8: DNA, Genes and Protein Synthesis Flashcards
Allele
One of a number of forms of a gene
Anticodon
A sequence of three bases on tRNA
Chance
The occurrence of events in the absence of any obvious cause.
Chromatin
The material that makes up chromosomes. It consists of DNA and the protein histone.
Chromatids
One of the two strands of a chromosome that are joined together by a single centromere
Deletion
A gene mutation when a nucleotide is lost from a sequence thus affecting the codon in the location of the deletion and all subsequent codons.
Chromosomes
A thread-like structure made of proteins and DNA by which hereditary information is physically passed from one generation to the other
Codon
The sequence of three bases on mRNA that codes for a single amino acid
Degenerate
Most amino acids are coded for by more than one triplet
Gene
Section of DNA on a chromosome coding for one or more polypeptides
Exons
Coding sequences
Gene Mutations
A change to one or more nucleotide bases in DNA resulting in a change genotype which may be inherited.
Diploid number
A term applied to cells in which the nucleus contains two sets of chromosomes
Locus
A section of DNA that is located at a particular position
Genome
The complete set of all genes in a cell
Histones
The protein that eukaryotic DNA associates with in chromosomes
Homologous pairs
A pair of chromosomes that have the same gene loci and therefore determine the same features
Haploid number
A term referring to cells that contain only a single copy of each chromosome
Introns
Non-coding sequences
mRNA (messenger RNA)
The type of RNA that transfers the DNA code from the nucleus to the cytoplasm, acts as a type of messenger
Non-overlapping
Each base is only included in one triplet code, each base in this sequence is only read once
Mutagenic
A factor that can cause mutations, such as ionising radiation or certain organic chemicals
Promoter
Sequence of DNA prior to to a gene to which transcription factors (and so RNA polymerase) can bind.
Proteome
The full range of proteins produced by the genome
Ribose
Pentose sugar found in RNA
RNA polymerase
Enzyme required for transcription that is responsible for breaking hydrogen bonds in a DNA molecule and simultaneously forming phosphodiester bonds in a mRNA molecule.
Transcription
The process where pre-mRNA is synthesised from DNA
Splicing
The process where introns are removed from pre-mRNA to form mRNA
Template strand
A strand of DNA which acts as a template for pre-mRNA synthesis
Substitution
A gene mutation where one nucleotide is replaced with another thus only affecting the codon in the location of the substitution (unless it produces a stop codon).
Translation
The process where mRNA is used as a template to form a polypeptide
tRNA
RNA molecule shaped like a clover-leaf with an attached amino acid that is specific to the anticodon on the other side of the molecule.
Universal
Each triplet codes for the same amino acids in all organisms
Uracil
Nucleotide base in RNA. Pairs with adenine
