Cytoskeleton

Question 1

What is the interior of the cell composed of?

Answer 1

Cytoskeleton, Cytosol. and organelles

Question 2

What are the filler structures of the cell?

Answer 2

Cytoskeleton and Cytososl
Do not contain essential biological molecules
function is structural

Question 3

Cytoskeleton

Answer 3

Protein filaments and is found throughout the inside of the cell

Question 4

Cytosol

Answer 4

provides 50% of the cell volume; site of protein synthesis

Question 5

How many types of actin are there and what is the size of 1 filaments?

Answer 5

6 types and 6nm

Question 6

How many types of Microtubules are there and what is the size of 1 filament?

Answer 6

12 type and 23 nm

Question 7

How many types of Intermediate filaments are there and what is the size of one filament?

Answer 7

31 types and 10nm

Question 8

Which filaments are like cables?

Answer 8

microfilaments and intermediate filaments

Question 9

Which filaments acts like a cellular support beam?

Answer 9

Microtubules

Question 10

What is the most abund. cytoskeletal element in eukaryotes?

Answer 10

Actin

Question 11

what is the main component of Microfilaments?

Answer 11

Actin
It is double stranded because the molecules work together
Form a double helix

Question 12

Where is actin found?

Answer 12

Near the cell membrane

Question 13

Describe actin

Answer 13

It is a linear polymer of actin subunits

generates force by elongation and shortening of opposing ends

Question 14

Actin is a tract for movement of which motor protein?

Answer 14

Myosin

Question 15

What controls Actin?

Answer 15

The Rho family of small GTP binding proteins that are ATP dependent

Question 16

What are the components of Rho family?

Answer 16

Rho - contractile acto-myosin filament
Rac- lamellipodia
CdC42 - filopodia

Question 17

Microvilli are made of?

Answer 17

F-Actin

Question 18

Which two elements stabilize anchoring and cross linking of F-actin?

Answer 18

Villin and Fimbrin

Question 19

Which two elements anchor the F-actin to the cell membrane?

Answer 19

Myosin I and Calmodulin

Question 20

What type of subunits make up microtubules?

Answer 20

tubulin -> alpha and beta -> bind together to form a protofilament
13 protofilaments make up a microtubule
bind GTP for polymerization

Question 21

which cytoskeletal element resist compression?

Answer 21

Microtubules

Question 22

Describe microtubules

Answer 22

long, hollow. and cylindrical 
Work separately to provide tracks on which organelles can travel from center of the cell outward  
More rigid than actin 
unstable/continuous growth and decay 
Minus end - nucleus 
Plus end - cell membrane

Question 23

Microtubules organize around?

Answer 23

Centrosome - which is at the center near the nucleus

one end of the microtubule is embedded in the centrosome and the microtubule grows out from there

Question 24

What are the key roles of microtubules?

Answer 24

Intracellular transport (w/ dyneins and kinesins) of orgganelles such as mitochondria and vesicle s
The axoneme
the mitotic spindle
synthesis of cell wall in plants

Question 25

What are the molecules that bind microtubules?

Answer 25

Colchicine Tau (abnormal in Alzheimer's) Dynein (moves toward minus end, center) Kinesin (moves towards plus end, cell membrane)

Question 26

What is the function of colchicine?

Answer 26

depresses MT assembly | Use to treat Gout - inhibits mitosis in neutrophils by inhibiting the mitotic spindle

Question 27

During cell division chromosomes attach to which part of the chromosome?

Answer 27

Kinetichore

Question 28

What are the two type of microtubule structurres?

Answer 28

9 triplet (star shaped) and the 9 doublet + 2 ( wheel shaped)

Question 29

What is an example of the nine triplet?

Answer 29

Centrioles and basal body

Question 30

What is an example of the 9 doublet +2?

Answer 30

Cilia and Flagella

Question 31

What is another name for the 9+2 arrangement?

Answer 31

axoneme

Question 32

Which protein connects the subunits (tubulin) together?

Answer 32

Dynein

Question 33

Which protein connects the doublets to one another?

Answer 33

Nexin

Question 34

Abnormal Ciliary Dynein causes?

Answer 34

Kartagener's Syndrome

Question 35

What are the characteristics of Kartagener's Syndrome?

Answer 35

Motor deficit | Respiratory System Abnormalities -> Situs Inversus

Question 36

What is situs Inversus?

Answer 36

When organs are switched to the opposite side of the body (thoracic and abdominal) Ciliary movement aids in organogenesis in the early embryo

Question 37

What is the cause of Bardet-Biedi Syndrome?

Answer 37

``` Disruption of the sensory function of cilia "genetic disorder" CNS malfunction (retinopathy, learning disability) ```

Question 38

Characteristics of Sensory Cilia

Answer 38

Primary - Nuerons, Chondrocytes, Kidney Epithelium

Question 39

Receptors for neurotransmitters and many other molecules are localized where?

Answer 39

To cilia

Question 40

How many cilium do CNS neurons commonly have?

Answer 40

One

Question 41

What are characteristics of intermediate filaments?

Answer 41

rope like and fibrous two anti-parallel helices/dimers forming tetramers Extend through cytosol (like a 3-D structure) more stabel heterogenous constituent anchors organelles

Question 42

Which cytoskeletal element help resist stress and increase cellular stability?

Answer 42

Intermediate filaments

Question 43

Which cytoskeleton element helps maintain cell shape by bearing tension?

Answer 43

Intermediate filaments

Question 44

What is the structural element of nuclear lamina and sarcomeres?

Answer 44

Intermediate Filaments

Question 45

What are examples of intermediate elements?

Answer 45

Vimentin (mesenchymal-connective tissue) Glial Fibrilary acid protein ( glial cells-astrocytes) Neurofilament proteins (neuronal processes) Desmin (muscle) Keratin (epithelium) Nuclear lamins (interconnect nuclear pores)

Question 46

Which intermediate element is inserted into desmosomes and involved in cell to cell adhesions and cell to matrix adhesions.

Answer 46

Keratin

Question 47

What is Myosin?

Answer 47

A motor protein that is ATP dependent | actin-based motility

Question 48

What are the actions of Myosin?

Answer 48

Actin binding ATP hydrolysis Force transduction

Question 49

T/F All Prokaryotic cells contain myosin isoforms

Answer 49

False. It is eukaryotes | some isoforms have specialized functions in certain cell types while other isoforms are ubiquitous

Question 50

What are the three molecular domains of Myosin?

Answer 50

Head, Neck, and body

Question 51

What is the function of the Myosin Head?

Answer 51

bind actin | use ATP hydrolysis to generate force and walk along filament toward the positive end

Question 52

What is the function of the Myosin neck?

Answer 52

it is the linker lever arm for transducing the force generated by the catalytic motor domain contains the binding site for myosin light chains (distinct protein that form part of macromolecular complex and have regulatory functions)

Question 53

What is the function of the Myosin tail?

Answer 53

mediates interaction w/ cargo molecules and/or other myosin subunits Sometimes regulates motor activity

Question 54

Which form of Myosin moves towards the negative instead of the positive end?

Answer 54

Mysoin VI (6)

Question 55

Myosin I is involved in?

Answer 55

Vesicular transport (monomer- 1 tail)

Question 56

Myosin II is involved in?

Answer 56

Muscle contraction (dimer - 2 tails wrapped and bound to Cap2 by Titin)

Question 57

In the sarcomere where is the head and tail located?

Answer 57

Tail - M line | Head - I band

Question 58

What does cell movement involve?

Answer 58

Myosin + actin Focal contact made of integrin proteins Movement of actin and loosening of focal contact permits cell movement