Lecture 13 – Feb 24th, 2026 DNA Replication Telomeres

These flashcards cover key vocabulary and concepts related to DNA replication, telomeres, and mutations based on the provided lecture notes.

End Replication Problem

The difficulty eukaryotic DNA polymerase faces completing replication at chromosome ends, leading to possible loss of genetic information.

Telomeres

Repeated sequences at the ends of chromosomes that protect against degradation; composed of TTAGGG in humans.

Telomerase

An enzyme that extends telomeres by adding repetitive sequences to the ends of chromosomes.

Elisabeth Blackburn

Nobel Prize-winning scientist who contributed to the discovery of telomerase.

Carol Greider

Nobel Prize-winning scientist known for her work on telomerase discovery.

ssDNA gap

Single-stranded DNA region left after RNA primer removal that DNA polymerase cannot fill.

Telomeric sequence loss

Loss of telomeric DNA over generations that can lead to chromosomal instability.

Holliday junction

A cross-shaped structure that forms during homologous recombination.

Duplication of genes

The process by which DNA sequences are copied, potentially leading to genetic diversity.

Mismatch repair

DNA repair system that corrects errors made during DNA replication.

Base-excision repair

DNA repair mechanism that removes damaged bases and replaces them.

Nucleotide-excision repair

Repair mechanism that targets bulky DNA lesions, like pyrimidine dimers.

Transposable elements

DNA sequences that can change positions within the genome, impacting gene function and genome stability.

Chemical mutagens

Agents that induce mutations through chemical reactions, such as deamination.

Pyrimidine dimer

DNA lesion caused by UV light, resulting in covalent bonding between adjacent thymine bases.

Replication fork

Y-shaped structure formed during DNA replication where the double helix separates into two single strands.

Excision repair

Repair process that removes damaged sections of DNA to allow for correct base pairing.

Polymerase chain reaction (PCR)

Biochemical technique used to amplify DNA sequences exponentially.

Point mutation

Change in a single nucleotide within a DNA sequence that can affect gene function.

Telomere elongation

The process of lengthening telomeres, typically achieved through telomerase action.