Biology 430: Molecular Biology Study Guide for Final Exam

Flashcards based on the key concepts from the lecture notes for exam preparation.

DNA Damage

Injuries to the DNA structure which can cause mutations or genomic instability.

Hydrolysis

A spontaneous DNA damage process leading to loss of base from a nucleotide, resulting in an abasic (AP) site.

Alkylation

The addition of alkyl groups to DNA bases or the phosphate backbone, which can lead to mispairing and strand breaks.

Deamination

The conversion of cytosine to uracil or adenine to hypoxanthine, altering base pairing properties and potentially causing transition mutations.

Ultraviolet Light (UV) Damage

Causes pyrimidine dimers (e.g., thymine dimers), blocking DNA replication and transcription.

X-rays

A type of ionizing radiation that induces single- and double-strand breaks in DNA.

Intercalating Agents

Molecules that insert between base pairs of DNA, causing insertions and deletions that can lead to frameshift mutations.

Base Excision Repair (BER)

A repair mechanism that corrects small base lesions by excising and replacing damaged bases.

Nucleotide Excision Repair (NER)

A repair pathway that removes bulky DNA adducts and helix-distorting lesions.

Mismatch Repair (MMR)

A mechanism that fixes mismatched bases that occur during DNA replication.

Translesion Synthesis (TLS)

A DNA damage tolerance process that allows DNA replication to continue past DNA lesions using specialized low-fidelity DNA polymerases.

SOS Response

A bacterial global response to severe DNA damage that induces the expression of multiple repair mechanisms.

RNA Polymerase

The enzyme responsible for synthesizing RNA from a DNA template.

Promoter

A DNA sequence that signals the start of transcription.

Initiation Factors

Proteins that assist RNA polymerase in recognizing and binding to the promoter.

Termination Signal

A sequence in mRNA that instructs RNA polymerase to stop transcription.

Ribosome

A cellular structure that synthesizes proteins by translating mRNA during the process of translation.

Peptidyl Transferase Activity

The enzymatic function of the ribosome that catalyzes the formation of peptide bonds between amino acids.

Ubiquitination

A post-translational modification where ubiquitin is added to a protein, marking it for degradation by the proteasome.

Heat-Shock Proteins (HSPs)

Molecular chaperones that assist in the proper folding of proteins during stress conditions.

Alternative Splicing

A regulatory mechanism by which different forms of mRNA are generated from the same primary transcript, leading to varied protein products.