Topic 2 - Cells And Control Key Words Flashcards
Anaphase
The stage of mitosis in which the separated chromosomes move away from each other.
Asexual reproduction
Producing new organisms from one parent only. These organisms are genetically identical to the parent.
Cancer cell
Cell that divides uncontrollably.
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 cell.
Clone
Offspring from asexual reproduction. All the cells in a clone are genetically identical to each other and to the parent’s cells.
Cytokinesis
When the cytoplasm of the cell is separated as the cell membrane is pinched to divide the cell into two daughter cells.
Daughter cell
New cell produced by cell division.
Diploid
A cell with two sets of chromosomes.
DNA replication
The copying of the DNA within a cell.
Haploid
A cell with one set of chromosomes.
Interphase
The stage when the cell prepares itself for the process of cell division, and DNA replication takes place. The cell also makes more of its sub-cellular structures.
Metaphase
The stage of mitosis when the chromates line up across the middle of the cell.
Mitosis
The process of cells dividing to produce two daughter cells that are genetically identical
to the parent.
Multicellular
An organism that is made of many cells.
Prophase
The stage of mitosis in which the nucleus starts to break down and spindle fibres appear.
Spindle fibre
Filament formed in a cell during mitosis, which helps to separate chromosomes.
Telophase
The stage of mitosis in which the chromosomes arrive at opposite ends of the cell and
the nucleus membrane reforms.
Tumour
Lump formed of cancer cells.
Differentiation
When cells differentiate into specialised cells.
Growth
A permanent increase in the number or size of cells in an organism.
Percentile
A 1/100th division of a group. For example, 10 per cent of the data items are below the 10th
percentile and 50 per cent are below the 50th percentile.
Elongation
When something gets longer (such as a cell in a plant root or shoot before it differentiates
into a specialised cell).
Meristem
A small area of undifferentiated cells in a plant, such as near the shoot tips and root tips, where cells are dividing rapidly by mitosis.
Adult stem cell
Stem cell found in specialised tissue that can produce more of the specialised cells in that tissue for growth and repair.
Cancer
Disease caused by the uncontrolled division of stem cells in a part of the body.
Embryonic stem cell
Stem cell from an early embryo that can produce specialised cells of many different types.
Meristem cell
Stem cell found in a plant meristem.
Rejection
When the immune system attacks and kills cells and tissue that come from another person, such as blood (after transfusion) or stem cells.
Stem cell
Unspecialised cell that continues to divide by mitosis to produce more stem cells and other cells that differentiate into specialised cells.
Axon
The long extension of a neurone that carries an impulse away from the dendron or dendrites towards other neurones.
Axon terminal
Small ‘button’ at the end of the branches that leave an axon.
Central nervous system
The main part of the nervous system - the brain and spinal cord. Abbreviated to CNS.
Dendrite
A fine extension from a neurone, which carries impulses towards the cell body.
Dendron
Large, long extension of a sensory neurone that carries impulses from dendrites towards the axon.
Impulse
Electrical signal transmitted along a neurone.
Myelin sheath
Fatty covering around the axons of many neurones. It speeds up the transmission of impulses along their length and helps to insulate them from one another.
Nerve cell
Another term for neurone, transmits electrical impulses in the nervous system.
Nervous system
An organ system that contains the brain, spinal cord and nerves, and carries impulses around the body. This system helps us to sense and respond quickly to changes inside and outside our bodies.
Neurotransmission
Impulses passing from neurone to neurone.
Receptor cell
Cell that receives a stimulus and converts it into an electrical impulse to be sent to the brain and/or spinal cord.
Response
Action that occurs due to a stimulus.
Sense organ
Organ that contains receptor cells.
Sensory neurone
Neurone that carries impulses from receptor cells, towards the central nervous system.
Spinal cord
Large bundle of nerves, leading from the brain and down the back.
Stimulus
Change in a factor (inside or outside the body) that is detected by receptors. Plural: stimul.
Effector
Muscle or gland in the body that performs an action when an impulse from the nervous system is received.
Motor neurone
Neurone that carries impulses to effectors.
Neurotransmitter
Substance that diffuses across the gap between two neurones at a synapse, and triggers an impulse to be generated in the neurone on the other side of the synapse.
Reflex
Response to a stimulus that does not require processing by the brain. The response is
automatic.
Reflex arc
Neurone pathway consisting of a sensory neurone passing impulses to a motor neurone (often via a relay neurone), which allows reflexes to occur.
Relay neurone
A short type of neurone, found in the spinal cord and brain. Relay neurones link with sensory, motor and other relay neurones.
Synapse
Gap between neurones.
