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1
NOITCES
CHAPTER
1
Basic structure and function of cells
Epithelial cells rarely operate independently of each other and com-
CELL STRUCTURE
monly form aggregates by adhesion, often assisted by specialized inter-
cellular junctions. They may also communicate with each other either
GENERAL CHARACTERISTICS OF CELLS by... | 31 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
0 | cells, or that of diffusion within them. Movement of macromolecules lial cells 20 µm tall and 10 µm wide (all measurements are approximate).
can be much accelerated and also directed by processes of active trans- Some cells are much larger than this: e.g. megakaryocytes of the bone
port across the plasma membrane and b... | 31 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
0 | cells, as in the amoeboid migration of tissue macrophages; the beating encloses the cytoplasm. All cells, except mature red blood cells, also
of flagella or cilia to move the cell (e.g. in spermatozoa) or fluids overly- contain a nucleus that is surrounded by a nuclear membrane or enve-
ing it (e.g. in respiratory epit... | 31 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
0 | filaments Nuclear envelope
Smooth endoplasmic Nucleus
reticulum
Nucleolus
Ribosome
Rough endoplasmic
reticulum
Microtubules
Golgi apparatus Centriole pair
Lysosomes
Cell surface folds
Fig . 1 .1 The main structural components and internal organization of a generalized cell . | 31 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | Cell structure
5
1
RETPaHC
CC MMVV AAPPMM
AAJJCC
Receptor
Transmembrane protein
pore complex
of proteins
Carbohydrate
residues
External
(extracellular)
surface
MM
MM
CCyy
LLPPMM
Internal
(intracellular)
surface
NN Lipid bilayer
appearance
in electron
microscope
Intrinsic
membrane
protein Extrinsic Transmembrane
protein... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | protein to ‘float’ in the plane of the membrane . Some proteins are
typical cell . This example is a ciliated columnar epithelial cell from human
restricted in their freedom of movement where their cytoplasmic domains
nasal mucosa . The central cell, which occupies most of the field of
are tethered to the cytoskeleton ... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | heavy metals such as osmium tetroxide appear in section as two densely
Department, Sheffield Teaching Hospitals, UK .)
stained layers separated by an electron-translucent zone – the classic
unit membrane. The total thickness of each layer is about 7.5 nm. The
and distinct compartments within the cytoplasm. Cytomembrane... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | membranous structures, called inclusions, which lie free in the cytosolic
extracellular face (EF) and protoplasmic face (PF) of each leaflet are
compartment. They include lipid droplets, glycogen aggregates and pig-
artificially produced during membrane splitting. This technique has
ments (e.g. lipofuscin). In addition... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | many soluble proteins, ions and metabolites.
(the PF). Where they have been identified, clusters of particles usually
represent channels for the transmembrane passage of ions or molecules
Plasma membrane
between adjacent cells (gap junctions).
Biophysical measurements show the lipid bilayer to be highly fluid,
Cells ar... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
1 | lipid molecule face the interior of the membrane and the hydrophilic and small organic molecules such as nutrients, through the activity of
ends face outwards. Most proteins are embedded within, or float in, the membrane transport proteins. However, lipid-soluble substances can
lipid bilayer as a fluid mosaic. Some pro... | 32 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
2 | Basic structure and function of cells
5.e1
1
RETPaHC
Combinations of biochemical, biophysical and biological tech-
niques have revealed that lipids are not homogenously distributed in
membranes, but that some are organized into microdomains in the
bilayer, called ‘detergent-resistant membranes’ or lipid ‘rafts’, rich i... | 33 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
6
1
NOITCES
of external signals, including hormones and other ligands, and sites for abundant proteins; SER is abundant in steroid-producing cells and
the recognition and attachment of other cells. Internally, plasma mem- muscle cells. A variant of the endoplasmic reticulum in musc... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | rich coat, the glycocalyx. The cell coat forms an integral part of the membranes of the smooth endoplasmic reticulum serve as surfaces for
plasma membrane, projecting as a diffusely filamentous layer 2–20 nm the attachment of many enzyme systems, e.g. the enzyme cytochrome
or more from the lipoprotein surface. The cell... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | the case of erythrocytes, blood group antigens. Therefore, the glycocalyx tains the enzyme glucose-6-phosphatase, which converts glucose-6-
plays a significant role in organ transplant compatibility. The glycocalyx phosphate to glucose, a step in gluconeogenesis.
found on apical microvilli of enterocytes, the cells for... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | endoplasmic reticulum membrane, where they remain. After passage
Compartments and functional organization from the rough endoplasmic reticulum, proteins remain in membrane-
bound cytoplasmic organelles such as lysosomes, become incorporated
The cytoplasm consists of the cytosol, a gel-like material enclosed by
into new... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | glycogen and pigments) and the cytoskeleton. The nuclear contents, Ribosomes, polyribosomes
the nucleoplasm, are separated from the cytoplasm by the nuclear
and protein synthesis
envelope.
