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SNAB biology hoe > 8B Brain, Behaviour, GMOs and HGP > Flashcards

8B Brain, Behaviour, GMOs and HGP Flashcards

1
Q

cerebrum

A

LARGEST part

made up of left and right cerebral hemisphere

thin outer layer = cerebral cortex -> large s.a so highly folded to fit into skull

vision -> in back of cortex
learning
thinking -> in front of cortex
emotions
movement

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2
Q

hypothalamus

A

beneath middle part

maintains BODY TEMP. (thermoregulation)

produces HORMONES that CONTROL PIT. GLAND

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3
Q

medulla oblongata

A

at base of brain , top of spinal cord

controls BREATHING rate and HEART rate

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4
Q

cerebellum

A

underneath cerebrum

also has folded cortex

coordinating movement
balance

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5
Q

how are CT scans used to investigate brain structure and function?

A
  • use radiation (x-rays) to produce cross-sectional images of brain
  • dense structures absorb more radiation so appear lighter
  • shows major structures but NOT FUNCTIONS
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6
Q

pros and cons of CT scans

A

PROS

  • non invasive

CONS

  • x-rays can cause more mutations of DNA -> may lead to CANCER
  • not in real-time
  • look at structures not functions
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7
Q

how are MRI scans used to investigate brain structure and function?

A

use v strong MAGNETIC FIELD and RADIO WAVES to produce cross-sectional images of brain

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8
Q

pros and cons of MRI scans

A

PROS
- higher quality images than CT

  • better resolution between tissue types
  • MRIs let you clearly see diff between NORMAL and ABNORMAL brain tissue

CONS
- image affected by movement

  • does not show bone
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9
Q

how fMRI scans are used to investigate brain structure and function? how do they work?

A
  • like MRI but show CHANGES in brain activity
  • detect levels of O₂ in blood -> more O₂ = more activity
  • molecules in oxygenated blood respond diff to magnetic field than deoxy blood
    -> signal stronger in oxy -> allows more active areas of brain to be identified
  • measures ratio of oxy to deoxy haemoglobin
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10
Q

how PET scans are used to investigate brain structure and function?

A

show how ACTIVE diff parts of brain are

  • radioactive tracer introduced to body and absorbed into tissues
  • scanner detects RADIOACTIVITY of tracer -> building up MAP of radioactivity
  • diff tracers can be used -> eg. radioactively labelled glucose used to look at glucose metabolism
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11
Q

how can you medically diagnose from PET scans?

A
  • to see if areas in brain are usually active / inactive
  • so useful for studying disorders that change brains activity -> eg. in Alzheimer’s certain areas activity reduced
  • PET scan shows this reduction compared to normal brain
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12
Q

habituation

A

process where if stimulus is repeated many times with no negative outcome -> animal learns not to respond to it

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13
Q

why is habituation important

A

so animals don’t waste energy responding to unimportant stimuli

spend more time doing other activities for their survival eg. feeding

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14
Q

visual cortex

A

area of cerebral cortex at BACK of brain

receive and process visual info

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15
Q

what are ocular dominance columns?

A

neurones in visual cortex that receive info from left / right eye

columns are SAME SIZE and arranged oil ALTERNATING PATTERN

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16
Q

what did Hubel and Wiesel discover?

A

structure of visual cortex

found left ocular columns used when cat uses right eye (stitched up left) and vice versa

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17
Q

describe Hubel and Wiesels experiment on KITTENS

(experiments repeated on young and adult monkeys to see same results)

A

used animal models to study electrical activity of neurones in visual cortex

  1. stitched one eye shut of each kitten
  2. kittens kept like this for several months before eyes unstitched -> eye was now blind
  3. ocular dominance columns were lot SMALLER than normal for stitched up eye and ocular dominance columns were a lot BIGGER in open eye

ocular dom. columns for open eye expanded to take over other columns that weren’t being stimulated

-> when this happens, NEURONES in visual cortex have SWITCHED DOMINANCE

-> this proves that visual cortex only develops into normal ocular dominance columns if both eyes visually stimulated in v early stages of life

