Molecular Biology Exam Review

These flashcards cover key concepts from molecular biology related to DNA, mutations, gene regulation, and repair mechanisms, based on the student's lecture notes.

What is a common characteristic of bacterial chromosomes?

Bacterial chromosomes generally consist of double-stranded, circular DNA.

Which component is NOT part of a nucleosome?

Histone acetyltransferases.

What happens when you methylate all positively charged amino acids in a histone protein?

Histones could not bind to DNA.

What is heterochromatin NOT associated with?

Inactivated X chromosomes.

Which type of mutation has the greatest likelihood of evolutionary impact?

Germline mutation.

If a GAG codon is mutated to a GUG codon, what type of mutation is this?

Missense mutation.

What type of mutation occurs when an ATT codon is mutated to AT?

Frameshift mutation.

What results from a mutation of CUU to CUG?

Silent mutation.

What occurs when the UGC codon is mutated to UGA?

Nonsense mutation.

What is the most common way UV radiation causes mutations?

Energy from UV radiation causes adjacent thymine bases to covalently bond.

Which repair mechanism involves removing thymine dimers?

Nucleotide excision repair (NER).

What does direct repair in DNA entail?

Alkyltransferase converts methylguanine directly back to guanine.

What happens when a regulatory repressor unbinds from a gene promoter?

The gene is expressed.

True or False: Both bacteria and eukaryotes use operons to control gene expression.

False.

What happens if LacI has a mutation preventing repressor binding to lactose?

Lac operon genes will be expressed.

What causes an increase in CAP binding in positive control of operons?

Decrease in glucose and increase in cAMP.

What would occur in a cell with glucose but no lactose?

Lac genes would not be expressed.

What happens if a large segment of bacteriophage DNA is deleted from the CRISPR locus?

The cell would not have resistance to that bacteriophage.

What concept regarding lactose and the mutation of lacZ is currently unclear?

The student is having difficulty with the concept of lactose and the mutation of lacZ.