IGCSE Biology Vocabulary Flashcards
movement
an action by an organism or part of an organism causing a change of position or place
respiration
the chemical reactions in cells that break down nutrient molecules and release energy for metabolism
sensitivity
the ability to detect or sense stimuli in the internal or external environment and make appropriate responses
growth
a permanent increase in size and dry mass by an increase in the cell number or cell size or both
excretion
removal from organisms of the waste products of metabolism, toxic materials, and substances in excess of requirements
nutrition
taking in materials for energy, growth, and development
reproduction
making more of the same kind of organism
species
group of organisms that can reproduce to produce fertile offspring
binomial system
an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species
tissue
a group of cells with similar structures, working together to perform a shared function
organ
a structure made up of a group of tissues, working together to perform specific functions
organ system
a group of organs with related functions working together to perform body functions
diffusion
the net movement of particles from a region of their higher concentration to a lower concentration down a concentration gradient, as a result of random movement
osmosis
the net movement of water molecules from a region of higher water potential (a dilute solution) to a region of lower water potential (a concentrated solution) through a partially permeable membrane
active transport
the movement of particles through a membrane fro ma region of lower concentration to a region of higher concentration using energy from respiration
catalyst
a substance that increases the rate of a chemical reaction and is not changed by the reaction
enzyme
a protein that functions as a biological catalyst
photosynthesis
the process by which plants manufacture carbohydrates from raw materials using energy from light
limiting factor
something present in the environment in such short supply that it restricts life processes
ingestion
taking substance into the body through the mouth
mechanical digestion
breakdown of food into smaller pieces without chemical change to the food molecules
chemical digestion
breakdown of large, insoluble molecules into small soluble molecules
absorption
movement of small food molecules and ions through the walls of the intestine into the blood
assimilation
movement of digest food molecules into the cells of the body where they are used, becoming part of the cells
egestion
passing out of food that has not been digested or absorbed, as feces, through the anus
transpiration
the loss of water vapor from plant leaves by evaporation of water at the surfaces of mesophyll cells followed by diffusion of water vapor through the stomata
translocation
the movement of sucrose and amino acids in phloem from regions of production to regions of storage (source) or regions where they are used in respiration or growth (sink)
source
region of the plant from which sucrose or amino acids are being transported
sink
region of the plant to which sucrose or amino acids are being transported
pathogen
a disease causing organism
transmissible disease
a disease in which the pathogen can be passed from one host to another
active immunity
defense against a pathogen by antibody production in the body
passive immunity
short-term defense against a pathogen by antibodies acquired from another individual (mother to infant)
aerobic respiration
the chemical reaction in cells that use oxygen to break down nutrient molecules to release energy
anaerobic respiration
the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
deamination
the removal of of the nitrogen-containing part of amino acids to form urea
synapse
a junction between two neurons
sense organ
groups of receptor cell responding to specific stimuli (light, sound, touch, temperature, and chemicals)
hormones
a chemical substance produced by a gland and carried by the blood, which alters the activity of one or more specific target organs
homeostasis
the maintenance of a constant internal environment
gravitropism
a response in which parts of a plant grow towards or away from gravity
phototropism
a response in which parts of a plant grow towards or away from the direction from which light is coming
drug
a substance taken into the body that modifies or affects chemical reactions in the body
asexual reproduction
a process resulting in the production of genetically identical offspring from one parent
sexual reproduction
a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from one another
fertilization
the fusion of gamete nuclei
pollination
the transfer of pollen grains from the anther to the stigma
self-pollination
the transfer of pollen grains from the anther of a flower to the stigma of the same flower, or a different flower on the same plant
cross-pollination
the transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
sexually transmitted infection
an infection that is transmitted via body fluids through sexual contact
allele
version of a gene
inheritance
the transmission of genetic information form generation to generation
chromosome
a thread-like structure made of DNA, which carries genetic information in the form of genes
gene
a length of DNA that codes for a protein
haploid nucleus
a nucleus containing a single set of unpaired chromosomes (such as in gametes)
diploid nucleus
a nucleus containing two sets of chromosomes (such as in body cells)
mitosis
nuclear division giving rise to cells that are genetically identical
meiosis
reductive division in which chromosome number is halved from diploid to haploid, resulting in genetically different cells
genotype
the genetic make-up of an organism in terms of alleles present
phenotype
the observable features of an organism
homozygous
having two identical alleles of a particular gene
heterozygous
having two different alleles of a particular gene
dominant
an allele that is expressed if it present
recessive
an allele that is only expressed when there is no dominant allele of the gene present
sex-linked characteristic
a characteristic in which the gene responsible is located on a sex-chromosome and that makes it more common in one sex than in the other
variation
differences between individuals of the same species
mutation
change in the base sequence of DNA
adaptive feature
the inherited features of an organism that increase its fitness
fitness
the probability of an organism surviving and reproducing in the environment in which it is found
process of adaptation
the process resulting from natural selection by which populations become more suited to their environment over many generations
genetic engineering
changing the genetic material of an organism by removing, changing, or inserting individual genes
food chain
a diagram showing the transfer of energy from one organism to another, beginning with a producer
food web
a network of interconnected food chains
producer
an organism that makes its own organic nutrients, usually using energy from sunlight
consumer
an organism that gets its energy by feeding on other organisms
herbivore
an animal that gets its energy by eating plants
carnivore
an animal that gets its energy by eating other animals
omnivore
an animal that gets its energy by eating both plants and other animals
decomposer
an organism that gets its energy from dead or waste organic material
trophic level
the position of an organism in a food chain, food web, pyramid of numbers or pyramid of biomass
population
a group of organisms of one species living in the same area at the same time
community
all the population of different species in an ecosystem
ecosystem
a unit containing the community of organisms and their environment interacting together
sustainable resource
once that is produced as rapidly as it is removed from the environment so that it does not run out
sustainable development
development providing for the needs of an increasing human population without harming the environment
