Essay On Folding Analysis Of Protein

Essay On Folding Analysis Of Protein
3.2 Folding analysis of recombinant TGF–β1 protein
To analyze the folding of recombinant TGF–β1, purified protein was electrophoresed on native gel,
under non–reducing condition and stained with the silver stain. Electrophoresis of the purified TGF–
β1, under non–reducing condition, confirmed the presence of dimeric form of the TGF–β1, as a 25
kDa band on the non–denaturing gel (Figure 5 ). Here, there was no trace of a monomeric TGF–β1
band (13.5 kDa). This result indicated that the mature form of TGF–β1 is probably folded properly,
and secreted as a dimer into the culture medium.
3.4 Biological activity of recombinant TGF– β1
The biological activity of purified TGF–β1 was measured in classical growth–inhibition assay on
Mv1–Lu cells. ... Show more content on Helpwriting.net ...
Complicated processes of synthesis, folding and activation cause difficulties to achieve active TGF–
β1 from expression systems. Most previous studies were performed to express the full length of
TGF– β1 in mammalian cells and baculovirus–insect expression systems [11, 21, 22]. However, as
the major secreted proteins by theses cells, consisted of non–covalently associated propeptide with
the mature form of TGF–β1, the yields of biologically active purified proteins were not sufficient,
and significantly decreased after removal of LAP propeptide [11]. Therefore, some attempts were
made to express biologically active TGF– β1, using the DNA sequence, encoding the mature
domain in eukaryotic and prokaryotic systems. However, the expressed proteins were not active,
and in some cases, chemical refolding was required, to maintain the biological activity [9, 10]. Here,
we showed that the expression of biologically active TGF–β1, without the requirement of LAP
coding sequence and chemical refolding, is feasible in yeast expression system. In addition, one
limitation for the accumulation of mature TGF–β1 in the reported expression systems, was the low
stability of the expressed protein, resulted from the activity of endoproteases. To overcome this
problem, we used the engineered PichiaPink, strain 3, knocked out for protease B. Similar to higher
eukaryotes, secreted proteins in yeast can be processed
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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

Essay On Intracellular Trafficking
Research Strategy
A. Significance
Intracellular trafficking is an essential cellular communication process in which membrane vesicles
carrying lipids, proteins, and nucleic acids are taken up and transported through endosomes to
lysosomes (termed endocytosis) and vesicles carrying macromolecules are delivered to the plasma
membrane and outside of the cell (exocytosis) {Oka, 2005 #5437}. Uptake of external particles
through endocytosis is required for prolific growth and differentiation. For example, uptake of
transferrin provides iron necessary for growth and parasitism of the parasite Plasmodium falciparum
{Rodriguez, 1986 #5445}. In contrast, the synaptic release of neurotransmitters, including dopamine
and serotonin exemplifies ... Show more content on Helpwriting.net ...
By sharing only the N–terminal EH domains and CC region with ITSN1 plus a proline–rich (PR)
region, Pan1 has a role in endocytosis and the organization of cortical actin through interactions
with additional partner proteins, including EH proteins Ede1 and End3 {Wendland, 1998
#5492;Huang, 2007 #5510;Miliaras, 2004 #5491}. Pan1 homologs were identified from Candida
species and Magnaporthe oryzae (Mo), but not Cn, indicating that Pan1–mediated endocytic
trafficking is not universal among fungi ({Martin, 2007 #5481}, ZG Zhang and P Wang,
unpublished data).
Cn is an encapsulated basidiomycetous fungus infecting both immunocompromised and healthy
individuals causing life–threatening meningoencephalitis {Mitchell, 1995 #878}. It produces
virulence factors including melanin, the polysaccharide capsule, and extracellular ureases and
phospholipases {Kozel, 1995 #1696;Buchanan, 1998 #2608;engeler, 2000 #3148}. Previous studies
showed that secretory transport is important in virulence {Rodrigues, 2009 #5368;Jesus, 2009
#5368} and that Cn contains proteins with a conserved function in exocytosis, such as Sav1, Sec6,
and Sec14 {Yoneda, 2006 #5408;Panepinto, 2009 #5385;Chayakulkeeree, 2011 #5686}. We
identified cryptococcal intersectin 1 (Cin1) as a novel endocytic adaptor protein that is important not
only in intracellular transport but also in growth and virulence

It Is Estimated That About 17% Of The Worldwide Population
It is estimated that about 17% of the worldwide population is at risk of developing zinc deficiency
(Wessells KR and Brown KH 2012 7). Zinc as a biologically essential micronutrient, is important
for a proper functioning of human and animals. The human body contains 2–3 g of zinc located
mainly in the muscle and bone (Vela G. 2015 2015:972791). In the brain, the highest levels of zinc
are found in the cortex, hippocampus and amygdala (Takeda A. 2009 11;62(1):33–44; Swardfager
W. 37 2013 911–929; Grabrucker AM 2011 1(1):13–23). On a cellular level, 50% of zinc is
localized in the cytosol, 30–40% in the nucleus and 10% in the membrane. The total Zn2+
concentrations are extremely low in both the extracellular (100 μM) compartments. The ... Show
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Also rodent studies showed a relationship between dietary zinc deficiency and the development of
depressive behavior. It was found that zinc–deficient mice exhibit pro–depressive behavior observed
as increased immobility time in the forced swim test (FST) and tail suspension test (TST) (Whittle
N. 2009 36(1):147–58; Mlyniec K. 2012 64(2):249–55; Mlyniec K. 2012 64(3):567–75).
Furthermore, these effects were reversed by chronic administration of desipramine (Tamano H.
2009 55,536–541; Whittle N. 2009 36(1):147–58). Studies performed in rats showed that dietary
zinc deficiency induces anhedonia, social impairments and anxiety–like behavior, which are
common, co–morbid symptoms of depression (Takeda A. 2007 12;177(1):1–6; Tassabehji NM. 2008
95,365–369) (Doboszewska.......).
Zinc homeostasis is thus important for the proper functioning of the whole organism and zinc levels
must be adjusted properly to keep the cellular processes and biological responses necessary for life.
Zinc transporters are one group of the proteins responsible for the maintaining the adequate level of
zinc in the brain (Hara T 67 2017). Zinc transporters regulate zinc levels by controlling zinc
transport from the extracellular space or from intracellular vesicles to the cytoplasm (ZIP family) or
transport of Zn from the cytosol or influx into intracellular vesicles (ZnT family) (Liuzzi JP., 2004
24:151–72; Prakash A 2015 29(2):131–49.
The present paper is focused on the ZnTs family of

The Discovery of Vesicle Transportation System Essay
On October 7th 2013, the Nobel Assembly at Karolinska Institutet awarded the 2013 Nobel Prize in
Physiology or Medicine jointly to James E. Rothman, Randy W. Schekman and Thomas C. Sudhof
for "their discoveries of machinery regulating vesicle traffic, a major transport system in our cells".
Before this research, knowledge about the vesicle transportation system that eukaryotic cells utilized
was essentially limited to what could be observed, including its various tasks and actions and its
huge significance in cell survival. The question that remained unanswered, however; was exactly
how this system was able to perform and control its tasks with such efficiency and precision
throughout the cell body and beyond. Therefore, Rothman, ... Show more content on
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This sophisticated intracellular setup has understandingly raised questions about its mechanics and
remained an enigma until the three Nobel Laureates presented their discoveries.
Randy Schekman was able to identify the genes that controlled vesicle trafficking through the use of
yeast cells and it's genetics as a model. In order to identify which genes participate in vesicle
transportation, Schekman used genetic screening, which is a process where mutant organisms are
created and isolated based on the desired phenotype to determine the presence of a gene associated
with a disorder. Through this genetic screening, Randy Schekman observed mutated yeast cells and
isolated those with flawed vesicle transport systems. He observed that these cells experienced
congestion of vesicles in certain areas of the cell, specifically in the endoplasmic reticulum, Golgi
complex and the cell surface. Therefore he was able to accredit control of vesicle trafficking to the
twenty–three specific genes he later identified and classified in relationship to the location of the
vesicle blocks. James Rothman discovered how vesicles are able to fuse with its target membrane
when transporting molecules by a protein complex. Rothman was able to arrive to this discovery
through the use of his work with a specific viral protein. He used a system where infected cells
would produce the

