Unit 2 - The Cell Episode 5 Flashcards
1
Q
are membrane enclosed compartments associated with all the endocytic pathways
restricted to a portion of the cytoplasm near the cell membrane
A
Early endosomes
2
Q
are vesicles originating in early endosomes travelling to deeper structures in the cytoplasm
Typically mature into lysosomes
A
Late endosomes
3
Q
Early endosomes - Cellular localization
A
found in the more peripheral cytoplasm
4
Q
Early endosomes - Morphology
A
have a tubulovesicular structure
5
Q
Early endosomes - State of acidification
A
exhibits only a slightly acidic environment (pH 6.2 to 6.5) than the cytoplasm of the cell
6
Q
Early endosomes - Function
A
to sort and recycle (ang clathrin and adaptin) proteins internalized by endocytotic pathways
7
Q
- Essential Enzyme
- mature into lysosomes
A
Late endosomes
8
Q
Late endosomes - cellular localization
A
positioned near the Golgi apparatus and the nucleus
9
Q
Late endosomes - Morphology
A
have a more complex structure and often exhibit onionlike internal
10
Q
Late endosomes - State of acidification
A
more acidic, averaging 5.5
11
Q
Inactive precursor of hydrolase)
released by the late endosomes
A
Prohydrolase
12
Q
This help package the hydrolases into vesicles that bud from the trans-golgi network to deliver their contents to endosomes that ultimately will develop into mature lysosomes
A
Mannose-6-Phosphate receptor (M6P receptor)
13
Q
Endosomes can be viewed either as __________ cytoplasmic organelles or as ________________________
A
stable; transient structures
14
Q
Two different models that explain the origin and formation of the endosomal compartments in the cell:
A
Stable Compartment Model
Maturation model
15
Q
describes early and late endosomes as stable cellular
A
Stable Compartment Model
16
Q
endosomes and then to lysosomes early endosomes are formed then matures to late endosomes and then to lysosomes
A
Maturation Model
17
Q
digestive organelle
A
Lysosomes
18
Q
Spherical, with 0.05-0.5 μm diameter
Present a uniformly granular, electro-dense appearance in TEM
A
Lysosomes
19
Q
Lysosomes is a membrane-limited vesicles that contain about
A
40 hydrolytic enzymes
20
Q
Lysosomes has lysosomal enzymes that can be seen using
A
histochemical procedure
21
Q
Lysosomal enzymes synthesized in the rER (rough ER) and sorted in the golgi apparatus based on their binding ability to
A
M-6-P receptors (Mannose-6-Phosphate receptor)
22
Q
Most common are hydrolases:
A
PROTEASOMES, NUCLEASES, PHOSPHATASES, PHOSPHOLIPASES SULFATASE, BETA- GLUCURONIDASE
23
Q
Lysosomes have a unique membrane that is resistant to the hydrolytic digestion occurring in their _____
A
lumen
24
Q
Lysosomal membrane has unusual phospholipid structure that contains cholesterol and a unique lipid called
A
Lysobisphosphatidic acid
25
lysosome-associated membrane proteins (lamps), lysosomal membrane glycoproteins (Igps), and lysosomal integral membrane proteins (limps).
represent more than 50% of the total membrane of the proteins
Membrane proteins
26
Lysosomes and late endosomes contain _________ and __________ that transport the final products of digestion.
proton (H) pumps; transport proteins
27
proteins are synthesized in the rER and have specific lysosomal targeting signals.
