Biology 2581B Study Guide - Quiz Guide: Axoplasmic Transport, Motility, Keratinocyte

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2 May 2020

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Motor and structural proteins that facilitates movement and transport = motile system. Cytoskeleton = scaffold for mechanoenzymes/motor proteins convert chemical atp energy into mechanical that cells can use to move. Muscle contraction, cell migration and intercellular transport. At the tissue level we got muscle contraction or movement of a whole organism. At cellular level: cells move, subceullular: transport of cargo or organelles and cell division. Cell level: migration of keratinocytes into wounded open space, entire sheet moves, cell flow around each other. Sliding of microtubules in cilia and flagella. Proteins mt based movement (mt provide rigid transport tracks)- Also has atp force of motion provides mechanical energy to allow motor proteins to walk along mts and carry cargo with them. Kinesin outbound to + (from interior to exterior of cell) Light chain region that attaches to vesicles and organelles. Used atp hydrolysis for energy and conformational change. Celia and flagella mts (axonemal) required for cilia and flagella movements-

Related Questions

not too details, just main points please...

1. What you should know about microtubles

- MT structure, what they are made of

- MT function

- Motor proteins(kinesins&dyneins)

- How kinesins move, coupling to ATP hydrolysis

- Microtubule Organizing Center (MTOC), how MTs are nucleated

- MT dynamics, how it's affected by drugs and MAPs

- dynamic instability and how its linked to GTP/GDP cycle

- cilia/flagella, axoneme structure

- how cilia/flagella move and the role of dynein

-intra-flagellar transport

2. What you should know about actin filaments

- F-actin structure

- F-actin Function

- Motor proteins (myosins)

- Actin dynamics, how it's affected by actin-binding proteins

- the concept of critical concentration

- actin/myosin structure and function in the contezt of muscle

- how muscle contract

- actinomyosin cycle (myosin movement), coupling to ATP hydrolysis

- How cells move and change shape, using actin

3. What you should know about IF

- IF strcuture, what they are made of

- IF function, roles inside and outside cells

- Regulation of nuclear IF in the cell cycle

- be able to compare major features of IF, Actin, and MTs

Bacterial cytoskeleton, that bacteria have proteins that

- polymerize

-affect cell shape, cytokinesis, ect.

- play analogous roles to MT, F-actin

4. what you should know about the cell cycle

- parts of the cell cycle, stages of mitosis

- MPF; how it was identified, what it is made of (cyclin and cdk)

- Universality of cyclin/Cdks (in yeast, frogs, etc.)

-how Cdk activity is regulated (many mechanisms)

- how Cdks function (by phosphorylation)

- how multiple cdks divide their function

- how the spindle is formed and mistakes corrected

- the role of motors and MY dynamics in above

- the tolr of proteolysis in mitotic transitions

- what a checkpoint is

- how checkpoints provide an additional layer of cell cycle regulation in case of damage

pearcrab948

1. Kinesin-1 motors can move long distances on microtubule tracks without dissociating. By contrast, myosin II motors in skeletal muscle take only one or a few steps before letting go. What is most likely the difference between these two motors that allow two different types of movement?

A. Differences in length of the stalk of each respective motor allow for differences in step size

B. Differences in ATP versus GTP hydrolysis alter the motor head movement along filaments

C. Actin filaments are smaller in diameter and have less space for movement

D. Binding affinity of the Kinesin-1 motor head to microtubules is high, whereas binding affinity of the myosin II motor head to actin filaments is low

E. Microtubules are larger in diameter and have more space for movement

2. Dynamic instability causes microtubules either to grow or to shrink rapidly. What is the most likely reason for a microtubule to undergo rapid growth?

A. GTP hydrolysis exceeds the rate of heterodimer addition

B. GTP hydrolysis of alpha tubulin causes an outward bend in the heterodimer conformation

C. A low concentration of tubulin heterodimers are in solution

D. Heterodimer addition exceeds the rate of GTP hydrolysis

E. Increased trafficking of microtubule motor proteins favors stability

3. There are no known motor proteins that move on intermediate filaments (IFs). What property of intermediate filaments would most likely explain the lack of motor proteins?

A. Tissue specific expression of IFs prevent a single type of motor protein to evolve over time

B. Lateral bundling of IFs prevent motor movement

C. IFs are less dynamic than microtubules and actin filaments

D. IFs are unpolarized

E. IFs do not bind a nucleotide

4. You discover a mutation that results in less rapid hydrolysis of GTP by the beta-tubulin subunit. What would most likely occur?

