Histology - Cell biology Flashcards
1
Q
Where are ribosomes made?
A
Nucleolus
2
Q
Where are ribosomes found in the cell?
A
RER or free
3
Q
What is the fate of membrane-bound ribosomes?
A
Go to Golgi
4
Q
What do membrane-bound ribosomes produce?
A
(LSP)
- Lysosomal proteins
- Secreted proteins
- Plasma membrane proteins
5
Q
What is the fate of proteins synthesized on free ribosomes?
A
- Nuclear proteins
- Mitochondria
- Cytosol
- Perixosomes
6
Q
What is the role of the ER? Differentiate between SER & RER
A
Lipid (SER) & protein synthesis (RER)
7
Q
With what is the ER continuous?
A
Nuclear envelope
8
Q
Who plays a major role in detoxifying within the sER?
A
Cytochrome p450 of SER (example/ hepatocyte)
9
Q
What are the two faces of the Gogli Network?
A
Cis- entry
Trans- exit
10
Q
Secretory cells have an especially well developed __________________. Give 2 examples of cells with this.
A
Golgi apparatus
- Plasma cells (secrete Ab)
- Pancreatic acinar cells (secrete digestive enzymes)
11
Q
What are the functions of the Golgi apparatus?
A
- Post-translational modification
- Sorting
- Packaging
12
Q
What are common processes that occur in the Golgi network?
A
- PSG & P-
1. Glycoyslation
2. Sulfation
3. Phosphorylation
4. Proteolysis
13
Q
Who mediates bidirectional traffic between the ER & Golgi? What are two types?
A
Coatomer-coated vesicles
COP-I: Retrograde (back to rER)
COP-II: Anterograde (to Golgi)
14
Q
Neutrophil cytoplasm contains numerous vesicles. Another name for these vesicles is…
A
Granules
15
Q
What are the 3 types of granules found in neutrophils?
A
- Azurophilic (primary)
- Specific (secondary)
- Tertiary
16
Q
What are the components of the 3 types of granules found within neutrophils?
A
- Azurophilic - peroxidase (kill bacteria), defensins, lysozyme
- Specific - lysozyme, lactoferrin, complement activators
- Tertiary - phosphatases, metalloproteinases – facilitate naviagion
17
Q
T/F Lysosomes require an acidic environment
A
True (pH 4.7)
18
Q
Who are the digestive enzymes of the cell?
A
Lysososomes
19
Q
Give 2 examples of a lysosomal storage disorder.
A
- Tay-Sachs (accumulation of undigested substrate)
2. Pompei disease (glycogen-storage)
20
Q
Which receptor in the Golgi recognizes lysosomal proteins for transport to lysosomes?
A
Mannose-6-phosphate
21
Q
What are the 3 pathways to lysosomal digestion?
A
(A-E-P)
- Autophagy
- Endocytosis
- Phagocytosis
22
Q
Who destroys proteins without involving the lysosome?
A
Proteasome
23
Q
T/F Proteasomes require ATP
A
True
24
Q
Proteins targeted for destruction are covalently tagged by this molecule.
A
Ubiquitin
25
Destruction of abnormal proteins & short-lived regulatory proteins (i.e. cyclins, transcription factors, tumor suppressors) is done by this protein complex
Proteasome
26
What are 3 examples of cellular structures formed from metabolic products of the cell?
1. Glycogen
2. Lipids
3. Pigments
27
Give 3 examples of cellular-membrane bound pigments.
1. Lipofucsin
2. Hemosiderrin
3. Melanin
28
These cellular complexes would generally be used as anti-cancer drugs.
Proteasomes
29
When lipid droplets accumulate in abnormal amounts or locations, what happens?
Lipidoses (aka. lipid storage disease)
30
How many membranes do mitochondria have?
2
31
Give 2 examples of mitochondrial dysfunctional diseases.
1. MERRF
| 2. Leber hereditary optic neuropathy
32
Mitochondria were derived from aerobic bacteria that were engulfed by primitive eukaryotes. Is the DNA ss or ds; linear, circular; maternally or paternally derived?
DS; Circular; maternal
33
What are the 4 functional zones of a mitochondria?
1. Outer membrane - porins (free passage of small molecules), several enzymes, i.e. acetyl CoA synthase
2. Intermembrane space - creatine kinase, adenylate kinase, cytochrome c (intrinsic apoptosis pathway)
3. Inner membrane - oxidation reactions, sythesize ATP, regulate metabolite transport
4. Matrix - PDH, TCA, storage Ca, mitochondrial DNA, ribosomes & tRNAs
34
This factor (found in the mitochondria's intermembrane space) is an important factor in the intrinsic apoptosis pathway.
Cytochrome c
35
These small organelles are particularly important in fat metabolism.
Peroxisomes
36
Name 1 disease that results from a defective import of peroxisomal proteins
Zellweger Syndrome
37
The cytoskeleton is composed mainly of these 3 things.
1. Actin (microfilaments)
2. Intermediate filaments
3. Microtubules (tubulin)
38
What is the function of the cytoskeleton?
