BIO 203: Ch. 8

Genetics?

Study of genes

Gene?

Segment of DNA that encodes a functional product (usually protein)

Genome?

All the genetic information in a cell

Genomics?

Molecular study of genomes

Genotype?

Genetic makeup of an organism

Phenotype?

Actual expression of the genes

Chromosome?

Structure containing DNA

What is transcription?

Transcribing DNA to RNA

What is translation?

Translating RNA to protein

What is DNA ligase?

Makes covalent bonds to join DNA strands; joins Okazaki fragments and new segments in excision repair

What is DNA polymerase?

Synthesizes DNA; proofreads and repairs DNA

What is helicase?

Unwinds double - stranded DNA

What is primase?

Makes RNA primers from a DNA template

What is RNA polymerase?

Copies RNA from DNA template

What is topoisomerase?

Relaxes supercoiling ahead of replication fork

What is the start codon?

AUG

What are the stop codons?

UAA, UAG, UGA

What are constitutive genes?

Genes that are expressed at a fixed rate

What are repressible genes?

Mechanism that inhibits gene expression

What are inducible genes?

Mechanism that initiates transcription

What is a mutagen?

Agent that causes mutations

What are spontaneous mutations?

Occur in the absence of a mutagen

What is a base substitution?

Change in one base

What is a missense mutation?

Results in change in amino acid

What is a nonsense mutation?

Results in a nonsense codon

What is a frameshift mutation?

Insertion or deletion of one or more nucleotide pairs

What does ionizing radiation (X rays and gamma rays) cause?

Causes the formation of ions that can react with nucleotides and the backbone

What is replication?

Genetic information transferred between generations of cells

What is recombination?

Genetic information can be transferred between cells of the same generation