The Role Of Proteins Of Cell Membrane Transport

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
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Essay on Endosymbiosis
Endosymbiosis
Endosymbiosis is the theory that eukaryotic cells were formed when a prokaryotic cell ingested
some aerobic bacteria. The first step of the evolution of a eukaryotic cell is the infolding of the
cellular membrane. This process takes place when the plasma membrane folds inwards and develops
an envelope around a smaller prokaryotic cell. Once the smaller cell is engulfed, it becomes
dependent upon its host cell. It relies on the host cell for organic molecules and inorganic
compounds. However, the host cell also benefits because it has an increased output of ATP for
cellular activities and becomes more productive. This ATP comes from the mitochondrion (the
aerobe) that is engulfed.
All eukaryotic cells contain the ... Show more content on Helpwriting.net ...
The protein–synthesizing machinery in mitochondria and chloroplasts resemble prokaryotes. This is
shown through their ribosomal RNA and the structure of the ribosomes. The ribosomes are similar
in size and structure to bacterial ribosomes. fMat is always the first amino acid that is in the
mitochondria and chloroplasts transcripts. The antibiotics that act by blocking protein synthesis in
bacteria also block protein synthesis in mitochondria and chloroplasts. These antibiotics do not
interfere with protein synthesis in the cytoplasm of the eukaryotes. The inhibitors that effect the
protein synthesis of eukaryotic ribosomes do not change the protein synthesis of the bacteria,
mitochondria, or chloroplasts.
Mitochondria and chloroplasts have two membranes that surround them. The inner membrane is
probably from the engulfed bacterium and this is supported by that the enzymes and proteins are
most like their counterparts in prokaryotes. The outer membrane is formed from the plasma
membrane or endoplasmic reticulum of the host cell. The electron transport enzymes and the H+
ATPase are only found in the mitochondria and chloroplasts of the eukaryotic cell. (2)
Currently, there are two major competing theories for the endosymbiotic origin of eukaryotic cells.
The first theory claims that the eukaryotic cell is a combination of an archaeon with a

Structure and Function of Eukaryotic Cell Organelles
Structure and Function of Eukaryotic Cell Organelles
What are eukaryotic and prokaryotic cells?
Organelles in Eukaryotic Cells
The Nucleus.
Nearly all animal cells have a nucleus, with the only exception being the red blood cell. The nucleus
has two major functions, which are housing the DNA and controlling the cell's activities. In the
centre of the nucleus is the nucleolus. This doesn't have a membrane, but holds itself together. In the
nucleolus, ribosomes are created through the mixture of RNA and proteins. These proteins are
originally found in the cytoplasm, outside the nucleus, but they travel through the pores in the
nuclear envelope, through the chromatin and into the nucleolus. The structure of the nucleolus
allows easy ... Show more content on Helpwriting.net ...
The body has two faces, the cis face which fuses with incoming transport vesicles, and the trans face
which excretes the secretory vesicles. The cis face fuses with vesicles coming from the ER
effectively from many directions due to its convex shape, whereas the concave trans face can direct
the secretory vesicles to their destination. When fusing with the cis face, the transport vesicles
release their proteins to be absorbed for modification. Each cisternal layer of the Golgi body holds
different enzymes which each modify the passing proteins in separate ways. Between the layers the
proteins are moved through the gaps by small vesicles. When a protein has been modified correctly,
it leaves the Golgi body via secretory vesicles which then carry the modified proteins to the cell
membrane or another organelle. The proteins that are transported to the cell membrane are either
excreted from the cell, or absorbed into the membrane to aid with its function. Some of the secretory
vesicles which hold hydrolytic enzymes stay within the cytoplasm and function as lysosomes.
Lysosomes.
Lysosomes are specialized vesicles that are created by the Golgi body. Their role is to digest any
worn out, excess or unwanted bodies within the cell. This could include bacteria or viruses as well
as mitochondria which are no longer effective. To do this they contain an

Purified Protein Lab Report
Biotechnology industry, Research, Pharmaceutical industry used purified proteins in large quantities
for their purposes. This able genetic engineer to set up some technics to easily extracted from
variable source proteins in large amount.
Several approaches can be envisaged to address the function of a gene. The techniques of molecular
biology and biochemistry allowing for example to localize the expression of a gene or its product
(Northern, western, in situ hybridization, immunofluorescence, etc.), to determine the structure of
the protein (NMR, crystallography ...) or to find partners proteins (double hybrid,
immunoprecipitation ...) give important information on the function of a gene (V Ecochard –2011).
This experiment will focus on SDS PAGE of purified protein and cell lysate samples, Western blot
analysis procedure, interpretation of purified protein and lysate samples; Sequence analysis of
tagged fusion proteins, and why and how to choose cell type, and why cell expression mater? The
following samples containing human dihydrofolate reductase (DHFR) protein will be analyzed:
Purified His–tagged DHFR, expressed and purified from E.coli, ... Show more content on
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Place the gel in the electrophoresis chamber and fill chamber with with 1X running buffer, and
carefully rinse wells by pipetting to remove any bubbles.
Sample preparation: purified protein and cell lysate have been already and denatured in Laemmli
sample buffer and are in His–tagged DHFR, GST–tagged DHFR, Myc–Flag–tagged DHFR aliquots.
Control lysate is provided by TA. Wear goggles before to hreat samples for 2 minutes at 95˚C.
Centrifuge samples and load gel at room temperature. Obtain an aliquot of the each of the following:
1X Laemmli buffer and Kaleidoscope prestained protein standard (Bio–Rad

Endomembrane System Study Guide
The Endomembrane System
Endomembrane System– is a system of membrane based organelles within the eukaryotic cell that
are either in direct contact with each other or communicate through the use of vesicles. A primary
role this system plays in intracellular processes is treatment and transport of proteins. The
membranes and organelles include the nuclear envelope, the endoplasmic reticulum, Golgi
apparatus, lysosomes, vacuoles, and peroxisomes.
Components/Process of the Endomembrane System
1. Nuclear Envelope
Made up and inner and an outer compartment o Nuclear pores formed where these membranes meet
Nuclear pores allow molecules to pass through the nuclear envelope
This is the first component of the endomembrane system
2. Rough ... Show more content on Helpwriting.net ...
Insertion of membrane proteins: membrane proteins appear on the membrane while protein
synthesis
Glycosylation: Carbohydrate attach themselves to proteins and lipids
Proteins move from rough ER by means of transport vesicles
3. Smooth Endoplasmic Reticulum
Metabolism: enzymes promote the detoxification of hydrophobic molecules, which are harmful, into
hydrophilic molecules which can easily be transported out of the body
Storage of Ca2+: contains calcium pumps that facilitate secretion of calcium from the ER lumen
into the cytosol
Lipid synthesis and modification: synthesizes phospholipids and enzymes modifies lipid
cholesterols into steroid hormones such as testosterone
4. Golgi Apparatus
There are two theories for process of moving material through the Golgi apparatus o Vesicular
transport model
Move from compartment to compartment (like a ghost through walls) o Cisternal maturation model
Vesicle gets swallowed by cis face, and the cis face morphs into the medial cisterna
Also participates in protein