Spironucleus Mesnili Trophozoites
1. Describe the characteristics of the Retortamonadida and Diplomonadida orders. Both
Retortamonadida and Diplomonadida lack mitochondria as well as a Golgi apparatus, which are also
known as dictyosomes. Retortamonadida and Diplomonadida also possess a recurrent flagella
within a groove and can occupy low oxygen environments. Both orders of Retortamonadida and
Diplomonadida are commonly found within humans.
2. Describe the morphology of Chilomastix mesnili trophozoites. In the cyst stage of Chilomastix
mesnili, the cyst has a thick wall and is shaped similar to a pear or lemon. It is usually found in the
stool. The cyst has a single nucleus located closer to the anterior end as well as other cytoplasmic
organelles. During the trophozoite ... Show more content on Helpwriting.net ...
There is a fifth flagellum that curves backward along the undulating membrane. There is an
accessory filament that runs along the undulating membrane. The costa arises from the kinetosome
and the parabasal body lies near the nucleus. An axostyle tube is formed by a sheet of microtubules
and has three parts. The anterior portion called the capitulum, the middle part called the trunk, and
the posterior regions called the caudal tip. The pelta is made up of microtubules that supports the
paraflagellar canal, which is a shallow depression from which all flagella emerge. The trophozoites
also contain microbodies also known as the paracostal

Essay On Extracellular Trafficking
Intracellular trafficking is a complex and dynamic process involving the participation of many
proteins. Multiple domains of Cin1 allow its interactions with proteins involved in endocytosis and
exocytosis, actin cytoskeleton maintenance, and signaling events. In Cn, virulence factors including
melanin, the capsule, and proteinases are actively transported via exocytosis. Disruptions of the
genes encoding Sav1, Sec6, and Sec14 attenuated the production of capsule, melanin, and
phospholipase, respectively {Yoneda, 2006 #5408; Panepinto, 2009 #5385; Chayakulkeeree, 2011
#5686}. In contrast, the disruption of the CIN1 gene encoding Cin1 resulted in not only the defect in
cellular transport but also many other defects {Shen, 2010}. How Cin1 ... Show more content on
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Approximately 100 ng cDNA each was subject to illumina deep sequencing (BGI, Shenzhen, China)
that yieled high quality data. In this aim, we will complete annotation, identification, validation, and
functional analysis of all RNA–Seq data.
3a. sRNA analysis To date, exRNA has not been used to investigate intracellular trafficking or
pathogenesis in fungi. We first isolated EVs from the cin1 mutant and WT strains and extracted
exRNA with Trizol. Since the cin1 mutant is drastically reduced in growth, 3x more culture volume
than WT was necessary to obtain a yield comparable to that of WT. Using BGISEQ–500 technology,
a total of 27,084,174 cleans reads was obtained from the cin1 mutant while 27,402,307 clean sRNA
reads were obtained from WT (JEC21). The length of sRNA is between 18 nt and 30 nt. Initial
sRNA annotation provided by BGI suggested that approximately same 96% of sRNA sequence was
mapped to available sRNA database including miRBase and Rfam. This and other early reports such
as annotation and prediction, miRNA and siRNA target prediction, and validation by expression will
be re–analyzed with the help of collaborator Dr. Taylor. Through this effort, we will determine the
role of Cin1 in expression and secretion of sRNA.
3b. mRNA and lncRNA analysis In addition to sRNA, mRNA and lncRNA encapsulated in EVs
were also included in RNA–Seq. In comparison to mRNA that convey genetic codes from DNA to
protein, lncRNA are non–protein

Cell Classification And Its Effect On The Human Body Essay
While water is commonly referred to as the "elixir of life" because of its universal qualities, cells are
credited as being responsible for making the human organism "alive". It is the difference between a
cluster of organic atoms or molecules that can react chemically, and a single living cell, the smallest
unit of life.
The study of cells is called cytology, and any research usually requires the use of a high–definition
microscope, as most cells in the human body are between 1 micrometer (μm) and 100 μm in
diameter. However, some cells, such as red blood cells (erythrocytes) or the human oocyte, can
theoretically be observed directly as they are larger in size.
CELL CLASSIFICATION
Human adults have hundreds of different cell types in their body. A quick search on Wikipedia
resulted in a long list of more than 100 types of cells. They are classifed in three broad categories:
1. Cells that are derived primarily from endoderm
2. Cells that are derived primarily from ectoderm
3. Cells that are derived primarily from mesoderm
Endoderm–derived cells are secreting cells, and are subdivided by function into exocrine epithelial
cells and hormone–secreting cells. Exocrine epithelial cells are usually gland cells whose function is
to secrete fluid, from milk secretion (mammary gland cell), lacrimal gland cell (tear secretion), to
salivary gland cells or stomach–lining mucuous cells. Hormone–secreting cells are manifold as well,
including thyroid gland and adrenal gland cells,

Glaucoma Research Paper
"Stem cell secretions may protect against glaucoma" Science Daily. January 27, 2017.
Recently there has been a new study about a secretion from stem cells that is very eye opening!
Stem cells are used in lots of studies today due to their ability to transform into any type of cell, but
they can also cause complications like rejection. Stem cells contain small membrane bound
packages that are known as exosomes. They are filled with proteins and can be used to signal other
cells to begin producing certain proteins. Researchers at the National Eye Institute studied the roles
that exosomes played on retina ganglion cells. These cells help send information from the eyes to
the brain. Glaucoma causes these cells to die and leads to the loss of

Extracellular Vesimona Essay
EVs as Pathogenic Mediators in NASH Cells release diverse types of membrane–bound
extracellular vesicles into the extracellular milieu. These can be further classified into three main
subgroups based on their cellular biogenesis: exosomes, microvesicles, and apoptotic bodies.21
Exosomes (~50–100 nm diameter) originate from the multivesicular body (MVB); MVBs are well–
characterized endosomal precursors of the lysosomal degradation pathway. MVBs can also fuse
with the plasma membrane. In this case, their intraluminal vesicle contents are released into the
extracellular space; thus becoming "exosomes".22 Microvesicles (~50–1000 nm diameter) bud
directly from the plasma membrane. Apoptotic bodies (more than 500 nm in diameter) represent ...
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One of the early reports of their role in an animal model of NASH was the observation that adoptive
transfer of EVs isolated from the serum of high fat diet–fed mice into chow diet–fed mice results in
immature myeloid cells activation and homing to the liver, which was associated with increased
levels of hepatic proinflammatory markers and serum aminotransferases.32 Subsequent reports
demonstrated a significant increase in the release of EVs from hepatocytes upon treatment with
lipids such as palmitate and its active metabolite lysophosphatidylcholine (LPC),27 28 33 toxic
lipid–induced EV release by hepatocytes was observed across different species.28 EVs derived from
hepatocyte under lipotoxic stress are heterogeneous regarding their biogenesis, selected cargo,
release, and intended target cells. For example, LPC–induced EV release is mediated by the stress
kinase mixed lineage kinase 3 (MLK3).33 Furthermore, MLK3 regulates the chemotactic cargo of
the EVs. Genetic or pharmacological inhibition of MLK3 results in a reduced abundance of the
potent C–X–C motif chemokine ligand 10 (CXCL10) in vesicles derived from LPC–treated
hepatocytes.33 Likewise, MLK3–/– mice fed a NASH–inducing diet34 have reduced CXCL10
levels in their plasma EVs. This, in turn, is

