Definitions Flashcards
Diffusion
Diffusion is the passive movement of particles from a region of high concentration to a region of low concentration.
Osmosis
Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.
Enzyme
Enzyme: globular proteins that act as catalysts for biochemical reactions.
Active Site
Active site: specific region on the surface of an enzyme to which substrates bind and which catalyzes biochemical reactions.
Denaturation
Denaturation is a structural change in a protein that results in the loss (usually permanent) of its biological properties. Refer only to heat and pH as agents.
Cell Respiration
Cell respiration is the controlled release of energy from organic compounds in cells to form ATP.
Gene
Gene: a heritable factor that controls a specific characteristic.
Allele
Allele: one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene.
Genome
Genome: the whole of the genetic information of an organism.
Gene Mutation
A change in the base-sequence of an allele.
Homologous Chromosomes
Chromosome pairs, one from each parent, that are identical or very similar in gene composition. Can be identified by size, banding pattern and centromere position.
Genotype
Genotype: the alleles of an organism.
Phenotype
Phenotype: the characteristics of an organism.
Dominant Allele
Dominant allele: an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state
Recessive Allele
Recessive allele: an allele that only has an effect on the phenotype when present in the homozygous state.
Codominant Alleles
Codominant alleles: pairs of alleles that both affect the phenotype when present in a heterozygote.
Homozygous
Homozygous: having two identical alleles of a gene.
Heterozygous
Heterozygous: having two different alleles of a gene.
Locus
Locus: the particular position on homologous chromosomes of a gene.
Carrier
Carrier: an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele.
Test Cross
Test cross: testing a suspected heterozygote by crossing it with a known homozygous recessive.
Sex Linkage
An association between genes in sex chromosomes that makes some traits more prevalent in on gender than the other. These genes are located on the non-homologous region of the X-chromosome in humans.
Clone
Clone: a group of genetically identical organisms or a group of cells derived from a single parent cell.
Species
Species: a group of organisms that can interbreed and produce fertile offspring.
Habitat
Habitat: the environment in which a species normally lives or the location of a living organism.
Population
Population: a group of organisms of the same species who live in the same area at the same time.
Community
Community: a group of populations living and interacting with each other in an area.
Ecosystem
Ecosystem: a community and its abiotic environment.
Ecology
Ecology: the study of relationships between living organisms and between organisms and their environment.
Trophic Level
A class of organisms that share the same position in a food chain (such as producers, primary consumers etc)
Evolution
Evolution is the cumulative change in the heritable characteristics of a population.
Pathogen
Pathogen: an organism or virus that causes a disease.
Resting Potential
Resting potential: the electrical potential across the plasma membrane of a cell that is not conducting an impulse.
Action Potential
Action potential: the reversal and restoration of the electrical potential across the plasma membrane of a cell, as an electrical impulse passes along it (depolarization and repolarization).
Nutrient
Nutrient: a chemical substance found in foods that is used in the human body.
Stimulus
A stimulus is a change in the environment (internal or external) that is detected by a receptor and elicits a response.
Response
A response to a change in (internal or external) environment, detected by a receptror.
Reflex
A reflex is a rapid, unconscious response.