Why Proteins Are Essential For Cellular Function
Proteins are essential for cellular functions in all forms of life. Though proteins have been studied
for decades, membrane proteins have not been properly understood due in part to their physical
complexity and the difficulties in testing. Though many challenges hinder the discoveries in this
area of biochemistry, Professor Alessandro Senes believes that the difficulties encountered only
make the results more worthwhile. Researching these proteins advances our understanding of the
importance of the protein structure on the molecular function in the cells. As Professor Senes and his
team continue to explore recurring patterns in these membrane proteins, they further explore new
topics in this growing area of science. Membrane proteins vary immensely in three–dimensional
structure, resulting in a variety of functions in the cells. Some membrane proteins only interact with
one side of the lipid bilayer, limiting their functions to primarily involve the core of the lipid bilayer
or the surface of membrane. Other proteins extend to both sides of the membrane, allowing proteins
to interact with the inside and outside of the lipid bilayer. All transmembrane proteins researched to
date consist of alpha helices or beta sheets that transport molecules through the membrane, signal
internal functions, or complete a variety of other functions. Professor Senes is particularly interested
in transmembrane proteins containing two alpha helices that cross over each other with a

Golgi Research Paper
The nucleus contains chromosomes in which the DNA encodes proteins. The mRNA molecules
transcribed from the DNA leave through the nuclear pores in the nuclear envelope to attach to free
ribosomes or ribosomes on the rough Endoplasmic Reticulum (rER). mRNA molecules try to bind
to ribosomes as they contain ribosomal RNA (rRNA) transcribed from DNA in the nucleolus. The
attachment of mRNA allows protein synthesis to occur at the ribosome, producing proteins in their
primary structure. These polypeptide chains then travel through the rER where they are packaged
and pinched off into little vesicles and carried to the Golgi complex. They are then chemically
modified and folded into newly synthesised proteins which can then leave the cell (exocytosis)
through secretory vesicles produced at the Golgi complex.
1. Nucleus
2. Nuclear pore
3. rER
4. Vesicle
5. Golgi complex
6. Secretory ... Show more content on Helpwriting.net ...
Phospholipids
Phospholipids form the basis of the plasma membrane structure. As a main component of the
membrane they form bilayers with two layers of phospholipid molecules facing inwards, opposite
one another. They are arranged in this manner as the phosphate heads are hydrophilic meaning they
are attracted to water. They can therefore interact with water in the cytoplasm and with water
surrounding the cell. The hydrophobic tails of the two phospholipid layers therefore point inwards
towards each other as they repel water. The lipid component of the bilayer allows lipid–soluble
molecules across the membrane.
Proteins
Proteins are scattered throughout the bilayer and are imbedded in two ways.
Intrinsic proteins are generally classified as the larger proteins within the bilayer and are extended
across both layers of the membrane. Some of these are carrier proteins transporting water–soluble
substances across and others are channels which allow the transport of

Ap Biology Chapter 4 Study Guide
Chapter 4
Microscopes
Two important factors in microscopy are:
1) Magnification: an increase in the object's apparent size compared with its actual size.
2) Resolving Power: the ability of an optical instrument to show two objects are separate.
Three types of microscopes:
1) Light Microscope (LM) M: 1000x RP 0,2 micrometer (small bacterial cell)
2) Electron Microscope (EM) uses a beam of electrons to resolve electrons, better resolving powers
than light microscope M:100,000x RP 0,2 nanometer
A) Scanning Electron Microscope (SEM) Surface
B) Transmission Electron Microscope (TEM) Internal Structure
Preparing specimen for electron microscope hard, light microscope still very useful as a window on
living cells.
The ... Show more content on Helpwriting.net ...
How DNA Directs Protein Production
1) DNA programs protein production in the cytoplasm by transferring its coded information to a
molecule called RNA (mRNA). The RNA then carries the order to build this type of protein from the
nucleus to the cytoplasm.
2) The mRNA exits through the pores in the nuclear envelope and travels to the cytoplasm, where it
then binds to ribosomes.
3) As a ribosome moves along the mRNA, the genetic message is translated into a protein with a
specific amino acid sequence.
The Endomembrane System: Manufacturing and Distributing Cellular Products
Cytoplasm of eukaryotic cell is partitioned by organelle membranes. Organelles together form the

endomembrane system.
This system includes:
1) The Nuclear Envelope
2) The Endoplasmic Reticulum
3) The Golgi Apparatus
4) Lysosomes
5) Vacuoles
The Endoplasmic Reticulum
One of the main manufacturing facilities within a cell. Consists of rough ER and smooth ER, they
are physically connected but differ in structure. Consist of membrane–enclosed tubes and sacs
within the cytoplasm. Rough ER, named for the ribosomes attached to its surface, make membrane
and secretory proteins. One function of rough ER is to produce new membrane. Some products by
rough ER are dispatched to other locations by transport vesicles.
Functions of smooth ER include lipid synthesis and detoxification. Big diversity of enzymes. As
liver cells are exposed to a drug amount of