Ribosomes are macromolecular machines that catalyse the synthesis of
Endoplasmic reticulum proteins from amino acids; synthesis and... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | exterior. The cisternal space is continuous with the perinuclear space. bled into two unequal subunits. The subunits can be separated by their
Structurally, the channel system can be divided into rough or granu- sedimentation coefficients (S) in an ultracentrifuge into larger 60S and
lar endoplasmic reticulum (RER), wh... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | storage of calcium within the cisternal space and regulated release into A typical cell contains millions of ribosomes. They may form groups
the cytoplasm. In general, RER is well developed in cells that produce (polyribosomes or polysomes) attached to messenger RNA (mRNA),
which they translate during protein synthesis... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
3 | attachment and translation of mRNA. The 60S subunit is responsible
for the release of the new protein and, where appropriate, attachment
to the endoplasmic reticulum via an intermediate docking protein that
directs the newly synthesized protein through the membrane into the
cisternal space.
Golgi apparatus (Golgi compl... | 34 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
4 | Basic structure and function of cells
6.e1
1
RETPaHC
The glycocalyx plays a significant role in maintenance of the integrity
of tissues and in a wide range of dynamic cellular processes, e.g. serving
as a vascular permeability barrier and transducing fluid shear stress to
the endothelial cell cytoskeleton (Weinbaum et ... | 35 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
4 | artificial siRNAs as a therapeutic tool for silencing disease-related genes. | 35 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
5 | Cell structure
7
1
RETPaHC
A B
N
GG
V
GG M
C Phagocytic pathway Secretory pathway Membrane recycling Receptor-mediated endocytosis
Clathrin-coated pit
Early endosome
Late endosome
Lysosomal
fusion
Secondary lysosome
Residual body
Vesicle shuttling
between cisternae trans-Golgi network
Golgi cisternae
cis-Golgi network
... | 36 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
5 | and cis-medial cisternae (red, green) to the trans-Golgi network (blue, yellow, orange–red); immature proinsulin granules (condensing vesicles) are
shown in pale blue and mature (crystalline) insulin granules in dark blue . The flat colour areas represent cut faces of cisternae and vesicles . E, Rough
endoplasmic retic... | 36 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
8
1
NOITCES
salts. Traffic between the endoplasmic reticulum and the Golgi appara- Endocytic (internalization) pathway
tus is bidirectional and takes place via carrier vesicles derived from the
The endocytic pathway begins at the plasma membrane and ends in
donor site that bud, tet... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | mixing of contents of endosomes and lysosomes. Early endosomes
lipid flow in the secretory pathway; it is the site where protein and lipid
derive from endocytic vesicles (clathrin-coated vesicles and caveolae).
glycosylation occurs; and it provides membrane platforms to which
Once internalized, endocytic vesicles shed ... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | at one face of the Golgi stack, the convex cis-face (entry or forming
internalize ligands bound to surface receptor molecules and is also
surface). Here, they deliver their contents to the first cisterna in the
termed receptor-mediated endocytosis. Caveolae (little caves) are struc-
series by membrane fusion. From the ... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | The cis-Golgi and trans-Golgi membranous networks form an inte-
phagy) as well as endogenous material (autophagy). Phagocytosis
gral part of the Golgi apparatus. The cis-Golgi network is a region of
consists of the cellular uptake of invading pathogens, apoptotic cells
complex membranous channels interposed between the... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | The trans-Golgi network, at the other side of the Golgi stack, is also
Autophagy involves the degradation and recycling within an
a region of interconnected membrane channels engaged in protein
autophagosome of cytoplasmic components that are no longer needed,
sorting. Here, modified proteins processed in the Golgi cis... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | (vesicles entering the exocytosis pathway) or by pumping in protons to
but autophagy refers specifically to a lysosomal degradation–recycling
acidify their contents (lysosomes destined for the intracellular sorting
pathway. Autophagosomes are seen in response to starvation and cell
pathway).
growth.
