BME 1532 - CELL BIOLOGY - DNA, Replication, and Repair

A collection of vocabulary flashcards based on key concepts from cell biology focused on DNA, its replication, and repair mechanisms.

What is the structure and function of nuclein?

Nuclein is a complex of DNA and protein isolated by Friedrich Miescher, which plays a critical role in genetic information storage and transmission.

Can you explain the process of semiconservative replication in detail?

Semiconservative replication involves each original strand serving as a template for a new strand, resulting in two DNA molecules, each consisting of one old strand and one new strand.

What were the specific findings of the Avery-Maclow McCarty Experiment?

The experiment showed that DNA extracted from virulent bacteria could transform non-virulent bacteria into a virulent form, highlighting that DNA is the genetic material.

Describe the methodology and conclusion of the Hershey and Chase Experiment.

In this experiment, bacteriophages were labeled with radioactive isotopes to differentiate between DNA and protein. It concluded that DNA, not protein, is the carrier of genetic information.

What are Chargaff's Rules, and why are they significant?

Chargaff's Rules state that the amount of adenine (A) equals thymine (T), and the amount of guanine (G) equals cytosine (C) in DNA. This base pairing is essential for the structure of DNA.

What is the distinction between euchromatin and heterochromatin?

Euchromatin is less condensed and transcriptionally active, allowing gene expression, while heterochromatin is highly condensed, transcriptionally inactive, and generally contains inactive genes.

How does polymerase function in DNA synthesis?

Polymerase synthesizes new DNA strands by adding complementary nucleotides to a growing chain during replication.

What is the significance of Okazaki fragments in DNA replication?

Okazaki fragments are synthesized on the lagging strand, allowing for discontinuous replication due to the antiparallel nature of DNA strands.

Explain the role of telomeres in chromosome stability.

Telomeres are repetitive sequences at the ends of chromosomes that protect them from degradation and prevent fusion with neighboring chromosomes.

What is the mechanism of mismatch repair in DNA?

Mismatch repair involves recognizing and correcting base-pairing mismatches that escape the proofreading activity of DNA polymerases.

What is homologous recombination and its importance?

Homologous recombination repairs double-strand breaks in DNA using an undamaged homologous DNA sequence as a template, ensuring genetic stability.

How does nucleotide excision repair differ from other DNA repair mechanisms?

Nucleotide excision repair removes damaged nucleotides and replaces them with correct ones, addressing a variety of DNA lesions including those from UV radiation.

What is the function and process of DNA ligase?

DNA ligase connects DNA fragments together by catalyzing the formation of phosphodiester bonds, essential during replication and repair.

Explain the role of primase in DNA replication.

Primase synthesizes a short RNA primer that provides a starting point for DNA polymerase to begin DNA synthesis.

What is the function of DNA helicase and its significance during replication?

DNA helicase unwinds the DNA double helix at replication forks, enabling the accessible single strands for the replication process.

Define a 'genome' and its significance in genetics.

A genome is the complete set of genetic material in an organism, encompassing all its genes and non-coding sequences, pivotal for understanding heredity.

What is a karyotype, and how is it utilized in genetics?

A karyotype is an ordered profile of an organism's chromosomes, used to detect chromosomal abnormalities and understand genetic diseases.