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

An Organelle That
1) Lysosome: An organelle that is enclosed in a membrane. It contains digestive enzymes that are
able to break down polymers such as nucleic acids, proteins, lipids and carbohydrates. They are
shaped like a dense sphere but vary in size depending on what material they have taken in to digest.
2) Microfilament: Microfilaments are narrow protein fibers within the cytoskeleton. They are made
up of two twisted proteins called actin; this is why they are also known as actin filaments. Their
function is to give the cell its shape and also aid in cellular movement.
3) Nuclear envelope: The nuclear envelope is a double lipid bilayer that borders the nucleolus and
separates it from the cytoplasm. It also protects the DNA by keeping it away from ... Show more
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8) Microtubules: Microtubules are different to microfilaments as they are much thicker and are
made up of a protein called tubulin. Microtubules and microfilaments form to make the
cytoskeleton. But they also aid in cell division, as they are a part of centrioles. This involves the
separation of chromosomes. They can also combine together to form cilia and flagella, these help
the whole cell to move.
9) Mitochondria: responsible for aerobic respiration where ATP is produced in the form of energy.
They have a double membrane where the inner membrane is folded into a cristae to maximise the
surface area and the inside is called the matrix where enzymes for aerobic respiration are found.
10) Smooth Endoplasmic Reticulum: Smooth ER transports materials throughout the cell. It
synthesises lipids and carbohydrates and distributes these around the cell and also other parts in the
organism.
11) Cell membrane: Separates the intracellular components from the extracellular components.
Selectively permeable to ions and organic molecules, controlling the movement of substances in and
out of cells. It consists of a phospholipid bilayer imbedded with proteins. The membrane is found
inside the cell wall of plant cells and on the surface of animal cells. It also has receptor molecules
which allow it to respond to chemicals like hormones.
12) Ribosomes: assemble amino acids to make proteins. Also

The Smooth Er's Membrane
The smooth ER does not have any ribosomes on it's membrane. It's functions can vary depending on
the differences of the cell it is located in. The smooth ER makes lipids, breaks down carbohydrates,
and detoxifies substances that may be harmful to the cell.
The rough ER appears rough on a microscope because it's surface is covered with small ribosomes.
The ribosomes synthesize proteins, and the membrane keeps those proteins separate from the rest of
the cell. In addition to making and storing proteins, it also creates it's own proteins and
phospholipids to put in it's membrane. Portions of the rough ER's membrane are closed to form
sealed sacs called transport vesicles. These vesicles carry the proteins to the Golgi apparatus.
The endoplasmic

8 Cell Organelles
When creating my game I included 8 organelles that are found in the cell. One of these organelles is
the nucleus. The nucleus is a large membrane–enclosed structure that contains genetic material in
the form of DNA and controls many of the cell's activities. The job of the nucleus is to protect the
DNA and the RNA from anything outside the nucleus. Another organelle is the ribosome.
Ribosomes are small particle of RNA and protein found throughout the cytoplasm in all cells. The
ribosome is responsible for making protein by following the coded information from the DNA. The
endoplasmic reticulum is where lipid components of the cell membrane are assembled, along with
proteins and other materials that are exported from the cell. The endoplasmic reticulum is in charge
of ... Show more content on Helpwriting.net ...
The golgi apparatus is an organelle that modifies, sorts, and packages proteins and other materials
from the endoplasmic reticulum for storage in the cell or release outside the cell. The job of the
golgi apparatus is to package the proteins so that they are able to travel out of the cell. The vacuole
can be found inside the cell. The vacuole is a saclike, membrane–enclosed structure. The vacuole is
in charge of storing materials like water, salts, proteins, and carbohydrates. Another organelle found
in the cell is a lysosomes. A lysosome is a small organelle filled with enzymes. This organelle breaks
down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.
The cell wall is an important organelle in the plant cell. The cell wall is a strong supporting layer
around the membrane. The cell wall is responsible for protecting the cell and providing structure to
the cell. Lastly, the vesicles are very important to the cell. Vesicles are membrane enclosed storage
organelles that are smaller than vacuoles. The job of vesicles is to store and move materials between
organelles and to and from the cell

Nucleus Essay
The nucleus is one of the most important parts of any animal or plant cell. It has four really main
functions and parts. It holds DNA in chromosomes, includes the nucleolus, controls protein
synthesis, and lastly the nuclear membrane. This parts and functions really make up what we know
as the nucleus. First, let's begin with the DNA that the nucleus holds in chromosomes. This is a big
factor in why the nucleus is such an important part of any animal or plant cell. These DNA polymer
is a double helix made up of multiple nucleotides. Each nucleotide is either a guanine, adenine,
thymine, and cytosine. Except only adenine will only bond with thymine, and guanine will only
bond with cytosine. DNA also has a big role in the development of living ... Show more content on
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The nucleolus is the biggest structure in any nucleus. The nucleolus is known for making and
producing ribosomes. The nucleolus stores genes for pre–RRNA that make up a strong base for the
nucleolus. The nucleolus also has many unique functions. These functions include assembly of
recognition particles, changing and modifying RNA, and sensing stress on the cell. Another
important function or part is the ability of the Nucleus to control protein synthesis. Protein synthesis
is where cells make and generate new proteins. This function takes place mostly during translation
and transcription, but takes place in the nucleus. In protein synthesis tRNA molecules are brought
together and matched with an mRNA. Protein synthesis varies differently in plant and animal cells,
but at the same time is very similar. Next, another important part of the nucleus is the nuclear
membrane. The nuclear membrane is a lipid bilayer membrane that encases the contents of the
nucleus including the the DNA, and the nucleolus in animal cells. The nuclear membrane has holes
in it for materials and proteins to pass in and out of the nucleus. These holes also link the inner and
outer membrane. Another important function that the nuclear membrane does is it keeps the contents
of the nucleus completely separate from cells cytoplasm. Without the nuclear membrane the DNA
would be at risk of the chemical reactions that happen in the

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

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

Membrane Proteins And Non Membrane Bound Organelles
Chapter 4: Membrane Bound Organelles and Non–Membrane Bound Organelles
Membrane Bound Organelles: are contained within an isolated environment surrounded by a
membrane. The composition of these organelles differ in composition, shape and enzyme inclusion.
Members of Membrane Bound Organelle Systems include the Endoplasmic Reticulum, Golgi
Apparatus, Lysosomes, Mitochondria and Peroxisomes.
Endoplasmic Reticulum (ER): is a continuous membrane system which forms flattened sacs within
the cytoplasm of Eukaryotic cells and acts a barrier between Cytosol and fluid with the structure.
The Endoplasmic Reticulum plays a variety of different roles including the synthesis, folding,
modification and transport of proteins. There are two different ... Show more content on
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Lysosomes: contain hydrolytic enzymes which aid in the digestion of particles and disintegration of
cells. Formed by the Golgi Apparatus, Lysosomes are surrounded by a membrane–bound cell
organelle which contain acidic enzyme material, because of their small sac–like appearance and the
digestive acidic material contained within, Lysosomes are often referred to as "suicide sacs" or
"suicide bags".
Mitochondria: are oblong in appearance and contain a double membrane. Present in the cytoplasm
of nearly all Eukaryotic cells, the primary function of Mitochondria is in the creation of energy.
Commonly referred to as "The Powerhouse of the Cell", Mitochondria is responsible for most of the
cell 's supply of Adenosine Triphosphate (ATP). Other vital roles include cell growth, cycle and
death, signaling and cellular differentiation.
Peroxisomes: are membrane–bound organelles similar in appearance to Lysosomes, yet they are
smaller in comparison. Peroxisomes contain catalese, peroxidase and oxidative enzymes which aid
in metabolic function, specifically in the beta–oxidation of fatty acid and the conversion of
hydrogen peroxide into water and oxygen.
Non–Membrane Bound Organelles: are organized structures which are not bound by a membrane.
Members of Non–Membrane Bound Organelles are Centrosome, Cytoskelaton, Ribosomes and
Proteasomes.
Centrosome: are usually located near