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18
Q

describe Hubel and Wiesels experiment on CATS

A

same as kittens BUT EYE HADN’T GONE BLIND

cats fully recovered vision and ocular dominance columns remained the same

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19
Q

compare use of CT scans and MRI scans for studying brain structure

A
  • MRI offers more IMAGE RESOLUTION
  • MRI uses magnetic field whereas CT uses x-rays
  • MRI more EXPENSIVE than CT
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20
Q

against use of animals in medical research ethical and moral points

A

AGAINST:

  • testing on human cells and tissues and use of computer modelling provide alternative option to testing on animals
  • animals should have same rights as humans when it comes to welfare and consent
  • animals do still suffer distress and pain during research
    -> some killed
  • animal and human anatomy / physiology not identical
    -> medications can often have different effects on humans and animals
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21
Q

pro use of animals in medical research points

A

FOR:

  • New drugs need to be tested on the whole organism NOT just on groups of cells
  • testing medications on humans before we know that they are safe is UNETHICAL -> animals provide more
    acceptable alternative
  • animal research only carried out when no alternative options and governed by strict welfare regulations
  • animal anatomy is often similar to humans so results in these cases can be transferable
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22
Q

describe how you would investigate habituation in a snail

A
  1. allow snail to get used to surroundings for a few mins
  2. firmly touch damp cotton bud between eye stalks and immediately start stop watch
  3. measure length of time between poke and snail being fully emerged from shell again with eye stalks fully extended
  4. repeat prev. step 15 times, timing how long each time
  5. records results in suitable table
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23
Q

explain how animals, including humans, can learn by habituation

A

fewer electrical impulses are sent to effectors

why?
- repeated exposure to stimulus DECREASES amount of Ca²⁺ entering PRESYNAPTIC NEURONE

  • this decrease means less neurotransmitter released from vesicles into synaptic cleft …
  • … so fewer neurotransmitters can bind to receptors in postsynaptic membrane
  • as a result -> fewer signals sent to effector to carry out response

v vocab heavy so LEARN!!!!

24
Q

why is it difficult to investigate the effects of nature and nurture?

A
  • genetic (nature) and env. (nurture) factors interact -> hard to know which is main influence
  • lots of diff genes and env. factors to investigate
  • to do ACCURATE EXPERIMENT -> need to cancel out one factor to be able to investigate other
    -> v v difficult as would need to cancel out all env. factors to look at role of genetics and vice versa
25
Q

how are animal experiments used to investigate effects of NURTURE on brain development?

A

scientists study the effects of diff env on brain development of animals of same species

  • indiv. of same species are genetically similar …
  • … so any diff in brain development are more likely to be due to NURTURE than nature
26
Q

how are animal experiments used to investigate effects of NATURE on brain development?

A
  • to study effects of diff genes -> scientists genetically engineer mice to lack a particular gene then raise mice with and without gene in similar env.
  • diff in brain development of genetically engineered mice and normal mice are more likely to be due to NATURE than nurture
27
Q

what are the features of good animal models?

A
  • easy to breed
  • easy to obtain
  • similar to humans
  • short life cycle
28
Q

what are the 2 ethical standpoints of using animals in medical research?

A

absolutist: use of animals is always unacceptable

relativist: use of animals is justified in certain circumstances

29
Q

how can MRI scan be used in diagnostics? (diagnosing ppl)

A

for soft tissue it shows…

  • excess fluid
  • diseased structures
  • exact size and position of tumours

tumour cells respond diff to magnetic field than healthy cells
so show up as a LIGHTER COLOUR

can also work out what brain functions may be affected by tumour

30
Q

how can fMRI scan be used in diagnostics? (diagnosing ppl)

A

shows abnormal patterns of activity in brain
eg related to seizures

-> scan taken before and during to find which part of brain isnt working properly -> finds cause of seizure

31
Q

suggest the adv. and disadv. of fMRI scans

A

adv.

  • can investigate normal functioning of brain
  • no radiation -> safer than others
  • suitable for use in real time

diadv.