lysosomal membrane
28
an agent used in the treatment and prevention of malaria, is a lysosomotropic agent that accumulates in the lysosomes. It raises the pH of the lysosomal content, thereby inactivating many lysosomal enzymes. (By raising pH)
Chloroquine
29
causative agent of Malaria
Plasmodium falciparum
30
The action of chloroquine on lysosomes accounts for its antimalarial activity; the drug concentrates in the acidic food vacuole of the malaria parasite (Major digestive organelle) and interferes with its digestive processes, eventually
killing the parasite
31
Three pathways of material delivery for intracellular digestion in lysosomes:
Extracellular large particles
Extracellular small particles
Intracellular particles
32
such as bacteria, cell debris, and other foreign matenals are engulfed in the process of phagocytosis
Extracellular large particles
33
phagocytosis occur through your
phagosomes
34
such as extracellular proteins, plasma-membrane proteins, and ligand- receptor complexes are internalized by pinocytosis and receptor-mediated endocytosis
Extracellular small particles
35
such as entire organelles, cytoplasmic proteins, and other cellular components are isolated from the cytoplasmic matrix by endoplasmic reticulum membranes, transported to lysosomes, and degraded- autophagy
Intracellular particles
36
Three well-characterized pathways of autophagy:
Macro- autophagy
Micro- autophagy
Chaperone- mediated autophagy
37
____________ is a nonspecific process
A portion of the cytoplasm or an entire organelle is first surrounded by the isolation membrane of endoplasmic reticulum, to form a vacuole called _____________which matures into lysosomes
Isolation membrane disintegrates within the hydrolytic compartment of a lysosome
Macroautophagy; autophagosomes
38
is also a nonspecific process
Cytoplasmic proteins are degraded in a slow, continuous process under normal physiologic conditions
Small cytoplasmic soluble proteins are internalized by invagination of the lysosomal membrane
Microautophagy
39
the action or process of being turned inside out or folded back on itself
invagination
40
is a selective process of protein degradation
This process is activated during nutrient deprivation and responsible for the degradation of approximately 30% of cytoplasmic proteins in organs such as the liver and kidney
Chaperone-mediated autophagy
41
Chaperone-mediated autophagy requires assistance from specific cytosolic chaperones such as heat-shock chaperone protein called
hsc73
42
Secondary lysosome) 0.2 - 2 UM
active organelles, are generally somewhat larger and have more heterogenous appearance in the TEM because of the wide variety of materials they may be digesting
Heterolysosomes
43
a debris-filled vacuole resulting from hydrolytic breakdown of the contents of lysosomes
Normal feature of cell aging
Can accumulate as lipofuscin (Lipid-containing residual of lysosomal digestion)
Residual body
44
Residual body is also known as
Telolysosomes
45
are cause by pathologic accumulation of undigested substrate in residual bodies due to absence of certain lysosomal enzymes
Lysosomal storage diseases
46
- lysosomal membrane mutation
Accumulation of autophagic vacuole
Danon disease
47
Lack of lysosomal acid lipase
lipid product will accumulate (ex. cholestera esters, TAG (Trigylcerol))
Wolman disease
48
absence of lipids
deficiency of Gluco-cerebrosidase
Gaucher disease
49
lipids accumulate in brain cells
B-Hexoaminodase A deficiency
Tay-Sachs disease
50
build up of harmful amount of lipids
B-hexoaminodase deficiency
Sandhoff disease
51
abnormal amount of lipids build up
Sphinomyelinase deficiency
Niemann-pick disease
52
absence of a-1-4 glucosidase
glycogen will aggravate
Pompe disease
53
no protein aspartoacylase
Canavan disease
54
lysosomal membrane problem
Accumulation of cysteine
Cystinosis
55
Break songs:
Bibingka
Leaves
Araw-araw
56
protein destruction
is used by cells to destroy abnormal proteins that are misfolded, denaturated, or contain abnormal amino acids
Proteasome-mediated degradation
57
