNA and proteins which are the site for protein
synthesis. Endoplasmic reticulum is broken into two structures, the rough and smooth endoplasmic
reticulum. Rough ER provides area for storage and transport of proteins

Nobel Prize Awarded to Randy W. Schekman, James E....
Each year, The Nobel Assembly in Karolinska Institutet distributes various Noble Prizes to
recipients who have demonstrated a monumental contribution to the sciences. In 2013, the 50
professors that constitute the Nobel Assembly awarded The Nobel Prize in Physiology or Medicine
to Randy W. Schekman, James E. Rothman, and Thomas C. Südhof for their contribution in
uncovering the details of vesicle transport within a cell. More specifically, these scientists have
elaborated on the knowledge of how cargo is delivered to the correct place within a eukaryotic cell
at the correct time.
The compartmentalized eukaryotic cell must retain the ability to ensure that correct vesicles are
shipped to the required destination at appropriate times. ... Show more content on Helpwriting.net ...
In these mutant yeast cells, the typical vesicle transport system was abnormal, which allowed
detection of specific genes that were related to these mutations. These screenings eventually led to
the identification of twenty–three separate genes that could be classified into three groups based on
their effects on membranes involved in traffic. These membranes include the endoplasmic
reticulum, the Golgi Apparatus, and the plasma membrane (Novick and Schekman, 1979).
James Rothman dissected the transport mechanism by purifying and identifying proteins used in
transport. The NSF, SNAP and SNARE proteins act as docking sites to enable vesicles to fuse to
specific target membranes. This explains the precision of transport; the proteins only combined with
certain cargo. The ability to purify the NSF protein was made possible by the identification of the
VSV–G protein. The VSV–G protein is labeled by a sugar when it comes in contact with the Golgi
Apparatus, simplifying documentation. Genes code for proteins used in fusion, exemplified by how
the sec18 gene relates to NSF. Sec17 relates to the SNAP protein in a similar manner. The discovery
of the SNAP protein allowed for the revelation of SNARE proteins found in brain tissue. SNARE
proteins are a gateway to the fusion and docking of vesicles in a very specific manner: only an
exclusive number of target SNAREs (t–SNAREs) would bind to specific vesicle SNAREs, or v–
SNAREs

Important Parts Of A Cell
Introduction
The body is made up of billions and billions of cells that make up tissues that make up organs,
which make up organ systems. Within those cells are organelles including but not limited to a
nucleus, organelles, and cytosol. Cells are one of the most basic units of our bodies. With that being
said, it is safe to say that cells are extremely important. There are many parts of a cell and many
ways that a cell works. One of the most important parts of a cell is the plasma membrane. The
plasma membrane is the outer surface of a cell, which is made up of things called phospholipids,
which form a phospholipid bilayer. This bilayer is made up of phospholipids (75%), cholesterol
(20%), and glycoproteins (5%). This bilayer is only possible due to the phospholipids being
amphipathic (polar and non polar parts). Phospholipids are composed of a hydrophilic (water
loving) head and 2 hydrophobic (water fearing) tails. The Plasma membrane separates the cell's
internal environment from its external environment. It also "plays a key role in communication
among cells and between cells and their external environment," (Tortora 60).
Many different proteins are located all throughout the plasma membrane. Some float around freely
and others are stationary in specific locations. For example, integral proteins extend all the way
through the lipid bilayer and go further into the interior of the cell. This makes them transmembrane
proteins due to the fact that they go all the way

Membranes and Their Functions Essay
Membranes and Their Functions
Membranes form boundaries both around the cell (the plasma membrane) and around distinct sub
cellular compartments (e.g. nucleus, mitochondria, lysosomes, etc.). They act as selectively
permeable barriers allowing the inside environment of the cell or the organelle to differ from that
outside. Membranes are involved in signaling processes; they contain specified receptors for
external stimuli and are involved in both chemical and electrical signal generation. All membranes
contain two basic components: lipids (mainly phospholipids) and proteins. Some membranes also
contain carbohydrate. The decomposition of lipid, protein, and carbohydrates vary from one
membrane ... Show more content on Helpwriting.net ...
These proteins also assist the active transport of materials across the membrane and could act as
energy transducers or electron carriers. Also contained in the membrane in between the hydrophobic
tails are steroids; cholesterol, which makes the membrane fluid at higher temperatures but more
fluid at lower temperatures so as to maintain the structure of the membrane (more stable). It also
acts as a plug, reducing even further the escape or entry of polar molecules through the membrane.
The channel proteins in the membrane are involved in the selective transport of polar molecules and
ions across the membrane e.g. water.
In short, phospholipids provide the basic structure of membranes and restrict the entry and exit of
polar molecules and ions. However, the main function of the membrane is to obtain nutrients,
excrete waste substances, secrete useful substances, and generate the ionic gradients essential for
nervous and muscular activity and to maintain a suitable pH and ionic concentration within the cell
for enzyme activity. All these are done through the movement of substances across the cell surface
membrane through either passive, active or glucose transport. The movement of molecules across a
membrane by passive transport does not require an input of metabolic energy. The molecule moves
from a high concentration to a lower concentration. The rate of

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