Exam 1: Cell Flashcards
1
Q
3 Cellular consituents
A
Organelles
Inclusions
Cytoplasmic matrix (cytosol)
2
Q
Cytoplasm
A
part of cell external to nucleus
suspends organelles and inclusions
3
Q
Cytoplasmic matrix (cytosol)
A
cytoplasm devoid of organelles and inclusions
4
Q
Inclusions
A
nonliving entities found in cytoplasm and nucleus
Stored food, pigments, and crystalline not bound by membrane
5
Q
Stored foods
A
Glycogen - abundent in liver and skeletal and cardiac muscle cells
Lipid droplets - found in adipocytes, hepatocytes, muscle, and steroid secreting cells
6
Q
Glycogen demonstrated by
A
PAS reaction
7
Q
McArdle disease
A
genetic defect in skeletal muscle phosphorylase
Accumulations of glycogen under sarcolemma
Cramping, exercise intolerance, elevated myoglobin, creatine kinase elevated, venous lactate level does not increase with exercise
8
Q
Exogenous Pigments
A
Carotene - yellow orange color
Carbon particles
Tattoo pigments - stored in macrophages of dermis
9
Q
Anthracosis
A
accumulation of carbon particles in lungs and regional lymph nodes
Harmless
10
Q
Endogenous pigments
A
Hemoglobin - cyanosis and myoglobin Hemosiderin Bilirubin Melanin Lipofuscin
11
Q
Hemosiderin
A
Iron containing pigment
brown
spleen & liver
Hemosiderosis & Hemochromatosis - accumulation of iron
12
Q
Melanin
A
Eumelanin - brown/black found in epidermis
Neuromelanin - found in neurons - substantia nigra
Parkinson’s disease depigmentation
Phaemelanin - red pigment of skin/hair
13
Q
Plasmalemma (plasma membrane)
A
separates internal and external environment lipid bilayer (contains phospholipids, glycolipids, cholesterol) Cholesterol strengthens bilayer
14
Q
Lipid rafts
A
areas in membrane where sphingolipids and cholesterol concentrated
Thicker
involved in cell signaling
15
Q
simvastatin
A
cholesterol inhibitor that induces apoptosis by reduction in raft formation
down regulates cell survival signaling molecule, Akt
16
Q
Integral proteins
A
some partially embedded, other extend across entire plasma membrane
17
Q
Creutzfeldt-Jakob disease
A
normal prion protein is converted to abnormal variant.
Forms cross-linked filaments - resistant to proteolysis
18
Q
Functions of proteins
A
Receptors, transporters, enzymatic control of chemical rxns, linker protein for structural support, cellular identification tags, anchor cell to extracellular matrix, intercellular junctional complexes
19
Q
Carrier transport proteins
A
transport one or more chemicals in one direction or two chemicals in opposite direction without direct expenditure of energy
20
Q
Pump transport proteins
A
require direct expenditure of energy
21
Q
Na/K pump
A
cleaves ATP to transport 3 Na ions out of cell and 2 K ions into cell
regulate intracellular volume
22
Q
Digoxin
A
partially inhibits Na/K pump
decrease in Ca/Na transporter = increase in sarcoplasmic Ca ion concentrations - improves cardiac pump performance
23
Q
Na/K pump and cotransport of glucose and Na
A
secondary active transport
Na and glucose enter cell as Na moves down its concentration gradient
To maintain gradient Na is pumped out of cell by Na/K pump
24
Q
Multidrug resistant transporters
A
primary transporter proteins that are ATPases
MDR-1 expressed in kidney, intestine, liver, and blood-brain barrier - Transports drugs
Overexpression can cause cancer cells to become resistant to cytotoxic drugs
MDR-2 transports conjugated bilirubin
MDR-3 expressed in liver, flippase of phosphatidylcholine
25
Pores
Aquaporins - channels for water
26
Vesopressin
causes translocation of aquaporin receptors to plasma membrane of collecting tubule cells
27
Dystrophin
provides structural ingetrigy
link plasma membrane to underlying cytoskeleton
brown ring
28
Role of carbohydrates in membrane
attach to lipids and proteins forming glycolipids and glycoproteins, net negative charge repels other negatively charged substances, react with regulatory molecules, play role in cell to cell and cell to matrix recognition, protection
29
Glycolipids
exclusively on noncytosolic lipid monolayer
30
Endocytosis
transport into cell
| energy ATP and Ca required
31
Macropinocytosis
Actin-based, nonspecific ingestion
