Genetics Vocabulary

A gene that is active in producing its RNA or protein product.

expressed gene

Genes that are turned off but are still present in a cell.

repressed gene

The basic building blocks of proteins.

amino acids

A molecule which during protein synthesis transmits the information in an organism’s DNA

to the ribosome.

messenger RNA

Any change in the sequence of nucleotides in a strand of DNA

mutation

The process by which DNA is copied in a cell.

replication

The first phase of protein synthesis in which the information contained in DNA is converted into

a messenger RNA.

transcription

The second phase of protein synthesis during which the code in the mRNA is read for the correct amino acid sequence in the protein.

This reads the code in mRNA and then add amino acids in the correct sequence to form a

protein.

transfer RNA tRNA

deoxyribonucleic acid

DNA

ribonucleic acid

RNA

A structure composed of DNA wrapped with proteins.

chromosome

A phenomenon during prophase in meiosis I where pairs of chromosomes exchange

portions.

crossing over

Somatic cell which has pairs of chromosomes, or 2n

diploid

A gamete which contains one set of chromosomes or “n.”

haploid

A segment of an organisms genetic material (DNA) that produces a specific protein.

gene

A sexual reproductive cell such as a sperm or an egg cell.

gamete

An image of the chromosomal makeup of an individual, produced through staining, arranging

matching pairs and photographing.

karyotype

Proposed by Mendel, states that it is equally likely for a heterozygous dihybrid individual to produce any of four type of gametes.

e.g. PpSs could producePSPspSps

Law of Independent Assortment

The process of cell division that produces sex cells (gametes).

meiosis

The process of cell division that produces identical copies of cells.

mitosis

The failure of chromosomes to separate during cell division.

nondisjunction

body cells

somatic cells

The building blocks of DNA or RNA sugar + phosphate + nitrogen base

nucleotide

The four nitrogen bases found in DNA

adeninethyminecytosineguanine

The four nitrogen bases found in RNA.

AdenineUracil

CytosineGuanine

One of two forms of the same gene. A sexually reporduced organism has two of these for each gene, one from each

parent which may or may not be the same.

allele