James Rothman, Randy Schekman and Thomas Südhof's...
The 2013 Nobel Prize in Physiology and Medicine was awarded to James Rothman, Randy
Schekman and Thomas Südhof for the work that they did on transport vesicles within the cellular
membrane. The recipients discovered how the cellular transport system was organized so that
transport material was delivered to the correct site with proper timing. Rothman discovered how the
vesicle is able to fuse with a cell membrane or organelle to deliver its contents. Schekman through
the study of yeast isolated the genes required to code for vesicle transport. Südhof found the signals
that tell vesicles when to release their contents.
Schekman studied the cellular transport of system of yeast and documented his discoveries in his
1990 paper Distinct ... Show more content on Helpwriting.net ...
Further research showed that the NSF protein is interchangeable with the SEC18 gene (previously
discovered by Schekman) for vesicle binding in mammals and yeast. Rothman also discovered that
a calcium shift must occur before The NSF and SNAP proteins bind, so that the correct
conformation on the membrane is available. By studying the interaction of between NSF and SNAP
protein complexes and target cell membranes a derivative of the SNAP proteins were found, called
SNARE complexes. The SNARE complexes were needed for greater docking ability in the transport
vesicles.
Südhof discovered in his 1990 paper Phospholipid binding by a synaptic vesicle protein
homologous to the regulatory region of protein kinase C that vesicle binding is a specific and
precise process that is regulated by neurotransmitter release. The release of vesicles for membrane
bidding is monitored by the influxes of Ca2+ ions into the cell. An increase of Ca2+ triggers the
vesicle to bind to the phospholipid bilayer of a cell. Once bound the Ca2+ triggers a
neurotransmitter that signals the bound vesicle to release its contents into the cell membrane by
exocytosis. Südhof also confirmed that in order for certain vesicle to bind to target membranes a
SNARE protein complex must be present in order to promote vesicle binding.
When Schekman discovered the seven specific genes required to code and assist in transport, it

The Anatomical Structure Of Different Organelles
Analyze the anatomical structure of ten different organelles in the cell and their respective functions.
The cell's nonmembranous organelles include the cytoskeleton, microvilli, centrioles, cilia,
ribosomes, and proteasomes. Membranous organelles include the endoplasmic reticulum, the Golgi
apparatus, lysosomes, peroxisomes, and mitochondria.
Organelle Location and function
Cytoskeleton Serves as the cell 's skeleton. It is an interior protein system that gives the cytoplasm
quality and adaptability. The cytoskeleton of all cells is made of microfilaments, halfway fibers, and
microtubules. Muscle cells contain these cytoskeletal parts in addition to thick fibers. The fibers and
microtubules of the cytoskeleton frame a dynamic system whose ceaseless rearrangement influences
cell shape and capacity.
Microvilli Numerous cells have little, finger–formed projections of the plasma film on their
uncovered surfaces. These projections, called microvilli (solitary, microvillus), significantly
increment the surface territory of the phone presented to the extracellular environment. Likewise,
they cover the surfaces of cells that are effectively engrossing materials from the extracellular
liquid, for example, the cells coating the stomach related tract. Microvilli have broad associations
with the cytoskeleton. A center of small scale fibers hardens each microvillus and grapples it to the
cytoskeleton at the terminal web.
Centrioles Matched, tube shaped bodies that lie at right edges

Niemann-Pick Research Paper
Niemann–pick disease is a developmental disorder in which sphingomyelin accumulates in
lysosomes in cells. These lysosomes are normally used to transport material through the cell.
However, the disorder involves a dysfunctional metabolism of sphingolipids. Niemann– pick is
divided into three different types; A, B, and C. Types A and B occur when cells in the body do not
have an enzyme called acid sphingomyelinase (ASM). This enzyme helps break down a fatty
substance called sphingomyelin, which is found in every cell in the body. Since the Acid
Sphingomyelinase enzyme is dysfunctional, sphingomyelin usually builds up in the cells and in turn
kills the cells by making it harder for the organs to work properly. For the third type of Niemann–
pick, type C, occurs when the body cannot break ... Show more content on Helpwriting.net ...
Other symptoms include loss of function of nerves, the brain, and other organs. The reason
Niemann–pick is such a terrible disease is because there is currently no treatment that has been
proven to cure the children affected by this disorder. However, funding will need to be given
because there is a new hope for a drug called Zavesca for those battling this crippling disease. An
international study in which the drug was taken for two years has been showing improvement for
neurological symptoms which is why we should invest more money into the research needed to help
the 1 in 250,000 people that are affected. There are several organizations committed to helping the
families such as the National Niemann–Pick Disease Foundation, Inc., National Organization for
Rare Diseases, or NPUK.org. Something I would like to understand better about Niemann–Pick
disease is, why does it only affect certain minority groups from certain parts of the world? For
example, type C mainly affects occurs more frequently in people of French–Acadian descent in
Nova

The Organization Of Microtubules ( Mts )
The organization of microtubules (MTs) in the mitotic spindle apparatus has been shown to involve
a combination of centrosomal–based nucleation and hypothesized to involve acentrosomal
branching MT nucleation. Here, Petry et al. (2013) uses Xenopus egg extracts to successfully
observe branching MT nucleation from existing microtubules utilizing total internal reflection
microscopy (TIRF). Direct observation of branching MT nucleation highlighted both the activating
effect of RanQ69L and its effector protein TPX2 on branching MT nucleation, and the polarity
conservation of daughter MTs. Testing for required molecular factors using immunodepletion, it was
shown that the γ–tubulin ring complex (γ–TuRC) is required for primary nucleation while the
protein complex augmin is required for branching. Furthermore, components of the RanGTP
signaling pathway are shown to induce observed branching MT nucleation. The results by Petry et
al clearly demonstrate branching MT nucleation and is a significant achievement, being the first
ever visualized in a metazoan system. Further research should focus on deciphering the mechanistic
interactions between that RanGTP and TPX2, specifically its C–terminus CT–TPX2, that stimulate
MT nucleation. In addition, even though augmin has been shown to play a key role in spindle
morphogenesis through branched MT nucleation, its relationship with other molecular factors
should be further elucidated.
Background
Mitosis and meiosis are key cellular

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

Liquids, Vitamins, Minerals, Water And Fats Essay
Substances that need to move into the cells :
Oxygen,vitamins, minerals, water and fats.
Substances that need to move out of the cells:
Insulin, carbon dioxide, and enzymes. The plasma membrane is close to animal cells where the
exchange of substances inside and outside of cells revenue a place . Some of the substances have to
move between the extracellular fluid outside cells to inside of the cell, and some elements necessity
to interchange from inside to the extracellular fluid.
Proteins which are stuck into plasma membrane help to open the channels in the membrane, (for
example chemicals produced by the body )and ions are allowed to pass through the channels . They
either are "recognized" by a receptor ( EXP : protein molecule) in the cell membrane, or they
attribute to a transporter particle, which is permitted to go through the channels. Because the plasma
membrane is particular about what substances can permit through it,it is called permeable
(selectively) where liquids and gasses can flow through. Permeability defines the affluence with
which substances can permit through a border,for example, a cell membrane. Permeable resources
that furthermost substances can simply across through the membrane. Impermeable defines that
substances are not allowed across through the membrane.Semipermeable or Selectively defines that
only a few elements are allowed to through the membrane (Walpole, 2014) .
Transporting elements through the plasma membrane will require

