Cytoskeleton

Question 1

Why do anti-cancer drugs target the cytoskeleton?

Answer 1

Because it hampers their cell division

Question 2

What are microtubules comprised of?

Answer 2

Rigid, hollow cylinders of tubulin

Question 3

What are microfilaments comprised of?

Answer 3

Flexible, contractile filaments of actin

Question 4

Which cytoskeleton component is involved in organelle motility, chromosome separation, and cilia/flagella?

Answer 4

Microtubules

Question 5

What cytoskeleton component is involved in muscle contraction and cell migration?

Answer 5

actin

Question 6

What do microtubules require to form?

Answer 6

GTP

Question 7

Which end of a microtubule binds GTP and promotes polymeriztion.

Answer 7

+ end

Question 8

Which end of a microtubule associates with the centrosome?

Answer 8

• end

It can embed within the centrosome

Question 9

What drives transport along microtubules?

Answer 9

motor proteins

Question 10

Which motor protein moves organelles toward the plus end of a microtublue? Away?

Answer 10

Kinesisns – towards plus end

Dyneins – towards minus end

Question 11

What energy source does actin require to form?

Answer 11

ATP bound to G-actin

Question 12

Which cytoskeleton filament has continual turnover but no net change in length?

Answer 12

Actin

Question 13

What are stress fibers?

Answer 13

Actin bundles along basal cell surface that stabilize integrin adhesions.
Provide scaffold for intracellular signal transduction.

Question 14

What are adhesion belts?

Answer 14

Circumferential acitn near apical cell surface that stabilize cadherin-mediated adherens junctions

Question 15

What is an erythrocyte?

Answer 15

Red Blood Cell

Question 16

What is the cytoskeleton protein that lines the intracellular side of the plasma membrane and gives the cell shape, elasticity and flexibility?

Answer 16

Spectrin

Question 17

Spectrin is most prominent in what type of cell?

Answer 17

Erythrocytes

Sickle cell is a modification of spectrin skeleton

Question 18

What are epithelial cell intermediate filaments called?

Answer 18

cytokeratins

Question 19

What are the two types of cytokeratins?

Answer 19

Type 1 (acidic polypeptides)
Type 2 (neutral to basic polypeptides)

Question 20

What is Vimentin?

Answer 20

Type 3 intermediate filament found in mesenchymal, endothelial and leudocytes. Useful maker of dedifferentiation of invasive cancer carcinomas.

Question 21

What is carcinoma?

Answer 21

Cancer that develops from epithelial cells

Question 22

Desmin

Answer 22

Type three intermediate filament in skeletal muscle Z disk and smooth muscle

Question 23

Where are type 4 intermediate filaments (neurofilaments) found?

Answer 23

Axons and dendrites

Question 24

Where does ATP generation happen in mitochondria?

Answer 24

Along the membranes of the cristae (electron transport chain).

Question 25

What do mitochondrial porins do?

Answer 25

They are integral outer membrane proteins that form channels allowing molecules to pass from the cytoplasm to the intermembrane space.

Question 26

How do condensed mitochondria form?

Answer 26

An uncoupling of oxidation from phosphorylation.

Question 27

Why are condensed mitochondria found in brown fat?

Answer 27

Because they produce a lot of heat rather than ATP

Question 28

Mitochondria contain their own _______ but most _______ are encoded in the cell nucleus and transported into the organelle.

Answer 28

DNA, ribosomes, protein synthetic machinery | proteins

Question 29

What part of the body is a mitochondrial defect most likely to affecct?

Answer 29

Muscules and the nervous system because they use the most energy.

Question 30

What is the primary site for noncytosolic protein synthesis?

Answer 30

Rough ER

Question 31

What is the interior of ER called?

Answer 31

Lumen or cisterna

Question 32

What color does rER stain in H and E?

Answer 32

basophilic

Question 33

Where are phospholipids for new membranes produced?

Answer 33

cytosolic half of ER

Question 34

Cells that make _____ have a lot of smooth ER?

Answer 34

Steroid hormones

Question 35

What organelle is involved in drug detoxification?

Answer 35

Smooth ER

Question 36

Drugs that affect the ______ can cause a proliferation of smooth ER.

Answer 36

Liver

Question 37

Where is cholesterol produced in the cell?

Answer 37

ER

Question 38

What is a negative Golgi?

Answer 38

When the golgi doesn't take up the stain very well and appears as a translucent area in the cell.

Question 39

What organelle modifies the sugars on proteins before they are secreted?

Answer 39

Golgi appartus | "Assembles proteoglycans"

Question 40

What sugar does the golgi add to proteins that are targeted for lysosomes?

Answer 40

Mannose-6-phosphate

Question 41

Where are peroxisomes primarily found?

Answer 41

Liver

Question 42

What are the primary functions of the enzymes contained in peroxisomes?

Answer 42

Beta oxidation of long chain fatty acids Detoxification of substances like ethanol Also involved in bile acid synthesis in liver

Question 43

HMG-CoA reductase, a peroxisome enzyme, is involved in cholesterol synthesis. What drugs target and competitively inhibit this enzyme to lower cholesterol production?

Answer 43

Statins

Question 44

Name this syndrome. No peroxisomes so long chain fatty acids accumulate in tissue. Lethal within 1st decade of life Peroxisomal enzymes are not transported to the organelle so the peroxisome remains empty.

Answer 44

Zellweger syndrome

Question 45

The motor protein clathrin is found on the coating of vesicles and mediates transport of vesicles from where?

Answer 45

From the trans-golgi network and from the plasma membrane

Question 46

Coatprotein (COP) coated vesicles transport between where?

Answer 46

The rER and Golgi and the various Golgi stacks.

Question 47

What are the primary and secondary functions of lysosomes?

Answer 47

Primary -- storage | Secondary -- engaged in degradative process

Question 48

Tubulovesicular structures formed by endocytosis from plasma membrane. Usually fuse with lysosomes.

Answer 48

Endosomes

Question 49

Cell drinking via small vesicles

Answer 49

Pinocytosis

Question 50

In what organ are there a lot of pinocytotic vesicles?

Answer 50

Kidney, esspecially the proximal tuble

Question 51

What is the cholesterol binding protein that coats caveolae in clathrin independent endocytosis?

Answer 51

Caveolin

Question 52

Small vesicles secreted by cells

Answer 52

exosomes

Question 53

What lysosomal storage disease involves a deficiency in hexosaminidase and results in an accumulation of glycolipids in the nervous system?

Answer 53

Tay-Sachs Disease

Question 54

What is Gauchers syndrome?

Answer 54

A lysosomal storage disease that involves defective glucocerebrosidase- Glucocerebrosides accumulate in CNS and spleen.

Question 55

What are the 4 most common lysosomal storage diseases?

Answer 55

Tay-Sachs, Hurler's syndrome, Gauchers syndrome, neiman-pick disease

Question 56

What are some symptoms of Lysosomal storage diseases?

Answer 56

``` Unusual facial features Cloudy eyes Bluish skin rash Abdomen protrusions Short stature, skeletal deformities Muscle weakness/lack of control ```