SB2 - Cells and Control Flashcards
adult stem cells
A stem cell found in specialised tissue that can produce more of the specialised cells in that tissue for growth and repair.
asexual reproduction
Producing new organisms from one parent only. These organisms are genetically identical to the parent.
cancer
A disease caused by the uncontrolled divison of stem cells in a part of the body
cataract
Build up of protein in the lens of the eye.
cell cycle
A sequence of growth and division that happens in cells. It includes interphase and mitosis, and leads to the production of two daughter cells that are identical to the parent cells.
central nervous system (CNS)
The main part of the nervous system that includes the brain and the spinal cord.
cerebellum
cerebral cortex
The main part of the brain, which is used for most of our senses, language, memory, behavior and conciousness.
cerebral hemispheres
The cerebral cortex is divided into two cerebral hemispheres.
chemotherapy
Use of drugs that treat a disease, such as in treatment of cancer.
colour-blind
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An eye defect in which someone cannot see the full range of colours.
cones
A cell in the retina that detects different colours of light.
constrict
To make narrower
CT scan
A scan in which multiple X-rays are taken of the body and put together by a computer. CT stands for computed tomography.
daughter cells
A new cell produced from the division of a parent cell.
dilate
To make wider.
diploid
A cell or nucleus that has two sets of chromosomes. In humans, almost all cells except the sperm and egg cells are diploid.
DNA replication
Where DNA molecules are copied before cell division occurs.
effectors
A muscle or gland in the body that performs an action when an impulse from the nervous system is recieved.
elongation
When something gets longer such as a cell in a plant root or shoot before it differentiates into a specialised cell.
embryonic stem cells
A cell from an early stage of division of an embryo that can produce almost any kind of differentaiated cell.
gamma rays
A high-frequencey electromagnetic wave emitted from the nucleus of a radioactive atom.
haploid
A cell or nucleus that has one set of chromosomes. Gametes are haploid.
impulses
An electrical signal transmitted along a neurone.
interphase
The stage during which a cell prepares itself for cell division.
iris
The coloured part of the eye. Muscles in it control the diameter of the pupil.
long-sighted
An eye condition where close objects appear blurred.
meristem cells
A stem cell found in a plant meristem
meristems
A small area of undiffererentiated cells in a plant where cells are dividing rapidly by mitosis.
mitosis
The process of dividing to produce two diploid daughter cells that are genetically identical to the parent.
motor neurones
A type of neurone that carries impulses to effectors
nerves
A cell that transmits electrical impulses in the nervous system.
neurones
A cell that transmits electrical impulses in the nervous system.
optic nerve
The nerve that transmits impulses from the retina to the brain.
percentile
The value of a variable below which a certain percentage of observations fall.
pupil
The hole in the front of the eye that light can pass through.
quadriplegia
A condition in which both arms and legs are paralysed.
radioactive
A substance is radioactive if it emits ionisng particles or radiation.
radiotherapy
Use of ionising radiation to treat diseases, such as to kill cancer cells.
receptor cells
A cell that recieves a stimulus and converts it into ane electrical impulse to be sent to the brain and/or spinal cord.
reflex
relay neurones
A short type of neurone found in the spinal cord and brain. Relay neurones link with sensory, motor and other relay neurones.
rods
A cell in the retina that detects low levels of light. It cannot detect colours.
root hair cells
A cell found on the surface of plant roots that has a large surface area to absorb water and dissolved mineral salts quickly from the soil.
sense organs
An organ that contains receptor cells.
retina
The part at the back of the eye that changes energy transfeered by light into nerve impulses. Contains rods and cones.
short-sighted
An eye condition where distant objects seem blurred.
spinal cord
The large bundle of nervers leading from the brain and down the back.
stem cells
An unspecialised cell that continues to divide by mitosis to produce more stem cells and other cells that differentiate into specialised cells.
stimulus
A change in factor that is detected by receptors.
synapse
The point at which two neurones meet. There is a tiny gap between neurones at a synapse.
tumours
A lump formed of cancer cells.
xylem cells
A long, thick-walled tube found in plants, formed from many dead xylem cells.