Unit 5 P1 the Functions of the Main Cell Components of the...
In this report i will be writing brief description on the functions of the main cell components of the
body cell.
The cell membrane : is something that lets some things in and some things out of the cell. It is an
outer cover for the cell. If the cell membrane was non existences the cell would spill all over the
place. 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 is composed of a thin, double–layered sheet of
lipids, around the Cell and is a protective membrane layer around every Cell.
Nucleus [pic]
The nucleus is the control centre of a cell. It contains genetic material such as DNA and controls the
cell's growth and ... Show more content on Helpwriting.net ...
It acts as a storage organelle. It is important in the creation and storage of steroids. It also stores ions
in solution that the cell may need at a later time. Steroids are a type of ringed organic molecule used
for many purposes in an organism. They are not always about building muscle mass like a weight
lifter. The ion storage is important because sometimes a cell needs ions fast. It might not want to
search the environment for ions, so it is easier to have them stored in a pack for easy use.
Rough ER – looks rough on the surface because it is stubbed with very small organelles called
ribosomes. Ribosomes are made of RNA and protein and are the site of protein synthesis. They are
very important in the synthesis and packaging of proteins. Some of those proteins might be used in
the cell and some are sent out. The ribosomes are attached to the membrane of the ER. As the
ribosomes builds the amino acid chain, the chain is pushed into the ER. When the protein is
complete, the rough ER pinches off a vesicle. That vesicle, a small membrane bubble, can move to
the cell membrane or the Golgi apparatus
Golgi apparatus[pic]
The function of the Golgi apparatus is to modify, sort, and package proteins and other materials
from the endoplasmic reticulum for storage in the cell or secretion outside the cell.
Lysosome [pic]
Lysosomes are single, membrane–bound sacs that contain

The role of autophagy poses as a highly conserved...
The role of autophagy poses as a highly conserved catabolic phenomena where cells undergoing
stress develop a cytoplasmic crescent shaped phagophore that matures into an autophagosome. The
autophagosome is involved in engulfing damaged organelles and long lived proteins in order to
replenish the cellular energy content and building blocks for biosynthesis. The autophagy
phenomenon always occurs to maintain the cellular homeostasis. But, under stress there is triggering
of this autophagy event beyond its basal level. The most important breakthrough in our
understanding of the molecular pathway of autophagy came from yeast genetic analysis where 35
Atg (Autophagy–related) genes were identified. Various types of Cellular stress sparks an ... Show
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Ultimately, PI3P plays a crucial localization response to facilitate fusion at the last step of double–
membrane autophagosome synthesis. Binding between Vps34 and Beclin–1 is enhanced by Ambra–
1 (activating molecule in Beclin1–regulated autophagy protein–1), Bif–1 (Bax interacting factor–1),
and UVRAG (ultraviolet radiation resistance–associated gene) whereas Bcl–XL, Bcl–2 and Rubicon
(Run domain Beclin–1 interacting cysteine–rich containing protein) inhibits this interaction.
Another stress induced transmembrane protein is vacuole membrane protein 1(VMP1) which
interacts with Beclin–1 to induce autophagy. A couple of ubiquitin–like conjugation system gets
involved during autophagosome elongation through a chain of events. Atg 12 interacts with Atg 7
(E1 ubiquitin–like activating enzyme), following which Atg12 binds to Atg10 (E2–like ubiquitin
carrier), thereby linking Atg12 to Atg5; then, Atg16 dimers gets attached to this complex resulting in
phagophore expansion. The Atg5–Atg12–Atg16 complex helps in the growth of the nascent edges
of the phagophore. This trimeric conjugation drops out when the phagophore finally matures into
the autophagosome. A second ubiquitin– like system is involved in microtubule associated protein
light chain 3 (LC3, mammalian homolog of yeast Atg8) processing.Atg4 cleaves LC3 to an active
intermediate LC3I by conjugating with E1–like Atg7 through an ATP dependent

Human Physiology : Cells And Tissues
UNIT 4: HUMAN PHYSIOLOGY
CELLS AND TISSUES
This is a diagram of an animal cell with all its key components labelled
The structures within an animal cell are described as follows:
Plasma Membrane or Cell Membrane:
This is a thin membranous layer which surrounds the cell and acts as a barrier, it works to separate
the contents within the cell from its external environment as well as from other cells.
It 's structure is important as it provides structural support and protection of components within it as
it is made up of a double membrane layer or phospholipid bilayer. It works likes a gatekeeper or
pathway so allowing certain or selected molecules to pass through and exit the cell, such as water,
nutrients and waste substances.
Cytoplasm:
This is a jelly–like and clear fluid which is present within the cell surrounding all the internal
organelles.
This fluid is like water but thicker because it contains strands of proteins which help to hold the cell
organelles in place and helps to protect any damage from internal and external components as well
as for biochemical reactions.
Mitochondria:
This organelle is made up of two membranes, the outer membrane which is it 's outer protective
layer and the inner membrane which is highly folded and coiled and works to make it more efficient
by increasing the surface area in a small space, this layered structure is known as cristae. The fluid
or solution which is contained within

How Organelles Work Together to Make and Secrete the...
Human Biology Unit 1 Assignment
The human body is made up of 100 trillion cells. All cells have the same basic structure (see figure
1) however some cells are specialised to suit a specific purpose. An example of this is the pancreatic
beta cells found in the islets of Langerhans. These cells are specialised to synthesise the protein
insulin that is involved in the metabolism of glucose in the cells. (Layden, 2010)
Figure 1 – Picture to show basic structure of a cell.
(Farrabee, M J. 2007)
But how is insulin made? The production of insulin starts in the nucleus which is the cellular
organelle where the DNA (deoxyribonucleic acid) is found. They form a series of multiple linear
molecules which are then folded in the nucleolus in to ... Show more content on Helpwriting.net ...
(Mandal, no Date)
The rough ER is an extensive organelle composed of a greatly convoluted but flattened sealed sac.
Studded on its outer surface are ribosomes. It is involved in the production, folding, quality control
and despatch of proteins. (BSCB, 2013)
The smooth ER is a separate sealed interconnecting network. It is associated in the; metabolism and
production of lipids, steroid and hormone manufacturing, the transport of intracellular products and
detoxification. (BSCB, 2013)
A vesicle is bubble like membranous structure that stores and transports cellular products and
digests metabolic waste in a cell. (Biology Online, 2008)
The golgi complex is a structure composed of flattened sacs known as cisternae. It is involved in the
modification and packaging of proteins, the manufacturing of lysosomes and transport of products
via vesicles. (Bailey, R, 2013)
(Bailey, R. 2012)
Exocytosis is the process of how hormones, digestive enzymes and lipids are released from the cell.
Vesicles containing the product pinch off from the sacs of the golgi apparatus and move towards the
plasma membrane. The vesicles then fuse with the plasma membrane and release the product
outside the cell. (CGP, 2009) The cell membrane surrounds all living cells, and is the cell's most
important organelle. It controls how substances can move in and out of the cell and allows cell

