Definitions Flashcards
Abiotic factors
Non-living factors
Active immunity
The production of a persons own antibodies in response to foreign antigens that enter the body
Active site
The part of an enzyme that combines with the substrate
Active transport
Energy used to move molecules, often against a concentration gradient
Antagonistic pair
Two muscles that have opposite effects on each other
Antibiotics
Chemicals produced by micro organisms that stop the growth of, or kill, other microorganisms without damaging human tissue
Antibody
A protein produced by white blood cells in response to a specific antigen
Antigen
A foreign molecule that stimulates the production of antibodies
Artificial active immunity
Occurs when a pathogen is medically introduced into the body
Artificial passive immunity
Occurs when a person is given an injection containing antibodies made by another organism
Aseptic / asepsis
Means that measures are taken to exclude unwanted microorganisms
Balanced diet
One that contains all the necessary food types in the correct proportions
Biomolecules
Chemicals that are made inside a living thing
Bioprocessing
The use of enzyme-controlled reactions to produce a product
Bioreactor
A vessel or container in which living cells or their products are used to make a product
Biotechnology
The use of living things or their components to manufacture useful products or r to carry out useful reactions
Birth control
Methods taken to limit the number of children that are born
Blood pressure
The force exerted by the blood against the wall of the blood vessels
Bud
A potential growth point that may develop into a shoot, a leaf or a flower
Cancer
A group of disorders in which certain cells lose their ability to control both the rate of mitosis and the number of divisions
Catabolic reactions
The breaking down of large molecules into smaller ones with the release of energy
Catalyst
A substance that speeds up a reaction without being used up itself in the reaction
Cellular energy
Energy stored in the bonds of biomolecules
Chromatin
Elongated chromosomes that are not dividing
Chromosomes
Coiled threads of DNA and protein that become visible in the nucleus at cell division
Closed circulatory system
Blood remains in a continuous system of blood vessels
Competition
Occurs when organisms actively struggle for a resource that is in short supply
Conservation
Management of existing natural resources to ensure the survival of organisms and their habitats
Contraception
The deliberate prevention of fertilisation or pregnancy
Cross-pollination
The transfer of pollen from an anther to a stigma on a different plant
Denatured enzyme
One that has lost its shape and can no longer carry out its function
Denitrification
The conversion of nitrates to nitrogen gas
Diffusion
The spreading out of molecules from a region of high concentration to a region of low concentration
Diploid cell
Has two sets of chromosomes
Dispersal
The transfer of a seed or fruit away from the parent plant
DNA profile
A method of making a unique pattern of bands from the DNA of a person, which can then be used to compare with the DNA profile of another person
Dormancy
A resting period where seeds undergo no growth and have reduced cell activity or metabolism
Ecology
The study of the interactions between living organisms and their environment
Edaphic factors
Relate to soil
Endocrine gland
A ductless gland that produces hormones, which are released directly into the bloodstream
Enzymes
Biological catalyst
Enzyme specificity
Each enzyme will react with only one particular substrate
Ethics
Whether conduct is right or wrong
Eukaryotic cell
Have a nucleus and membrane bound organelles
Evolution
The way in which living things change genetically to produce new forms of life over a long period of time
Excretion
The removal of waste products of metabolism from the body
Exocrine glands
Release their products into ducts or tubes
Fertilisation
The fusing of male and female gametes to form diploid zygote
Fossil
The remains of something that lived a long time ago
Gene
A section of DNA that contains the instructions for the formation of a protein
General defence system
Acts as a barrier to all pathogens attempting to gain entry to the human body
Genetic engineering
The artificial manipulation or alteration of genes
Genetic screening
Testing DNA for the presence or absence of a particular gene or an altered gene
Germination
The regrowth of the embryo after a period of dormancy if the environmental conditions are suitable
Germ layers
Basic layers of cells in the blastocyst from which all adult tissues and organs will form
Habitat
Where a plant or animal lives
Haploid cell
A cell that has one set ot chromosomes
Helper T cells
Stimulate B cells and killer T cells
Herbivores
Animals that feed mainly on plants e.g rabbits
Heredity
The passing on of features from parents to offspring by means of genes
Heterotrophic
An organiser that takes in food made by another organism
Homeostasis
The ability of an organism to maintain a constant internal environment
Hormone
A chemical messenger produced by an endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect
Hypothesis
An educated guess based on observations
Immobilised enzymes
Enzymes that are fixed to each other or an inert material
Immunisation
When we are injected with antibodies against a pathogen
Immunity
The ability to resist infection
Implantation
The embedding of the fertilised egg into the lining of the uterus
