AP Biology Review

The leading and the lagging strands differ in that

• the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

• the leading strand is synthesized by adding nucleotides to the 3ʹ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5ʹ end.

A new DNA strand elongates only in the 5ʹ to 3ʹ direction because

• DNA polymerase can only add nucleotides to the free 3ʹ end

• Okazaki fragments prevent elongation in the 3ʹ to 5ʹ direction.

When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

• methylation and phosphorylation of histone tails

• nucleotide excision and reconstruction

Based your answer on the figure: A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

• an accumulation of A and no production of B and C

• an accumulation of A and B and no production of C

Tags

NGSS.HS-LS3-2

In which of the following actions does RNA polymerase differ from DNA polymerase?

• RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

• RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to double-stranded DNA.

Why might a point mutation in DNA make a difference in the level of proteinʹs activity?

• It might substitute an amino acid in the active site.

• It might exchange one stop codon for another stop codon.

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-2

Altering patterns of gene expression in prokaryotes would most likely serve the organismʹs survival in which of the following ways?

• allowing the organism to adjust to changes in environmental conditions

• organizing gene expression so that genes are expressed in a given order

• allowing environmental changes to alter the prokaryoteʹs genome

This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA:

• enhancer

• promoter

• repressor

What is the enzymatic function of restriction enzymes?

• to cleave nucleic acids at specific sites

• to add new nucleotides to the growing strand of DNA

Which of the following are characteristics of Prokaryotic DNA? (more than 1 answer applies)

• Single linear strand

• Single circular strand

• Multiple linear strands

• Plasmids

• Contains histones