| occurs in thyroid cells as they take up thyroglobulin and dendritic cells for immune surveillance
32
Clathrin-mediated endocytosis
occurs in clathrin coated pits
Dynamin (GTPase) is required to pinch of vesicle
receptor mediated - cholesterol, protein hormones
33
Phagocytosis
```
ingestion of large particles (cell eating)
mediated by receptors
dependent on actin
Phagosomes
fuse with lysosomes
```
34
Exocytosis (bulk secretion)
secretion of cellular synthetic products with secretory vesicles
35
Secretory vesicles
formed in Golgi complex
fuse with plasma membrane
intracellular trafficking orchestrated by COPs
36
Consitutive exocytosis
continuous secretory process
| secretory product not stored in secretory granules
37
Regulated exocytosis
secretory product stored in secretory vesicles until signal causes product to be secreted
38
Porocytosis
quantal release of neurotransmitters
39
Ribosome
basophilic
small electron dense particles
subunits exported from nucleus to cytoplasm where assemeble when actively synthesizing proteins
40
Polyribosomes free in cytoplasm
create proteins to be used in cell
41
Polyriosomes attached to endoplasmic reticulum
create proteins to be secreted
42
rER
membranous organelle, basophilic
| continuous with outer membrane of nuclear envelope
43
ER stress
accumulation of unfolded/misfolded proteins in ER cisterna
Chaperone synthesis increases, decreased protein synthesis, caspases activated, misfolded proteins tagged for degradation
44
Targeting signals
sequences of amino acids in protein
| direct proteins to their target compartments by binding to receptors specific for the organelles
45
sER
```
lacks polyribosomes
acidophilic
continuous with rER
Cisternae more tubular
Cholesterol homeostasis, steroid synthesis, phospholipid synthesis, detoxification of drugs, storage & release of Ca in muscle
```
46
van Gierke disease
defect in glucose 6 phosphatase or transporter; sER unable to transport glycogen - glycogen accumulation in cytoplasm and nucleus
liver enlargement, hypoglycemia, increased lactate
47
Cholera toxin gains entry into the cell by using
a glycolipid
48
Non-coated mediated endocytosis
Cholera and Shiga toxins
49
Caveolae mediated endocytosis
Simian virus 40
50
cytochrome p450 and alcohol detoxification takes place in
sER
51
Synthesis of phospholipids occurs in the lipid monolayer in the
sER and rER
52
Alastin
involved in shaping the ER
| Deficiency leads to fragmented ER & spastic paraplegia
53
Spastic paraplegia caused by
deficienty in atlastin (ER fragmented)
| stiff leg & gait disturbances
54
Proteasomes
large complex protease
| Proteolysis of regulating proteins, damaged proteins, and antigenic proteins (initiate immune response)
55
Proteasomes are dependent on
ubiquitin for degredation
56
Abnormal prion proteins inhibit
proteasomes
57
Defective ubiquination of proteins is implicated in
Parkinson's disease, as well as a form of cystic fibrosis
58
Bortezomib
partially inhibits proteasomes
| effective against multiple myeloma - promotes apoptosis of cancer cells
59
Golgi apparatus
Functions as major sorting and distribution center
| Proteins packaged into vesicles and moved throughout cell
60
Golgi apparatus lies between
nucleus and apical cytoplasm
61
Negative Golgi image
Found in active protein secreting cells
Pale staining of cytoplasm that may be seen in H and E staining
Does not contain ribosomes
62
Cis, convex, forming face Golgi
face presents towards transitional ER where transport vesicles forming
Transport vesicles carry newly synthesized proteins from ER to Golgi
63
Trans, concave maturing face Golgi
face opposite of cis
| Forms secretory granules (vesicles)
64
Wilson's disease
mutation in protein pump for copper in trans-Golgi network of liver cells
65
Membrane protein-transporting vesicles containing dysferlin
repair microperforations formed in skeletal muscle plasma membranes
Patching is calcium dependent
66
Mutations in dysferlin
muscular dystrophy
67
Proinsulinemia
mutated proinsulin missorted into unregulated pathway without prohormone enzyme
Absence of prohormone converting enzyme activity in unregulated pathway
68
Endosomes
