Topic 8 - Brain, Eye, Protein Synthesis Flashcards
(48 cards)
1
Q
what is the brain’s function?
A
- part of the CNS
- in charge of all of our complex behaviours
- controls and co-ordinates everything you do
2
Q
cerebrum
A
- largest part of brain
- divided into left and right cerebral hemispheres
- right controls muscles on left side
3
Q
3 things the cerebrum is responsible for ( LIV )
A
- language
- intelligence
- vision
4
Q
cerebellum
A
- found at back of brain
- controls muscle coordination and balance
5
Q
medulla oblongata
A
- found at the base of brain
- controls unconscious activities such as breathing and heart rate
6
Q
CT scanners
A
- uses X rays to produce physical image of the brain
- it shows main structures of brain and damaged area but not functions
- can deduce function
7
Q
PT scanners
A
- patient ingests radioactive chemical called tracer
- collected in different areas of brain
- more active parts of the brain take up more of the tracer and can be detected more vividly
8
Q
why is it difficult to treat problems in the CNS?
A
- hard to repair damage to neurones in CNS as they don’t readily repair
- the brain is complicated & delicate and surrounded by skull bones
- so it is hard to surgically remove some tumours
- treatment may cause further problems
9
Q
3 ways of treating cancer
A
- radiotherapy
- surgery
-chemotherapy
10
Q
cornea
A
- transparent outer layer at front of eye
- refracts light into eye
11
Q
iris
A
- coloured part of the eye
- contains muscles that allow it control how much light enters the eye
- by controlling size of pupil
12
Q
pupil
A
- hole in the centre of iris through which light enters
13
Q
lens
A
refracts light into our eye, focusing it on the retina
14
Q
retina
A
- layer at back of eye that contains 2 types of receptor cells
- rods : light intensity , cones : colour
15
Q
ciliary muscles and suspensory ligaments
A
- contracts and relaxes to control shape of lens
16
Q
optic nerve
A
- info from light converted into electrical impulses by rod and cone
- optic nerve carries impulses from recpetors to brain
17
Q
how is size of pupil affected by light intensity?
A
- in bright light the size of pupil is decreases : it constricts
- in dim light the size of pupil increases : it dilates
- this is controlled by an automatic reflex arc
18
Q
how does this happen?
A
- change in light intensity detected by rod in retina
- brain sends electrical impulses to muscles in iris to contract or relax
19
Q
pair of antagonistic muscles in iris
A
- radial muscles
- circular muscles
20
Q
which muscles contract in dim or bright light
A
- in dim light, the radial muscles contract
- in bright light, the circular muscles contract
21
Q
what is needed to see clear images
A
- light rays must be focused on retina at back of the eyes
- lens changes shape to allow us to see both near + far objects sharply
22
Q
looking at near objects
A
- ciliary muscles contracts
- which makes the suspensory ligaments loosen
- lens becomes rounder + thicker
- increases amount by which it refracts light
23
Q
looking at far objects
A
- ciliary muscles relax
- which makes the suspensory ligaments pull tight
- lens becomes less round and thinner
- decreases amount by which it refracts light
24
Q
cause of long-sightedness
( HYPEROPIA )
A
- unable to focus on near objects
- lens is the wrong shape, not round enough so can’t refract light strongly enough
- lens lost flexibility due to old age
- eyeball is too short
25
what happens in long-sightedness
- the images of near objects are brought in focus behind the retina
-this means the object is out of focus
26
cause of short-sightedness
( MYOPIA )
- unable to focus on distant objects
- lens is in wrong shape, too round so it refracts light too much
- eyeball is too long
27
what happens in short-sightedness
- the images of far objects are brought in focus in front of the retina
- this means the object is out of focus
28
how to treat long-sightedness
- glasses or contact lens
- with CONVEX lens
- refracts light towards retina
29
how to treat short-sightedness
- glasses or contact lens
- with CONCAVE lens
- refracts light away from retina
30
colour blindness
- can't distinguish difference between different colours ( usually red or green )
- it is when cones in the retina don't work properly
31
colour blindness cure
- no cure
- cones in retina can't be replaced right now
32
cataracts
- cloudy patch on lens
- which stops light entering lens normally
- colours look less vivd and difficulties seeing in bright light
33
cataracts cure
- surgical treatment
- replacing faulty lens with artificial one
34
what are proteins?
- made up of chains of molecules called amino acids
- each with different order of amino acids
35
why are proteins different shapes?
- amino acid chains fold up to form a different, specific shape
- each protein has a different function
36
what is a gene?
- a section of DNA that codes for a particular protein
37
what is an amino acid?
- it is coded for by a sequence of 3 bases in gene , called base triplet
- they are synthesised to form proteins in different orders
38
non-coding parts of DNA
- they don't code for any amino acids
- some control whether a gene is expressed or not
- all of an organisms's DNA makes up its' genome
39
mutation
- rare, random change to an organism's DNA base sequence that can be inherited
- produces a genetic variant that could code for a different sequence of amino acids
-
40
effects of mutations
- may change final shape of protein and so its' activity will change
- this could change phenotype of organism
41
2 stages of protein synthesis
1) transcription
2) translation
42
why is transcription required in protein synthesis?
- DNA which contains the bases is stored in nucleus
- it can't move out of nucleus due to it's size
- needs to get information in DNA to ribosome in cytoplasm
43
3 differences between mRNA and DNA
- shorter
- only single strand
- uses U instead of T as a base
44
how does transcription work (P1)
- RNA polymerase binds to non-coding DNA located in front of gene
- two DNA strands unzip and RNA polymerase moves along 1 of the strands
45
how does transcription work (P2)
- uses the coding DNA in gene as a template strand to make RNA nucleotides
- the mRNA strand is complementary to coding DNA
- mRNA molecule moves out of nucleus and attaches to ribosome
46
how does translation work ( P1 )
- amino acids are brought to ribosome by tRNA
- tRNA has anticodon which is complementary to codon for amino acid
- this ensures amino acids are brought to ribosome in right order
47
how does translation work ( P2 )
- the amino acids are synthesised by ribosomes making a polypeptide
- once they have deposited their protein the empty tRNA molecules move
48