Phosphocholine Lab Report
Ceramide is a lipid molecule comprised of sphigosine, an amino alcohol, and a free fatty acid. When
combined with phosphocholine a sphingomyelin is formed which is a member of the sphingolipid
family. These molecules are main components of the phospholipid bilayer that make up a cell's
membrane. Phosphoethanolamine can also be used in place of the phosphocholine to form a
sphingomyelin however *disadvantage*.
Ceramide is found in a high abundance in the cell membrane where it was thought that it only had
structural elements contributing to the bilayer. However it is now believed that ceramide contributes
in cell signalling. *REF*
There are a number of applications for the use of ceramide in clinical settings e.g. in the treatment of
some cancer via apoptosis. This process is vital to maintain a normal amount of cells in the body.
When combined ... Show more content on Helpwriting.net ...
The complete reaction involves four biological steps beginning with palmitate and serine and
resulting in a molecule of ceramide. The initial step is also the rate limiting step therefore the
slowest step. The enzyme serine palmitoyl transferase is used to catalyse the condensation reaction
between palmitate and serine which results in the molecule 3–keto–dihydrosphingosine. This
'molecule' is then reduced to dihydrosphingosine in the ........... Dihydroceramide synthase is used to
convert dihyrdosphingosine into dihydroceramide via acylation. The product has a similar chemical
structure, uptake and metabolism as ceramide and would have an effect on apoptosis except it lacks
the biological activity needed for this function. Finally, dihydroceramide desaturase catalyses the
final conversion to ceramide. Ceramide can be generated in the de novo synthesis via both the serine
palmitoyltranserase (SPT) and ceramide synthase which catalyse key steps in the pathway.
(Panjarian et al.,

Structure Of The Inner Compartment
1 Mitochondria– Appear as tiny thread like structure under light microscope.
Its wall are made of double membrane
The inner membrane is folded inside to form projections called cristae which
project into the inner compartment called matrix.
Function : Oxidises pyruvic acid (breakdown product of glucose) to release energy
which gets stored in the from of ATP for ready use. This process is also called
cellular respiration.
2 Chloroplast
Found in all green plant cells in the cytoplasm.
Shape: Usually disc–shaped or spherical.
Wall made of double membrane i.e. outer membrane and inner membrane
numerous stack–like (piles) groups are interconnected by lamellae.
Sac like structures called thylakoids. Placed one above the other ... Show more content on
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4 Gogli body
Is a stack of membranous sacs of the same thickness as ER. Exhibit great diversity in size and
shape. In animal cells present around the nucleus, 3 to 7 in number. In plant cells, many and present
scattered throughout the cell called dictyosomes. Synthesis and secretion as enzymes, participates in
transformation of membranes to give rise to other membrane structure such as lysosome, acrosome,
and dictyosomes, synthesize wall element like pectin, mucilage.
5 Ribosomes

Spherical about 150 – 250 Å in diameter, made up of large molecules of RNA and proteins
(ribonucleo proteins) Present either as free particles in cytoplasm or attached to ER. Also found
stored in nucleolus inside the nucleus. 80S types found in eukaryotes and 70S in prokaryotes
(Ssvedberg unit of measuring ribosomes).
6 Lysosomes
Lysosomes are present in almost all animal cells and some non – green plant cells They perform
intracellular digestion. Membranous sacs budded off from golgi body. Lysosomes are called
"suicidal bags" as enzymes contained in them can digest the cell's own material when damaged or
dead.Importance of intracellular digestion by the lysosomes help in nutrition of the cell by digesting
food, as they are rich in various enzymes which enable them to digest almost all major chemical
constituents of the living cell. Help in defence by digesting germs, as in white blood cells. Help in
cleaning up the cell by

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

discussion 1 Essay
Chapter 1: Cell Pathology
1–1
Which of the following accounts for differences in cells in a human body?
Differences in chromatin
Differences in chromosomes
Differential content of DNA
Differential expression of genes
1–2
Which of the following structures is not normally found in the cytoplasm of a resting cell?
DNA
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
1–3
Which of the following cytoplasmic organelles are not found in most all nucleated cells?
Endoplasmic reticulum
Golgi apparatus
Mitochondria
Myofilaments
1–4
Which of the following is the primary purpose of mitochondria?
Maintenance of cell shape
Modification of proteins
Production of energy
Replication of cellular structures
1 ... Show more content on Helpwriting.net ...
Autocrine
Endocrine
Exocrine
Paracrine

1–11
Which of the following best accounts for cellular swelling during reversible cellular injury
occurring by transient hypoxia?
The extra oxygen directly damages the plasma membrane, allowing in water
The extra oxygen overwhelms the Na+/K+ ATPase
The lack of oxygen results in decreased energy and shutdown of the Na+/K+ ATPase
The lack of oxygen directly destabilizes the plasma membrane, allowing in water
3
1–12
Which of the following is NOT associated with reversible cellular injury?
Cellular swelling
Decreased energy production
Increased autophagy
Increased protein synthesis Decreased protein synthesis NOT
"increased" pg. 8
1–13
A cell is subject to hypoxic conditions for 20 minutes, then observed under the microscope. The
nucleus has become shrunken, with marked condensation of the chromatin. This nuclear change is
best described as which of the following?
Autophagy
Karyolysis
Karyorrhexis
Pyknosis
1–14
Which of the following is NOT a key factor in determining if a cell will be reversibly or irreversibly
damaged during hypoxia?
Cellular location
Cellular type
Degree of hypoxia
Hypoxia duration
1–15
Which of the following is most directly responsible for postperfusion injury to cells?
Formation of oxygen radicals
Hyperfunctioning of Na+/K+ ATPase
Overproduction of catalase
Shrinkage of cellular membranes
4
1–16
A new drug, Drug X, is

3d Animation Essay
Animation has been revolving for over a few decades but the first ever 3–dimension (3D) animation
was founded in 1980s. 3D animations involve the use of 3D models and moving images that are
produced in a 3D digital environment. The 3D model is a mathematical representation of a three
dimensional object. The process of animating a 3D model is considered to be complex as it has its
own software to develop the models. The skills of the designer will determine the quality of the
model and animation.
There are things that needed to be considered to produce a good animation such as the model,
lighting placement, texture assigned and camera angle. It requires a process called rendering in
order for the product to be visually displayed as a two–dimensional image. Animators take time to
plan the details and work on the creativity of the content. 3D animation basically renders the model
in every angle into images and then the images ... Show more content on Helpwriting.net ...
For instance, architects are able to show their ideas and designs of how a building would turn out
using 3D animation. There are many industries that use 3D animation such as film making, gaming,
business, interior designing and many others. 3D animation is able to promote a product's concept as
it appears to be more attractive and appealing compare to a flat image design. 3D animation has the
capability to do this because it combines the use of other multimedia such as sounds, images and
graphic effects depending on what product it is.
The difference between a 2D animation and 3D animation is that 2D animation only consists of flat
objects or illustrations that can be hand drawn and can be played back one after another. With the
use of 3D animation in this project, audience will be able to view the animation of the human brain
that will be divided into parts. They will be able to experience a life–like appearance of the

