Biology A-Level AQA Keywords - Unit
4
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.
4
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.
