Definitions Flashcards
chromosomes
one DNA molecule that is made up of coding DNA and non-coding DNA between and within genes
homologous pair
two chromosomes that are made up of the same genes in the same order
gamete
a sex cell
haploid
containing one copy of each type of chromosome
diploid
containing two copies of each type of chromosome
gene linkage
the tendency of alleles that are located close together on a chromosome to be inherited together during meiosis
sex linkage
genes that are located on the sex chromosome are sex-linked as their specific trait will be passes on with either male or female
crossing over
non-sister chromatids exchange corresponding sections of DNA to give new combinations of alleles on the chromatids
independent assortment
the variable arrangement of homologous pairs during metaphase that give different combinations of paternal and maternal chromosomes
cell
the basic unit that living organisms are made of a specific function.
tissue
a group of similar specialised cells working together to carry out one function
organ
a structure made of different tissues which work together the carry out one or many functions
organ systems
a group of organs working together to carry out a particular function
gene
a sequence of nucleotides on DNA that codes for a protein
allele
one form of a gene
locus
the location of a gene on a chromosome
phenotype
the appearance of the characteristic in an indivudal
genotype
the alleles the individual has for a particular characteristic
variation
the difference that exists between members of a single species
two main courses of variation
genetic and environmental factors
continuous variation definition
where there is a complete range of measurements from one extreme to the other, there is no discrete categories and is based on measurable features
discontinuous variation definition
where an individual falls into distinct categories and based on features which are not measured
continuous variation characteristics
caused by polygenic genes, often with multiple alleles and there is a large environmental influence.
discontinuous variation characteristic
caused by different alleles of the same gene at a single loci, there is no environmental influence on the phenotype.