The Microstructure of a Typical Animal Cell Essay
Unit 13, task 1.
P1 – Describe the microstructure of a typical animal cell and the functions of the main cell
components. A typical animal cell is seen as a tiny, three dimensional sac which is in fact made up
of many components, each as important as the other. The microstructure of an animal cell was in
fact uncovered mainly through the use of both cell fractionation and electron microscopy. Each
main component has its own, individual function which helps a cell to function and maintains the
cell membrane. The components that I will be describing include the cell membrane, nucleus,
cytoplasm, mitochondria, lysosomes, Golgi bodies, centrioles, endoplasmic reticulum (both smooth
and rough) and ribosomes.
The cell membrane – The cell ... Show more content on Helpwriting.net ...
Smooth Endoplasmic Reticulum (Smooth ER) – The smooth endoplasmic reticulum is very similar
in terms of structure and chemically to the rough endoplasmic reticulum with the exception of not
being able to attach ribosomes like the rough ER can. The smooth ER has more than just one main
function and in simple terms these are control of calcium release within the muscle cells, breakdown
of lipid soluble toxins in the liver and lipid steroid hormone synthesis. It primarily makes and
process fat within a typical animal cell. The structure of the smooth ER is usually said to be tubular
rather than sheet like and it may be separate from the rough ER or in some cases may in fact be an
extension of it. The smooth ER is said to be most common in cells that metabolise fat and it is a
continuation of the outer nuclear membrane of a cell. It is made up of a vast network of membrane
which is usually covered in tubules and vesicles. Depending on the type of cells, the amount of
rough and smooth endoplasmic reticulum that is present within it varies somewhat greatly.
Endoplasmic means inside of the cytoplasm and the term reticulum means network. Rough
Endoplasmic Reticulum (Rough ER) – The surface of the rough endoplasmic reticulum is covered
in ribosomes which are

Phosphatidylcholine
I. Overall Lung Function and Organization The human lung is a series of blind end tubes, hollow
tubes that that allow for the conduction of air. The conduction of air starts from the nasal cavity or
oral cavity, continues to flow through the trachea and bronchus and finally reaches the bronchioles
that lead into the alveolus that allows for gas exchange to occur (Phalen et al. 1983). This system
can be broken down into two different region; a conducting region and a region of gas exchange.
The conduction portion of the respiratory system begins in the nasal cavity and the oral cavity and
continues to the bronchioles. The transition from the bronchioles to the alveolar duct results in the
transition from the conducting region of the respiratory ... Show more content on Helpwriting.net ...
De novo synthesis of surfactant phospholipids are dependent on the amount of fatty acids available
in circulation. During fetal development, the type II alveolar cells use intracellular stores of
glycerol–3–phosphate for lipid synthesis. Type II Alveolar cells in the postpartum lung need to
synthesize lipids and proteins to establish the reduction in surface tension needed to maintain a
proper liquid–air barrier(Ridsdale et al. 2004). Glycogen appears to be the main source of carbons
needed to develop the glycerol backbone within surfactant lipids. Ridsdale et al. (2004) states the
metabolic demands required of type II alveolar cells during close term requires a build up of
glycogen which could play the role of an energy source in surfactant lipid synthesis. Lamellar
bodies contain Golgi apparatus, Endoplasmic Reticulum(ER), and mitochondria that is necessary for
the production of the lipids and protein components of surfactant. The build up of glycogen changes
the orientation of the type II alveolar cell organelles. In the presence of the glycogen, the golgi
appartus, ER, and mitochondria are surround the glycogen. However glycogen region is where the
lamellar bodies are present. Risdale et al. illustrates with Figure 2– C,D and E labeled with arrows
pointing to the ER, the mitochondria labeled

Leukocyte adhesion deficiencies (LAD) are autosomal...
Leukocyte adhesion deficiencies (LAD) are autosomal recessive immunodeficiency syndromes
characterized by severe and recurrent bacterial infections, impaired wound healing and leukocytosis.
Blocks in different steps in the leukocyte adhesion cascade cause different types of leukocyte
adhesion deficiencies, LAD type I, II and III.
Leukocyte adhesion deficiencies (LAD) are autosomal recessive immunodeficiency diseases
characterized by severe and recurrent bacterial infections, impaired wound healing and neutrophilia
[1]. Leukocyte adhesion and movement of leukocytes from blood stream to tissues are crucial for
rapid leukocyte accumulation at sites of inflammatory response and tissue injury [2]. Leukocyte
adhesion cascade involves several ... Show more content on Helpwriting.net ...
Here, we describe two siblings with a novel mutation ın GFPT. Secundum atrial septal defect was
present in both of the patients in addition to the characteristic features.
Leukocyte adhesion deficiency type II (LAD II) or congenital disorders of glycosylation (CDG)
type IIc belongs to a group of CDG [7]. In LAD type II, the fucosylation of glycoconjugates is
affected. Fucose is a deoxyhexose present in a variety of organisms. In the defects of fucosylation,
many cell functions like protein folding, intracellular transport/localization, protein activity and
degradation may be affected causing defects in cellular interactions and numerous ontogenic events,
including signalling events. Fucosylation is clearly implicated in the TGF–β1, Notch, Fringe, and
selectin functions or signalling [8, 9].
The defect in LAD II is in the specific GDP–fucose transporter (GFTP) gene [10,11].
Process of fucosylation by GDP–fucose transporter in the Golgi apparatus has different steps.
GFTP translocates GDP–fucose from the cytosol through the Golgi membrane into the Golgi lumen.
Fucose required is provided via de novo pathway (90%), synthesis from mannose, or by alternate
salvage pathway (10%) from exogeneous/dietary fucose [9]. Than, fucosyl transferase transfers the
fucose to form glycolipids and glycoproteins [12], which are transported to the cell membrane.
Seven different mutations are described in the patients with LAD type II

The Structures Within An Animal Cell
The structures within an animal cell are described as follows:
Plasma Membrane or Cell Membrane:
This is a thin membranous layer which surrounds the cell and acts as a barrier, it works to separate
the contents within the cell from its external environment as well as from other cells.
It 's structure is important as it provides structural support and protection of components within it as
is is made up of a double membrane layer or phospholipid bilayer. It works likes a gatekeeper of
pathway so allowing certain or selected molecules to pass through and exit the cell, such as water,
nutrients and waste substances.
Cytoplasm:
This is a jelly–like and clear fluid which is present within surrounding all the internal organelles.
This ... Show more content on Helpwriting.net ...
It is known to be the site of aerobic respiration. (Pickering, 1994).
Ribosomes:
This organelle is small round organelles and are not made of membrane and are made up of protein
and RNA. This is an important organelle as the cell requires this to make proteins.
The proteins produced are mainly to be used within the cell and the enzyme which are products by
proteins help in speeding up certain biological processes.
They are found within the cell, either free in the cytoplasm or they can be attached to the
Endoplasmic reticulum.
Endoplasmic reticulum:
This organelle is a network of membranes which are either attached to the nucleus or found
throughout the cytoplasm.
It is a folded membrane which gives the appearance of tubes if interconnected sheets.
These membranes may vary from cell to cell depending of the function and size of particular cells.
Rough Endoplasmic Reticulum:

This is known as such due to the ribosomes which are attached to the surface of the Endoplasmic
reticulum and gives it the appearance of bumpy looking membranes.
It can also be attached to the nuclear envelope which is found surrounding the nucleus.
This is the site of protein production due to the ribosomes attached to the surface of the
Endoplasmic reticulum.
Smooth Endoplasmic Reticulum
These organelles have the appearance of tubules or a series of smooth sheets which do not have
ribosomes attached to the surface. It is important as it it the organelle which