A. There would be no change in filament assembly

B. There would be enhanced instability of the microtubule

C. There would be enhanced stability of the microtubule

D. Microtubules would not form

E. There would be enhanced treadmilling

5. Which of the following statements describes common features of cadherins and integrins?

A. They can link to microtubules using specific adapter proteins

B. They mediate heterophillic interactions

C. They achieve high binding affinity through clustering

D. They are responsible for interactions of a cell with the extracellular matrix

E. They are found in the apical plasma membrane of an epithelial cell

6. Intermediate filaments are uniquely non-polar and built by lateral bundling in five steps: 1) synthesis of an alpha-helical monomer, 2) formation of a coiled-coil dimer, 3) formation of a staggered tetramer of two coiled-coil dimers, 4) lateral association of 8 tetramers, and 5) addition of 8 tetramers to a growing filament. At what step is polarity lost?

A. Step 1

B. Step 2

C. Step 3

D. Step 4

E. Step 5

7. Collagenase is an enzyme that breaks peptide bonds in collagen to help destroy extracellular structures. What would be the most likely reason to use collagenase in a cell biology laboratory?

A. Disrupt cadherin interaction with the extracellular matrix

B. Disrupt cell-cell contacts to passage cells in cell culture

C. Dissociate epithelial cells from the underlying basement membrane to separate tissues

D. All of the answers are likely uses for collagenase

E. Lyse cells to expose intracellular proteins and organelles

yellowherring775

Hello everyone, i'm working on thesepractices multiple choices for my finals. If you know any of theseanswer, please help. i appreciate your time and your help. Thankyou!!!

1. ___ Which of thefollowing statements about the cytoskeleton is false?

(a) The cytoskeletonis made up of three types of protein filament.

(b) The bacterialcytoskeleton is important for cell division and DNAsegregation.

(d) The cytoskeleton of acell can change in response to the environment.

2. ___ Which of thestatements below about intermediate filaments is false?

(a) They can stayintact in cells treated with concentrated salt solutions.

(b) They can befound in the cytoplasm and the nucleus.

(d) Each filament is about10 ?m in diameter.

3. ___ Keratins,neurofilaments, and vimentins are all categories of intermediatefilaments. Which of the following properties below is nottrue of these types of intermediate filaments?

(a) They strengthencells against mechanical stress.

(b) Dimers associateby noncovalent bonding to form a tetramer.

(d) Phosphorylation causesdisassembly during every mitotic cycle.

4. ___ Which of thefollowing statements about microtubules is true?

(a) Motor proteinsmove in a directional fashion along microtubules by using theinherent structural polarity of a protofilament.

(b) The centromerenucleates the microtubules of the mitotic spindle.

(d) ATP hydrolysis by atubulin heterodimer is important for controlling the growth of amicrotubule.

5. ___ Thehydrolysis of GTP to GDP carried out by tubulin molecules________________.

(a) provides theenergy needed for tubulin to polymerize

(b) occurs becausethe pool of free GDP has run out

(d) allows the behavior ofmicrotubules called dynamic instability

6. ___ The microtubulesin a cell form a structural framework that can have all thefollowing functions except which of the following?

(a) holding internalorganelles such as the Golgi apparatus in particular positions inthe cell

(b) creating longthin cytoplasmic extensions that protrude from one side of thecell

(d) moving materials fromone place to another inside a cell

7. ___ Which of thefollowing statements about organellar movement in the cell isfalse?

(a) Organellesundergo saltatory movement in the cell.

(b) Only themicrotubule cytoskeleton is involved in organellar movement.

(d) Organelles areattached to the tail domain of motor proteins.

8. ___ Which of thefollowing statements is correct?

Kinesins and dyneins____________________.

(a) have tails thatbind to the filaments

(b) move along bothmicrotubules and actin filaments

(d) derive their energyfrom GTP hydrolysis

9. ___ Cell movementinvolves the coordination of many events in the cell. Which of thefollowing phenomena are not required for cell motility?

(a) Myosin-mediatedcontraction at the rear of the moving cell.

(b) Integrinassociation with the extracellular environment.

(d) Release ofCa²⁺ from the sarcoplasmic reticulum.

10. ___Which of the followingstructures shorten during muscle contraction?

(a) myosinfilaments

(b) flagella

(d) actin filaments

7. ___ Referring to Figure Q16-29,which of the following statements below is false?

(a) A constitutivelyactive mutant form of PKA in skeletal muscle cells would lead to adecrease in the amount of unphosphorylated phosphorylasekinase.

(b) A constitutivelyactive mutant form of PKA in skeletal muscle cells would notincrease the affinity of adrenaline for the adrenergicreceptor.

(c) A constitutivelyactive mutant form of PKA in skeletal muscle cells would lead to anexcess in the amount of glucose available.

(d) A constitutivelyactive mutant form of PKA in skeletal muscle cells would lead to anexcess in the amount of glycogen available.

8. ___ Match the targetof the G protein with the appropriate signaling outcome.

adenylyl cyclase________ A. cleavageof inositol phospholipids

ion channels_________ B.increase in cAMP levels

phospholipase C_________ C. changes in membranepotential

azureprairie-dog165

Biology 2581B Study Guide - Quiz Guide: Axoplasmic Transport, Motility, Keratinocyte

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