sorting and identifying molecules for recycling or degradation by lysosomes
early, recycling, multivescular, and late
69
Early and recycling endosomes
cell periphery
| pH 6.2 to 6.5
70
Multivesicular bodies
```
located between early and late endosomes
pH 5 - 6.2
large amounts of membrane and vesicles
fuse with late endosomes
Secretory role
```
71
Late endosomes
located near nucleus
fuse with lysosomes
pH 5
72
achondroplasia
FGFR3 is recycled instead of degraded, amplifying FGF signaling
abnormal bone growth leads to dwarfism
73
Lysosomes
acidophilic
| enzymes able to digest most biologic molecules
74
Autophagolysosome (secondary lysosome)
primary lysosome + autophagosome
Macroautophagy - send structures to lysosome
Microautophagy - eliminates proteins and smaller molecules
Chaperone mediated direct transport
75
Heterophagolysosome (secondary lysosome)
primary lysosome + heterophagosome
76
Secondary lysosomes
are heterogeneous at EM level (light and dark regions)
77
Type II Pompe's disease
Glycogen accumulation in lysosome
| alpha-1,4-Glucosidase deficiency
78
Clathrin
used in endocytosis and at Golgi to create secretory vesicles
79
COPII
anterograde transport from ER to cis Golgi network
80
COPI
retrograde transport from cis Golgi network to ER
| needed to return membrane, vSNARE proteins, and missorted ER proteins back to ER
81
SNARE proteins
allow vesicle to recognize its target domain and dock
vesicle SNARES - on vesicle
Target SNARES on target membrane
82
Neurotoxins of tetanus and botulism
enter nerve terminals and proteolyse SNARE proteins
prevent neurotransmitter vesicles from docking with nerve cell membrane and releasing neurotransmitter
Braking effect on motoneurons = paralysis
83
Mitochondria
Acidophilic
Pleomorphic - change shape
Located in areas of high metabolic activity - increase in skeletal and cardiac muscle
84
Outer mitochondrial membrane
permeable
large channel forming proteins (porins)
Translocator protein
85
Inner mitochondrial membrane
selectively permeable
high concentration of phospholipid cardiolipin
enzymes for ETS
86
Tubular Cristae
steroid-secreting cells
| synthesize steroid hormones
87
Cristae in cardiac and muscle cells
shelf like
88
Mitochondrial matrix contains
Enzymes of Kreb cycle
Enzymes for fatty acid beta oxidation
Matrix granules
89
Mutations in mitochondrial DNA are implicated in
diabetes, deafness, heart disease, Alzheimers, Parkinson, LHON
90
MERRF (myoclonic epilepsy with ragged red bifers)
red appearing mitochondria seen with Gomori trichrome stain
at EM - parking lot inclusions
myoclonus, seizures, ataxia
91
Peroxisomes
contain oxidative enzymes
enzymatically forms water and oxygen from hydrogen peroxide
enzymes for beta-oxidation of fatty acids
ingested ethanol oxidation
synthesis of plasmalogens
92
Zellweger syndrome
peroxisomal enzymes not transported into peroxisome - defective import protein on unit membrane of peroxisome
93
Import of peroxisomal proteins
Enzymes formed by free polyribosomes in cytoplasm, then transported into organelle
Phospholipid exchange proteins move phospholipids from ER membrane to peroxisomal membrane
94
Antilipidemics
increased uptake of triglycerides and cholesterol by hepatic cells
Ramps up beta oxidation of fatty acids by mitochondria nd peroxisomes - peroxisomes increase in number
95
Defects in synthesis of plasmalogens lead to
abnormalities in myelination of nerve cells
96
Cytoskeleton
made of microtubules, microfilaments, thick filaments, & intermediate filaments
97
Microtubules
13 longitudinally arranged protofilaments made of tubulin dimers
98
Colchicine, vinblastine, and vincristine
inhibit polymerization of microtubules
99
Taxol
inhibits depolymerization of microtubules
100
Microtubules function to
support cytoplasm and organelle, cell division, motility of cilia and flagella, long-range transport of vesicles
101
Kinesin
transport vesicles toward periphery (negative to positive)
102
Defect in kinesin
decrease in transport of serotonin receptors - development of anxiety disorders
103
Dynein
transport vesicles toward nucleus (positive to negative)
104
Microtubule-associated proteins (MAPS)
stabilize microtubules
105