Within the Golgi st... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | somal acid hydrolases to degrade the endosomal contents. The products
phosphate groups). Some modifications serve as signals to direct pro-
of hydrolysis either are passed through the membrane into the cytosol,
teins and lipids to their final destination within cells, including lyso-
or may be retained in the secondary... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | which transport and secretion occur more or less continuously, as with ondary lysosomes). Two classes of proteins participate in lysosomal
immunoglobulins produced by plasma cells, or it is regulated by exter- function: soluble acid hydrolases and integral lysosomal membrane
nal signals, as in the control of salivary s... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | at the apical plasma membrane. Glandular epithelial cells secrete into somes may be completely degraded to soluble products, e.g. amino
a duct lumen, as in the pancreas, or on to a free surface, such as the acids, which are recycled through metabolic pathways. However, degra-
lining of the stomach. In hepatocytes, bile... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
6 | vesicles takes place in the trans-Golgi network. Delivery of secretory inclusions. As their contents are often darkly pigmented, this may
vesicles to their correct plasma membrane domains is achieved by change the colour of the tissue; e.g. in neurones, the end-product of
sorting sequences in the cytoplasmic tails of v... | 37 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
7 | Basic structure and function of cells
8.e1
1
RETPaHC
Carrier vesicles in transit from the endoplasmic reticulum to the
Golgi apparatus (anterograde transport) are coated by coat protein
complex II (COPII), whereas COPI-containing vesicles function in the
retrograde transport route from the Golgi apparatus (reviewed in ... | 38 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | Cell structure
9
1
RETPaHC
may also be secreted – often as part of a process to alter the extracellular A
matrix, as in osteoclast-mediated erosion during bone resorption. For
further reading on lysosome biogenesis, see Saftig and Klumperman
(2009).
lysosomal dysfunction
Lysosomal storage diseases (LSDs) are a conseque... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | (GM2 gangliosidosis), in which a faulty β-hexosaminidase A leads to
the accumulation of the glycosphingolipid GM2 ganglioside in neu-
rones, causing death during childhood. In Danon disease, a vacuolar
skeletal myopathy and cardiomyopathy with neurodegeneration in
hemizygous males, lysosomes fail to fuse with autophago... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | lytic protease found in the cytosol and the nucleus that degrades intra-
cellular proteins conjugated to a polyubiquitin chain by an enzymatic
cascade. The 26S proteasome consists of several subunits arranged into
two 19S polar caps, where protein recognition and adenosine 5′-
triphosphate (ATP)-dependent target proces... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | Peroxisomes are small (0.2–1 µm in diameter) membrane-bound Histopathology Department, Sheffield Teaching Hospitals, UK .)
organelles present in most mammalian cells. They contain more than
50 enzymes responsible for multiple catabolic and synthetic biochemi-
cal pathways, in particular the β-oxidation of very-long-cha... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | proteins and some peroxisomal membrane proteins are synthesized by ate ATP; and the mitochondrial matrix, a space enclosed by the inner
cytosolic ribosomes and contain a peroxisome targeting signal that membrane and numerous cristae. The permeability of the two mito-
enables them to be imported by proteins called perox... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | acids, D-amino acids, urate, xanthine and very-long-chain fatty acids) cells. Mitochondria are the site of the citric acid (Krebs’) cycle and the
and produce hydrogen peroxide that is detoxified (degraded) by per- electron transport (cytochrome) pathway by which complex organic
oxisomal catalase. Peroxisomes are partic... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
8 | phy is an X-linked peroxisomal disease affecting mostly males, caused drial membrane.
by deficiency in β-oxidation of very-long-chain fatty acids. The build-up The intermembrane space houses cytochrome c, a molecule involved
of very-long-chain fatty acids in the nervous system and suprarenal in activation of apoptosis.... | 39 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
9 | Basic structure and function of cells
9.e1
1
RETPaHC
The transcription factor EB (TFEB) is responsible for regulating lyso-
somal biogenesis and function, lysosome-to-nucleus signalling and
lipid catabolism (for further reading, see Settembre et al (2013)). If any
of the actions of lysosomal hydrolases, of the lysosome... | 40 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
9 | cholesterol across the outer mitochondrial membrane. A mutation
in the gene encoding StAR causes defective suprarenal and gonadal
steroidogenesis. | 40 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
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1
NOITCES
erythrocytes lack mitochondria altogether. Cells with few mitochondria ent and its electronic charge, and the potential difference across the
generally rely largely on glycolysis for their energy supplies. These membrane. These factors combine to produce an electrochem... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | constantly change shape and intracellular position; they multiply by sequent closure of channels selectively permeable to sodium and
growth and fission, and may undergo fusion. potassium).
