Definitions Flashcards
Define diffusion:
Diffusion as the net movement of particles from a region of their higher concentration to
a region of their lower concentration down
a concentration gradient, as a result of their random movement
Define osmosis:
Osmosis as 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
Define enzymes:
Enzymes as proteins that function as biological catalysts
Define photosynthesis:
Photosynthesis as the process by which plants manufacture carbohydrates from raw materials using energy from light
Define ingestion:
Ingestion as the taking of substances. e.g. food and drink into body through the mouth.
Define digestion:
Digestion as the breakdown of large, insoluble food molecules into small, water- soluble molecules using mechanical and chemical processes
Define mechanical digestion:
Mechanical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules
Define chemical digestion:
Chemical digestion as the breakdown of large, insoluble molecules into small, soluble molecules
Define absorption:
Absorption as movement of digested food molecules through the wall of the intestine into the blood
Define assimilation:
Assimilation as the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
Define egestion:
Egestion as passing out of food that has not been digested, as faeces, through the anus
Define transpiration:
Transpiration as loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata
Define translocation:
Translocation in terms of the movement of sucrose and amino acids in phloem:
– from regions of production (source)
– to regions of storage OR to regions where
they are used in respiration or growth (sink)
Define aerobic respiration:
Aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
Define anaerobic respiration:
Anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
Define a hormone:
Hormone as a chemical substance, produced by a gland, carried by the blood, which alters the activity of one or more specific target organs
Define homeostasis:
Homeostasis as the maintenance of a constant internal environment
Define gravitropism:
Gravitropism as a response in which parts of a plant grow towards or away from gravity
Define phototropism:
Phototropism as a response in which parts of a plant grow towards or away from the direction from which light is coming
Define asexual reproduction:
Asexual reproduction as a process resulting in the production of genetically identical offspring from one parent
Define sexual reproduction:
Sexual reproduction as 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
Define pollination:
Pollination as the transfer of pollen grains from the anther to the stigma
Define inheritance:
Inheritance as the transmission of genetic information from generation to generation
Define chromosome:
Chromosome as a thread-like structure of DNA, carrying genetic information in the form of genes
Define gene:
Gene as a length of DNA that codes for a protein
Define allele:
Allele as a version of a gene
Define haploid nucleus:
Haploid nucleus as a nucleus containing a single set of unpaired chromosomes, e.g. in gametes
Define diploid nucleus:
Diploid nucleus as a nucleus containing two sets of chromosomes, e.g. in body cells
Define mitosis:
Mitosis as nuclear division giving rise to genetically identical cells
Define meiosis:
Meiosis as reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells
Define genotype:
Genotype as the genetic make-up of an organism in terms of the alleles present
Define phenotype:
Phenotype as the observable features of an organism
Define homozygous:
homozygous as having two identical alleles of a particular gene
Define heterozygous:
Heterozygous as having two different alleles of a particular gene
Define dominant:
Dominant as an allele that is expressed if it is present
Define recessive:
Recessive as an allele that is only expressed when there is no dominant allele of the gene present
Define variation:
Variation as differences between individuals of the same species
Define mutation:
Mutation as a change in a gene or chromosome
Define the process of adaptation:
The process of adaptation as the process, resulting from natural selection, by which populations become more suited to their environment over many generations
Define food chain:
Food chain as showing the transfer of energy from one organism to the next, beginning with a producer
Define food web:
Food web as a network of interconnected food chains
Define producer:
Producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
Define consumer:
Consumer as an organism that gets its energy by feeding on other organisms
Define herbivore:
Herbivore as an animal that gets its energy by eating plants
Define carnivore:
Carnivore as an animal that gets its energy by eating other animals
Define decomposer:
Decomposer as an organism that gets its energy from dead or waste organic matter
Define ecosystem:
Ecosystem as a unit containing all of the organisms and their environment, interacting together, in a given area, e.g. a lake
Define trophic level:
Trophic level as the position of an organism in a food chain or food web
