8B Brain, Behaviour, GMOs and HGP Flashcards
(55 cards)
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
2
Q
hypothalamus
A
beneath middle part
maintains BODY TEMP. (thermoregulation)
produces HORMONES that CONTROL PIT. GLAND
3
Q
medulla oblongata
A
at base of brain , top of spinal cord
controls BREATHING rate and HEART rate
4
Q
cerebellum
A
underneath cerebrum
also has folded cortex
coordinating movement
balance
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
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
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
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
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
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
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
12
Q
habituation
A
process where if stimulus is repeated many times with no negative outcome -> animal learns not to respond to it
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
14
Q
visual cortex
A
area of cerebral cortex at BACK of brain
receive and process visual info
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
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
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
- stitched one eye shut of each kitten
- kittens kept like this for several months before eyes unstitched -> eye was now blind
- 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
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
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
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
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
22
Q
describe how you would investigate habituation in a snail
A
- allow snail to get used to surroundings for a few mins
- firmly touch damp cotton bud between eye stalks and immediately start stop watch
- measure length of time between poke and snail being fully emerged from shell again with eye stalks fully extended
- repeat prev. step 15 times, timing how long each time
- records results in suitable table
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
how are **animal experiments** used to investigate effects of **NURTURE** on brain development?
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
how are **animal experiments** used to investigate effects of **NATURE** on brain development?
- 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
what are the features of good animal models?
- easy to breed
- easy to obtain
- similar to humans
- short life cycle
28
what are the 2 ethical standpoints of using animals in medical research?
absolutist: use of animals is **always unacceptable**
relativist: use of animals is **justified** in **certain circumstances**
29
how can MRI scan be used in diagnostics? (diagnosing ppl)
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
how can fMRI scan be used in diagnostics? (diagnosing ppl)
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
suggest the adv. and disadv. of fMRI scans
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
how can a PET scan be used in diagnostics?
- shows **tumours**
- shows amyloid plaques associated with **Alzheimer's**
33
pros and cons of PET scans
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
how can a CT scan be used in diagnostics?
bleeds appear white on image eg. after a **stroke**
35
what is the **critical period** for visual development?
- **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
how are **twin studies** used to investigate effects of **nature and nurture** on brain development?
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
how are **cross-cultural studies** used to investigate effects of **nature and nurture** on brain development?
- 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
how are **newborn studies** used to investigate effects of **nature and nurture** on brain development?
- 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
how are **brain damage studies** used to investigate effects of **nature and nurture** on brain development?
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
explain how **depression** is linked to an imbalance of a naturally occuring transmitter in brain, also stating the name of this transmitter
(3 marks)
- 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
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)
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
L-dopa is a drug used to treat symptoms of parkinson's disease.
explain how this drug works
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
describe how ectasy effects synaptic transmissions in the brain
(4 marks)
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
desribe the **risks** associated with GMOs
- 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
genome
all DNA present in organism
46
suggest how doctors can use the HGP to treat a patient
**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
suggest some social, moral and ethical issues the HGP raises
- 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
genetic engineering
**transferring genes**
from organism of **one species** to organism of **another species**
49
what is a genetically modified organism (GMO)?
organism that has had its **DNA altered**
50
describe how drugs can be produced using genetically modified **microorganisms**
| doesn't come up a lot
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
describe how drugs can be produced using genetically modified **plants**
| **agrobacterium method**
## Footnote
gene therapy in terms of plants
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
describe how drugs can be produced using genetically modified **animals**
| **v v small part of syllabus**
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
what are the social, moral and ethical viewpoints of the HGP?
- 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
vector
| GMOs
smt that **carries genes into organism**
55
describe the **benefits** associated with GMOs
- 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**
