Cytoskeleton and protein synthesis (powerpoint)

Question 1

What is the cytoskeleton?

Answer 1

A network of protein threads inside the cytoplasm.

Question 2

What are the 2 components of the cytoskeleton?

Answer 2

Microtubules and microfilaments

Question 3

Describe microtubules

Answer 3

20nm in diameter
Hollow tubes made of tubulin
Can be assembled and disassembled - this requires energy.

Question 4

Describe microfilaments

Answer 4

5nm in diameter
Solid strands of the protein actin
Can be assembled and disassembled - this requires energy.

Question 5

What are the 4 main roles of the cytoskeleton?

Answer 5

• Support the organneles and keep them in place.
• Strengthen the cell and maintain its shape.
• Movement of materials in the cell
• Movement of cell by movement of cilia, flagella and undulipodia.

Question 6

How are proteins synthesised?

Answer 6

1) mRNA copy of the instructions (gene) for insulin is made in the nucleus.
2) mRNA leaves the nucleus through a nuclear pore.
3) mRNA attaches to a ribosome, in this case one attached to the endoplasmic reticulum. Ribosome reads the instructions to assemble the protein (insulin)
4) Insulin molecules are “pinched off” in vesicles and travel towards the golgi apparatus.
5) Vesicle fuses with Golgi apparatus.
6) Golgi apparatus processes and packages insulin molecules ready for release.
7) Packaged insulin molecules are “pinched off” in vesicles from the Golgi apparatus and move towards the cell surface membrane.
8) Vesicle fuses with cell surface membrane.
9) Cell surface membrane opens to release insulin molecules outside.