sb2 cells and control (paper 1) Flashcards
what are the stages of mitosis
- prophase
- metaphase
- anaphase
- telophase
(for mitosis) what happens in prophase ?
- chromosones are condensed
(for mitosis) what happens in metaphase ?
- chromosones line up in the middle
(for mitosis) what happens in anaphase ?
- the chromosones are pulled apart by spindle fibres
(for mitosis) what happens in telophase ?
- the cell NUCLEI splits into two, resulting in two diploid daughter cells
what is the main state a cell goes under
interphase
what happens in interphase
when the cell does it’s normal activities, and duplicates dna
- it is NOT part of the process of mitosis !!
what happens after telophase
cytokinesis
what happens in cytokinesis
- when the actual CELL splits into two
what causes tumours
uncontrollable cell division
what can unctrolled cell division result in
tumours
what are the two types of tumours
cancerous and non cancerous
what makes a tumour cancerous
the fact that it can move around the body and attatch itself to another part of the body
what does CNS stand for
central nervous system
what are the parts of CNS
the brain and spinal cord
what are the three neurons/nerve cells part of the cns
sensory, motor and relay
- note : neurons and nerve cells are synonyms
what is a reflex arc
an action responding to a stimuli that doesn’t require the brain
(e.g moving your hand away after touching something hot)
what is a synapse
the gap between two neurons
what is the gap between two neurons called ?
the synapse
describe what happens when an electrical impulse travels between a neuron to the next neuron (between the synapse)
- it travels as an electrical impulse
- as it reaches the end of the neuron, the electrical impulse turns into a chemical
- it travels as a chemical in the synapse
- it’s then recieved by receptors from the next neuron, then turned back into an electrical impulse
what is a stimuli
a change in the environment
explain how our CNS responds to a stimuli
- the relay neurons recieves the signal and passes it onto the sensory neuron
- the sensory neuron recieves the signal (our five senses) and passes it onto the motor neurons
- the motor neurons are connected to the muscle, which allows us to have a physical response
what are the four main components of the brain ?
- cerebral cortex
- cerebellum
- medulla oblongata
- hypothalamus
in the brain, what is the cerebral cortex
- outer layer of the brain divided into two hemispheres
- high order processes such as intelligence, memory, consciousness, and personality
in the brain, what is the cerebellum
- under cerebral cortex
- balance, muscle coordination and movement
in the brain, what is the medulla oblongata
- unconscious activities
- heart rate and breathing
in the brain, what is the hypothalamus
regulates temperature and water balance within the body
in the eye, what are cataracts
when protein builds up in the lens and makes your vision blurry
in the eye, how can you fix cataracts
replace the lens with plastic
in the eye, what is being short sighted
when the eye is short so the image is focused behind the retina
in the eye, how can you fix being short sighted
correction by a diverging lens to spread out rays before reaching the eye
in the eye, what is being long sighted
when they eye is too long so the image is focused in front of the retina
in the eye, how can you fix being long sighted
correction by a converging lens to bend rays before they reach the eye
in the eye, what is being colour blind
when the eyes have some cones that do not work properly, the most common form is red-green
in the eye, how can you fix being colour blind
you can’t lol
what is a meristem
- the parts of a plant where cell division/mitosis is happening quickly near the end of each shoot
- the root allows plants to continue growing through their life
how can we measure growth
- taking measurements or mass
- it is NOT when we become a fatty when consuming food
is mitosis sexual or asexual
asexual
what are the stages of growth in plants
- cell division/mitosis: when cells divide quickly
- elongations: when cells increase in length
- differentiation: when cells differentiate into specialised cells that have different functions
why is cell differentiation important for the growth of plants
it allows cells to specialise and perform specific functions in an organism
what is cell differentiation
when new cells may change in different ways resulting them becoming specialised for different functions
give an example of a specialised plant cell
palisade cell - have many chloroplasts in cytoplasm to capture energy from light for photosynthesis
why can brain tumours be hard to treat
- protected by the skull
- difficult to access
- the nerves don’t regenerate
