Genetic Information, Variation, and Relationships Flashcards
adaptation
a feature of an organism that increases its chance of survival in its environment (an adaptation may be anatomical, physiological, or behavioural)
allele
a version of a gene
anticodon
a sequence of three nucleotide bases at one end of a tRNA molecule that is specific to an mRNA codon
arithmetic mean
the average of a set of numbers calculated by dividing the sum of the values by the number of values
artificial classification
a type of classification that divides organisms into groups based on analogous characteristics such as leaf shape, number of legs, and type of wing
binomial system
a universal system of naming organisms that consists of two parts: the generic name and the specific name
biodiversity
the variety of genes, species, and habitats, within a particular area
cellular proteome
the proteins expressed in a given type of cell
chromatid
one strand of a replicated chromosome
chromosome
a structure consisting of a long, coiled molecule of DNA and its associated proteins, by which genetic information is passed from generation to generation
chromosome mutation
a change to the number of structure of chromosomes that can occur spontaneously
classification
the organisation of organisms into groups (artificial and phylogenetic)
codon
a sequence of three bases on mRNA that codes for a specific amino acid
conservation
the maintenance of ecosystems and biodiversity by humans in order to preserve the earth’s resources
courtship
the behaviour by which members of a species select reproductive partners (it enables organisms to recognise their own species, identify a mate with a capacity to breed, form a pair bond, synchronise mating, and become able to breed themselves)
crossing over
the process in meiosis 1 in which homologous chromosomes pair up, their chromatids wrap around one another and their alleles are exchanged at equivalent portions of chromatids (this creates genetic variation)
degenerate
a feature of the genetic code, mode than one triplet can code for a particular amino acid
deletion
a form of gene mutation in which one or more nucleotide bases are removed from a DNA sequence (this may change all amino acids in a sequence, rendering the protein non-functional)
directional selection
a type of selection that favours individuals that differ in one direction (fall to the left or the right) from the population mean (this changes the traits of the population)
ecosystem diversity
a measure of the range of different habitats in a particular area
eukaryotic DNA
linear molecules of DNA which, together with histones, form chromosomes (DNA in the mitochondria and chloroplasts of eukaryotic cells is circular and does not have associated proteins)
exon
a sequence of DNA that codes for an amino acid sequence
fertilisation
the random fusion of haploid gametes during fertilisation to produce a diploid zygote (genetic information is mixed, creating genetic variation)
gene
a length of DNA on a chromosome that codes for the production of one or more polypeptide chains and functional RNA
gene mutation
a change to at least one nucleotide base in DNA or the arrangement of bases (gene mutations can occur spontaneously during DNA replication)
generic name
denotes the organism’s genus (the first letter is written in upper case)