It also degrades normal short-lived regulatory proteins that need to be rapidly inactivated and degraded such as mitotic cyclins that regulate cell-cycle progression, transcriptional factors, tumor suppressors, or tumor promoters
Proteasome-mediated degradation
58
Individual ubiquitin molecules are activated by:
E1 - ubiquitin activating enzymes
E2 - ubiquitin conjugating enzymes
E3 - ubiquitin protein-ligase enzymes
59
how many molecule of ubiquitin to gave a ubiquitin chain
4
60
occurs when Ubiquitin molecules are attached end-to-end to a single lysine residue on a substrate protein to form a poly-ubiquitin chain
Polyubiquitination
61
Malfunction of proteasome-mediated degradation:
- Loss of proteasome function because of mutations in the system of ubiquitin (once magkaroon ng ubiquitin) activating enzymes that leads to a decrease in protein degradation and their subsequent accumulation in the cell cytoplasm
- Accelerated degradation of proteins by overexpressed proteins involved in system
62
convoluted membranous network
Extends from the surface of the nucleus to the cell membrane
Rough Endoplasmic Reticulum
63
RER encloses a series of intercommunicating channels and sac, called _______
With the TEM, the rER appears as a series of interconnected, membrane-limited, flattened sacs membrane called ______ with particles studding the exterior surface of the
cisternae
64
Functions of RER
- synthesis and segregation of proteins not - -
- destined for the cytosol
- initial glycosilation of glycoproteins
- posttranslational modification of newly formed polypeptide
- assembly of multichain proteins
65
The protein synthetic system of the cell:
Rough Endoplasmic Reticulum
Ribosomes
66
The cytoplasm of a variety of cells engaged chiefly in protein synthesis are ________ due to presence of RNA
basophilic
67
The ________ in secretory cells is the light microscopic image of the organelle called the rough endoplasmic reticulum (ER)
ergastoplasm
68
portion of the cells that stains with basic dye
Ergastoplasm
69
Protein synthesis the two processes:
Transcription
Translation
70
production of proteins by the cell begins within the nucleus in which the genetic code for a protein is transcribed from DNA to pre-mRNA then to mRNA after post- transcriptional modifications
Transcription
71
in which the coded message contained in the mRNA is read by ribosomal complexes to form a polypeptide
Translation
72
many ribosomes are formed by binding of single cytoplasmic mRNA to many ribosomes
Polyribosome complex
73
can translate single mRNA
- Can produce many copies of protein
Attach to the cytoplasmic surface of rER
Polyribosome complex
74
Polyribosome complex is also known as
polysomes
75
renders the rER unable to export 1-antitrypsin (A1AT), a single amino acid substitution
This leads to decreased activity of A1AT in the blood and lungs and abnormal deposition of defective A1AT within the rER of liver hepatocytes, resulting in emphysema (COPD) and impaired liver function.
alpha-1-antitrypsin deficiency (A1AT)
76
Several types of ________ inhibit protein synthesis by binding to different portions of bacterial ribosomes
antibiotics
77
ex of aminoglycosides
(gentamicin, chloramphenicol, fusidic acid) (erythromycin, mutamycin)
78
non-membranous organelle
Site of protein synthesis which will be transmitted to Golgi complex for packaging and secretion out of the cell
Ribosomes
79
Svedberg unit of ribosomes
Prokaryotes = 30s - 50s = 70S
Eukaryotes = 40s - 60s = 80s
80
Ribosomes in cytosol has four segments of rRNA and approximately____ different proteins
80
81
have two subunits of different sizes and act to catalyze the process of protein translation
Bound to mRNA
82
ribosomes occupying a single mRNA
intensely basophilic, because of numerous phosphate group present
Polyribosomes
83
exhibits eosinophilia
lack bound polyribosomes
continuous with RER
Smooth Endoplasmic Reticulum
84
cisternae are often more tubular and appear as interconnected channels
not basophilic and best seen in TEM
Smooth Endoplasmic Reticulum
85
Smooth Endoplasmic Reticulum functions:
- glycogen and lipid metabolism
- detoxification reactions
- temporary Ca2+ sequestration
- phospholipid synthesis
86
