Chpt 12

Question 1

A single adenine in DNA of a fertilized ovum was replaced by cytosine. What is the likeliest result of this change?

Answer 1

No observable effect.

Question 2

The function of the normal P53 which is frequently mutated cancer cells, are:

Answer 2

To stop the progression of cells with damaged DNA around the cell cycle.
To initiate apoptosis (programmed cell death.)

Question 3

Cancer increases in frequency as people get older. The main reason for this is:

Answer 3

It takes many years to accumulate, by chance, the number of somatic mitigation a leading to disease.

Question 4

Current stradegies for treating disseminated cancers include the use of drugs that inhibit DNA replication. Normal tissues that are also affected by these drugs include.

Answer 4

Skin

Question 5

In the Ames test for carcinogenic activities, the material to be tested is incubated with a liver extract before being brought into contact with test bacteria. The purpose of the liver extract is:

Answer 5

To convert non reactive pre carcinogens into more reactive substances.

Question 6

Be so a pyrene in tobacco smoke, although a known carcinogen, is not mutagenic for bacteria unless it is first incubated with liver extract. The reason is:

Answer 6

Bento a pyrene cannot react with DNA unless it is covered into a more receptive compound.

Question 7

Ultraviolet radiation

Answer 7

Joining of two adjacent thymine in DNA

Question 8

Nitrite

Answer 8

Joining of two adjacent thymines in DNA

Question 9

The p53 gene is a Tumor supressor gene. Cells in which this gene is disabled by mutation.

Answer 9

Both a and b

Question 10

A proposed food additive that has been shown to be non mutagenic for bacteria in the Ames test is likely to

Answer 10

Undergo further testing to ensure that it is not carcinogenic