topic 2:cell division Flashcards
what is a haploid cells
haploid cells contain one copy of each chromosome
what type of cells are haploids
Gametes (sperm and egg cells)
what are diploid cells
cells that contain two copies of each chromosome (46)
why does a red blood cell not have DNA
to contain as much oxygen as possible
what stage is a cell in when it is not dividing
interphase, when a cell is just being a cell.
why are people long sighted and how to correct
.occurs when the eyeball is too short so the image is focus behind the retina
fixed with a converging lens to bend rays before they reach the eye
what is the definition of genetically identical
an exact clone of the original cell
What is a stem cell
An undifferentiated cell
growth
define
An increase of size as a result of an increase in the number or size of cells
define a stimulus
anything your body is sensitive to
what are impulses
an electrical signal
what is a synapse
a junction between two neurons across which electrical signals pass
what are the chemicals diffuse across the synapse
neurotransmitters
what releases the neurotransmitter molecules
postsynaptic cell
Describe how the arrival of an impulse at the end of one neurone can cause an impulse in a neighbouring neurone
impulse triggers the release of a neurotransmitter (1)
neurotransmitter is released into synapse (1)
next neurone detects the
neurotransmitter (1)
new impulse is generated in the next neurone. (1)
what are effectors
organs, muscles, cells that act in response to a stimulus
name the different parts of the brain
cerebral cortex (right and left hemisphere)
brain stem (medulla oblongata)
cerebellum
what happens in a CT Scan
An X-ray beam moves around in a circle around the head and detectors measure the absorption of X-rays throughout different parts of the body.
The computer then builds up a view of the body with a series of photos.
Explain the process of a PET scan
.pateint is injected with radioactive glucose
.in the machine the more active cells take in more glucose for respiration
.the scanner detects gamma rays emitted
.allows to see different activity in different parts of the brain
compare a CT scan with a PET scan
what are some drawbacks with using embryonic stem cells in medicine
. ethically questionable
.only a small amount as they only come from embryos
.there is a chance that the body might reject the stem cells
tudying the brain involves matching specific regions of the brain with specific functions.
What are the three main ways that scientists can do this?
.study people with brain damage
.use scans (CT, PET, MRI)
.electrically stimulate different parts of the brain
What are the three main reasons treating the brain is so difficult?
.many things can go wrong including, infection or mental illness
.it is encased in the skull and hard to access
.complicated and hard to target with medications
why is mitosis so important (GRAPE)
mitosis is used in:
growth
repair
asexual reproduction to create genetic clones
what does mitosis produce
two genetically identical diploid daughter cells
why are people short sighted and how can it be fixed
short sightedness occurs when the eyeball is too long so the image focuses in front of the retina
it can be manged with a diverging lens that spreads out rays before they reach the eye
what is cataracts how is it treated
when a protein builds up inside the lens making vision cloudy
can be fixed by replacing the clouded lens with a plastic one
How does colour blindness happen
when some cones cells in the eye do not work properly and so make it harder for people to see certain colours
