D1.1 DNA Replication (HL)

These flashcards cover key concepts related to DNA and heredity based on the lecture notes.

Heredity

The passing of genetic information from parents to offspring.

DNA Replication

A semi-conservative process in which DNA is copied to produce two identical DNA molecules.

Nucleotide

The basic building block of DNA, consisting of a sugar, phosphate group, and a nitrogenous base.

Semi-conservative

A method of DNA replication where each new molecule consists of one old strand and one new strand.

Complementary Base Pairing

The arrangement of nitrogenous bases in DNA whereby adenine pairs with thymine and guanine pairs with cytosine.

Hershey-Chase Experiment

An experiment that demonstrated DNA is the genetic material by using radiolabeled viruses.

Chromatography

A laboratory technique used to separate mixtures and analyze the frequency of nucleotide bases.

Nucleosome

A structural unit of a chromosome, consisting of a segment of DNA wrapped around a core of histone proteins.

Hydrogen Bonds

Weak bonds that form between the complementary bases of DNA, contributing to the stability of the double helix.

DNA Ligase

An enzyme that connects DNA fragments, such as those created during replication on the lagging strand.

DNA Gyrase

An enzyme that alleviates the strain from supercoiling during DNA replication.

DNA Polymerase III

An enzyme responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand.

Okazaki Fragments

Short, discontinuous segments of DNA synthesized on the lagging strand during DNA replication.

Exonuclease Activity

The ability of an enzyme to remove nucleotides from the end of a DNA strand.

Directionality of DNA

The orientation of the DNA strands, which run in opposite directions (5’ to 3’ and 3’ to 5’).

Replication Fork

The area where the two strands of DNA are unwound and replicated.

Proofreading

The process by which DNA polymerase checks and corrects base pairing errors during DNA replication.

Euchromatin

Loose form of chromatin that is transcriptionally active, allowing for gene expression.

Heterochromatin

Tightly packed form of chromatin that is generally transcriptionally inactive.

Pyrimidine

A category of nitrogenous bases in DNA that includes cytosine and thymine.

Purine

A category of nitrogenous bases in DNA that includes guanine and adenine.