03. Definitions Flashcards
(41 cards)
Evolution
the long-term adaptive process spanning generations, that equips each species for life in its ever changing natural habitat
Structural proteins
form the structure of every cell of the body
enzymes
control the rate of every chemical reaction in every cell
Coding genes
code for unique protein molecules
Regulatory genes
work through various biological means to help activate or suppress specific coding genes and thereby influence the body’s development.
Environment
every aspect of an individual and his or her surroundings except the genes themselves
Genotype
refers to the set of genes that the individual inherits
Phenotype
refers to the observable properties of the body and behavioural traits
Mitosis
Cell division to produce new cells (other than egg or sperm cells). Each chromosome precisely replicates itself.
Meiosis
when cells divide to produce an egg or sperm cell, cells are not genetically alike
Zygote
The result of a sperm and egg cell uniting (each is unique)
Monozygotic twins (identical twins)
Twins from one zygote
Fraternal twins
Dizygotic twins, originate from two zygotes. As genetically similar as non-twin siblings
Homozygous
Identical genes occupying the same locus on a pair of chromosomes
Heterozygous
non-identical genes which occupy the same locus on a pair of chromosomes
Alleles
Different genes that can occupy the same locus and thus can potentially pair with each other
Dominant gene
A gene which will produce its observable effects in either the homozygous or heterozygous condition
Recessive gene
A gene which will produce its effects only in the homozygous condition.
Normal distribution
most scores fall near the middle of the range and the frequency tapers off toward the two extremes
Polygenic charactersitics
Are characteristics that vary in a continuous way and are generally affected by many genes
Selective breeding
This procedure involves the mating of individuals that lie toward the same extreme on the measure in question. For single-gene characteristics the effects of selective breeding are immediate, but for polygenic characteristics the effects are gradual and cumulative over generations.
Epigenetics
“changes in gene function that do not alter its underlying structure of DNA but result in genes being switched on or off in a reversible way”
Artificial selection
Used by Darwin to refer to human-controlled selective breeding
Mutations
Are errors that occasionally and unpredictably occur during DNA replication, causing the “replica” to be not quite identical to the original