Defini�ons
movement
ac�on by an organism or part of an organism causing a
change of posi�on or place
respira�on
chemical reac�ons in cells that break down nutrient
molecules and release energy for metabolism
sensi�vity
ability to detect and respond to changes in the internal or
external environment
growth
permanent increase in size and dry mass
reproduc�on
processes that make more of the same kind of organism
excre�on
removal of the waste products of metabolism and
substances in excess of requirements
nutri�on
taking in of materials for energy, growth and development
species
group of organisms that can reproduce to produce fer�le
offspring
catalyst
substance that increases the rate of a chemical reac�on
and is not changed by the reac�on
enzymes
proteins that are involved in all metabolic reac�ons, where
they func�on as biological catalysts that increases the rate
of a chemical reac�on and is not changed by the reac�on
binomial system
of naming species
an internationally agreed system in which the
scientific name of an organism is made up of
two parts showing the genus and species
diffusion the net movement of particles from a region of their higher
concentration to a region of their lower concentration (i.e. down a
concentration gradient), as a result of their random movement
osmosis the net movement of water molecules from a region of
higher water potential (dilute solution) to a region of lower water
potential (concentrated solution), through a partially permeable
membrane
active transport the movement of particles through a cell membrane
from a region of lower concentration to a region of higher
concentration (i.e. against a concentration gradient), using energy
from respiration
photosynthesis
process by which plants synthesize carbohydrates from raw materials using
energy from light (light energy to chemical energy)
Limi�ng factor
Something present in the environment in short supply and restricts life
process
inges�on
taking of substances, e.g. food and drink, into the body
Physical
diges�on
The breakdown offood into smaller pieces without chemical change to the
food molecules to increase its surface area.
Chemical
diges�on
The breakdown of large, insoluble molecules into small, soluble molecules
using enzymes
Absorp�on
The movement of small food molecules and ions through the wall of the
intes�ne into the blood
Assimila�on
The movement of digested food molecules into the cells of the body where
they are used, becoming part of the cells.
Eges�on
The passing out of food that has not been digested or absorbed, as faeces,
through the anus
transpira�on
Loss of water vapour from leaves by evapora�on of water from the surface
of mesophyll cells followed by diffusion of water vapour through stomata
Transloca�on
movement of sucrose and amino acids in phloem from sources to sinks
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Fer�liza�on
fusion of the nuclei of gametes to form diploid zygote
Sink
parts of plants that use or store sucrose or amino acids
Pollina�on
transfer of pollen grains from an anther to a s�gma
Single
circula�on
Blood passes through the heart once In one complete circuit
Selfpollina�on
transfer of pollen grains from the anther of a flower to the s�gma of
the same flower or a different flower on the same plant
Double
Circula�on
Blood passes through the heart twice in one complete circuit
Crosspollina�on
transfer of pollen grains from the anther of a flower to the s�gma of
a flower on a different plant of the same species
Pathogen
A disease-causing microorganism
Transmissible
disease
disease in which the pathogen can be passed from one host to another
Sexually
transmited
infec�on
infec�on that is transmited through sexual contact (Human
immunodeficiency virus)
ac�ve
immunity
defence against a pathogen by an�body produc�on in the body
Chromosome
Thread-like structures of DNA & Proteins, carrying gene�c
informa�on in the form of genes
passive
immunity
short-term defence against a pathogen by an�bodies acquired from
another individual, including across the placenta and in breast milk
Inheritance
Transmission of gene�c informa�on from genera�on to genera�on
Gene
Length of DNA, codes for making protein
Diarrhea
Loss of watery faeces
Allele
Version of a gene
aerobic
respira�on
chemical reac�ons in cells that use oxygen to break down nutrient
molecules to release energy
Haploid
Contains one set of chromosomes
anaerobic
respira�on
chemical reac�ons in cells that break down nutrient molecules to
release energy without using oxygen
Diploid
Contains two sets of chromosomes
Mitosis
nuclear division giving rise to gene�cally iden�cal cells
Deamina�on
Removal of nitrogen containing part of amino acid in liver to form
ammonia then urea
Meiosis
reduc�on division in which the chromosome number is halved from
diploid to haploid resul�ng in gene�cally different cells
reflex ac�on
automa�cally and rapidly integra�ng and coordina�ng s�muli with the
responses of effectors (muscles and glands)
Genotype
Gene�c make up of the organism and the alleles present
Phenotype
observable features of an organism
synapse
Junc�on between two neurones
Homozygous
having two iden�cal alleles of a par�cular gene
Sense organ
groups of receptor cells responding to specific s�muli
Heterozygous
having two different alleles of a par�cular gene
Hormone
chemical substance, produced by a gland and carried by the blood,
which alters the ac�vity of one or more specific target organs
Dominant
allele
Allele that is expressed if it is present in the genotype
Homeostasis
maintenance of a constant internal environment
Gravitropism
response in which parts of a plant grow towards or away from gravity
Recessive
allele
allele that is only expressed when there is no dominant allele of the
gene present in the genotype
Phototropism
response in which parts of a plant grow towards or away from the
direc�on of the light source
Codominance
situa�on in which both alleles in heterozygous organisms contribute
to the phenotype
Drug
Chemical substance taken into the body that modifies or affects
chemical reac�ons in the body
Sex-linked
characteris�c
Asexual
reproduc�on
produc�on of gene�cally iden�cal offspring from one parent
a feature in which the gene responsible is located on a sex
chromosome and that this makes the characteris�c more common
in one sex than in the other
Varia�on
differences between individuals of the same species
Sexual
reproduc�on
fusion of the nuclei of two gametes to form a zygote and the produc�on
of offspring that are gene�cally different from each other
Gene
muta�on
random change in the base sequence of DNA
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Adap�ve
feature
inherited feature that helps an organism to survive and reproduce in its environment
Fitness
Probability of organism surviving and reproducing in its environment
Adapta�on
the process, resul�ng from natural selec�on, by which popula�ons become more suited to their environment over many genera�ons
Food chain
showing the transfer of energy from one organism to the next, beginning with a producer
Food web
network of interconnected food chains
Producer
organism that makes its own organic nutrients using energy from sunlight, through photosynthesis
Consumer
organism that gets its energy by feeding on other organisms
Herbivore
animal that gets its energy by ea�ng plants
Carnivore
animal that gets its energy by ea�ng other animals
Decomposer
organism that gets its energy from dead or waste organic material
Trophic
level
posi�on of an organism in a food chain, food web or ecological pyramid
popula�on
group of organisms of one species, living in the same area, at the same �me
community
all of the popula�ons of different species in an ecosystem
Ecosystem
unit containing the community of organisms and their environment, interac�ng together
Biodiversity
number of different species that live in an area
Sustainable
resource
one which is produced as rapidly as it is removed from the environment so that it does not run out
Gene�c
modifica�on
changing the gene�c material of an organism by removing, changing or inser�ng individual genes
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