Biology Sl Flash Cards

Front 1

Diffusion

Back 1

The net movement of particles from a region of high concentration to a region of low concentration (along the gradient) until equilibrium

Front 2

Osmosis

Back 2

The net movement of water molecules across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration until equilibrium is reached

Front 3

Enzyme

Back 3

A globular protein that increases the rate of a biochemical reaction by lowering the activation energy threshold (i.e. a biological catalyst)

Front 4

Active Site

Back 4

The site on the surface of an enzyme which binds to the substrate molecule

Front 5

Denaturation

Back 5

A structural change in a protein that results in the loss (usually permanent) of its biological properties

Front 6

Cell Respiration

Back 6

Cell respiration is the controlled release of energy from organic compounds in cells to form ATP (adenosine triphosphate)

Front 7

Gene

Back 7

"A heritable factor that controls a specific characteristic

Hint 7

consisting of a length of DNA occupying a particular position on a chromosome (locus)"

Front 8

Allele

Back 8

"One specific form of a gene

Hint 8

differing from other alleles by one or a few bases only and occupying the same locus as other alleles of the gene"

Front 9

Genome

Back 9

The whole of the genetic information of an organism

Front 10

Gene mutation

Back 10

A change in the nucleotide sequence of a section of DNA coding for a particular feature

Front 11

Homologous chromosomes

Back 11

Chromosomes that share the same structural features and the same genes at the same loci

Front 12

Genotype

Back 12

The allele combination of an organism

Front 13

Phenotype

Back 13

The characteristics of an organism (determined by a combination of genotype and environmental factors)

Front 14

Recessive Allele

Back 14

An allele that only has an effect on the phenotype when present in the homozygous state

Front 15

Codominant alleles

Back 15

Pairs of alleles that both affect the phenotype when present in a heterozygote

Front 16

Trophic level

Back 16

The position an organism occupies in a food chain

Front 17

Evolution

Back 17

The cumulative change in the heritable characteristics of a population

Front 18

Pathogen

Back 18

"A disease-causing micro-organism

Hint 18

virus or prion"

Front 19

Resting potential

Back 19

"The charge difference across the membrane when a neuron is not firing (-70 mV)

Hint 19

as maintained by the sodium-potassium pump"

Front 20

Action potential

Back 20

The charge difference across the membrane when a neuron is firing (about 30 mV)

Front 21

Allele frequency

Back 21

The proportion of an allele within a population

Front 22

Gene pool

Back 22

The sum total of alleles present in a sexually reproducing population

Front 23

Clone

Back 23

A clone is a group of genetically identical organisms or a group of cells derived from a single parent cell

Front 24

Locus

Back 24

The particular position on homologous chromosomes of a gene

Front 25

Homozygus

Back 25

Having two identical alleles of a gene

Front 26

Heterozygous

Back 26

Having two different alleles of a gene

Front 27

Carrier

Back 27

An individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele

Front 28

Test cross

Back 28

Testing a suspected heterozygote by crossing it with a known homozygous recessive

Front 29

Sex linkage

Back 29

when a gene controlling a characteristic is found on a sex chromosome

Front 30

Species

Back 30

"A group of organisms that can interbreed and produce fertile

Hint 30

viable offspring"

Front 31

Population

Back 31

A group of organisms of the same species who live in the same area at the same time

Front 32

Community

Back 32

A group of populations living and interacting with each other in an area

Front 33

Ecosystem

Back 33

A community and its abiotic environment

Front 34

Ecology

Back 34

The study of relationships between living organisms and between organisms and their environment

Front 35

Habitat

Back 35

The environment in which a species normally lives or the location of a living organism

Front 36

Half-life

Back 36

a measure of the time taken for the radioactivity to fall to half its original level

Front 37

Stimulus

Back 37

A change in the environment (external or internal) that is detected by a receptor

Front 38

Response

Back 38

A change in an organism (an action) resulting from a stimulus

Front 39

Reflex

Back 39

A type of response that is rapid and involuntary (unconscious)

Front 40

Dominant Allele

Back 40

An allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state