Animal Cells - Structure & Function

Question 1

What are three types of fibre make up the complex structure of the cytoskeleton?

Answer 1

Microtubules, intermediate filaments and microfilaments (from the inside of the cell outwards, towards the plasma membrane).

Question 2

What protein are microtubules made of?

Answer 2

Tubulin.

Question 3

What protein are microfilaments made of?

Answer 3

Actin.

Question 4

What protein are intermediate filaments made of?

Answer 4

Keratin.

Question 5

What is the purpose of the cytoskeleton?

Answer 5

It organises the cell contents, maintains the cell’s shape, allows anchorage, facilitates cell movement and division and allows contact and signals to be transmitted between cells.

Question 6

There are three ‘other’ proteins in the cytoskeleton, aside from tubulin, actin and keratin. What are they?

Answer 6

Myosin: muscle motor protein.
Kinesin and dyenin: microtubule motor proteins.

Question 7

How does kinesin protein transport vesicles along the microtubules?

Answer 7

Kinesin ‘walks’ a vesicle along a microtubule ‘highway’, using it’s ‘foot’. ATP is used in this process.

Question 8

What are HeLa cells?

Answer 8

Cancer cells which use cellular scaffolding for anchorage, organisation and shape.

Question 9

Explain the ‘tensegrity hypothesis.

Answer 9

The tensegrity hypothesis suggests that the cytoskeleton has compression-resistant struts and tensile cables which protect the cell from pressure.

Question 10

Where is the extracellular matrix found?

Answer 10

Just outside the cell membrane.

Question 11

Integrin proteins go through the…?

Answer 11

Plasma membrane.

Question 12

Name two proteins, other than integrin, found in the extracellular matrix.

Answer 12

Fibronectin and collagen.

Question 13

What do integrin proteins attach to in the extracellular matrix?

Answer 13

Other proteins, such as fibronectins.

Question 14

Are the majority of cells anchorage-independent or anchorage-dependent?

Answer 14

Anchorage-dependent.

Question 15

Name three examples of anchorage-dependent cells.

Answer 15

Bone cells, muscle cells, skin cells, body cavities.

Question 16

Name two examples of anchorage-independent cells.

Answer 16

Blood plasma cells, some cancer cells.

Question 17

True or false? If an anchorage-dependent cell loses anchorage, they can die!

Answer 17

True. When an anchorage-dependent cell loses its anchorage, it can lose direction, ceas to function correctly or even die!

Question 18

How do cells benefit from being anchorage-dependent?

Answer 18

Their attachment enable cells to maintain their phenotype.

It also allows them to move, have direction and polarity and create functional tissues.

Question 19

‘Cells only function correctly when attached to an appropriate surface and they are exposed to the correct extracellular matrix’ - true or false?

Answer 19

True! (for anchorage-dependent cells).

Question 20

Do intestinal cells have to be the right way up?

Answer 20

Yes, because they have villi at the top, they wouldn’t work properly if they were the wrong way round!

Question 21

What changes when an anchorage-dependent cell loses it’s anchorage?

Answer 21

The cell’s phenotype changes when it loses it’s anchorage.