very important in lipid metabolism and principle organelles for detoxification and conjugation of noxious organelles
Smooth Endoplasmic Reticulum
87
Because of these widely disparate functions, numerous other enzymes are associated with the SER, depending on its functional role including
hydrolases, methylases, glucose-6- phosphatase, ATPases, and lipid oxidases
88
cannot be stained using H & E staining (Hemotoxin and Eosin staining)
composed of smooth membranous saccules containing enzymes
Golgi Apparatus
89
Golgi apparatus is named after
Camillo Golgi
90
Camillo Golgi discovered Golgi Apparatus in
1898
91
Golgi Apparatus functions:
- Completes posttranslational
- modifications of proteins
- Packages and addresses proteins to proper destinations
92
small membrane-enclosed carriers where material from RER move to the Golgi apparatus
Transport vesicles
93
has a flattened cisternae located closes to RER
cis-golgi-network (cis face)
94
larger saccules or vacoules carry completed proten produce organelles away from the golgi
Shipping or trans face (trans-golgi-network)
95
complex coated transport vesicle
Cop II (co-protein II ) complex
96
undergo a series of post-translational modifications that involve remodeling of N-linked oligosaccharides previously added in the ER as they travel through the Golgi stacks
Proteins and lipids
97
middle of trans and cis face
medial-golgi-network
98
Membrane-enclosed organelles with arrays of enzymes specialized for aerobic respiration and production of ATP
are usually elongated structures with diameter of 0.5-1.0 um and length up to ten times greater
Mitochondria
99
Mitochondria is present in all cell Except in
RBC and terminal keratinocytes
100
A CELL WITHIN A CELL
Mitochondria
101
-has mitochondrial DNA that encode 13 enzymes
- has 2 rRNA and 22tRNA
- Complete system of protein synthesis
Mitochondria
102
Number of mitochondria is related to the cells energy need:
Cells with high energy metabolism have abundant mitochondria (cardiac cells, cells of some kidney tubules)
Cells with a low-energy metabolism have few mitochondria
Mitochondria of differentiated cells are concentrated in cytoplasmic region where energy utilization is more intense
103
Mitochondria possess two membranes that delineate distinct compartments:
Inner mitochondrial membrane
Outer mitochondrial membrane
104
surrounds a space called the matrix (may product: CO2, NADH)
Rich in cardiolipin
Inner mitochondrial membrane
105
- is in close contact with the cytoplasm
- Voltage dependent
- ion channel (channels that are large permeable)
Ex: Mitochondrial proteins
Outer mitochondrial membrane
106
intermembrane space contain ____________ that is essential for apoptosis
Cytochrome C
107
abnormal mitochondria, mutation of mitochondrial DNA
MERRF - Myoclonic Epilepsy with Ragged- Red Fibers
108
Microbodies (oxidative enzymes)
Membrane-enclosed organelles with arrays of enzymes specialized for aerobic respiration and production of ATP
are spherical organelles enclosed by a single membrane and named for their enzymes producing and degrading hydrogen peroxide, H2O2
Peroxisomes
109
removes hydrogen atoms that are transferred to molecular O₂ producing H₂O₂
Oxidases
110
breakdowns H₂O, which is potentially damaging to the cell
Catalase
111
Peroxisomes forms in two ways:
Building of the precursor vesicle from the ER
Growth and Division of pre-existing peroxisomes
112
Found in cells that store product until its release by exocytosis is signaled by metabolic. hormonal, or neural message
Surrounded by membrane and contain a concentrated form of secretory products
Secretory Granules
113
with dense content of digestive enzymes
Zygomen granules
114
Responsible for transport, storage, and secretion of digestive enzymes
Secretory granules
115
Polymeric structures composed of equal parts of alpha-tubulin and beta-tubulin
A structure that confer cell rigidity to help maintain cell shape
Can rapidly disassemble and reassemble
Microtubules
116
MICROTUBULES are fine tubular structures also organized into large arrays called ______ in the cilia and flagella
axoneme
117
Function of Microtubules
- Intracellular vesicular transport.
