Question 1

It is generally believed that the three causes of cancer are inherited genetic variations, environmental factors, and random mutations.

Accepted Answer

A) True 
 B)False  True

Question 2

In cells with DNA damage, p53 either ___ if the DNA can be repaired or ___ if the DNA cannot be repaired.

Accepted Answer

blocks cell division, initiates apoptosis

Question 3

There are approximately ___ genes that are known to be associated with carcinogenesis but a typical cancer contains mutation in only ___.

Accepted Answer

140, 2 to 8

Question 4

To perform PCR, which of the following describes the reagents that must be included in the reaction mixture?

Accepted Answer

A)  DNA fragment, primers flanking the region of interest, dNTPs, DNA polymerase 
B)  DNA fragment, primers flanking the region of interest, dNTPs, ddNTPS, DNA polymerase 
C)  DNA fragment, one primer, dNTPs, DNA polymerase, DNA ligase 
D)  DNA fragment, primers flanking the region of interest, dNTPs, DNA ligase 
E)  none of the above

Question 5

What reagents are required to perform PCR?

Accepted Answer

A)  DNA fragment, primers flanking the region of interest, dNTPs, DNA polymerase 
B)  DNA fragment, primers flanking the region of interest, dNTPs, ddNTPs, DNA polymerase 
C)  DNA fragment, one primer, dNTPs, DNA polymerase, DNA ligase 
D)  DNA fragment, one primer, dNTPs, DNA polymerase, DNA endonuclease 
E)  DNA fragment, primers flanking the region of interest, dNTPs, DNA endonuclease

Question 6

What are the two components of supercoiling?

Accepted Answer

A)  twist and writhe 
B)  twist and anti-twist 
C)  writhe and relaxation 
D)  negative supercoiling and positive supercoiling 
E)  single stranded and double stranded

Question 7

Which tumor suppressor gene is found to be mutated in at least half of all human tumors?

Accepted Answer

A)  BRCA1 
B)  BRCA2 
C)  retinoblastoma 
D)  p53 
E)  none of the above

Question 8

In most organisms, replication proceeds in a _____ manner from the _____.

Accepted Answer

A)  bidirectional; replication origin 
B)  bidirectional; theta site 
C)  bidirectional; lagging strand 
D)  unidirectional; chromosome ends 
E)  none of the above

Question 9

What is the nucleophile in the DNA polymerase mechanism?

Accepted Answer

A)  an oxygen anion on the  $\gamma$ -phosphate of the dNTP 
B)  the oxygen on the  $\beta$ -phosphate of the dNTP 
C)  the oxygen on the  $\alpha$ -phosphate of the dNTP 
D)  the 5   hydroxyl on the deoxyribose 
E)  the 3   hydroxyl on the deoxyribose

Question 10

An E. coli cell actively undergoing replication contains a single replisome.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following explains supercoiling in naturally occurring DNA?

Accepted Answer

A)  positively supercoiled, making the helix tighter 
B)  positively supercoiled, making the helix looser 
C)  negatively supercoiled, making the helix tighter 
D)  negatively supercoiled, making the helix looser 
E)  negatively supercoiled without changing the nature of the helix

Question 12

DNA damage activates ___ and leads to an increase in the cellular concentration of ___.

Accepted Answer

The answer of DNA damage activates ___ and leads to...

Question 13

Describe the structure of a DNA molecule by listing six characteristics.

Accepted Answer

The answer of Describe the structure of a DNA molecule...

Question 14

Which of the following explains why circular DNA, such as the chromosomes of some viruses and bacteria, appears to be twisted?

Accepted Answer

A)  hybridization 
B)  supercoiling 
C)  circular DNA is Z-form 
D)  viral and bacterial DNA is always single stranded 
E)  none of the above

Question 15

An example of a viral infection leading to cancer is ___ causing ___.

Accepted Answer

The answer of An example of a viral infection leading...

Question 16

If the smallest human chromosome is 4.6 * 107 base pairs in size, which of the following is the best estimate of the number of Okazaki fragments resulting from its replication?

Accepted Answer

A)  300,000 
B)  30,000 
C)  3,000 
D)  300 
E)  30

Exam 20: DNA Replication and Repair

It is generally believed that the three causes of cancer are inherited genetic variations, environmental factors, and random mutations.

In cells with DNA damage, p53 either _ if the DNA can be repaired or _ if the DNA cannot be repaired.

There are approximately _ genes that are known to be associated with carcinogenesis but a typical cancer contains mutation in only _.

To perform PCR, which of the following describes the reagents that must be included in the reaction mixture?

What reagents are required to perform PCR?

What are the two components of supercoiling?

Which tumor suppressor gene is found to be mutated in at least half of all human tumors?

In most organisms, replication proceeds in a _ manner from the _.

What is the nucleophile in the DNA polymerase mechanism?

An E. coli cell actively undergoing replication contains a single replisome.

Which of the following explains supercoiling in naturally occurring DNA?

DNA damage activates _ and leads to an increase in the cellular concentration of _.

Describe the structure of a DNA molecule by listing six characteristics.

Which of the following explains why circular DNA, such as the chromosomes of some viruses and bacteria, appears to be twisted?

An example of a viral infection leading to cancer is _ causing _.

If the smallest human chromosome is 4.6 * 10⁷ base pairs in size, which of the following is the best estimate of the number of Okazaki fragments resulting from its replication?