Enveloped Virus Research Paper
Viruses are obligate intracellular parasites; their lack of biochemical machinery makes them
dependent on the host cell for replication.5,8 The viral replication process involves assembly
individual components into viral progeny. Viruses consist of a DNA or RNA genome that is
packaged into a protective protein capsid shell; additionally, some viruses are surrounded by an
outer, membranous envelope.2,5,8 Viral genomes are used to express viral proteins.5 However,
because these viral genomes do not encode for the machinery necessary to carry out protein
synthesis, viral genomes must be copied into mRNA that can be read by host ribosomes.5,7,8 There
are seven major types of viral genomes that are classified by the Baltimore system. 5 All viruses ...
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4,5 The DNA intermediate is integrated into the host chromosome to become a cellular gene. 4,5
This DNA an also serves as a template for viral mRNA and genome RNA synthesis by host cell
DNA–dependent RNA polymerase. 4,5,7,8 The retroviral genome consists of three genes that
encode polyproteins for Gag (capsid, matrix and nucleic acid binding proteins), Pol (polymerase,
protease and integrase) and Env (envelope proteins).

Eukaryotic And Prokaryotic Of Cells
There are two major groups that cells can be grouped into to. These are eukaryotic and prokaryotic
cells. All eukaryotic cells contain a plasma membrane, as well as cytoplasm and organelles such as
mitochondria, rough endoplasmic reticulum (ER), Golgi apparatus, smooth ER, ribosomes, a
nucleus which is surrounded by a double membrane known as the nuclear envelope, and secretory
vesicles. There are some eukaryotic cells which contain more organelles as well as theses. Some
eukaryotic cells, specifically in plants, have chloroplasts. Chloroplasts are organelles that contain
stacks of granum known as thylakoid stacks. The granum contains chlorophyll, and the first stage of
photosynthesis occurs here. Some eukaryotic cells contain centrioles, which are strands of protein
involved in the process of mitosis and meiosis. Pant cells have a cell wall made from cellulose. This
prevents the cell from bursting from too much water uptake via osmosis. Fungi do not have
chloroplasts. They do have a cell wall like plant cells, but whereas the cell walls in the plant cells are
made from cellulose, the cell wall in a fungal cell is made from chitin. This is a polymer made from
N–acetylglucosamine. Prokaryote is the name of a kingdom for organisms, and all bacteria fall into
this kingdom. The prokaryote kingdom is enormous, and prokaryotes are found in every known
habitat on the planet. Bacteria are very useful, they can be used in biomedical sciences to help
develop medicines, and

Prokaryotic Vs Eukaryotic Essay
Prokaryotic are organisms whose DNA is not confined within a membrane–enclosed nucleus.
Prokaryotic organisms are single, but some prokaryotic organisms are multicellular. Eukaryotes are
organisms who cells are organized into complex structures by internal membranes and a
cytoskeleton. (Cundy, 2012) The most characteristic membrane bound structure is the nucleus.
Animals, plants, fungi, and protists are eukaryotic. Prokaryotic organisms are typically between 0.1
to 5.0 um in size while Eukaryotic organisms are between 5–10 um. Prokaryotic organisms have
pili, cytosol, ribosomes, capsule, cell wall, plasma membrane, DNA, and chromosome also known
as plasmids. (Cundy, 2012) They do not have a nucleus, lysosomes, microtubules, endoplasmic
reticulum, ... Show more content on Helpwriting.net ...
This is what allows prokaryotes to attach to other surfaces. Cytosol is a water like fluid found in the
cytoplasm. Cytoplasm is inside the plasma membrane but outside the nucleus. The cell wall is made
of polysaccharides just outside the plasma membrane and its made of cellulose. (Cundy, 2012) The
plasma membrane is the outer boundary of the cell with a layer made of phospholipids. DNA is a
double polymer of nucleotides that store genetic information. DNA stands for Deoxyribonucleic
Acid with a phosphate group of four nitrogenous bases which are adenine, cytosine, guanine, and
thymine. The largest organelle is the nucleus. The nucleus contains DNA. The mitochondria have a
double membrane and it is known for supplying energy to the cell. Ribosomes produce proteins.
These ribosomes can be found in the cytosol of cells. The nucleolus is what makes ribosomes and
RNA. Lysosomes have digestive enzymes. The endoplasmic reticulum is an inner membrane system
that makes some proteins. (Cundy, 2012) There are two endoplasmic reticulum, one is rough and the
other is smooth. The rough endoplasmic reticulum has ribosomes on it while the smooth
endoplasmic reticulum does not have ribosomes on them. The Golgi apparatus prepares proteins to
be taken out of the cell. The vacuole is storage for water and other nutrients a call may need and this
is most commonly found in plant cells. The cytoskeleton shapes the cell wall and consists of protein