- Movement of cilia and flagella
- Attachment of chromosome to the mitotic spindle
- Cell elongation and movement
- Maintenance of cell shape
118
actin filaments
composed of actin allow cellular motility and most contractile activity in cells
Microfilaments
119
Microfilaments function:
- Anchorage and movement of membrane protein
- Formation of the structural core of microvilli
- Locomotion of cells
- Extension of cell processes
120
rope-like filaments, intermediate in size between microtubules and microfilament
Diameter: averaging 10 nm
Intermediate Filaments
121
present only in epithelial cells
KERATIN (I and II class)
122
found in most cells derived from mesenchyme
VIMENTIN (Class III (3))
123
present in cell body and processes of neurons
NEUROFILAMENT (Class IV (4))
124
form the nuclear lamina inside the nuclear envelope
LAMINS (Class V (5)
125
found in almost all muscle cells
DESMINS (Parts of neurofilaments
126
Glial Fibrillary Acidic Proeteins (GFAP), present in glial cells
GLIAL FILAMENTS(Class III (3))
127
Beaded filaments (Phakinin and Filensin)
Class 6
128
cid cytokeratin -> Epidermolysis bullosa
Basic -> keratoderma
Keratin
129
Desmin myopathy
GFAP (Glial Fibrillary ACidic Protein) - Amyotrophic lateral sclerosis
Kimentin
130
Charcot- Marie-Tooth Disease
Parkinson’s disease
Neurofilaments
131
Emery Dreifuss muscular dystrophy
Limb-girdle muscular dystrophy
Lamins
132
Juvenile onset cataracts
Phakinin (Beaded Fil)
133
Congenital cataracts
Filesin (beaded fil)
134
have little or no metabolic activity, but contain accumulated metabolites or other substances not enclosed by membrane
- Fat droplets
- Glycogen granules
- Lipofuscin
- Hemosiderin
Cytoplasmic Inclusions
135
The region of cells containing the centrioles in periventricular mat.
aka Centrosome
Microtubules Organizing Center
136
centrosphere or cell center
specialized zone of the cytoplasm containing the centrioles center of activity associated with cell division
Centrosome
137
called diplosome in nondividing cells
EM: hollow cylinder closed at one end and open at the other
Centrosome
138
self-duplicating organelles that exhibit continuity form one cell generation to another
Double in number immediately before cell division
Centriole
139
Prominent in mitosis
Essential for the formation of cilia and flagella
Serve as basal bodies and sites of epithelial cilia
Centriole
140
long, semi-rigid, helical, hollow tubular structures mostly composed of protein, FLAGELLIN
Show undulating wave type of movement
Flagella
141
Hair-like processes
Very numerous in:
- Epithelial cells of upper RT
- Parts of female and reproductive tracts
- Ependymal lining the cavities of the CNS
Cilia
142
contains a blueprint for all cell structures and activities encoded in the DNA of the chromosomes.
It also contains the molecular machinery to replicate its DNA and to synthesize an RNA
Nucleus
143
Components of the nucleus:
Nuclear envelope
Chromatin
Nucleolus
144
the disappearance of nuclei due to complete dissolution of DNA by increased activity of DNAsE
Karyolysis
145
condensation of chromatin leading to shrinkage of the nuclei (they appears as dense basophilic masses)
Pyknosis
146
fragmentations of nuclei
Karyorrhexis
147
Selectively permeable membrane that is seven times thicker than plasma membrane and perforated by nuclear pores
Nuclear Envelope
148
Nuclear Envelope has two eccentric membranes separated by perinuclear space
Outer Nuclear Membrane
Inner Nuclear Membrane
149
continuous with rER membrane. It has attached polyribosomes
Outer Nuclear Membrane
150
The inner nuclear membrane is supported by a rigid network of intermediate protein filaments attached to its inner surface called the
nuclear lamina
151
formed by intermediate filaments that lies adjacent to the inner nuclear membrane
nuclear (fibrous) lamina
152
contains specific lamin receptors and several lamina-associated proteins that bind to chromosomes and secure the attachment of the nuclear lamina
Nuclear Envelope
153
a composition of nuclear lamina
lamin
154
a family of lamina receptors
Emerin
155
mutation of emerin (X-linked)
associated with mutations in either lamins or lamin receptors.
characterized by early-onset contractures of major tendons, very slow progressive muscle weakness, muscle wasting in the upper and lower limbs, and cardiomyopathy (weakening of the heart muscle).