Exosomes As A Whole Has Gained Momentum Through The Area...
The interest and research invested into the area of exosome biogenesis and the topic of exosomes as
a whole has gained momentum in the last decade (Urbanelli, L. et al. 2013). Their discovery in
1983, detailed in two papers published in JCB (Harding et al) and in Cell (Pan and Johnstone),
showed that the nomenclature had been prescribed wrongly to a broad range of membrane vesicles
that bud directly from the plasma membrane (Clifford V. Harding. et al. 2013). When in fact the
term 'exosome' more accurately describes small vesicles, ranging from 30–100nm in diameter
(Urbanelli, L. et al. 2013), that originate via a different mechanism of budding than apoptotic bodies
and microvesicles, (Yu, S. et al. 2015).
Exosome function was initially ... Show more content on Helpwriting.net ...
Whilst exosomes have been retrieved in many body fluids, for example; blood, urine, saliva and
cerebrospinal fluid (Urbanelli, L. et al. 2013). They are recently thought to be present in all
biological fluids.
Exosome Biogenesis
Exosomes are exceptional from other types of vesicles based on a number of factors; including their
size (relatively small in comparison), morphology, cargo composition and most distinctly, their
endosomal origin (Théry C. 2002). Familiar types of vesicles such as microvesicles are formed at
the cell surface, budding directly from the plasma membrane (Alenquer, M. et al. 2015). Exosome
biogenesis follows an alternative method that begins in the early endosome (Huotari, J and
Helemius, A. 2011), whereby the ultimate result is the formation of intraluminal vesicles (IVL's)
inside the lumen of the endosome, this aggregate body is known as the multivesicular body (MVB)
or the multivesicular endosome (MVE).
Initially the early endosomal membrane, tube–like in shape (Beach, A. et al, 2014), buds inwards via
intraluminal invagination (Lopez–Verrilli, M and Court, F. 2013), randomly engulfing sections of
the cytosol contents such as the peripheral and transmembrane proteins. This formation of the IVL's
noticeably augments as the endosomes mature (Huotari, J and Helemius, A. 2011) and after
transformation the late endosome is more spherical in shape (Beach, A. et al. 2014). It is known

Endocytis Research Paper
Endocytosis is the general term that refers to a form of active transport in which the cell internalizes
fluids, molecules, parts of its plasma membrane, particles and other extracellular components such
as bacterias, by the invagination of the plasma membrane and the formation of vesicles through a
process of membrane fission and budding.
Endocytosis is a conserved process in eukaryotic cells, mainly used to regulate nutrient
internalization and maintain or modify the composition of the plasma membrane. However, it is also
important in signal transduction, as endocytic pathways integrate diverse signals and orchestrate cell
signaling.
2.2.1 Early endosomes
Early endosomes, or EEs, were defined as the cell compartment (organelle) that first ... Show more
content on Helpwriting.net ...
Early endosomes suffer several modifications and mature to late endosomes. This process and its
molecular players are not completely known yet. When LEs mature, there is a dramatic remodeling
of the endosome: they become larger, membrane–bound receptors are sorted into internal vesicles,
their associated machinery is changed and they move faster towards the nucleus of the cell (Collinet
et al, 2010).
Late endosomes (LEs), also known as multivesicular bodies because of their multivesicular
morphology, are derived from the vacuolar domains of EEs and they also are quite heterogeneous in
terms of size (250–1000 nm) and composition. Their membrane is marked with Rab7, Rab9,
lysosomal–associated membrane protein–1 (LAMP1), and lysobisphosphatidic acid (LBPA), which
confers a high negative surface charge (Falguieres et al, 2008; Gruenberg et al, 2004). LEs are very
active in the trafficking pathway, sending and receiving vesicles from other compartments. For
instance, LEs receive vesicles from TGN that are loaded with acid hydrolases. This, along with the
proton pumps located in the membrane of these endosomes, modifies their lumen, which becomes
increasingly acidic. Finally, late endosomes fuse with lysosomes, delivering the intraluminal
vesicles for

Vinculin: A Structural Protein Analysis
The morphology and functions of specialized cells within tissues such as muscle requires the unique
organization of the actin cytoskeleton this actin cytoskeleton rely on actin network, vinculin, to
locked the filamentous actin (F–actin) to the membrane.1 Vinculin is a structural protein that plays
an important role in multiple protein assemblies linking the extracellular matrix to actin
cytoskeleton.2 Vinculin is an 116 kDa cytoskeletal protein linked to cell–matrix and cell–cell
junctions. It is said to work as one of a few interconnecting proteins required to secure the F–actin
to the membrane. Vinculin has a helical head and tail domains attached by a flexible proline–rich
linker.3 The head and tail domain mingle in an autoinhibitory manner, blocking binding to a
significant number of prospective ligands.4 In addition to vinculin, there is metavinculin (MV),
which is a splice variant of vinculin. MV is a muscle–specific splice of vinculin and is expressed in
smooth and cardiac muscle tissue. MV is linked to dilated cardiomyopathy (DCM) deficiency which
is a form of heart disease.

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

The And Of The Nervous System
In 1906, the Nobel Prize was awarded jointly to Camillo Golgi and Santiago Ramón y Cajal. Both
scientists were recognized for their contribution of their work on the structure of the nervous
system. (Bentivoglio) Each one of them was great advocates of conflicting theories of how the
nervous system was organized. Golgi was a great supporter of the reticular theory, of which he very
much defended in his Nobel Lecture. (Golgi) While Ramon y Cajal stated that neurons where
independent of each other and this is the basis of the commonly accepted Neuron doctrine. (Ramon
y Cajal Nobel) It is not known that the awarding members of the Nobel were aware of their rivalry
but it was well recorded that both were not amicable to each other. (Mörner) ... Show more content
on Helpwriting.net ...
Ramon y Cajal used this technique as stated in the recollection of his life:
"Impregnate fragments of gray matter for several days in solutions of potassium bichromate (or of
Muller's fluid)... and treating them afterwards with dilute solutions (0.75 per cent) of crystalline
silver nitrate". (Ramon y Cajal: Recollections pg. 306)
Ramon y Cajal later improved this technique by double impregnation. (Ramon y Cajal:
Recollections pg. 323) Originally his studies focus on the structure of the neuron and gave two very
important conclusions. The first was the discovery and naming of the dendritic spines. Second was
the idea that each nerve cell is an independent unit of a whole and not a single network. (DeFelipe
and Ramón y Cajal pg 28). His secondary observations concluded that the nervous system could not
be a pre–set network but a set of independent structures that could have the potential of being
modified and created new pathways. This shows the property of brain plasticity. (DeFelipe and
Ramon y Cajal pg 31)
Ramon y Cajal's initial work was on the layers of the cerebellum of humans and other higher
mammals. He later focussed his work on the visual cortex and even recorded his personal
observations of the aging visual and auditory systems and muscle debilitation in a more literary non
scientific way. His most important observation is that the brain will compensate for the

A Cell With Mutation Essay
3. What might you expect to find in a cell with mutation that yielded the following organelles (1)
50% functional and (2) non–functional. Justify your answers. Mitochondria, rough ER, smooth ER,
Peroxisomes, Golgi, and Chloroplasts.
In Eukaryotic cells, organelles play a major part in function and maintenance. If parts of these
organelles are not functioning properly, or at all, major issues could be caused within that cell. The
mitochondria is known as the "power house" of a cell that functions at the site of respiration. Within
the inner membrane, ATP synthesis occurs which provides energy to the cell and it other parts.
Without function of a mitochondria, a cell would die; it has no energy to repair itself, has no energy
to transport molecules across the membrane, transport nutrients, send signals to other cells, or any
other processes. Metabolism, release of energy, movement, or forming new nucleotides would not
occur simply because energy is not available. The rough ER is a connected system that is the site of
protein synthesis. Proteins are a part of all processes in life including break down of food, aerobic
respiration, transport of molecules through the body, glycolysis, DNA replication, DNA folding, and
many more. If the rough ER of a cell was non–functional, a cell would not produce the proteins
needed for these processes, therefore, in a human, many bodily functions would not occur which
could eventually lead to death. Plants may also die because their