Structure And Structure Of Membrane Proteins Essay
Thickness: 6–8nm
Unit: Amphoteric phospholipid, claiming to be from a polymeric phosphate (hydrophilic), including
the same unbranched chain fatty liver (hydrophobic).
Distribution of 2 portions: hydrophilic heads would laid open of the outside nature 's domain
alternately those cytoplasm. Those greasy liver chains purpose inward, confronting one another
because of hydrophobic impacts (staying out starting with water). membrane proteins need aid
found On Different positions inside the membrane, through particular associations with
phospholipid particles These proteins comprise for 3 fundamental groups:.. essential analytics
proteins, outer–surface proteins Also inner–surface proteins They assume dissimilar parts clinched
alongside cell division exercises. .
Integral proteins: In the cytoplasmic membrane called UNIPORT3 solid basic tools to do the
installation of the membrane, transporting material cross, symporter more importantly antiporter
Outer–surface proteins: As a rule before, Gram–negative bacteria, vice–band unit, at about broad
atom transfer periplasmic proteins.
Inner–surface proteins: To work together to win the building energy capacity is also important to
reflect different cell division of different proteins.
How do bacteria store genetic information?
Both forms of genetic information in bacteria DNA sequence stored, i.e. bacterial chromosome and
plasmids. The following are the properties of a bacterial chromosome.
Location: Within nucleoid region

Cell Membranes Of Proteins And Proteins Essay
CHAPTER ONE INTRODUCTION
Cell membranes of eukaryotes are complex structures, comprised of a highly regulated heterologous
distribution of lipids and proteins (Hanada, 2010). This distribution is determined to some extent by
the location and topology of lipid synthases, and results from the trafficking of proteins and lipids
(Hanada, 2010). Within the cell, transport vesicles and tubules mediate trafficking by loading
desired sets of proteins at one organelle and delivering them to the subsequent (Hanada, 2010;
Kumagai et al., 2005). Lipid influx routes such as the endocytosis of membrane lipids add further to
the diversity (Hanada, 2010). The result is an asymmetric distribution of protein and lipid types
across the membrane bilayer (Hanada, 2010).
Ceramides are an example of a family of cellular lipids (Yasuda et al., 2001). Ceramides are
synthesised at the endoplasmic reticulum from precursor compounds and are transported to the
Golgi apparatus for conversion into one of the several sphingolipids (Yasuda et al., 2001). The
transport of such compounds is highly selective if not specific (Kumagai et al., 2005; Yasuda et al.,
2001). Inhibiting transport is a useful tool in investigating the role of substrates (Yasuda et al., 2001)
and makes an attractive target for biochemical manipulation of the cell (Ueno et al., 2001).
Intracellular trafficking of ceramides is highly regulated. Two ceramide transport pathways have
been identified (Kumagai et al., 2005). The first is

Kinesin Heavy Chain Of Protein Analysis
The purpose is to transfer biological samples from a gel to a membrane and their subsequent
detection on the surface of the membrane. An antibody is used to specifically detect its antigen for
protein analysis. The specificity of the antibody–antigen interaction enables a target protein to be
identified in the middle of a complex protein mixture.
Kinesin heavy chain is my target protein. It has 975 amino acids. Drosophilia Melanogaster is the
organism. A kinesin is a protein belonging to a class of motor proteins found in eukaryotic cells.
Kinesins move along microtubule filaments, and are powered by the hydrolysis of ATP. The active
movement of kinesins supports several cellular functions including mitosis, meiosis and transport of
cellular cargo, such as in axonal transport. Most kinesins walk towards the positive end of a
microtubule, which, in most cells, entails transporting cargo such as protein and membrane
components from the center of the cell towards the periphery. In contrast, dyneins are motor proteins
that move toward the microtubules' negative end. ... Show more content on Helpwriting.net ...
The stalks of two kinesin heavy chains intertwine to form a coiled–coil that directs dimerization of
the two kinesin heavy chain.
The steps I will follow for western blot will be as follows:
1. Wear

Essay about Describe the structural compartmentation of...
DESCRIBE THE STRUCTURAL COMPARTMENTATION OF MAMMALIAN CELLS
AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS
All mammalian cells are eukaryotic, and whilst the eukaryotic type of cell is not exclusive to
mammals, mammalian cells differ from other eukaryotic cells because of the organelles that are or
are not present. For instance some plant cells have chloroplasts which are not present in mammalian
cells, but both plant cells and mammalian cells are eukaryotic in nature. The term eukaryotic refers
to the cell having specific membrane bound organelles, which are not present in prokaryotic cells.
The defining feature of a eukaryotic cell is usually its membrane bound nucleus (the exception being
the red blood cell) [1].
Because of ... Show more content on Helpwriting.net ...
The small ribosomal subunit, amongst other things, is initiates the engagement of the mRNA and is
responsible decoding the genetic information during translation [4].
The endoplasmic reticulum is specialised for protein processing and lipid biosynthesis. One of its
primary functions is to regulate the ionic concentration in the cytoplasm via the movement of Ca2+,
via ionic pumps and channels. It also contains enzymes responsible for the metabolising of drugs.
Endoplasmic reticulum (ER) can come in two forms. As depicted in Fig. 2 Rough ER has ribosomes
present as part of the membrane of the organelle, and together with these ribosomes takes
polypeptides and amino acids from the cytosol and synthesises proteins destined for attachment to
cell membranes. It is in the lumen of the rough ER that the proteins are folded into the specific three
dimensional shapes that are so important for biochemical recognition and linking sites [6]. It is
called rough because of the presence of ribosomes makes the surface of the membrane look rough,
unlike smooth ER, which lacks the ribosomes so the membrane looks smooth. Rough ER is
composed of a large but convoluted flattened sac. The main function of the smooth ER is the
production of lipids and the metabolism of compounds (such as the breakdown of glycogen into
glucose). Because of the different functions between the rough and smooth ER, different specialised
cells will have different amounts of each; for example, hepatic

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
Helpwriting.net ...
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 Membranes Of Proteins And Proteins Essay
Chapter One – Introduction
Cell membranes of eukaryotes are complex in structure, comprised of a highly regulated
heterologous distribution of lipids and proteins (Hanada, 2010). This distribution is determined to
some extent by the location and topology of lipid synthases, and results from the trafficking of
proteins and lipids (Hanada, 2010). Within the cell, transport vesicles and tubules mediate
trafficking by loading desired sets of proteins at one organelle and delivering them to the next
(Hanada, 2010; Kumagai et al., 2005). Lipid influx routes such as the endocytosis of membrane
lipids add further to the diversity (Hanada, 2010). The result is an asymmetric distribution of protein
and lipid types across the membrane phospholipid bilayer (Hanada, 2010).
Ceramides are an example of a family of cellular lipids found in the cell membrane (Yasuda et al.,
2001). Ceramides are synthesised at the endoplasmic reticulum from precursor compounds and are
transported to the Golgi apparatus for conversion into one of several sphingolipids (Yasuda et al.,
2001). The transport of such compounds is highly selective if not specific (Kumagai et al., 2005;
Yasuda et al., 2001). Inhibiting transport is a useful tool in investigating the role of substrates
(Yasuda et al., 2001) and makes an attractive target for biochemical manipulation of the cell (Ueno
et al., 2001).
Intracellular trafficking of ceramides is highly regulated. Two ceramide transport pathways have
been identified