Emery-Dreifuss muscular dystrophy (EDMD)
156
mutation of lamin
Autosomal dominant EDMD
157
In nondividing cells, consists of the DNA and its attendant protein in a largely uncoiled state
In dividing cells, condensed and organized into discrete bodies called chromosomes
Chromatin
158
two types of chromatin:
HETEROCHROMATIN
EUCHROMATIN
159
EM: appear as coarse electron-dense material
LM: basophilic clumps
Heterochromatin
160
dense mass of heterochromatin found in females
Barr bodies
161
EM: finely dispersed granular material
LM: lightly stained basophilic areas
Euchromatin
162
The smallest units of chromatin structure are macromolecular complexes of DNA an called
Nucleosome
163
with much euchromatin and few heterochromatic clumps, more DNA surface is available for transcription
light stained nuclei
164
rich in highly condensed heterochromatin, tightly coiled DNA is less accessible for transcription
dark-stained nuclei
165
T/F; Cells with lightly stained nuclei are more active in protein synthesis
True
166
Each chromosome is formed by two chromatids that are joined together at a point called the
centromere
167
area located at each end of the chromosome
Shorten with each cell division; studies indicate that telomere length is an important indicator of the lifespan of the cell
Telomere
168
a spherical, highly basophilic sub domain of nuclei in cells, actively making proteins
It is a non-membranous region of the nucleus that surrounds transcriptionally active rRNA genes It is the primary site of ribosomal production and assembly.
Nucleolus
169
is the site of ribosomal RNA (rRNA) synthesis and initial ribosomal assembly
varies in size but is particularly well developed in cells active in protein synthesis
Nucleolus
170
The three morphologically distinct regions of nucleolus:
Fibullar Center
Fibullar Material
Granular Material
171
contain DNA loops of five different chromosomes (13, 14, 15, 21, and 22) that contain rRNA genes, RNA, Polymerase I, Transcription factors
Fibrillar Center
172
contain ribosomal genes that are actively undergoing transcription and large amounts of rRNA
Fibrillar material
173
represents the site of initial ribosomal assembly and contains densely packed preribosomal particles
Granular Material
174
Newly identified proteins in nucleolus
-> Nucleostemin
175
Cell division - Cell accumulation
In humans, as in all other multicellular organisms, the rates of cell proliferation and cell death determine the net cell production
Cell Death
176
disorders of cell accumulation
hyperplasia, cancer, autoimmune diseases
177
disorders of cell loss
atrophy, degenerative diseases, AIDS, ischemic injury
178
Two Major Mechanisms of Cell Death
Necrosis
Apoptosis
179
accidental cell death, is a pathologic process.
It occurs when cells are exposed to an unfavorable physical or chemical environment that causes acute cellular injury and damage to the plasma membrane
Necrosis
180
(Necrosis) Damage to the plasma membrane may also be initiated by viruses, or proteins called
perforins
181
Characteristic feature of Necrosis:
Rapid Cell Swelling and Lysis
182
[Gr., falling off, as petals from flowers] was referred to in the past as programmed cell death
Cellular suicide
Apoptosis
183
It is characterized by controlled Autodigestion
The cell "dies with dignity" without spilling its contents and damaging its neighbors
Apoptosis
184
Morphologic and Biochemical Features of Apoptosis:
DNA Fragmentation
Decrease in cell volume
Loss of mitochondrial function
Membrane blebbing
Formation of apoptotic bodies
185
an irreversible event that commits the cell to die.
a result of Ca2-dependent and Mg2-dependent activation of nuclear endonucleases
DNA Fragmentation
186
Achieved by shrinking of cytoplasm
cytoskeletal elements become reorganize ribosomes become clumped within the cytoplasm
rER forms a series of concentric whorls, and most of the endocytotic vesicles fuse with the plasma membrane
Decrease in cell volume
187
Where cytochrome activate the caspase dismantle
caused by changes in the permeability of the mitochondrial membrane channels
Loss of mitochondrial function
188
results from cell membrane alterations
Membrane blebbing
189
the final step of apoptosis, results in cell breakage
Formation of apoptotic bodies
