Biology definitions

Ele Vassanelli
Flashcards by Ele Vassanelli, updated more than 1 year ago
Ele Vassanelli
Created by Ele Vassanelli over 4 years ago


All the biology definitions

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Question Answer
Movement is an action by an organism or part of an organism causing a change in position or place
Respiration is a chemical reaction in cells that break down nutrient molecules and releases energy for metabolism
Sensitivity is the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
Growth is a permanent increase in size and dry mass by an increase in cell number or cell size or both
Reproduction is the process that makes more of the same kind of organism
Excretion is the removal from organisms of the waste products of metabolism (chemical reactions in cell including respiration) toxic materials, and substances in excess of requirements
Nutrition is the taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds and ions and usually need water
Species are a group of organisms that can reproduce to produce fertile offsprings
Binomial system is an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species
Tissue is a group of cells with similar structures, working together to perform a shared function
Organ is a group of tissues, working together to perform a specific function
Organ system is a group of organs with related functions, working together to perform body functions
Diffusion is the net movement of particles from a region of high concentration to a region of low concentration down a concentration gradient as a result of their random movement
Osmosis is the net movement of water molecules through a partially permeable membrane from a region of high water potential to a region of low water potential through a water potential gradient
Active transport is the movement of particles through a cell membrane from a region of low concentration to a region of high concentration against a concentration gradient using energy from respiration
Catalyst is a substance that increases the rate of a chemical reaction and is not changed by the reaction
Enzyme is a protein that functions as a biological catalyst
Photosynthesis is 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 is the taking in of substances eg. food and drink into the body through the mouth
Mechanical digestion the breakdown of food into smaller pieces without chemical change to the food molecules
Chemical digestion the breakdown of large, insoluble molecules into small, soluble molecules
Assimilation the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
Absorption the movement of small food molecules and ions through the wall of the intestine into the blood
Egestion the passing out of food that has not been digested or absorbed, as feces, through the anus
Transpiration loss of water vapor from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapor through stomata
Translocation Movement of sucrose and amino acids in phloem from regions of production (source) to a region of storage or to regions where they are used in respiration or growth (sink)
Pathogens Disease-causing organisms
Transmissible disease disease in which the pathogens can be passed from one host to another
Active immunity Defense against a pathogen by antibody production in the body
Aerobic respiration Chemical reaction in cells that use oxygen to break down nutrient molecules to release energy
Anaerobic respiration chemical respiration in cells that breakdown nutrient to release energy without using oxygen
Deamination the removal of the nitrogen-containing part of amino acids to form urea
Synapse a junction between two neurones
Sense organs groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals
Hormone 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 response in which parts of a plant grow towards or away from gravity
Phototropism response in which parts of a plant grow towards or away from the direction from which light is coming
Drug any 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 (sex cells) to form a zygote and the production of offspring that are genetically different from each other
Fertilization the fusion of gamete nuclei
Self-pollination the transfer of pollen grains from the anther of a flower to the stigma of the same flower or different flower on the same plant
Cross-pollination 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 infections (STI) an infection that is transmitted via body fluids through sexual contact
Inheritance the transmission of genetic information from generation to generation
Chromosome a thread-like structure of DNA, carrying genetic information in the form of genes
Gene a length of DNA that codes for a protein
Allele a version of a gene
Haploid nucleus a nucleus containing a single set of unpaired chromosomes, e.g. in gametes
Diploid nucleus a nucleus containing two sets of chromosomes, e.g. in body cells
Mitosis nuclear division giving rise to genetically identical cells
Meiosis reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells
Genotype the genetic make-up of an organism in terms of the 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 is present
Recessive an allele that is only expressed when there is no dominant allele of the gene present
Sex-linked characteristics a characteristic in which the gene responsible is located on a sex chromosome and that this makes it more common in one sex than in the other
Variation Difference between individuals of the same species
Gene mutation Change in the base sequence of DNA
Adaptive feature an inherited functional feature of an organism that increases its fitness
Fitness the probability of an organism surviving and reproducing in the environment in which it is found
Adaptation the process, resulting from natural selection, by which populations become more suited to their environment over many generations
Food chain showing the transfer of energy from one organism to the next, beginning with a producer
Trophic level the position of an organism in a food chain, food web, pyramid of numbers or pyramid of biomass
Food web Network of interconnected food chains
Producer an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
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
Decomposers an organism that gets its energy from dead or waste organic material
Population a group of organisms of one species, living in the same area, at the same time
Community all of the populations of the different species in an ecosystem
Ecosystem a unit containing the community of organisms and their environment, interacting together, eg. a decomposing log or a lake
Genetic engineering a changing the genetic material of an organism by removing, changing or inserting individuals genes
Sustainable development development providing for the needs of an increasing human population without harming the environment
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