CB2 Cells And Control Flashcards
What is mitosis?
A type of cell division that creates two identical daughter cells.
What are the six stages of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
How many chromosomes do body cells contain?
46
How many chromosomes does a diploid cell have?
46
How many chromosomes does a haploid cell have?
23
What happens during the interphase phase?
The chromosomes duplicate.
What happens during the prophase phase?
The nucleus breaks down
Spindle fibre appears
What happens during the metaphase phase?
The chromosomes are lined up on the spindle fibres.
What happens during the anaphase phase?
The chromosomes are pulled to opposite ends of the cell on the spindle fibres.
What happens during the telophase phase?
A membrane forms around each set of chromosomes to form nuclei.
What happens during the cytokinesis phase?
A cell surface membrane forms, separating the two cells.
Creating two identical daughter diploid cells.
What is asexual reproduction?
When organisms use mitosis to produce offspring with identical genetics.
What are cancer cells?
Cells that undergo uncontrollable cell division.
What do cancer cells cause?
Tumours.
What is growth?
An increase in size as a result of an increase in number or size of cells.
What is differentiation?
The process that changes less specialised cells into specialised ones.
How are red blood cells adapted to their function?
Biconcave - increase surface area
No nucleus - more space for haemoglobin
Contains haemoglobin - binds to oxygen
How are muscle cells adapted to their function?
They contain contractile proteins that shorten the cell.
What are meristems?
A group of unspecialised cells at the end of the roots of plants that are capable of cell division.
How are meristems adapted to their function?
The divide rapidly by mitosis, which increase length and differentiate into specialised cells.
How do you measure the growth in plants (formula)?
New - Old
—————x 100
Old
What are stem cells?
Cells that divide repeatedly over a long period of time to produce cells that differentiate.
Where are stem cells found?
Meristems
Bone marrow
Embryos
How do you use stem cells to treat disease?
The stem cells are stimulated to make them produce the specialised cells that are needed and injecting them into the places that are needed.
What are the health risks of using stem cells?
Can lead to cancer.
Can be rejected
What makes up the central nervous system?
Brain
Spinal cord
What makes up the nervous system?
Central Nervous System
Nerves
What does the nervous system allow you to do?
Allows parts of your body to communicate using electrical signals called impulses.
What is a stimulus?
Changes in and out of your body that your body is sensitive to.
What organs contain receptor cells?
Sense organs:
Eyes
Ears
Skin
What do receptor cells detect?
Stimuli
What do receptor cells do?
Create impulses which travel to the brain, which processes the information and sends impulses to cause a response.
What is neurotransmission?
The transmission of impulses.
What is the function of a sensory neurone?
To carry impulses from receptor cells to the CNS.
Where does the receptor cell impulse pass onto?
A branch called a dendtrite , which transmits it along the dendron and the axon.
What allows impulses to be transmitted to other neurones?
Axon terminals
What is the myelin sheath?
A fatty layer surrounding the dendron and axon.
What is the function of the myelin sheath?
It insulates a neurone from neighbouring neurones, stopping the signal losing energy.
What do motor neurones do?
Carry impulses to effectors.
What do relay neurones do?
Link motor and sensory neurones.
What is a synapse?
A tiny gap where two neurones meet.
What do synapses do?
Slow down neurotransmission.
Allows fresh impulses to be generated, so the neurone doesn’t lose ‘strength’.
What are reflex actions?
Responses that are automatic and quick, used to protect the body.
What does the reflex arc do?
Bypass parts of the brain used to process information, so the responses are quicker.
What are effectors?
Muscles or glands that bring about responses
What are malignant tumours?
Tumours that are cancerous and that can spread around the body
What are benign tumours?
Tumours that aren’t cancerous and that don’t spread
