B5 Flashcards
Define “active site”
The part of the enzyme which is specific to the substrate and has a complementary shape to it
Define “allele”
A version of a gene (also known as a variant)
Define “antibiotic”
A type of medication that helps cure bacterial disease by killing infective bacteria inside the body
Define “antibiotic resistance”
The ability of a bacteria to become resistant to the treatment that is being used to kill it, i.e. antibiotics.
This provides evidence for evolution
Define “artificial classification”
The classification of organisms based on observable characteristics
Define “asexual reproduction”
A form of reproduction that only involves a single parent and creates genetically identical offspring
Define “biodiversity”
The variety of different organisms living in an ecosystem
Define “chromosome”
A long, coiled molecule of DNA that carries genetic information in the form of genes
Define “continuous variation”
Variation that can take any value between two extremes, e.g. height or weight
Define “DNA (deoxyribonucleic acid)”
A polymer that is made of two strands twisted around each other forming a double helix, and contains all the genetic information
Define “diploid”
A cell with a full set of chromosomes
Define “discontinuous variation”
Variation that can only take discrete values, e.g. eye colour
Define “dominant”
An allele that is always expressed when present, and is represented by a capital letter. Only one copy of it is needed for it to be expressed
Define “enzyme”
A biological catalyst that increases the rate of chemical reactions
Define “evolution”
A change in the inherited characteristics of a population over time, through the process of natural selection, which may result in the formation of new species
Define “extinction”
When all members of a species have died
Define “fossil record”
The remains or impressions of dead organisms found in rocks that are millions of years old.
They provide evidence for evolution
Define “gamete”
Sex cells (sperm and egg cells) with half the usual number of chromosomes.
They are involved in reproduction
Define “gene”
A section of DNA that codes for a specific amino acid sequence which is polymerised to make a specific protein
Define “genetic variation”
The variation in the genes of a species
Define “genome”
The entire genetic material of an organism
Define “genotype”
The genetic makeup of an organism
Define “haploid”
A cell that has half the number of chromosomes
Define “heterozygous”
When an individual has two non-identical alleles of a gene, e.g. Bb
Define “homozygous”
When an individual has two identical alleles of a gene, e.g. bb
Define “meiosis”
A form of cell division that produces gametes. They are not genetically identical and contain half the number of chromosomes
Define “messenger RNA (mRNA)”
An RNA subtype that carries genetic information from the nucleus to the ribosomes during protein synthesis
Define “molecular phylogenetics”
Finding evolutionary relationships between organisms on the basis of their DNA. This method can only be used on fossils that have DNA present
Define “mutation”
A random change in DNA which increases variation. They may have a neutral, beneficial or damaging effect on the phenotype
Define “natural classification”
The classification of organisms based on their evolutionary relationships
