DNA Structure and Function

Vocabulary flashcards covering key terms and concepts related to DNA structure and function, gene regulation, and associated experiments.

DNA

Deoxyribonucleic acid, the molecule that carries genetic information.

Nucleotide

Building block of DNA, consisting of a sugar (deoxyribose), a phosphate group, and a nitrogen base.

Adenine (A)

One of the four nitrogen bases in DNA that pairs with Thymine (T).

Thymine (T)

One of the four nitrogen bases in DNA that pairs with Adenine (A).

Cytosine (C)

One of the four nitrogen bases in DNA that pairs with Guanine (G).

Guanine (G)

One of the four nitrogen bases in DNA that pairs with Cytosine (C).

Antiparallel strands

Strands of DNA that run in opposite directions.

Hershey & Chase Experiment

An experiment that proved DNA, rather than protein, is the genetic material.

Genome

All the DNA in an organism.

Gene

A sequence of DNA that codes for RNA or protein.

Gene Promoter

A region of DNA that turns gene transcription on or off.

Flow of Information

The process of DNA being transcribed to RNA and then translated to protein.

mRNA

Messenger RNA, which carries genetic information from DNA to the ribosome.

rRNA

Ribosomal RNA, a component of the ribosome.

tRNA

Transfer RNA, which brings amino acids to the ribosome during protein synthesis.

Transcription Steps

1. Initiation: RNA polymerase binds to the promoter. 2. Elongation: RNA is synthesized. 3. Termination: Transcription ends.

Codon

A three-base sequence on mRNA that codes for an amino acid.

Translation Steps

1. Initiation: Ribosome binds mRNA and finds start codon. 2. Elongation: tRNA brings amino acids. 3. Termination: Reaches stop codon and releases the protein.

Semiconservative replication

The process of DNA replication where one old strand and one new strand are combined.

Helicase

An enzyme that unwinds the DNA double helix during replication.

DNA Polymerase

An enzyme that adds nucleotides to form a new DNA strand.

Ligase

An enzyme that seals the backbone of DNA after replication.

Point Mutation

A mutation that changes one base in the DNA sequence.

Silent Mutation

A mutation that does not change the resulting protein.

Missense Mutation

A mutation that alters one amino acid in the protein.

Nonsense Mutation

A mutation that creates an early stop codon in the protein.

Frameshift Mutation

A mutation caused by insertion or deletion that changes the reading frame.

Operon

A cluster of related genes in prokaryotes regulated together.

Repressor

A protein that blocks transcription by binding to the operator.

Lac Operon

A set of genes that respond to lactose availability in prokaryotic cells.

Eukaryotic Gene Regulation

Includes pre-transcriptional changes (chromatin structure), transcriptional, and post-transcriptional modifications such as splicing.