Molecular Biology: DNA Replication, Transcription, and Gene Regulation

replication

process of copying DNA prior to cell division

Base paring

principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine

Bacteriophage

A virus that infects bacteria

Transformation

process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

telomere

repetitive DNA at the end of a eukaryotic chromosome

Transfer RNA

type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

rna

single-stranded nucleic acid that contains the sugar ribose

ribosomal rna (r RNA)

type of RNA that combines with proteins to form ribosomes

Messenger RNA (mRNA)

RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

Translation

Process of synthesizing proteins from mRNA. (into amino acids of protein)

genetic code

collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis

Polypeptide

long chain of amino acids that makes proteins

exon

expressed sequence of DNA; codes for a protein

intron

sequence of DNA that is not involved in coding for a protein

promoter

specific region of a gene where RNA polymerase can bind and begin transcription

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

condon

group of three nucleotide bases in mRNA that specify a particular amino acid to be incorporated into a protein

Transcription

synthesis of an RNA molecule from a DNA template

point mutation

gene mutation in which a single base pair in DNA has been changed

framshift mutation

Mutation that shifts the "reading frame" of the genetic message by inserting or deleting nucleotides

mutation

change in a DNA sequence that affects genetic information

hox gene

a group of homeotic genes clustered together that determine the head to tail identity of body parts in animals. All hox genes contain the homeobox DNA sequence.

homobox gene

genes that code for transcription factors that activate other genes that are important in cell development and differentiation

DNA polymerase

principle enzyme involved in DNA replication

homeotic gene

a class of regulatory genes that determine the identity of body parts and regions in an animal embryo. Mutations in these genes can transform one body part into another

Differentiation

process in which cells become specialized in structure and function

Operator

short DNA region, adjacent to the promoter of a prokaryotic operon, that binds repressor proteins responsible for controlling the rate of transcription of the operon

operon

A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions.

anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon