R Flashcards
Receptor
Cells or organs that are sensitive to a stimulus.
Recessive
An allele that is expressed only when there is no dominant allele of the gene present (e.g. t or g)
Rectum
The last part of the large intestine where faeces are stored before passing out through the anus.
Recycle
to convert material back into a form that can be useful to humans.
Reflex action
An automatic, rapid response to a stimulus which is often protective.
Reflex arc
The arrangement of neurones that controls a reflex action.
Relay (connector) neurone
A neurone in the central nervous system that transmits impulses from sensory to motor neurones.
Renal dialysis
The use of a machine to remove the body’s waste chemicals when the kidney’s fail.
Reproduction
Processes that make more of the same kind of organisms.
Respiration
A complex series of reactions, taking place in all living cells, that break down nutrient molecules to release energy from food.
Response
The reaction of an organism to a particular stimulus.
Restriction enzyme
An enzyme used in genetic engineering to cut DNA at specific places.
Retina
The part of the eye that contains light sensitive cells.
Ribosome
Small cell structure where proteins are made.
Rod
A sensory cell in the retina of the eye that responds to light of low intensity.
