DNA, genes and protein synthesis - Yr 1 Flashcards
Gene
Section of DNA on a chromosome that controls a feature by coding for formation of one or more specific polypeptides or a functional RNA (including rRNA and tRNA).
Chromosome
A thread like structure made of protein and DNA by which hereditary information is physically passed from one generation to the next.
Chromatin
The material that makes up chromosomes. It consists of DNA and the protein histone.
Autosome
A chromosome which is not a sex chromosome
Genetic code
The sequence of triplets of nucleotides (codons) in DNA which determines the sequence of amino acids in an organism’s proteins. It is degenerate; non-overlapping; universal ; has start and stop codons
Degenerate
A single amino acid may be coded for by more than one triplet code.
Non-overlapping
Each base appears in only one triplet – each base is only read once.
Universal
The genetic code is the same in all organisms – this is indirect evidence for evolution.
Histones
Proteins, which together with DNA, make up the chromosomes of eukaryotic cells.
Chromatid
Each of the two thread-like strands into which a chromosome divides that are joined together by a single centromere prior to cell division
Locus
The specific linear position of a particular gene on a certain chromosome
Alleles
Alternative forms of a particular gene with different base sequences, and therefore different codes
Protein synthesis
The process by which the genetic code codes for proteins in the cell. The template strand of DNA codes for mRNA in transcription, which is then translated into an amino acid sequence at the ribosomes.
Genome
The complete set of genetic material present in a cell or an organism.
Human Genome
The complete set of genes in a cell, including those in mitochondria and/or chloroplasts
Proteome
The full range of proteins produced by the genome. This is sometimes called the complete proteome, in which case the term proteome refers to the proteins produced by a given type of cell under a certain set of conditions.
Transcription
Formation of messenger RNA molecules from the DNA that makes up a particular gene. It is the first stage of protein synthesis.
RNA Polymerase
Enzyme that joins together nucleotides to form messenger RNA during transcription
nucleotides
Complex chemicals made up of an organic base, a sugar and a phosphate. They are the basic units of which the nucleic acids DNA and RNA are made.
mRNA
The type of RNA that is a long strand arranged in a single helix and its base sequence is determined by the sequence of bases on a length of DNA
Triplet
A sequence of three bases in DNA.
Template strand
The strand of DNA which is used during transcription to make mRNA. It runs in a 3’ to 5’ direction so the mRNA is built in a 5’ to 3’ direction.
Codon
A sequence of three adjacent nucleotides in mRNA that codes for one amino acid
Intron
Portions of DNA within a gene that do not code for a polypeptide. They are removed from pre-messenger RNA after transcription.
Exon
Portions of DNA within a gene that codes for proteins. They are joined together during splicing.
Splicing
The process by which base sequences corresponding to the introns are removed and the functional exons are joined together.
Translation
The latter part of protein synthesis when the mRNA is used as template to which complementary tRNA molecules attach and the amino acids link to form a polypeptide.
tRNA
The type of RNA made of around 80 nucleotides and has an anticodon, which is complementary to a section of mRNA. Each molecule is specific to one amino acid.
Anti-codon
A sequence of three adjacent nucleotides on a molecule of transfer RNA that is complementary to a particular codon on a messenger RNA molecule.
Ribosome
An organelle consisting of rRNA and proteins found in large numbers in the cytoplasm and on the RER of living cells. They bind to mRNA and use tRNA to synthesise polypeptides.
Polypeptide
A polymer consisting of a large chain of amino acids bonded together by peptide bonds.