The mitochondrial matrix is an aqueous environment. It contains a Carrier proteins bind their specific solutes, such as amino acids... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | differ in the precise genetic code used in protein synthesis. At least 13 movement of an ion down its electrochemical gradient. Linked trans-
respiratory chain enzymes of the matrix and inner membrane are port can be in the same direction as the solute, in which case the carrier
encoded by the small number of genes alo... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | genetic variations and mutations) are passed only through the where they carry out their functions. Others, such as integral membrane
female line. proteins or proteins for secretion, are translocated across intracellular
Mitochondria are distributed within a cell according to regional membranes for post-translational m... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | Moreover, a number of genetic diseases of mitochondria affect particu- the correct intracellular membrane compartment.
lar tissues exclusively, e.g. mitochondrial myopathies (skeletal muscle)
and mitochondrial neuropathies (nervous tissue). For further informa-
Cell signalling
tion on mitochondrial genetics and disorde... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | renal cortex) and lipid droplets. The signal may act over a long distance, e.g. endocrine signalling
through the release of hormones into the blood stream, or neuronal
lipid droplets synaptic signalling via electrical impulse transmission along axons
Lipid droplets are spherical bodies of various sizes found within man... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | (2012) for further reading on obesity and perilipins. In cells specialized mechanism, in which cells of one type release molecules into the inter-
for lipid storage, the vacuoles reach 80 µm or more in diameter. They stitial fluid of the local environment, to be detected by nearby cells of
function as stores of chemica... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | Lipid bilayers are increasingly impermeable to molecules as they signalling molecule. The most extreme form of short-distance signalling
increase in size or hydrophobicity. Transport mechanisms are therefore is contact-dependent (juxtacrine) signalling, where one cell responds to
required to carry essential polar molec... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
10 | and close under the regulation of intracellular signals, e.g. G-proteins,
Signalling molecules and their receptors
to allow the flux of solutes (usually inorganic ions) of specific size and
charge. Transport through ion channels is always passive, and ion flow The majority of signalling molecules (ligands) are hydrophi... | 41 | Gray's Anatomy | temp.pdf | https://archive.org/download/GraysAnatomy41E2015PDF/Grays%20Anatomy-41%20E%20%282015%29%20%5BPDF%5D.pdf | PDFPlumberTextLoader |
11 | 4
1
NOITCES
CHAPTER
1
Basic structure and function of cells
Epithelial cells rarely operate independently of each other and com-
CELL STRUCTURE
monly form aggregates by adhesion, often assisted by specialized inter-
cellular junctions. They may also communicate with each other either
GENERAL CHARACTERISTICS OF CELLS by... | 31 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
11 | cells, or that of diffusion within them. Movement of macromolecules lial cells 20 µm tall and 10 µm wide (all measurements are approximate).
can be much accelerated and also directed by processes of active trans- Some cells are much larger than this: e.g. megakaryocytes of the bone
port across the plasma membrane and b... | 31 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
11 | cells, as in the amoeboid migration of tissue macrophages; the beating encloses the cytoplasm. All cells, except mature red blood cells, also
of flagella or cilia to move the cell (e.g. in spermatozoa) or fluids overly- contain a nucleus that is surrounded by a nuclear membrane or enve-
ing it (e.g. in respiratory epit... | 31 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
11 | filaments Nuclear envelope
Smooth endoplasmic Nucleus
reticulum
Nucleolus
Ribosome
Rough endoplasmic
reticulum
Microtubules
Golgi apparatus Centriole pair
Lysosomes
Cell surface folds
Fig . 1 .1 The main structural components and internal organization of a generalized cell . | 31 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | Cell structure
5
1
RETPaHC
CC MMVV AAPPMM
AAJJCC
Receptor
Transmembrane protein
pore complex
of proteins
Carbohydrate
residues
External
(extracellular)
surface
MM
MM
CCyy
LLPPMM
Internal
(intracellular)
surface
NN Lipid bilayer
appearance
in electron
microscope
Intrinsic
membrane
protein Extrinsic Transmembrane
protein... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | protein to ‘float’ in the plane of the membrane . Some proteins are
typical cell . This example is a ciliated columnar epithelial cell from human
restricted in their freedom of movement where their cytoplasmic domains
nasal mucosa . The central cell, which occupies most of the field of
are tethered to the cytoskeleton ... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | heavy metals such as osmium tetroxide appear in section as two densely
Department, Sheffield Teaching Hospitals, UK .)
