lec 2

Question 1

neurons (dendrites + axons)

Answer 1

• specialized, receive and send info
• there’s approx 100 billion in the brain

aborilizations - branching of neurons

• dendrites receive signals from other cells, axon transmits signals to other cells, axon terminals release chemical neurotransmitters

Question 2

transmitting and receiving of neurotransmitters

Answer 2

synaptic vesicles come to the pre and then post synaptic membrane receptors in the synaptic cleft which aid in the neurotransmitters being moved

Question 3

the case of ARC - neurons that exchange genetic material

Answer 3

ARC (activity-regulated cytoskeleton-associated protein) is involved in memory formation; more is produced with greater neuronal activity

• arc proteins form capsids which that release arc mrna into nearby cells that then make arc mrna

Question 4

resting potential

Answer 4

difference in electrical charge across neuron membrane (-70 mv)

• the electrical gradient concentration across the membrane (high na outside, low inside)

Question 5

neurotransmitter reuptake

Answer 5

transporter proteins repackage and reuse the neurotransmitters, transport them back into the presynaptic terminal

Question 6

autoreceptors

Answer 6

receptors proteins that monitor the levels of neurotransmitters and control the release

Question 7

synaptic communication 3 steps

Answer 7

1. Reception – receiving the signal
2. Transduction – conversion between chemical / electrical signals
3. Transmission – signal propagation e.g. axon terminal (presynaptic) to dendrite (post-synaptic)

Question 8

Neurotransmitter Receptors

Answer 8

Specialized proteins that are involved in reception and transduction of the signal

• Activated by a specific neurotransmitters in extracellular space (synaptic cleft)
• Results in a functional change in the cell e.g. opening and closing of ion channels

Question 9

Ionotropic receptors

Answer 9

• function both as receptors and ion channels
• Extracellular domain → binds neurotransmitter
• Membrane spanning domain → forms ion channel

Neurotransmitter binding results in a conformation change in the receptor → opens or closes the ion channel (depolarization (neg to pos, pos going in) or hyperpolarization (becomes more neg) depends on neurotransmitter)

Question 10

Metabolic receptors

Answer 10

• influence indirectly, binding activates downstream signalling cascade (g proteins) and production of second messengers
• affects cell function over longer term

Question 11

synaptic integration

Answer 11

each neuron receives multiple inputs from diff sources

• combined signals from excitatory and inhibitory signals lead to single response

Question 12

agonist

Answer 12

drugs that increase neurotransmission

Question 13

antagonist

Answer 13

drugs that decrease neurotransmission

Question 14

antipsychotics (how do they work)

Answer 14

dopamine receptor antagonists

• block inflow of + charge ions in dopamine system to suppress overactivation
• eg. schizophrenia

Question 15

benzodiazepines (how do they work)

Answer 15

GABA receptor agonist

• decrease neuron excitability by activating GABA → inflow of negative ions
• calming effect, used for anxiety

Question 16

human genome project goals

Answer 16

identify all genes, sequence of base pairs, improve tools for data analysis etc.

Question 17

clone by clone sequencing

Answer 17

clone by clone = insert BACs into chromosomes to make clones and fragment dna into small pieces, subclone those

Question 18

shotgun sequencing

Answer 18

shotgun = breaking dna into lots of small pieces, sequencing them and then reassembling using overlapping regions

Question 19

major finding of the HGP

Answer 19

individuals have only 0.5 difference genetic differences (2 people are 99.5% identical sequence wise) → this combined with environmental factors defines our physical and behavioral phenotypes

unique to humans

• example is NOTCH2NL and human brain size

Question 20

positive selection

Answer 20

process where new advantageous variants enter the population (eg. big brain)

Question 21

pseudogenization

Answer 21

a sequence alteration that makes a gene inactive

Question 22

identifying genes

Answer 22

1. compare genomic dna sequences to mrna sequences
2. look for signal sequences that indicate a presence of a gene
3. compare genomic sequences from other species

Question 23

single nucleotide polymorphism (SNPs)

Answer 23

• common, single nucleotide difference, at protein coding region contributes to phenotypic differences
• international HapMap project (see patterns of snps in diff pops)

Question 24

copy number polymorphism (CNPs)

Answer 24

• differences in the number of copies for particular sequence
• extra = more protein → phenotypical changes
• genetic fingerprinting

Question 25

genome wide association study (GWAS)

Answer 25

find genetic variants associated with disease or trait without any prior knowledge of gene function - is there an association between genetic polymorphisms and human traits - snps inherited together = haplotypes

Question 26

steps in GWAS

Answer 26

1. collect samples from case vs control 2. snp genotyping - major one (look at haplotype blocks) 3. statistical analysis 4. replication

Question 27

identification of susceptibility variants (new vs improved tag snps)

Answer 27

→ new biological insights, clinical advances, prevention etc. → improved measures, personalized medicine, diagnoses etc.