  • hard to interpret results -> one brain region may be responsible for many processes
  • cannot show action of indiv. neurones
32
Q

how can a PET scan be used in diagnostics?

A
  • shows tumours
  • shows amyloid plaques associated with Alzheimer’s
33
Q

pros and cons of PET scans

A

PROS

  • can investigate normal functioning of brain
  • suitable for use in real time
  • can show how a disease progresses over time

CONS

  • gamma radiation is harmful
34
Q

how can a CT scan be used in diagnostics?

A

bleeds appear white on image eg. after a stroke

35
Q

what is the critical period for visual development?

A
  • developmental stage where organism has heightened sensitivity to light stimuli
  • vital for full visual capacity since synaptic connections form
  • non-overlapping ocular dominance columns develop equally
36
Q

how are twin studies used to investigate effects of nature and nurture on brain development?

A

if identical twin raised separately …

identical genes (nature) diff env (nurture)

  • so any diff due to nurture and any similarities due to nature eg. twins have v similar IQ scores -> suggests nature plays big role in intelligence
  • so scientists can use comparison to show relative contribution of env and genetic factors to brain development
  • BUT twins shared same env in womb -> so env and genetic factors not completely separated

identical twins raised together and genetically identical compared to non-identical raised together and are genetically diff -> act like control to cancel out env influence

-> any diff between identical and non-identical more likely due to NATURE than nurture

37
Q

how are cross-cultural studies used to investigate effects of nature and nurture on brain development?

A
  • children brought up in diff cultures have diff env influences eg. beliefs, education
  • so scientists study effects of diff upbringing on brain development by comparing large groups of children
    -> same age from diff cultures
  • look for major diff in characteristics -> any brain development diff due to nurture
    -> any similarities due to nature

eg. mapping abilities of young children well-developed across cultures

38
Q

how are newborn studies used to investigate effects of nature and nurture on brain development?

A
  • brain of newborn hasn’t been affacted by env (except from womb env)
  • scientists use newborns to see what functions they’re born with (due to nature) and how developed diff parts of brain are

eg. babies born can cry, feed and recognise human face -> so nature controls these abilities

39
Q

how are brain damage studies used to investigate effects of nature and nurture on brain development?

A

adult brain damage can lead to loss of brain function -> eg. stroke can lead to vision loss

  • adult brain = already fully developed so can’t repair itself well
  • child brain = still developing so can study effects of brain damage on development
  • compare chosen function in kids with and without brain damage

-> if characteristic still develops in brain damage kids -> due to nurture

40
Q

explain how depression is linked to an imbalance of a naturally occuring transmitter in brain, also stating the name of this transmitter

(3 marks)

A
  • serotonin transmits nerve impulses across synpases in parts of brain that control mood
  • scientists know depression linked to low level serotonin so developed drugs (antidepressents) to increase serotonin levels in brain
  • some drugs used to treat depression (SSRIs) increase serotonin by preventing reuptake in synpases
41
Q

explain how Parkinson’s disease is linked to an imbalance of a naturally occuring transmitter in brain, also stating the name of this transmitter

(5 marks)

A

dopamine

Parkinson’s is brain dissorder -> affects motor skills

in Parkinson’s -> neurones in parts of brain that control movement are destroyed

  • these normally make dopamine -> so losing them = less dopamine
  • less dop. released into synaptic clefts so less dop. available to bind to receptors on postsynaptic membranes
  • less Na⁺ channels open -> so postsynaptic neurone less likely to depolarise
  • so less action potentials produced -> leading to symptoms eg. tremors, slow movement
  • developed drugs (L-dopa) to increase dopamine levels in brain
42
Q

L-dopa is a drug used to treat symptoms of parkinson’s disease.

explain how this drug works

A

structure v similar to dopamine

  • absorbed into brain and converted into dopamine by dopa-decarboxylase (enzyme)
    -> straight up dopamine can’t be given as can’t enter brain
  • increases dopamine levels = more nerve impulses transmitted across synapses in part of brain that control movement…
  • giving patients more control over movement
43
Q

describe how ectasy effects synaptic transmissions in the brain

(4 marks)