stained layers separated by an electron-translucent zone – the classic
unit membrane. The total thickness of each layer is about 7.5 nm. The
and distinct compartments within the cytoplasm. Cytomembrane... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | membranous structures, called inclusions, which lie free in the cytosolic
extracellular face (EF) and protoplasmic face (PF) of each leaflet are
compartment. They include lipid droplets, glycogen aggregates and pig-
artificially produced during membrane splitting. This technique has
ments (e.g. lipofuscin). In addition... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | many soluble proteins, ions and metabolites.
(the PF). Where they have been identified, clusters of particles usually
represent channels for the transmembrane passage of ions or molecules
Plasma membrane
between adjacent cells (gap junctions).
Biophysical measurements show the lipid bilayer to be highly fluid,
Cells ar... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
12 | lipid molecule face the interior of the membrane and the hydrophilic and small organic molecules such as nutrients, through the activity of
ends face outwards. Most proteins are embedded within, or float in, the membrane transport proteins. However, lipid-soluble substances can
lipid bilayer as a fluid mosaic. Some pro... | 32 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
13 | Basic structure and function of cells
5.e1
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RETPaHC
Combinations of biochemical, biophysical and biological tech-
niques have revealed that lipids are not homogenously distributed in
membranes, but that some are organized into microdomains in the
bilayer, called ‘detergent-resistant membranes’ or lipid ‘rafts’, rich i... | 33 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
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of external signals, including hormones and other ligands, and sites for abundant proteins; SER is abundant in steroid-producing cells and
the recognition and attachment of other cells. Internally, plasma mem- muscle cells. A variant of the endoplasmic reticulum in musc... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | rich coat, the glycocalyx. The cell coat forms an integral part of the membranes of the smooth endoplasmic reticulum serve as surfaces for
plasma membrane, projecting as a diffusely filamentous layer 2–20 nm the attachment of many enzyme systems, e.g. the enzyme cytochrome
or more from the lipoprotein surface. The cell... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | the case of erythrocytes, blood group antigens. Therefore, the glycocalyx tains the enzyme glucose-6-phosphatase, which converts glucose-6-
plays a significant role in organ transplant compatibility. The glycocalyx phosphate to glucose, a step in gluconeogenesis.
found on apical microvilli of enterocytes, the cells for... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | endoplasmic reticulum membrane, where they remain. After passage
Compartments and functional organization from the rough endoplasmic reticulum, proteins remain in membrane-
bound cytoplasmic organelles such as lysosomes, become incorporated
The cytoplasm consists of the cytosol, a gel-like material enclosed by
into new... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | glycogen and pigments) and the cytoskeleton. The nuclear contents, Ribosomes, polyribosomes
the nucleoplasm, are separated from the cytoplasm by the nuclear
and protein synthesis
envelope.
Ribosomes are macromolecular machines that catalyse the synthesis of
Endoplasmic reticulum proteins from amino acids; synthesis and... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | exterior. The cisternal space is continuous with the perinuclear space. bled into two unequal subunits. The subunits can be separated by their
Structurally, the channel system can be divided into rough or granu- sedimentation coefficients (S) in an ultracentrifuge into larger 60S and
lar endoplasmic reticulum (RER), wh... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | storage of calcium within the cisternal space and regulated release into A typical cell contains millions of ribosomes. They may form groups
the cytoplasm. In general, RER is well developed in cells that produce (polyribosomes or polysomes) attached to messenger RNA (mRNA),
which they translate during protein synthesis... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
14 | attachment and translation of mRNA. The 60S subunit is responsible
for the release of the new protein and, where appropriate, attachment
to the endoplasmic reticulum via an intermediate docking protein that
directs the newly synthesized protein through the membrane into the
cisternal space.