The Vesicles Transport Hormones, Enzymes, and Chemicals Essay
The human body is a complex structure that contains billions and billions of small living cells. Each
of these cells houses many structures that function together to run the body. Some of these structures
are the endoplasmic reticulum, the nucleus, the mitochondria, lysosomes, the cell membrane and
many more. Scientists were able to explain the processes in which most of these structures carry out
to run the body, but it wasn't until this year, 2013, that the scientific world was introduced to the
process in which small cellular bodies called vesicles transport hormones, enzymes and other
chemicals through out the cell. The 2013 Nobel Prize in Medicine or Physiology was awarded to
three researchers
who used their knowledge and ... Show more content on Helpwriting.net ...
Much of this process is done by the Golgi apparatus, one of the essential organelles of a living cell.
The Golgi complex contains a numerous number of these vesicles. These vesicles are then used to
transport different molecules to the cellular membrane. At the cellular membrane, these vesicles are
then excreted. Larger secretory that are found are used for selective excretion. Furthermore, the
vesicles mediate the sorting of molecules because the Golgi apparatus is responsible for controlling
molecular traffic in the cell6. Overall, the role of the vesicles is to
transport molecules within the cell. The explanations that have won this year's Nobel Prize unsolved
the mysteries that explain the mechanism of how this is done.
Back in the 1970's, Dr. Schekman used what is known as genetic screening, or a new technology at
that time, to observe yeast cells that had dysfunctional transport system because those cells would
have a shortage of enzymes and proteins. This allowed Dr. Schekman to compare the dysfunctional
yeast cells to a normal one. He was then able to isolate three different classes of genes that caused
the shortage of materials.1 With this experiment, he was able to identify 23 genes that can be
categorized into those three different classes of genes, although at first, he only found two genes that
he called sec1 and sec2. He also found that the sec17 and sec18 are the mutants that participant in
vesicle fusion. Theses works allowed Schekman to

The Universal Intracellular Messenger, Calcium ( Ca2 + )
The universal intracellular messenger, Calcium (Ca2+ ) regulates a wide range of cellular processes
such as gene transcription, muscle contraction and cell proliferation. Ca2+ diffuses into organelles
such as mitochondria and the nucleus as it is elevated in the cytosol (Martin D Bootman, 2006).
Ca2+ is suited to this role as an intracellular messenger as it is a divalent cation and therefore it can
form more stable complexes with other compounds compared to monovalent ions like magnesium
and chloride. Moreover, Ca2+ has a larger radius and a stable electron configuration which provides
flexibility that allows the formation of bonds with coordination sites that have irregular geometry
(Bading, 2013). Although Ca2+ is important for cells the cytosolic concentration is maintained at a
nanomolar concentration. Therefore, cells have obtained different ways to cope with this situation
by reducing their cytosolic levels (Clapham, 2007). Ca2+ concentration inside cells is controlled by
counteracting processes that act as 'on and off' mechanisms based on whether they serve to increase
or decrease cytosolic Ca2+ levels (Martin D Bootman, 2006). Ca2+ cannot be chemically altered
within cells. Therefore to control Ca2+, cells must chelate, compartmentalize or extrude it in order
to maintain nanomolar concentrations of the ion (Clapham, 2007). Ca2+ 'on' mechanisms consist of
channels located at the plasma membrane (PM) that controls the amount of Ca2+ entering the
intracellular Ca2+

Role Of Sacsin In Lysosomal Transport
Discussion
Sacsin is involved in lysosomal transport
Overexpression of the HEPN domain in HeLa cells following three hours of starvation indicates that
sacsin plays a key role in lysosomal transport due to the reduced efficiency of perinuclear lysosomal
clustering. HEPN's property of dimerizing may be disrupting the function of with full–length sacsin
by preventing endogenous sacsin from dimerizing within the cell. Thus, dimerization may be
essential to sacsin's function, particularly for binding JIP3, which is necessary for lysosomal
transport7. HATPase 3 overexpression may be occupying JIP3 binding, but was not found to disrupt
lysosomal localization following starvation, perhaps due to the truncated size of this deletion
construct. ... Show more content on Helpwriting.net ...
Moreover, further deletion mapping could be performed to narrow down the specific sequence
within the third SIRPT of sacsin that binds JIP3.
HEPN dimerization
Due to the HEPN domains property of dimerizing, sacsin's interaction with JIP3 may not occur
exclusively though the HEPN domain in the absence of full–length sacsin. A mutated construct of
HEPN called ARSACS Asn–4549 can disrupt HEPN dimerization due to the replacement of an
asparagine with aspartic acid in the α4–α5 loop near the edge of the HEPN dimer interface2.
Performing a pulldown assay with a mutated HEPN construct that retains the property of JIP3
binding, but is unable to dimerize would indicate that HEPN interacts with JIP3. However, this
construct was found to destabilize HEPN folding through the loss of two polar contacts and the
introduction of a charge at the dimer interface. Furthermore, the expression of this mutant HEPN
domain in a bacterial system results in an insoluble protein which is unable to fold correctly and
dimerize 2. Therefore, cloning a mutant HEPN construct, which is unable to dimerize would disrupt
the protein's tertiary structure, and a pulldown assay with this construct would likely be inefficient
due to insolubility. Further experiments must be performed using a brain lysate from sacsin KO
mice in a JIP3 pulldown assay to examine the role of HEPN dimerization in JIP3 binding.
Furthermore, post translational modifications are not conserved between bacteria and mammals11,

Physiology & Neurobiology
Department of Physiology & Neurobiology
PNB 2264 Exam I
Unlike the abdominal viscera, the thoracic viscera are separated into two cavities by an area called
the mediastinum. What is the clinical importance of this compartmental arrangement?
The clinical importance of this compartmental arrangement is that the mediastinum region contains
a lot of major and essential parts of the human body. The mediastinum contains the pericardial
cavity, thymus, trachea, esophagus, and major blood vessels. The fact that it's placed in a sort of
central space of the upper body provides these major parts with a protective barrier of tissues and
serous membranes. Even though the mediastinum itself doesn't have a serous membrane most of the
thoracic ... Show more content on Helpwriting.net ...
Perspiration is the main way the integumentary system goes through homeostasis. Perspiration is
sweat that mostly consists of water and inorganic salts. The movement of liquid thru perspiration
also controls the body temperature. People sweat when they are hot while doing physical activities
in order to cool down the body. Dehydration is known by signals sent through the concentrations of
sodium in the extracellular and intracellular fluids.
The cardiovascular system is responsible for transporting blood carrying oxygen through the body.
Homeostasis is especially important in this system because the blood cells maintain the human body
functioning. The water and intracellular fluids are constantly performing osmosis as the cells travel
through the body.
An important buffer system in the human body involves carbon dioxide (CO2) and bicarbonate ion
(HCO–) in the reversible reaction CO2 + H2O  H2CO3  H+ + HCO3–. If a person becomes
excited and exhales large amounts of CO2, how will the pH of the person's body be affected?
The rate of cellular respiration (and hence oxygen consumption and carbon dioxide production)
varies with level of activity. Vigorous exercise can increase by 20–25 times the demand of the
tissues for oxygen. Getting excited has that similar effect and also increase the tissues desire for
oxygen. This is met by increasing the rate and depth of breathing. It is a rising concentration of
carbon dioxide not a

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