Gene Expression Flashcards
Genome
The complete set of nucleotide sequences encoded in the total DNA of an organism.
Structural Gene
Sections of DNA that carry to instructions for production of a protein.
Structural Gene
Sections of DNA that carry to instructions for production of a protein.
Gene Expression
The ability of a gene to be transcribed.
Genetic Code
The code the body uses to convert the instructions contained in the DNA into the proteins essential for life.
Non-Coding DNA
The greater part of the DNA molecule that does not contain structural genes.
Regulatory Gene
A non-coding segment of DNA that produces transcription factors for gene expression.
mRNA
Messenger RNA; RNA molecule formed during transcription.
Transcription
First step of gene expression, in which a particular segment of DNA is copied into mRNA.
Codon
Triplet of nucleotides on mRNA specifying an amino acid.
Split Gene
A gene that contains sections of non-coding DNA called exons (expressed as RNA and protein) interrupted by sections of DNA called introns.
Inrons
A non-coding section of DNA within a split gene.
Exon
A coding section of DNA within a split gene.
Trimming
Removal of non-coding sections at the beginning and end of mRNA.
Capping
The addition of methyl-Guanine at the start of the trimmed mRNA.
tRNA
Small segments of a long tail of adenines at the end of mRNA.
Anticodon
Triplet of nitrogen bases found on tRNA.
rRNA
RNA component of a ribosome.
Polysome
Chain of ribosomes that ‘read’ mRNA
Translation
Production of a polypeptide sequence from a sequence of mRNA codons.
Transcription Factor
A protein produced by regulatory genes that controls gene expression.
Epigenome
A system of gene control outside of the DNA (‘Above the genome’).
Heterochromatin
Chromatin tightly coiled around histone proteins in the nucleosome.
Euchromatin
‘Relaxed’ chromatin that contains genes that can be transcribed.
Histone Modification
Addition of chemical tags that vary the width between nucleosomes and so determine whether or not a gene can be transcribed.
DNA Methylation
The addition of a chemical tag (a methyl group) to the start of a structural gene to block transcription.
Dizygotic Twins
Each twin develops from a separate egg and each egg is fertilised separate from the sperm cell.
Fraternal Twins
An alternative name to dizygotic twins.
Monozygotic Twins
Twins that develop from one zygote, which splits and forms two embryos; since they have the same genotype, they are considered to be identical.
Homeotic Gene
Any group of related genes that control the body plan of an embryo along the head-tail axis during early embryonic development.
Homeobox
DNA sequence of about 180 base pairs) contained in a gene (e.g. the Hox genes) that is highly conserved and can bind to DNA to control gene expression.
Homebox (Hox) Genes
A sub-group of homeotic genes that control the body plan of an embryo aling the head-tail axis.
Hoz Protein
A transcription factor produced by a Hox gene.
SRY Gene
The gene on the Y chromosome responsible for initiating male sex determination in humans.