Proteins And The Membrane
a) It is known that the majority of proteins exist outside the cell. This is because they are transported
via a "biosynthetic secretory pathway" which is known as the ER–Golgi pathway 2. That is, they are
transported from the ER to the Golgi. From the Golgi, the protein(s) are then sent to their respective
locations which can be to the plasma membrane (lining the outside of a cell), secretory vesicles, or
lysosomes 2.
There are certain transport vesicles which exist on the ER exit sites which are are COPII coated2.
The synthesized proteins are first packed into these transport vesicles before being sent to the Golgi
apparatus 2. This process can also be selective 2. That is, it can happen with the help of some
transport signals which are ... Show more content on Helpwriting.net ...
The vesicles from the medial Golgi containing the medial resident proteins then fuse with the
previously formed vis Golgi to form a new medial Golgi 2. This process then repeats in the trans
Golgi, forming a new trans Golgi 2. After this, the membrane proteins are finally processed by the
Golgi resident proteins 2. Then, the vesicle which contains the membrane proteins fuses with the
plasma membrane; its final destination 2.
It is suspected that the lumen of the trans Golgi network is responsible for grouping the proteins into
their respective transport vesicles which then carry them to their final destinations 2.
b) It has been found that many proteins are transported to their final destinations in certain
unconventional ways. That is, they do not depend on the ER–Golgi pathway for
transportation/secretion because they lack the signal peptides 10.
The four different types of unconventional protein secretion can be categorized based on whether
they are non–vesicular or vesicular 10.
(1) Type I and II are non–vesicular pathways 10. Type I is said to include "self–sustained protein
translocation across plasma membrane", which means direct transportation of proteins from the
cytoplasm to the plasma membrane, and type II is described as "ABC–transport–based–secretion"
10.
(2) Type III and IV are vesicular based pathways 10. Type III includes "autophagy based secretion",
while type IV is for "proteins that

Prokaryotic Cells Essay
Prokaryotic Cells
All living things are made of cells, and cells are the smallest units that can be alive. Life on Earth is
classified into five kingdoms, and they each have their own characteristic kind of cell. However the
biggest division is between the cells of the prokaryote kingdom (monera, the bacteria) and those of
the other four kingdoms (animals, plants, fungi and protoctista), which are all eukaryotic cells.
Prokaryotic cells are smaller and simpler than eukaryotic cells, and do not have a nucleus.
Prokaryotic means 'pre–nucleus' and eukaryotic means 'true nucleus'. The nucleus in eukaryotic cells
contains the DNA in linear chromosomes and is bounded by a nuclear membrane, but since ... Show
more content on Helpwriting.net ...
The cell membrane is made of phospholipids and proteins, like eukaryotic membranes, and controls
the entry and exit of substances into and out of the cell. The mesosome is a tightly folded region of
the cell membrane containing all the membrane–bound proteins required for respiration and
photosynthesis. The flagellum is a rigid rotating helical–shaped tail used for propulsion. The motor
is embedded in the cell membrane and is driven by a H+ gradient across the membrane. A clockwise
rotation drives the cell forwards, while an anticlockwise rotation causes a chaotic spin. This is an
example of a rotating motor in nature. The prokaryotic flagellum does not have the same the same
structure as eukaryotic flagellum. The cytoplasm contains all the enzymes needed for all metabolic
reactions, since there are no organelles. Nutrients and reserves may be stored in the cytoplasm in the
form of granules of glycogen, lipids, polyphosphate, or in some cases, sulphur or nitrogen. The
ribosomes are for protein synthesis just like eukaryotic ribosomes but they are smaller than
eukaryotic ribosomes. Plasmids are small circles of DNA, which carry additional genes and are used
to exchange DNA between bacterial cells. DNA is always circular, and not associated with any
proteins to form chromatin, it carries the genes for the proteins the cell needs. Prokaryotic cells do
not have membrane bound organelles, like

Why Mitochondria And The Cell With Versatile Operating...
Abstract:
Although mitochondria and chloroplasts encodes handful of their own proteins, however, majority
of their required proteins have to be synthesized in the cytosol and translocated into their correct
destinations using specialized transporting networks: TOM/TIM complexes in mitochondria and
TOC/TIC complexes in chloroplasts. Molecular chaperones play critical roles in facilitating
functional competent–protein import from the cytosol to their correct destinations, utilizing catalytic
motor components and other transporting channels. Biogenesis of both mitochondria and
chloroplasts and their maintenances in terms of transcription, translation and protein import into
their various numerous compartments requires very tight coordination to overcome energetic
barriers, protein aggregation and protein degradation. This essay describes molecular chaperones
involvement in protein import from the cytosol into these double membraned organelle
compartments.
Introduction:
Mitochondria are the powerhouse of the cell with versatile operating systems (i.e. converts energy
derived from foods into cellular energy e.g. ATP, Amino Acid and lipid metabolisms, iron–sulphur
clusters and haem biosynthesis, and also the regulation of apoptosis) (Harbauer et al., 2014,
Bolender et al., 2008, Wiedemann et al., 2004). Equally, chloroplasts are also very versatile and
operates several metabolic and cellular processes (i.e. photosynthesis, amino acid and lipid
metabolism, cellular signalling and

Types Of Cells And Prokaryote And Eukaryote
M1
There are two types of cells; Prokaryote and Eukaryote. They have many differences including their
structures and functions. The main difference being that a Eukaryote cell has an organised nucleus
with a nuclear envelope, whereas a prokaryote cell does not have a nucleus at all.
Eukaryotes are much more complex than a prokaryote cell. They have multiple organelles with
many different functions. Eukaryotic cells are bigger in size than Prokaryotic cells. Some examples
of eukaryotic cells are: animals, plants, fungi etc. Most eukaryotic cells are multi–cellular. All
eukaryotic cells have a nucleus, genetic material, a plasma membrane, ribosomes and a cytoplasm.
They also have membrane–bound structures called organelles.
Eukaryotic ... Show more content on Helpwriting.net ...
Cytoplasm This is a gel–like substance that contains mostly water as well as nutrients, enzymes,
wastes and gases. They carry out functions for growth, metabolism and replication. Contains cell
structures e.g. ribosomes.
Nucleus This is where the genetic information is contained in the form of chromatin. It controls the
cell's growth and reproduction making it the most prominent organelle in a cell. The nucleus is
enclosed by a double membrane called the nuclear envelope. The membrane has pores to allow
substances into and out of the nucleus.
Nucleolus This is a dense region of the nucleus where RNA is made as well as Ribosomes. It has no
membrane, it sits in the nucleus. The primary function is to assemble ribosomes.
Endoplasmic Reticulum There are two types of endoplasmic reticulum that differ in both structure
and function; Rough and Smooth. Both endoplasmic reticulum consist of flattened membrane bound
sacs called cisternae. Rough endoplasmic reticulum is covered with ribosomes and Smooth
endoplasmic reticulum lacks ribosomes. The Rough ER has the job of transporting proteins that
were made on the attached ribosomes. Whereas the Smooth ER is where lipid synthesis takes place.
(Kennedy, 2008)
Golgi apparatus It has a structure of flattened membranous sacs. The proteins made at ribosomes are
modified and packaged into vesicles. It modifies proteins. It then takes the molecules and

The Intracellular Trafficking Of Proteins And Plasma Membrane
CHAPTER 1 INTRODUCTION
1.1 Overview The intracellular trafficking between several membranes enclosed organelles and
plasma membrane is essential for all living ukaryotic cells. It's involved in many fundamental
cellular processes such as hormone secretion, ciliogenesis, cell migration, and so on. Intracellular
trafficking is mostly mediated by membrane–enclosed vesicles which are budded from donor
compartments and fused with target compartments. Vesicular transport is observed among most of
the organelles. In many cases, the transport is reciprocal between two organelles. The overview of
intracellular trafficking pathways is shown in Figure1 (adapted from Orlando, et al, 2001). Studies
on intracellular trafficking can be traced back ... Show more content on Helpwriting.net ...
In particular, cargoes and v–SNARE are sorted into newly–forming buds with the assistance of
cargo receptors, coat proteins and some other factors. Vesicle movement is mediated by motor
proteins along with cytoskeletons elements which refer to actin filaments or microtubule in most
cases. Upon vesicles arrival to the vicinity of target membrane, tethering proteins initiate the first
physical contact between vesicles and the target membrane. Finally, the fusion of vesicular and
target membrane is mediated by the interaction of v–SNARE on vesicles and t–SNARE on target
compartment.
My study has been focused on the tethering and fusion steps between secretory vesicles and PM in
yeast. Next, I will review the major findings on SNARE proteins and the exocyst which mediate the
tethering and fusion, respectively.
1.1 SNARE
1.1.1. Overview
It has been well established that SNARE proteins stimulate fusion reactions by forming a complex
with four–alpha–helix bundle known as the trans–SNARE complex or SNAREpin. One alpha–helix
is contributed by the SNARE proteins residing on vesicle by its C–terminus trans–membrane
domain (TMD). Therefore, this SNARE protein is named as v–SNARE. The other three alpha
helixes are provided by t–SNARE which are associated with target membrane by either C–terminus
TMD or other mechanisms such as palmlation (spelling?). Formation of the SNARE complex
provides energy to overcome the repulsive force between the opposite

Nucleus Cell Structure
Nucleus
The nucleus conducts all the activities occurring in the cell and consists of hereditary substances that
is constructed of proteins and DNA. The function of the nucleus is to allow materials to properly
enter and exit among the several openings in the membrane. In addition, the nucleus encloses
various instructions for everything and in which is found on long, threadlike, genetic components
made of DNA.
B. Nucleolus
The nucleolus is a sphere body containing protein in a cell nucleus. The role of the nucleolus is to
create the ribosomes which are known as the workers of the cell. Also, the proteins necessary to
make them seep through the pores of the nuclear membrane.
C. Cell Membrane
The cell membrane is the protective ... Show more content on Helpwriting.net ...
Golgi Bodies
The Golgi bodies are organelles that are bundle cellular components and transport themselves inside
the cell or exterior of the cell. The role of the Golgi bodies is to categorize proteins and other
cellular materials that go by the name of vesicles.
F. Lysosome
Lysosomes are organelles that contain digestive chemicals that aid in the decomposure of food
particles, cell wastes, and worn–out cell fractions. The function of this organelle is to avoid the
digestive chemicals located in the interior from seeping into the cytoplasm and damaging the cell.
G. Free Ribosome
Free Ribosomes are sphere structures that drift freely within the cytoplasm. The main function of the
free ribosome is to produce proteins that are used within that cell. The free ribosome are produce
proteins that are vital for all cellular activities.
H. Cytoskeleton
The cytoskeleton is a framework which gives the cell its structure, shape, and allows movement.
The function of this is to keep all of the organelles containing in its interior protected and insulated.
Also, there are three proteins that are produced within the cytoskeleton named microfilaments,
microtubules, and Immediate filaments which all have different

Using Binary Complex Assembly And Membrane Fusion By The...
Promoting t–SNARE Binary Complex Assembly and membrane Fusion by the Exocyst Protein Sec3
Peng Yue
A DISSERTATION in Biology
Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the
Requirements for the
Degree of Doctor of Philosophy
2015
Supervisor of Dissertation
______________________
Wei Guo, Professor of Biology
Graduate Group Chairperson
______________________
Michael Lampson, Associate Professor of Biology
Dissertation Committee
Fevzi Daldal, Professor of Biology
Tatyana Svitkina, Professor of Biology
Erfei Bi, Professor of Cell and Developmental Biology
Claudio G. Giradudo, Assistant Professor of Pathology and Laboratory Medicine
James Shorter, Associate Professor of Biochemistry and Biophysics
ACKNOWLEDGMENT (optional)
ABSTRACT
Promoting t–SNARE Binary Complex Assembly and membrane Fusion by the Exocyst Protein Sec3
Exocyst is an octameric protein complex that mediates the initial contact between secretory vesicles
and the plasma membrane. The final fusion event is mediated by SNAREs (Soluble N–
ethylmaleimide Sensitive Factor Attachment Protein Receptor), proteins residing on both vesicles
and the PM. The assembly of the SNARE complex drives membrane fusion. SNARE mediated
fusion at the plasma membrane in yeast begins with the formation of a binary t SNARE complex
composed of Sso1/2 and Sec9 followed by its binding to the v SNARE protein Snc1/2. It was
previously shown that SNARE assembly is

