Etc. Exam 2

Question 1

Intermediate filaments

Answer 1

Tensile strength due to rope-like property.
Give structure to the cytoplasm.
Form the nuclear lamina.
Can be further stabilized by accessory proteins.

Question 2

Cytoplasmic (3) and Nuclear (1) intermediate filaments

Answer 2

Cytoplasmic:
Keratin (epithelial cells)
Vimentin (CT, muscle, glia)
Neurofilaments (nerve cells)
Nuclear:
Nuclear lamina.

Question 3

Microtubules

Answer 3

Organization main role.
Rapid assembly/disassembly.
Extend from centrosome to periphery to form tracks for vesicles, organelles, etc.
Form mitotic spindle, cilia, flagella.

Question 4

+ and - end of microtubules

Answer 4

+ grows faster

- nucleating site

Question 5

Drugs affecting microtubules and their affect (3)

Answer 5

Taxol: binds and stabilizes microtubules.

Colchicine and Vinblastin: bind tubulin dimers and prevent polymerization.

Question 6

Microfilaments

Answer 6

Acting filaments.
In all cells.
Unstable.
Essesntial for cell movement.

Question 7

Drugs affecting actin filaments (3)

Answer 7

Phalloidin: binds and stabilizes filaments.
Cytochalasin: Caps filament plus ends, stopping poymerization.
Latrunculin: Binds monomers and prevents polymerization.

Question 8

ECM and basal lamina (3)

Answer 8

1. Their components produced intracellularly and secreted and aggregate.
2. Interacts with cels/tissues via transmembrane proteins.
3. Composition and properties controlled and vary depending on location.

Question 9

Collagen (3)

Answer 9

1. Main structural protein in ECM/connective tissues/basal lamina.
2. Trimeric protein and form triple helix.
3. Can associate as fibers, sheets or transmembrane structures.

Question 10

Synthesis of collagen (4)

Answer 10

1. RER: procollagen synthesized, secreted into lumen of ER.
2. Hydroxylation and glycosylation occurs in lumen.
3. Self-assembly of tropocollagen and synthesis of triple helix in lumen of ER and golgi.
4. Procollagen secreted from cell and is cleaved to become collagen in ECM.

Question 11

Cell junctions/connections (4) AOCS

Answer 11

Anchored: cells anchored to each other and ECM. Strcuture main role.
Occulding: seals the space between cells of an epithelium in such a way that it creates a barrier.
Channel-forming: allow passage of molecules.
Signal-relayaing: relay a message (action potential).

Question 12

Cadherins

Answer 12

Ca2+ dependent adhesion molecule.
Important in forming junction between cells.
Homophilic interactions.
Interacts with actin.
(E, N, VE, LI cadherins)

Question 13

Ig Superfamily

Answer 13

Ca2+ independent transmembrane glycoproteins.
Immune cell intercations.
Homo and heterophilic binding.
Involved in recognition, binding, or adhesion processes of cells.

Question 14

EMT and Cadherin switching

Answer 14

Epithelia to Mesenchymal Transition.
Increase in N cadherin and decrease in E cahderin.
Increased invasiveness of tumor and metastatic potential.

Question 15

Selectins

Answer 15

Ca2+ dependent glycoprotein.
Binds to EC carbs.
Low affinity for WBC allows to slow them (rolling affect).
E, L, P selectins.

Question 16

Integrins

Answer 16

Couple ECM to cytoskeleton.
Can activate signaling pathways (RTKs, regulating cell growth, etc.)
Adhere to WBCs via B2 family to aid in transmigration.

Question 17

Laminin

Answer 17

Fibrous protein in basal lamina. Cell attachment, differentiation, movement, etc.

Question 18

Fibronectin

Answer 18

Aids in blood clots. Has adhesion, growth,migration and differentiation roles as well.

Question 19

Elastin

Answer 19

Allows tissues to resume shaped.

Question 20

Proteoglycans

Answer 20

“Filler”. Large size facilitates movement of thins through the ECM.

Question 21

Transit amplifying cells

Answer 21

Cells that are committed to become a certain tissue type. They divide often and “transit” from stem cellto differentiated cell.

Question 22

Immortal strand hypothesis

Answer 22

Some cells selectively retain original DNA. Original strand of DNA is preserved in stem cells from generation to generation. Helps to prevent genetic errors.

Question 23

Cord blood

Answer 23

Undifferentiated blood from placenta. Kept as a source of hematopoetic stem cells.

Question 24

Hematopoetic stem cells

Answer 24

Blood components (RBC, WBC, platelets).

Question 25

Mesenchymal stem cells

Answer 25

Found in bone marrow, fat, tooth pulp.

Question 26

iPS overview

Answer 26

Introduce TFs to adult differentiated cell to make it have pluripotent properties.. These cells are not patient specific, but have an increased risk for teratoma.

Question 27

SCNT overview

Answer 27

Remove nucleus from egg. Add pt’s nucleus from differentiated cell. Allow blastulation to occur and remove inner cell mass, which has pluripotent cells.
High risk for ethical problems.

Question 28

Components and volumes of hematocrit

Answer 28

Plasma: 55%
Buffy coat (WBCs and platelets): 1%
RBCs: 45%

Question 29

Functions of Albumin

Answer 29

Responsible for exerting concentration gradient between RBC and EC tissue fluid.
Source of colloid osmotic pressure.
Carries thryoxine, bilirubin and barbiturates.

Question 30

Plasma proteins

Answer 30

Albumins
Globulins (immuno and non immuno)
Fibrinogen

Question 31

Erythrocyte cytoskeleton (5)

Answer 31

Glycophorin C: attaches cytoskeleton to CM.
Band 3: binds Hb and anchors cytoskeleton proteins (most abundant)
Spectrin: form lattics.
Band 4.1: interacts with glycophorin 4.1.
Ankyrin: interacts with band 3.

Question 32

Neutorphils basics

Answer 32

Multi-lobed nucleus.

Fxn in acute injury/inflammation and bacterial infections.

Question 33

Eosinophils basics

Answer 33

Bi-lobed nuclei.
Secrete arylsulfatase and histaminase.
Increased counts with allergies and parasitic infection and chronic inflammation.

Question 34

Basophils basics

Answer 34

Hard to see nucleus.
Related to mast cells.
Responsible for problems associated with hypersensitivity and anaphylaxis.

Question 35

T and B cells basics

Answer 35

Large nucleus. Cannot differentiate.

Question 36

Monocytes basics

Answer 36

Heart-shaped nucleus.

Differentiate into phagocytes and macrophages in tissues.