Kartagener Syndrome (Cytoskeleton)

Question 1

These are small bead-like sub units that make up Actin

Answer 1

What are “G-actin” monomers assembled into a helical polymer called “F-actin”

Question 2

Can have a growing (+) and shrinking (-) end: Which end happens when ATP binds to G-actin and which end happens after hydrolysis to ADP?

Answer 2

+ is when ATP binds to G-actin

- is after hydrolysis to ADP

Question 3

What percentage of muscle cell protein is made up of actin?

Answer 3

10% of muscles cells and 1-5% of total protein in non-muscle cells

Question 4

Myosin is really nothing more than assembled …. ?

Answer 4

Protein motors

Question 5

T or F: Myosin is an enzyme?

Answer 5

TRUE!!! The head region is the enzyme part; can “walk” on actin by hydrolyzing ATP … thus, also considered protein motors

Question 6

ATP is used in two ways w/ the myosin head. What are they?

Answer 6

ATP is used to change its conformation, and to set up a “power stroke”

Question 7

What is it called when Myosin head is bound to Actin?

Answer 7

Rigor Complex

Question 8

What is the ultimate control of contraction?

Answer 8

temporarily opening Ca++ channels

Question 9

Which type of receptor releases Ca++ from SER?

Answer 9

Ryanodine receptor (voltage-gated ion channel)

Question 10

T of F: Myosin can bind to actin when tropomyosin is covering binding site?

Answer 10

True. But it cannot slide on actin until Ca++ is released

Question 11

Actin and myosin are also in non-muscle cells. Give some examples.

Answer 11

• Contractile ring forming a cleavage furrow to complete telophase
• Interior of microvilli
• attach cytoskeleton to plasma membrane at anchoring points

Question 12

Which transmembrane linker anchors to another cell? to an ECM protein?

Answer 12

Cadherin = to another cell
Integrin = to an ECM protein

Question 13

All intermediate microfilaments play a functional or structural role?
Actin and myosin play a functional or structural role?

Answer 13

Intermediate = structural role

Actin and Myosin = both functional and structural roles

Question 14

What type of filament is Keratin? Where is it found? What does it do?

Answer 14

Intermediate filament
Found in epithelial cells
Provides flexibility and resilience

Question 15

What type of filament is Desmin? Where is it found? What does it do?

Answer 15

Intermediate filament
Found in muscle cells
Forms Z-lines (links myofibrils together)

Question 16

Vimentin is found …?

Answer 16

connective tissue cells

Question 17

What are neurofilaments?

Answer 17

structural proteins in neurons

Question 18

What are microtubules? What are they made of?

Answer 18

They are protein rods made up of tubulin

Question 19

Where does addition and deletion happen in a mircrotubule in a living cel?

Answer 19

Both addition and deletion of tubulin dimers happen at the plus end ONLY. The minus end is capped

Question 20

What does the addition of tubulin on a microtubule require?

Answer 20

GTP-binding. When GTP is hydrolyzed to GDP, the tube shrinks

Question 21

What is a centrosome?

Answer 21

Collection of 2 microtubules (centrioles)

Question 22

What arrangement do centrioles have?

Answer 22

9 + 0 arrangement; 9 groups of 3 w/ 0 in middle

Question 23

What do most microtubules function involve?

Answer 23

Movement (ciliary and flagellar, intracellular transport of vesicles…etc)

Question 24

What does movement of microtubules require?

Answer 24

Requires “motors” kinesin and dynein, and these motors require the hydrolysis of ATP

Question 25

Which direction do Kinesin and Dynein walk?

Answer 25

Kinesin walks toward + end, Dynein walks toward - end

Question 26

What is an example of microtubules and movement during mitosis/meiosis?

Answer 26

Microtubles move chromosomes apart during anaphase

Question 27

Axoneme, the core of cilium and flagellum is made up of ether microfilaments or microtubules?

Answer 27

Microtubules (microvilli contain microfilaments actin and myosin)

Question 28

Where are flagella found?

Answer 28

Sperm

Question 29

What structure do axoneme have?

Answer 29

9 + 2 arrangement; = 9 groups of 2 plus 2 in the middle

Question 30

What anchors axoneme (9+3)?

Answer 30

A basal body of 9+0 arrangement

Question 31

Movement of the entire cell uses both microfilaments and microtubules. Slow movements use …. system; fast movements use ….. system?

Answer 31

Slow movements use actin-myosin system (microfilaments)

Fast movement use ameboid movement = rapid changes in viscosity of cytoplasm

Question 32

What are the steps of cell motility?

Answer 32

Chemotaxis
lamellipodium
Cytoskeletal anchoring/movement
Plasma membrane recycling

Question 33

Describe the steps of cell motility

Answer 33

Chemotaxis = signal is received (from inflamed tissue) and forms a lamella in direction specified by signal;
Lamellipodium = (moves like a slug) actin is pulled out into lamellipodium area, temporarily attaches, allows leukocytes out to attack injured tissue

Question 34

What is the term for the departure of defender cells from the blood?

Answer 34

Diapedesis (or extravasation)

Question 35

Essentially, how is Kartagner Syndrome manifested?

Answer 35

Defective gene results in the mis=synthesis of dyne in in RER; Therefore, abnormal or missing dynein in the axoneme = microtubules can’t walk on each other = failed cilia/flagella = chronic respiratory infections…etc