Alzheimer's results from
hyperphosphorylation of tau - leads to tangles
106
Microfilaments
comprised of actin;
| structural support, core of microvilli and stereocilia, movement, cytokinesis, formation of filopodia
107
Cytochalasin B
prevents polymerization of actin - affects microfilaments
108
Thick filaments
comprised of protein myosin;
| mutation in gene coding for mysoin causes severe form of cardiomyopathy
109
Intermediate filaments
Cytokeratin, Desmin, Vimentin, Neurofilaments, Glial fibrillary acidic protiens, Nuclear lamins
110
Cytokeratin
in epithelial cells
forms tonofilaments
Mallory bodies - characteristic of alocholic liver disease
Epidermolysis bullosa simplex - skin becomes fragile and damaged
111
Desmin
found in striated muscle and nonvascular smooth muscle
| mutations involve cardiac and skeletal myopathies
112
Vimentin
fibroblasts and chondroblasts
113
Neurofilaments
most nerve cells, mutations associated with neuropathies
114
Glial fibrillary acidic proteins (GFAP)
```
astrocytes
Alexander disease (degenerative disease of brain white matter), astrocytomas, chronic gliosis have aggregates of GFAP
```
115
Function of Intermediate Filaments
structural support
116
Centrosome
Microtubule-organizing Center (MTOC)
Specialized region near nucleus containing two centrioles
conductor of microtubule
117
Centrioles
perpendicular to one another
microtubules arranged in 9x3
form mitotic spindle
118
Nucleus
one per cell usually
Basophilic
Nuclear envelope, nuclear matrix, chromatin, nuclear bodies
119
Cajal bodies
modifying and assembling molecules needed to splice pre-mRNA into mRNA
include snRNA, snoRNA, snRNPs
120
Spinal muscular atrophy
muscle wasting
defective SMN protein localized to GEMS (resemble Cajal bodies)
death of motor neurons in gray horns of spinal cord
121
Interchromatin granule clusters (speckles)
storage depots of snRNAs and proteins
| can become engaged in pre-mRNA splicing
122
Promyelocytic leukemia (PML) bodies
modify and assembeling proteins involved in DNA repair and triggering apoptosis
123
Nuclear (fibrous) lamina
support inner membrane
Disassembly of nuclear envelope during prometaphase - lamins phosphorylated
Reassembly of nuclear envelope during telophase - lamins dephosphorylated
124
Heterochromatin
coiled
transcriptionally inactive
Barr body - inactiated X chromosome in female
125
Euchromatin
uncoiled
| Synthetically active
126
Nucleolus
not membrane bound
rich in rRNA and protein
3 components: Nucleolar-organizer DNA, Pars fibrosa, Pars granulosa
127
Nucleolar-organizer DNA
contains sequence of bases that code for transcription of rRNA
128
Pars fibrosa
Newly transcribed rRNA just beginning to become complexed with proteins
129
Pars granulosa
Maturing subunits of ribosomes
130
G1 (interphase)
replication of centrioles begins
Checkpoints for G1 DNA-damage
Restriction - point of no return
131
S (synthesis) of interphase
DNA synthesis can occur
| S DNA damage checkpoint
132
G2 (interphase)
```
accumulate ATP for mitosis
synthesis of tubulin to form microtubules
centriole replication complete
Checkpoints:
Unreplicated DNA
G2 DNA damage
```
133
G0
nondividing cells
| Striated muscle, most neurons
134
Prophase
chromatids condensed
| centriolar pairs migrate to opposite ends of cell
135
Prometaphase
nuclear envelope starts to disappear
136
Metaphase
chromatids line up at equator of cell
| Colchicine will arrest dividing cells at metaphase
137
Anaphase
chromatids separate
138
Telophase
nuclear envelope reforms
139
M phase checkpoints
Spindle assembly
| chromosome segregation
140
Telomerase
maintains length of telomere sustaining capacity of cell to divide - expressed in most tumor cells & germinal cells
141
Apoptosis
programmed cell death
| Phosphatidylserine - translocated to extracellular monolayer - marks cell as dead
142
Extrinsic pathway
Fas ligand and Fas receptor
Adaptor protein
caspase-8
143
Intrinsic pathway
cell injury causes release of cytochrome c
| activated caspase-9
144
FasL counterattack
tumor cells evade immune attack by expressing FasL - destroy immune cells by triggering their elimination via apoptosis
145
Estrogen
anti-apoptotic effect on osteoblasts
