CLEP Biology DNA Structure and Replication 5

Question 1

The end-replication problem refers to the inability of DNA polymerase to fully replicate:

Accepted Answer

The lagging strand at the 3' end of linear chromosomes, causing telomere shortening

Answer

After the final RNA primer on the lagging strand is removed from the 5' end, there is no upstream 3'-OH to fill in the gap, causing progressive shortening of linear chromosome ends.

Question 2

Which of the following nucleotides is found in DNA but NOT in RNA?

Accepted Answer

Deoxythymidine monophosphate (dTMP)

Answer

Thymine (as deoxythymidine) is found only in DNA; RNA uses uracil instead of thymine and contains ribose instead of deoxyribose.

Question 3

A DNA molecule is described as B-form. This means it is:

Accepted Answer

The standard right-handed double helix with approximately 10.5 base pairs per turn

Answer

B-form DNA is the most common form under physiological conditions: a right-handed double helix with about 10.5 base pairs per helical turn.

Question 4

If one strand of a DNA molecule has the sequence 5'-ATCGGC-3', what is the sequence of the complementary strand?

Accepted Answer

5'-GCCGAT-3'

Answer

The complement of 5'-ATCGGC-3' is written antiparallel as 3'-TAGCCG-5', which is the same as 5'-GCCGAT-3'.

Question 5

Which of the following correctly describes semi-conservative replication?

Accepted Answer

Each daughter molecule contains one original parental strand and one newly synthesized strand

Answer

In semi-conservative replication, the double helix unwinds and each original strand serves as a template for a new complementary strand, so each daughter molecule is a hybrid.

CLEP Practice Test

CLEP Practice Test

CLEP Biology DNA Structure and Replication 5