A

MDMA increases serotonin levels in brain

  • usually serotonin taken back into presynaptic neurone after triggering action potential to be used again
  • BUT MDMA inhibits reuptake of serotonin into presynaptic neurones -> binds to and blocks reuptake proteins on presynaptic membrane
  • also triggers release of serotonin from presynaptic neurones
  • so serotonin levels stay high in synapse -> cause depolarisation of postsynaptic neurones in parts of brain that control mood
  • so MDMA causes mood elevation (happy!!)
44
Q

desribe the risks associated with GMOs

A
  • transmission of genetic material to wild plants
    -> result in superweeds resistant to pesticides
  • if drug crops interbreed with other crops
    -> ppl eat drugs they don’t need (harmful)
  • unforeseen consequemces / impacts of using GMOs
  • wrong to genetically modify animals purely for human benefit
  • may result in antibiotic-resistant genes introduced into other species as marker gene used to select are sometimes antibiotic resistant
  • potential formation of harmful products (toxic compounds / new allergens) by new gene
45
Q

genome

A

all DNA present in organism

46
Q

suggest how doctors can use the HGP to treat a patient

A

personalised medicine
-> personalise patient’s treatment by using genetic info to predict…

  • how they will respond to diff drugs
  • and prescribe more effective ones
47
Q

suggest some social, moral and ethical issues the HGP raises

A
  • genetic info used to unfairly discriminate eg. pay more for insurance
  • easier to cope if you don’t know in advance
  • will it lead to eugenics (designer babies)??
48
Q

genetic engineering

A

transferring genes

from organism of one species to organism of another species

49
Q

what is a genetically modified organism (GMO)?

A

organism that has had its DNA altered

50
Q

describe how drugs can be produced using genetically modified microorganisms

doesn’t come up a lot

A
  1. gene for protein isolated using restriction enzymes
  2. gene copied using PCR
  3. copies inserted into plasmids (type of vector)
  4. plasmids transferred into microorganisms
  5. modified microorganisms grown in large containers so they
    can ÷ and produce lots of useful protein
  6. protein purified and used as drug
51
Q

describe how drugs can be produced using genetically modified plants

agrobacterium method

gene therapy in terms of plants

A
  1. gene inserted into bacterium (vector)
  2. bacterium infects plant cell
  3. bacterium inserts gene into plant cell DNA -> plant cell now GMO
  4. plant cell grown into adult plant -> whole plant contains copy of gene in every cell
  5. protein produced from gene can be purified OR delivered straight via eating plant
52
Q

describe how drugs can be produced using genetically modified animals

v v small part of syllabus

A
  1. gene injected into nucleus of fertilised animal egg cell
  2. egg cell implanted into adult animal
    -> grows into whole animal that contains copy of gene in every cell
  3. protein produced from gene purified from milk of animal
53
Q

what are the social, moral and ethical viewpoints of the HGP?

A
  • creating drugs for specific genetic variation
    = v expensive -> leads to 2-tier health service -> only rich ppl can afford drug
  • might be refused expensive drug due to your genetic makeup as won’t be that effective to you BUT may be only drug available!!
  • genetic info accessible to others
    -> unfair genetic discrimination from eg. insurers to increase life insurance
54
Q

vector

GMOs

A

smt that carries genes into organism

55
Q

describe the benefits associated with GMOs

A
  • crops modified to give higher yields / more nutritious
    -> reduces famine and malnutrition risk
  • crops modified for pest resistance -> less pesticides needed
    -> reduces env problems and cost
  • enzymes produced in large quantities -> reduces cost
  • disorders treated with human proteins from GMOs instead of animal proteins (may cause allergic reactions)
  • vaccines produced in plant tissue don’t need to be refrigerated = more accessible to more ppl
  • producing drugs with GMOs v v cheap -> as once gene introduced -> reproduce using conventional farming methods

SNAB biology hoe (15 decks)

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