SSCE VCE Biology Cell Structure and Function: Scientists have investigated how

Question

Scientists have investigated how the nucleus accumulates the enzymes that it needs to function. They found a possible answer while studying a particular mutant form of the SV40 virus. A mutant polypeptide produced by this virus was not able to get into the host cell's nucleus in the way that the normal (non-mutant) form did.

The polypeptides for the normal (N) form and the mutant (M) form are shown below. A sequence of seven amino acids from the middle of the polypeptides is also shown below.

normal (N)

cut

A

cut

B

section of polypeptide magnified

Pro  Lys  Arg  Lys  Val

mutant (M)

cut

A'

cut

B'

cut

C'

same section of polypeptide magnified

Pro  Lys  Thr  Lys  Arg  Lys  Val

Both the normal and mutant forms of the polypeptides were cut into three smaller chains - A, B and C (A', B' and C') - as shown above. Each polypeptide was put into a cell and then its accumulation in the nucleus was measured. The table below shows the results of the experiment.

| Polypeptide | Accumulates in nucleus |
|-------------|-----------------------|
| N           | yes                   |
| M           | no                    |
| A           | yes                   |
| B           | yes                   |
| C           | no                    |
| A'          | yes                   |
| B'          | no                    |
| C'          | no                    |

Scientists have investigated how the nucleus accumulates the enzymes that it needs to function - VCE - SSCE Biology - Question 2 - 2014 - Paper 1

Worked Solution & Example Answer:Scientists have investigated how the nucleus accumulates the enzymes that it needs to function - VCE - SSCE Biology - Question 2 - 2014 - Paper 1

Identify how polypeptides accumulate in the nucleus.

Discuss the differences between normal and mutant polypeptides.

Explain the significance of the cut regions A, B, and C.

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