Lecture 24- Cell Movement

Question 1

What does it mean when a cell is mobile vs. when a cell is motile?

Answer 1

Mobile- cell can move ex: RBC can flow in the blood but they can’t propel themselves

Motile- cell can swim using its own energy ex: Sperm cell

Question 2

Diffusion

Answer 2

net movement of molecules from regions of high to low concentrations

ex: ions, proteins

Question 3

What is a telomerase and what is its role in DNA replication (S phase specifically)

Answer 3

During DNA replication (during S phase), telomerase needs to find telomere sequences and replicate the DNA

Question 4

Membrane transport proteins

Answer 4

proteins move molecules across a membrane

ex: Glucose Transporter (GLUT)

Question 5

Receptor proteins

Answer 5

proteins that deliver cargo to target organelles

ex: M6P receptors deliver lysosome proteins

Question 6

Two examples of protein assembly

Answer 6

Formation of large protein complexes:

1. Clathrin- there is a bending force (assembly of clathrin proteins during RME shapes membrane)
2. Microtubules- there is a pushing force (growing MTs push against plasma membrane)

Question 7

In protein disassembly, there is a ____ force

Answer 7

pulling force.

The chromosomes are pulled towards the edge of the cell as the MT is dismantled.

6 tubulins -> 2 tubulins

Question 8

What happens to Microtubules during anaphase? (before anaphase and as anaphase progresses)

___ microtubules move chromosomes

Answer 8

shrinking microtubules move chromosomes.

Beginning of anaphase- we have centrosome, chromosome, and a long MT

As anaphase progresses, the chromosome is pulled towards the centrosome . As the chromosome is moving, the MT is being disassembled

Question 9

what does single-head motor protein mean?

Answer 9

means they act independently

Question 10

What movement does an object (ex: vesicle) do when a single head motor protein is attached to it? And there is also a protein filament underneath for them to walk along

Forward or backward movement?

Answer 10

forward movement

Question 11

Kinesins are ___ directed, ____ associated motor proteins

A. plus-end….. F-actin
B. plus-end….. Microtubule
C. minus-end….. F-actin
D. minus-end…. Microtubule

Answer 11

Kinesins are plus-end directed, Microtubule associated motor proteins

Question 12

Dyneins are ____ directed, _____ associated motor proteins

A. plus-end….. F-actin
B. plus-end….. Microtubule
C. minus-end….. F-actin
D. minus-end…. Microtubule

Answer 12

Dyneins are minus-end directed, microtubule associated motor proteins

Question 13

Myosins are ____ directed, ____ associated motor proteins

Dyneins are ____ directed, _____ associated motor proteins

A. plus-end….. F-actin
B. plus-end….. Microtubule
C. minus-end….. F-actin
D. minus-end…. Microtubule

Answer 13

Myosins are plus-end directed, actin filament associated motor proteins

Question 14

why do we need three different motor proteins?

Answer 14

There’s three directions we might want to move a vesicle or an organelle within a cell.

Question 15

What makes up the motor protein bundles?

Answer 15

cytoskeleton proteins + double-headed motor proteins = bundles

Question 16

What does contraction bundles of F-actins + Myosins do in animal cells?

Answer 16

Contraction bundles of F-actins + Myosins do cytokinesis of animal cells.

Question 17

What does the extension bundles of MTs and Kinesins do to animal cells during anaphase?

Answer 17

Extension bundles of MTs and Kinesis elongate animal cells during anaphase.

Question 18

What are the 8 ways cells move

Answer 18

1. Diffusion
2. Membrane transport proteins
3. Receptor proteins
4. Protein assembly
5. Protein disassembly
6. Water pressure
7. Single motor proteins
8. Motor protein bundles