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 ...
Show more content on Helpwriting.net ...
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

Descriptive Statistics And Trends Of Process Parameters
4.4. Descriptive Statistics and Trends of Process Parameters
Mean, standard deviation, CV, maximum and minimum values of process parameters from the 10
batches studied are shown in table 6 (see page 14 –15).
The variability (CV) of the studied process parameters ranged from 1.2% –108.3%. Buffer analyte
chemistry and charcoal mixing duration had CV less than 3 % (Range 1.2% –2.6%) and showed
very little variation. The starting volume, volume post diafiltration and final volume post aseptic
filtration had CV ranges from 9.6%–11.1 % indicating that the variability of plasma volume at three
important stages of the process was not high. Process parameters during diafiltration such as
volumetric concentration factor (VCF), membrane protein loading, process flux and number of
buffer exchanges had CV values between 11.6 % and 21.1 %. The throughput (volume filtered per
filter) for all filter types (M10, M90, Keystone, bag filters and 0.2 µm filters) exhibited variability
(CV) in the range of 24.9 % to 47.8 %. Freeze duration post Aresoil addition, freeze duration post
Aerosil removal and mix duration post Aerosil addition, all three factors involved with the
delipidation showed variability greater than 30% (range 30.7%–108.3 %).
The in–process parameters were analyzed for trends by plotting time series graph (see page 22 –25)
there was no significant trends in most of the parameters studied except for starting plasma volume,
which showed a gradual increasing pattern over

Cell Theory Research Paper
Cell structures are a very unique component in life. Cells have the ability to accomplish many tasks.
Theses tasks may include identifying genetic information, the gossamer endoplasmic reticulum
subway system and the fibril laced cytoskeleton. All of these parts are needed in order to have life.
Before all of this occurred, we developed a cell theory. The cell theory was basically used to explain
how every living thing is made out of cells. In the cell theory there were three principals that it
followed. The first principal was that all organisms are composed of one or more cell, and the life
processes of metabolism and heredity occur within these cells. The second was that cells are the
smallest living things, the basic units of organization ... Show more content on Helpwriting.net ...
The cytoskeleton consist of polymer of identical protein subunits that attracts one another and
assemble in long chains. In the cytoskeleton there are three different kinds of fibers. The three fibers
are actin filament, microtubules and intermediate filaments. Actin filament are composed of two
protein chains loosely twined together like two strands of pearls. Microtubules are the largest
cytoskeletal element and it is formed from nucleation centers near the center of the cell and radiate
toward the periphery. Meanwhile, the intermediate filaments is considered to be the most durable
element of the cytoskeleton. They are a mixed group of cytoskeletal

Importance of Glycophorin A Protein Found in Red Blood...
Glycophorin A (GpA) is a protein found in the human membrane red blood cell. The GpA protein is
obtained from the gene called glycophorin A (MNS blood group) or GpA. The GpA gene bears the
antigenic determinants for the MN and Ss blood groups, and 40 related variants of the Miltenberger
complex and several isoforms of Sta1. There are two classes of membrane glycoproteins, asialo and
sialoglycoproteins (glycophorins). These glycoproteins are determined by the presence of sialic acid
which is the negative charge on cell surface. GpA is the primary sialoglycoprotein of human
erythrocyte membranes that forms noncovalent dimers by sequence–specific, reversible association
of its single hydrophobic membrane–spanning domain2. The glycophorin ... Show more content on
Helpwriting.net ...
The glycosylated part of the N–terminus acts as receptors of MN blood group. The GpA protein is
receptors for influenza virus, Hepatitis A virus, and Plasmodium falciparum erythrocyte–binding
antigen 1751. It is also significant for the function and the activities of SLC4A1 (solute carrier
family 4 (anion exchanger)) such as to translocate it to the plasma membrane.
Glycophorins contain high carbohydrates which link to polypeptide chain through O–glycosidic
linkages either to serine or threonine residues and N–glycosidic linkage to asparagine residues of the
protein4. Human has 15 linkages of O–glycosidic and 1 of N–glycosidic. The carbohydrates and the
protein play important role in the antigenicity. If they are different then they will have different
antigenic behavior. Two genes within the human glycophorin family, the GpB and GpE, are
homologous to the GpA gene. These genes encode the GpB and GpE proteins which have the same
functions as GpA protein. The difference between GpA, GpB, and GpE proteins is that GpE carry
less blood group antigen than the other two.
Studies had shown that solution nuclear magnetic resonance (NMR) spectroscopy of a 40–residue
peptide solubilized in aqueous detergent micelles2. The experiment demonstrates that even though
some residues do not have the tendency to form alpha helices, hydrogen bonds are formed in the
backbone to yield the helix. The unfavorable residues in one monomer were predicted to interact
with the other monomer to

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

Mechanisms Of Ebv Latent Membrane Protein Trafficking Essay
I. TITLE: Mechanisms of EBV Latent Membrane protein trafficking to exosomes
II. BACKGROUND AND SIGNIFICANCE
A. Review of relevant literature
Epstein–Barr–virus (EBV) is a member of the gamma herpesvirus family that establishes a
persistent infection in approximately 90% of the world's population. In immunocompromised
individuals, EBV infection can contribute to cancer development like nasopharyngeal carcinoma,
Burkitt lymphoma and Hodgkin's disease. The latent membrane protein 1 (LMP1) is expressed in
most EBV–associated cancers and it is well established that LMP1 is a major viral oncogene.
Expression of LMP1 alone is sufficient to transform cells and recombinant EBV lacking LMP1 is
incapable of immortalizing B–cells in vitro. Moreover, transgenic mice expressing LMP1 behind a
B–cell specific promoter develop lymphomas.
Exosomes are a population of small (40–150 nm) endocytically–derived extracellular vesicles
produced from inward budding events on the limiting membrane of late endosomal organelles,
forming intraluminal vesicles in multivesicular bodies (MVBs). Epstein Barr virus (EBV) hijacks
the exosomal pathway to modulate cell–to–cell signaling by secretion of viral components such as
LMP1. Trafficking of LMP1 into multivesicular bodies can modify the content and functions of
exosomes. The molecular events orchestrated by LMP1 result in the activation of a plethora of
signaling pathways, including mitogen–activated protein kinase (MAPK/ERK),

The Role Of Proteins Of Cell Membrane Transport

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