Incomplete dominance
Both alleles are equally expressed in the heterozygous condition
Infertility
The inability to produce offspring
Insemination
The release of semen into the vagina, just outside the cervix
Interneuron
Carries information between sensory and motor neurons
Internode
Region on a stem between two nodes
In-vitro fertilisation (IVF)
The fertilisation of eggs outside the body
Joint
Where two or more bones meet
Killer T cells
Destroy abnormal human body cells
Lactation
The secretion of milk by the mammary glands (breasts) of the female
Law/principle
Arises from a theory that has proven to be true when fully tested over a long period of time
Law of independent assortment ( Mendel’s second law )
At gamete formation, either of a pair of alleles is equally likely to combine with either of another pair of alleles
Law of segregation ( Mendel’s first law )
Inherited characteristics are controlled by pairs of alleles, these alleles separate at gamete formation, with only one member of the pair being found in each gamete
Lenticels
Openings in the stems of plants that allow gas exchange
Ligaments
Tissues that connect bone to bone
Linkage
Genes are located on the same chromosome
Meiosis
A form of cell division where the daughter nuclei contain half the number of chromosomes as the parent nucleus
Menopause
When ovulation and menstruation stop happening in a female
Menstrual cycle
A series of events that occurs every 28 days on average in the female if fertilisation has not taken place
Menstruation
The discharge of the endometrium and the unfertilised egg
Meristem
A plant tissue capable of meiosis
Metabolism
The sum of all chemical reactions in an organism
Micropropogation
The growth of plants from small pieces of tissue under sterile conditions on a specially selected medium
Mitosis
Cell division where the parent cell divides to produce 2 daughter cells, each with the same number of chromosomes and identical to each other
Motor neuron
Takes message from CNS to a muscle or gland
Mutagens
Agents that cause mutation
Mutation
A spontaneous change in the amount or structure of DNA
Natural active immunity
When a pathogen enters the body in a normal way (i.e. when you get an infection)
Natural passive immunity
When a child gets antibodies from its mother
Natural selection
The process by which organisms with positive genetic adaptations will survive and reproduce to pass on their genes to following generations
Neuron
A nerve cell
Nutrition
The way an organism obtains and uses its food
Obligate parasite
Can only take its food from a live host
Requires a host cell to reproduce
Omnivores
Feed on plants and animals
Open circulatory system
Blood leaves blood vessels and flows around the cells of the body before reentering blood vessels again
Organ
A group of tissues working together to carry out one or more functions
Orgasm
The physical and emotional sensations experienced at the peak of sexual excitement
Osmosis
The movement of water molecules across a semi permeable membrane from a region of high water concentration to a region of low water concentration
Osteoblast
A bone forming cell
Osteoclast
A bone digesting cell
Ovulation
The release of an egg from the ovary
Parasites
Organisms that take in food from a live host, usually causing harm
Pathogen
Disease causing
Pedigree
A diagram showing the genetic history of a group of related individuals
Percentage cover
An estimate of the amount of ground in a quadrat covered by each species
Peristalsis
The rhythmic contraction and relaxation of the muscles of the gut wall to move food along
Pollination
Transfer of from the anther to the stigma of another plant of the same species
Population
All members of the same species living in an area
Portal system
A blood pathway that begins and ends in capillaries
Prokaryotic cells
Do not have a nucleus or membrane bound organelles
Pulse
The alternate expansive and contraction of the arteries
Reflex action
An automatic, involuntary response to a stimulus
Refractory period
A short time span after a neutron has carried an impulse during which a stimulus fails to carry a response
Response
The activity of a cell or organism as a result of a stimulus
Saprophytes
Organisms that take in food from dead organic matter
Secondary sexual characteristics
Features that distinguish males from females
Self-pollination
The transfer of pollen from an anther to a stigma on the same plant
Semen
A fluid containing sperm and seminal fluid
Serum
Plasma from which the clotting proteins have been removed
Sex linkage
Characteristic that is controlled by a gene on a sex chromosome
Sexual reproduction
The union of two gametes
Species
A group of organisms capable of interbreeding naturally to produce fertile offspring
Sterile
All micro-organisms are destroyed
Stimulus
Anything that causes a reaction in an organism or any of its parts
Substrate
The substance with which an enzyme reacts
Symbiosis
When two organisms of different species live in close association and at least one of them benefits
Synapse
A region where two neurous come into close contact
Taxonomy
Study of classification
Tendons
Fibres that connect muscle to bone
Theory
A hypothesis that has been supported by many experiments
Threshold
The minimum stimulus needed to cause an impulse to be carried in a neuron
Tissue culture
The growth of cells in or on an artificial sterile medium outside the body
Tissue
A group of similar cells that are adapted to carry out the same function
