AP Biology Molecular Genetics

Front

What molecule contains codons?

Back

mRNA (messenger RNA) contains codons, which are sequences of three nucleotides that correspond to specific amino acids.

Front

What is a nonsense mutation?

Back

A nonsense mutation is a type of mutation that results in an early stop codon, leading to a truncated protein.

Front

When are the genes in the lac operon expressed?

Back

The genes in the lac operon are expressed when lactose is present in the cell.

Front

If a DNA segment contains 22% adenine, what percentage of guanine is present?

Back

28%. According to Chargaff's rules, the percentage of guanine is equal to the percentage of cytosine, and the total percentage of adenine and thymine equals that of guanine and cytosine.

Front

What are exons?

Back

Exons are the segments of DNA that are coded for and expressed in the final mRNA product.

Front

What is the role of tRNA in protein synthesis?

Back

tRNA (transfer RNA) transports amino acids to the ribosome during protein synthesis, matching its anticodon with the codon on mRNA.

Front

What is a frameshift mutation?

Back

A frameshift mutation is a genetic mutation caused by insertions or deletions of nucleotides that shift the reading frame of the genetic message.

Front

What is the function of rRNA?

Back

rRNA (ribosomal RNA) is a component of ribosomes, which are the sites of protein synthesis in the cell.

Front

What is the significance of the promoter in gene expression?

Back

The promoter is a DNA sequence that initiates transcription of a particular gene, serving as a binding site for RNA polymerase.

Front

What is a silent mutation?

Back

A silent mutation is a change in the DNA sequence that does not alter the amino acid sequence of the protein.