Golgi apparatus (Golgi compl... | 34 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
15 | Basic structure and function of cells
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The glycocalyx plays a significant role in maintenance of the integrity
of tissues and in a wide range of dynamic cellular processes, e.g. serving
as a vascular permeability barrier and transducing fluid shear stress to
the endothelial cell cytoskeleton (Weinbaum et ... | 35 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
15 | artificial siRNAs as a therapeutic tool for silencing disease-related genes. | 35 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
16 | Cell structure
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1
RETPaHC
A B
N
GG
V
GG M
C Phagocytic pathway Secretory pathway Membrane recycling Receptor-mediated endocytosis
Clathrin-coated pit
Early endosome
Late endosome
Lysosomal
fusion
Secondary lysosome
Residual body
Vesicle shuttling
between cisternae trans-Golgi network
Golgi cisternae
cis-Golgi network
... | 36 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
16 | and cis-medial cisternae (red, green) to the trans-Golgi network (blue, yellow, orange–red); immature proinsulin granules (condensing vesicles) are
shown in pale blue and mature (crystalline) insulin granules in dark blue . The flat colour areas represent cut faces of cisternae and vesicles . E, Rough
endoplasmic retic... | 36 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
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salts. Traffic between the endoplasmic reticulum and the Golgi appara- Endocytic (internalization) pathway
tus is bidirectional and takes place via carrier vesicles derived from the
The endocytic pathway begins at the plasma membrane and ends in
donor site that bud, tet... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | mixing of contents of endosomes and lysosomes. Early endosomes
lipid flow in the secretory pathway; it is the site where protein and lipid
derive from endocytic vesicles (clathrin-coated vesicles and caveolae).
glycosylation occurs; and it provides membrane platforms to which
Once internalized, endocytic vesicles shed ... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | at one face of the Golgi stack, the convex cis-face (entry or forming
internalize ligands bound to surface receptor molecules and is also
surface). Here, they deliver their contents to the first cisterna in the
termed receptor-mediated endocytosis. Caveolae (little caves) are struc-
series by membrane fusion. From the ... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | The cis-Golgi and trans-Golgi membranous networks form an inte-
phagy) as well as endogenous material (autophagy). Phagocytosis
gral part of the Golgi apparatus. The cis-Golgi network is a region of
consists of the cellular uptake of invading pathogens, apoptotic cells
complex membranous channels interposed between the... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | The trans-Golgi network, at the other side of the Golgi stack, is also
Autophagy involves the degradation and recycling within an
a region of interconnected membrane channels engaged in protein
autophagosome of cytoplasmic components that are no longer needed,
sorting. Here, modified proteins processed in the Golgi cis... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | (vesicles entering the exocytosis pathway) or by pumping in protons to
but autophagy refers specifically to a lysosomal degradation–recycling
acidify their contents (lysosomes destined for the intracellular sorting
pathway. Autophagosomes are seen in response to starvation and cell
pathway).
growth.
Within the Golgi st... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | somal acid hydrolases to degrade the endosomal contents. The products
phosphate groups). Some modifications serve as signals to direct pro-
of hydrolysis either are passed through the membrane into the cytosol,
teins and lipids to their final destination within cells, including lyso-
or may be retained in the secondary... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | which transport and secretion occur more or less continuously, as with ondary lysosomes). Two classes of proteins participate in lysosomal
immunoglobulins produced by plasma cells, or it is regulated by exter- function: soluble acid hydrolases and integral lysosomal membrane
nal signals, as in the control of salivary s... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | at the apical plasma membrane. Glandular epithelial cells secrete into somes may be completely degraded to soluble products, e.g. amino
a duct lumen, as in the pancreas, or on to a free surface, such as the acids, which are recycled through metabolic pathways. However, degra-
lining of the stomach. In hepatocytes, bile... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
17 | vesicles takes place in the trans-Golgi network. Delivery of secretory inclusions. As their contents are often darkly pigmented, this may
vesicles to their correct plasma membrane domains is achieved by change the colour of the tissue; e.g. in neurones, the end-product of
sorting sequences in the cytoplasmic tails of v... | 37 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
18 | Basic structure and function of cells
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RETPaHC
Carrier vesicles in transit from the endoplasmic reticulum to the
Golgi apparatus (anterograde transport) are coated by coat protein
complex II (COPII), whereas COPI-containing vesicles function in the
retrograde transport route from the Golgi apparatus (reviewed in ... | 38 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | Cell structure
9
1
RETPaHC
may also be secreted – often as part of a process to alter the extracellular A
matrix, as in osteoclast-mediated erosion during bone resorption. For
further reading on lysosome biogenesis, see Saftig and Klumperman
(2009).
