AP Biology Gene Expression

Bacterial cells that contain pGal will fluoresce blue under ultraviolet light. Which of the following is the most likely outcome of replacing the lacA gene in the E. coli lac operon with the gene encoding pGal?

• When lacY and lac Z are breaking down and transporting lactose, the bacteria will fluoresce blue under ultraviolet light

• lacZ will only produce the enzyme for breaking down galactose in the presence of ultraviolet light

• the repressor enzyme will only be able to bind to the operator under the presence of lactose

• When the regulatory gene is stimulated by lactose, it will cause the gene to fluoresce blue

• All structural genes downstream from the placement of lacA will be inhibited due to this substitution mutation.

Tags

NGSS.HS-LS1-1

What kind of chemical bond is found between paired bases of the DNA double helix?

• hydrogen

• ionic

• covalent

What is meant by the description ʺantiparallelʺ regarding the strands that make up DNA?

• The 5ʹ to 3ʹ direction of one strand runs counter to the 5ʹ to 3ʹ direction of the other strand.

• One strand is positively charged and the other is negatively charged.

Which of the following covalently connects segments of DNA?

• helicase

• DNA polymerase

• ligase

Which of the following synthesizes short segments of RNA?

• helicase

• DNA polymerase

• primase

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.

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

The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except

• a gene from an organism could theoretically be expressed by any other organism.

• all organisms have a common ancestor.

• DNA was the first genetic material.

• the same codons in different organisms usually translate into the same amino acids.

Tags

NGSS.HS-LS4-1

What are the coding segments of a stretch of eukaryotic DNA called?

• introns

• exons

Introns are significant to biological evolution because

• their presence allows exons to be shuffled.

• they protect the mRNA from degeneration.