1. Maintain cell shape/support
2. Provide the mechanism for cell movement
3. Act as tracks for motor proteins that help move materials within the cell
39
Actin is a microfilament or microtubule.
Microfilament
40
What is the difference between G & F actin?
G-actin: free actin
| F-actin: ATP-dependent polymerized actin
41
T/F Actin is polarized
True
42
What is the function of actin?
Extension of cell processes, motility, anchorage
| * Structural core of microvilli & stereocilia
43
Among the following list, which are micofilaments & which are microtubules?
Actin, cilia, microvilli, stereocilia, flagella
Microfilaments:
Actin, Microvilli, Stereocilia
Microtubules:
Cilia, Flagella
44
Discuss the phalloidin toxin (A. phalloides).
Disrupts normal function of actin
- Promotes excessive polymerization and inhibits depolymerization
- Inhibits cell movement
45
Discuss cytochalasins.
A fungal product; Block polymerization of actin; can be used to inhibit cell movement, division & induce programmed cell death
46
Microvilli consist of microfilaments/microtubules. They terminate in a _________.
Microfilaments (25-30 actin); terminal web
47
T/F Sterocilia are long cilia.
False -- microvilli!
48
Where are stereocili distributed?
1. Epidiymis
2. Proximal ductus defererns
3. Sensory cells ear
49
Actin combines with __________ to form a molecular motor unit.
Myosin II
50
What are the 5 steps of the POWER STROKE?
1. Attachment
2. Release (ATP binds -- actin X myosin)
3. Bending (ATP hydrolysis) & conformational change
4. Force generation (POWER STROKE)
5. Reattachment (rigor)
51
T/F Intermediate filaments are polarized
False
52
What are the 6 classes of intermediate filaments?
1 & 2: Keratins (found in all epithelial cells)
3. Vimentin (most distributed; GFAP - astrocytes)
4. Neurofilaments (neurons)
5. Lamins (nuclear lamina)
6. Beaded filaments (lens)
53
Which structural component of cells form desmosomes & hemidesmosomes?
Intermediate filaments
54
What are centrioles?
9 triplets of microtubules arranged around a central axis
* Organizes the centrosome
* Basal body formation (cilia/flagella)
* Mitotic spindle formation
55
What are centrosomes?
MTOC (microtubule organizing center)
| * Contains a pair of centrioles
56
What are the functions of microtubules?
1. Intracellular transport [railroad tracks]
2. Cell motility
3. Mitotic spindle
4. Rigid intracellular skeleton
57
What does a microtubule consist of?
1. Non-branching, rigid, hollow tube
| 2. Alpha and beta tubulin
58
T/F Microtubules are polarized
True
59
T/F Microtubules are ATP dependent
False - GTP!
60
These microtubule associated proteins are associated with Alzheimer's disease
Tau proteins
61
T/F Actin requires ATP
True (microtubules require GTP)
62
Name 2 mitotic spindle poisons
Anti-cancer drugs
1. Colchicine -- prevents polymerization of tubulin-- related: vinblastine, vincristine
2. Taxol -- prevents microtubule disassembly
63
Microtubules consist of 2 families of proteins.
1. Kinesin family (- --> +)
| 2. Dyenin family (+ --> -)
64
T/F Cilia are composed of a 9+3 arrangement of microtubules
False: 9+2 (9 doublets, central doublet)
65
Cilia and flagella move by bending of the core. This core is referred to as:
Axoneme
66
The arrangement of microtubules in cilia is:
9+2
| * Pair of dyenin arms; move fluid and particles along epithelial surfaces
67
Non-motile cilia results in this disease
Kartenger's disease
68
Primary, non-motile ciliia, are arranged with microtubules in this fashion
9+0
69
Give 3 examples of primary cilia
1. Photoreceptors
2. Chemoreceptors
3. Mechanoreceptros
70
Defects in mechanoreceptors can lead to this disease.
PKD (polycistic kidney disease)
71
Plasma membrane protrusion is driven by
Actin polymerization
72
The movement of actin web is referred to as
Treadmilling (assembling at front, disassembling at back)
73
Describe the protein relationships:
Filopodia
Lamellipodia
Pseudopodia
Filopodia - Rho
Lamellipodia - Rac
Pseudopodia - Cdc42
74
Describe where we find these:
Filopodia
Lamellipodia
Pseudopodia
Filopodia - fibroblasts
Lamellipodia - fibroblasts, epi cells, neurons
Pseudopodia - neutrophils
75
Neutrophils migrate from the blood to the tissues through vessels. This is called
Extravasation
76
Migration of neutrophils across endothelium is called
Transmigration [the process of diapedesis]
77
Movement of leukocytes within tissue
Chemotaxis
78
Products of inflammation would promote the expression of these receptors on endothelial surfaces
Selectin receptors
79
Chemokines from injured cells induce the expression of ___________ on leukocytes & _____________ receptors on endothelial cells
Integrin
80
Microtubules grow at the plus/minus end by the polymerization of tubulin dimer
Plus
81
Kinesin move toward: +/-
| Dynein move toward +/-
Kinesin: +
Dynein: -
