Molecular Biology Concepts

These flashcards cover key vocabulary terms from molecular biology, focusing on DNA replication, transcription, translation, and genetic mutations.

Central Dogma

The flow of genetic information in cells, typically described as DNA to RNA to protein.

DNA polymerase I

The enzyme that replaces RNA nucleotides in a primer with DNA nucleotides during DNA replication.

σ subunit

A protein component of RNA polymerase involved in the initiation of transcription.

5' cap

A modified guanine nucleotide added to the 5' end of eukaryotic mRNA that protects it from degradation.

codon

A three-base sequence in mRNA that specifies a particular amino acid.

frameshift mutation

A type of genetic mutation caused by insertions or deletions that shift the reading frame of the genetic code.

nonsense mutation

A mutation that introduces a premature stop codon into the transcript.

photolyase

An enzyme that repairs thymine dimers caused by ultraviolet light.

operon

A cluster of genes under the control of a single promoter in prokaryotic cells, often involved in related functions.

constitutive expression

When an operon encoding genes that are continuously transcribed to provide the cell with constant protein levels.

transduction

The process by which DNA is transferred from one bacterium to another by a virus.

transcription

The process of synthesizing RNA from a DNA template.

exon

A segment of a gene that codes for a protein.

intron

A non-coding segment of a gene that is removed during RNA processing.

transformation

The uptake of naked DNA from the environment by a bacterial cell.

mRNA

A type of RNA that carries the genetic information from DNA to the ribosome for protein synthesis.

teleomerase

An enzyme unique to eukaryotes that extends telomeres at the ends of chromosomes.

mutagen

A substance that causes mutations in DNA.

repressor

A protein that binds to an operator and inhibits transcription of a gene.

nucleotide excision repair

A DNA repair mechanism that removes damaged nucleotides and replaces them.