lysosomal dysfunction
Lysosomal storage diseases (LSDs) are a conseque... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | (GM2 gangliosidosis), in which a faulty β-hexosaminidase A leads to
the accumulation of the glycosphingolipid GM2 ganglioside in neu-
rones, causing death during childhood. In Danon disease, a vacuolar
skeletal myopathy and cardiomyopathy with neurodegeneration in
hemizygous males, lysosomes fail to fuse with autophago... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | lytic protease found in the cytosol and the nucleus that degrades intra-
cellular proteins conjugated to a polyubiquitin chain by an enzymatic
cascade. The 26S proteasome consists of several subunits arranged into
two 19S polar caps, where protein recognition and adenosine 5′-
triphosphate (ATP)-dependent target proces... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | Peroxisomes are small (0.2–1 µm in diameter) membrane-bound Histopathology Department, Sheffield Teaching Hospitals, UK .)
organelles present in most mammalian cells. They contain more than
50 enzymes responsible for multiple catabolic and synthetic biochemi-
cal pathways, in particular the β-oxidation of very-long-cha... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | proteins and some peroxisomal membrane proteins are synthesized by ate ATP; and the mitochondrial matrix, a space enclosed by the inner
cytosolic ribosomes and contain a peroxisome targeting signal that membrane and numerous cristae. The permeability of the two mito-
enables them to be imported by proteins called perox... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | acids, D-amino acids, urate, xanthine and very-long-chain fatty acids) cells. Mitochondria are the site of the citric acid (Krebs’) cycle and the
and produce hydrogen peroxide that is detoxified (degraded) by per- electron transport (cytochrome) pathway by which complex organic
oxisomal catalase. Peroxisomes are partic... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
19 | phy is an X-linked peroxisomal disease affecting mostly males, caused drial membrane.
by deficiency in β-oxidation of very-long-chain fatty acids. The build-up The intermembrane space houses cytochrome c, a molecule involved
of very-long-chain fatty acids in the nervous system and suprarenal in activation of apoptosis.... | 39 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
20 | Basic structure and function of cells
9.e1
1
RETPaHC
The transcription factor EB (TFEB) is responsible for regulating lyso-
somal biogenesis and function, lysosome-to-nucleus signalling and
lipid catabolism (for further reading, see Settembre et al (2013)). If any
of the actions of lysosomal hydrolases, of the lysosome... | 40 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
20 | cholesterol across the outer mitochondrial membrane. A mutation
in the gene encoding StAR causes defective suprarenal and gonadal
steroidogenesis. | 40 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
21 | BaSIC STRuCTuRE aNd fuNCTION Of CEllS
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erythrocytes lack mitochondria altogether. Cells with few mitochondria ent and its electronic charge, and the potential difference across the
generally rely largely on glycolysis for their energy supplies. These membrane. These factors combine to produce an electrochem... | 41 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
21 | constantly change shape and intracellular position; they multiply by sequent closure of channels selectively permeable to sodium and
growth and fission, and may undergo fusion. potassium).
The mitochondrial matrix is an aqueous environment. It contains a Carrier proteins bind their specific solutes, such as amino acids... | 41 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
21 | differ in the precise genetic code used in protein synthesis. At least 13 movement of an ion down its electrochemical gradient. Linked trans-
respiratory chain enzymes of the matrix and inner membrane are port can be in the same direction as the solute, in which case the carrier
encoded by the small number of genes alo... | 41 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
21 | genetic variations and mutations) are passed only through the where they carry out their functions. Others, such as integral membrane
female line. proteins or proteins for secretion, are translocated across intracellular
Mitochondria are distributed within a cell according to regional membranes for post-translational m... | 41 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
21 | Moreover, a number of genetic diseases of mitochondria affect particu- the correct intracellular membrane compartment.
lar tissues exclusively, e.g. mitochondrial myopathies (skeletal muscle)
and mitochondrial neuropathies (nervous tissue). For further informa-
Cell signalling
tion on mitochondrial genetics and disorde... | 41 | Gray's Anatomy | temp.pdf | null | PDFPlumberTextLoader |
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