Definitions Flashcards
Tissue
A group of cells working together to perform a shared function
What is a species
A group of organisms that can reproduce to produce fertile offspring.
Organ
A group of tissues working together to perform a shared function
Organ system
A group of organs working together to perform a shared function
Diffusion
Net movement of particles from higher to lower concentration as a result of their random movement
Osmosis
Net movement of water from higher water potential to lower water potential through a partially permeable membrane
Active transport
Movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
Structure of DNA
Double helix, chemicals called bases, bonds between pairs of bases, A binds with T, C binds with G
Catalyst
Substance that increases the rate of a chemical reaction and is not changed or used up by the reaction
Enzyme
Proteins involved in all metabolic reactions; biological catalysts
Photosynthesis
Process by which plants synthesize carbohydrates from raw materials using energy from light
Balanced diet
Contains all food groups in correct proportions to stay healthy
Physical digestion
Breakdown of food into smaller pieces without chemical change, to increase surface area for enzyme activity
Chemical digestion
Breakdown of large insoluble molecules to small soluble ones that can be absorbed
Transpiration
Loss of water vapour from leaves; water evaporates from spongy mesophyll cells into the air spaces and then diffuses out of the stomata
Translocation
Movement of sucrose and amino acids from source to sink
Blood clot
Fibrinogen is converted to fibrin to form a mesh
Pathogen
A disease-causing organism
Transmissable disease
A disease in which the pathogen can be passed on from one host to another
Active immunity
Defence against a pathogen by antibody production
7 uses of energy
- muscle contractions
- protein synthesis
- cell division
- active transport
- growth
-passage of nerve impulses - maintenance of a constant body temp
Anaerobic respiration
Chemical reactions in cells that break down nutrient molecules to release energy without oxygen
Anaerobic respiration
Chemical reactions in cells that break down nutrient molecules to release energy with oxygen
Deamination
Removal of the ‘nitrogen - containing’ part of amino acids to form urea
Synapse
A junction between 2 neurones
Sense organs
A group of receptor cells responding to specific stimuli
Hormone
A chemical substance produced by a gland, carried by the blood, and alters the activity of one or more target organ
Homeostasis
Maintenance of a constant internal environment
Drug
Any substance taken into the body that modifies or affects chemical reactions in the body
Asexual reproduction
Process resulting int the production of genetically idential offspring from one parent
Sexual reproduction
Process involving the fusion of nuclei of 2 gametes to form a zygote; offspring are genetically different
Fertilisation
Fusion of nuclei of gametes
Self pollination
Transfer of pollen from anther to stigma on same flower, or a 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
STI
An infection transmitted through sexual contact
Gene
A length of DNA that codes for a protein
Allele
An alternative form of a gene
Mitosis
Nuclear division giving rise to genetically identical cells
Stem cells
Unspecialised cells that divide by mitosis to produce daughter cells that can become specialised
Meiosis
Reduction division in which chromosome number is halved from diploid to haploid resulting in genetically different cells
Inheritance
Transmission of genetic information from generation to generation
Genotype
Genetic makeup of an organism
Phenotype
Observable feature of an organism
Homozygous
2 identical alleles of a gene
Heterozygous
2 different alleles of a gene
Dominant allele
Expressed if it is present in the genotype
Recessive allele
Only expressed if no dominant allele is present
Codominance
Both alleles in heterozygous organisms contribute to the phenotype
Variation
Differences between individuals of the same species
Mutation
Random change in the base sequence of DNA
Adaptive feature
An inherited feature that helps an organism to survive and reproduce in its environment
Adaptation
The process resulting from natural selection by which populations become more suited to their environment over many generations
Producer
An organism that makes its own organic nutrients usually using energy from sunlight through photosynthesis
Decomposer
An organism that gets its energy from dead or waste organic material
Population
A group of organisms of one species, living int eh same area, at the same time
Community
All the populations or diiferent species in an ecosystem
Ecosystem
A unit containing the community of organisms and the environment interacting together
Biodiversity
Number of different species that live in an area
Sustainable resource
A resource that is produced as rapidly as it is removed from the environment so that it doesn’t run out
Genetic modification
Changing the genetic material of an organism by removing, changing or inserting individual genes
Movement
An action causing a change in position or place
