Define bio terms

Define homologous chromosomes

- the 23 pairs of chromosomes which are similar in shape and size and they carry the same genes as their partners. - same length, centromere in the same position, same genes at the same loci, one from maternal the other from paternal

Define allele frequency and gene pool

Allele frequency: a measure of the proportion of a specific variation of a gene in a population. Gene pool: all of the genetic information present in the reproducing members of a population at a given time.

Define carrier and test cross

Carrier: an individual who has a recessive allele of a gene that does not have effect on their phenotype. Test cross: testing a suspected heterozygote plant or animal by crossing it with a known homozygous recessive punnett grid.

Define clade and cladistics

Clade: a monophyletic group, composed of the most recent common ancestor of the group and all its descendants. Cladistics: a system of classification which groups taxa together according to the characteristics which have most recently evolved.

Define diffusion and osmosis

Diffusion: passive movement of particles from an area of high concentration to an area of low concentration, a membrane is involved in a living system. Osmosis: passive movement of water molecules from an area of high concentration to an area of low concentration across a semi permeable membrane.

Define enzyme and active site

Enzyme: a globular protein that accelerates or catalyzes a biochemical reaction by attaching to reactants called substrate, but stays unchanged at the end. Active site: location on the enzyme where the substrate binds to.

Define gene, allele and genome

Gene: heritable factor that controls a specific characteristic. Allele: one specific form or variation of a gene, alleles of the same gene occupy a corresponding place on each chromosome of a pair. Genome: the complete set of an organism's base sequences.

Define genotype, phenotype, dominant allele, recessive allele, codominant alleles

Genotype: the combination of alleles of a gene carried by an organism. (symbolic representation of pair of alleles by 2 letters) Phenotype: the expression of alleles of a gene carried by an organism. (characteristics/ traits of an organism) Dominant allele: an allele that has the same effect on the phenotype whether it is paired with the same allele/ different one. They are always expressed in the phenotype. Recessive allele: an allele that has an effect on the phenotype only when present in homozygous state. Codominant alleles: pairs of alleles that both affect the phenotype when present in a heterozygote, influence their phenotype, present in genotype.

Define homozygous and heterozygous

Homozygous: having 2 identical alleles of a gene (Dominant - having 2 copies of same dominant alleles. Recessive - having 2 copies of same recessive alleles, only expressed when homozygous) Heterozygous: having 2 different alleles of a gene, results from the fact that the paternal allele is different from maternal.

Define clone

a creation of an organism that is an exact genetic copy of somatic cell donor.

Define gene mutation

a random, rare change in genetic material.

Define polygenic inheritance

a single characteristic is controlled by multiple genes. As the number of genes increases, so does the phenotypic variation because they are found on the same chromosome.

Define half-life

amount of time it takes for half the radioactive isotope in a substance to decay.

Define incomplete dominance

an inheritance pattern where the heterozygote exhibits an intermediate between 2 homologous phenotypes; neither allele for trait is complete dominant.

Define linkage group

any 2 genes which are found on the same chromosome are said to be linked to each other. A group of genes that will be inherited.

Define sex linkage

any genetic trait whose allele has its locus on the X or Y chromosome. Sex linked diseases affect one gender (male) more than another.

Define evolution

process of cumulative change in the heritable characteristics of a population.

Define denaturation

structural change in a protein that results in a loss of its biological properties due to high temperatures or extreme pH.

Define cell respiration

the controlled release of energy in the form of ATP from organic compounds.

Define transpiration

the loss of water vapor from leaves and other aerial parts of the plant.

Define locus

the particular position on homologous chromosomes of a gene.

Define partial pressure

the pressure exerted from a single type of gas when it is found within a mixture of gases.