B2 Cells and Control Flashcards
Why do cells undergo mitosis?
To grow or replace cells that have been damaged
What are the main processes in mitosis?
Interphase –> prophase –> metaphase –> anaphase –> telophase –> cytokinesis
What happens in interphase?
The cell grows in size and duplicates its DNA
What happens in prophase?
The chromosomes condense and membrane around the nucleus breaks down
What happens in metaphase?
The chromosomes line up at the equator of the cell
What happens in anaphase?
Spindle fibres from each pole pull the chromosomes apart. Chromatids are then pulled to opposite ends of the cell
What happens in telophase?
Membranes form around each set of new chromosomes, becoming the nuclei of the new cells
What happens in cytokinesis?
The cytoplasm and cell membrane divide to form two separate cells
What is cell differentiation?
When a cell becomes specialised for a certain function
How does cancer occur?
When there is a mutation in the gene which causes the cell to divide uncontrollably
What are stem cells?
Undifferentiated cells that can divide and produce any type of specialised cell
What is the function spinal cord?
A long column of neurones that run from the base of the brain down the spine. They relay information between the brain and the rest of the body
What is the function of the cerebrum?
Controls different things such as movement, intelligence, memory, language and vision
What is the function of the cerebellum?
Controls muscle coordination and balance
What is the function of the medulla oblongata?
Controls unconscious activities like breathing and your heart rate
How does a CT scanner work?
Uses x-rays to produce an image of the brain. Shows the main structures of the brain
How does a PET scanner work?
Uses radioactive chemicals to show which parts of the brain are active and can be very detailed
What happens when you detect a stimulus?
- Receptors detect the stimulus and convert the information into electrical impulses, sent along the sensory neurone to the CNS
- The CNS coordinates the response and impulses travel through the CNS along relay neurones
- The CNS sends information to an effector through motor neurones
How do synapses send impulses through synapses?
The nerve signal is transferred by neurotransmitters which diffuse across the gap and bind to the receptor. They then set off a new electrical signal in the next neurone
What is the function of the cornea?
Refracts light into the eye
What is the function of the iris?
Controls how much light enters the pupil
What is the function of the lens?
Refracts light, focusing it onto the retina
What is the function of the optic nerve?
Carries the information from light to the brain
How can long-sightedness be corrected?
Use a convex lens
How can short-sightedness be corrected?
Use a concave lens
