Kalat Textbook Stop & Check Questions Flashcards
How does an evolutionary explanation differ from a functional explanation?
Evolutionary explanations state what evolved from what.
E.g. Humans evolved from earlier primates therefore we inherited features from those ancestors even if they don’t help us today.
Functional explanations state why something was advatangeous and there for evolutionarily selected
Define biological psychology
the study of physiological, evolutionary and developmental mechanisms of behaviour and experience
Suppose you have a high sensitivity to tasting PTC. If your mother can also taste it easily, what (if anything) can you predict about your fathers ability to taste it?
If your mother has a high sensitivity to the taste of PTC no predictions can be made about the father as it is a dominant gene and you inherited one copy of the gene from your mother
Suppose you have a high sensitivity to tasting PTC. If your mother has a low sensitivity, what (if anything) can you predict about your fathers ability to taste it?
If your mother has a low sensitivity you must have inherited the gene from your father (as PTC is dominant) as he must have a high sensitivity
How does a sex-linked gene differ from a sex-limited gene?
A sex linked gene is on a sex chromosome (usually the X chromosome).
A sex-limited gene can be on any chromosome but is activated by a sex hormone therefore the effects are only seen in one sex or the other.
Suppose someone identifies a ‘gene’ for certain aspects of sexual development. In what ways might that statement be misleading?
The effect of a gene depends on other influences.
E.g. a gene affecting sexual development is more likely to be active in adolescence and can be affected by diet, exercise, social influences e.t.c
How does an epigenetic change differ from a mutation?
A mutation is a permanent change in part of a chromosome.
Epigenetic change is an increased or decreased activity on a gene or group of genes - its effects can last months or years but are not likely to be present over multiple generations.
How does adding a methyl or acetyl group to a histone protein alter gene activity?
Methyl groups tighten the histone molecules ‘grip’ on DNA exposing fewer genes for activation.
Acetyl groups loosen the histone grip so increases gene activation
What are the main types of evidence to estimate the heritability of some behaviour?
- greater similarity between monozygotic twins than dizygotic twins.
- resemblance between adopted children and their biological parents.
- A demonstration that a gene is more common in a population exhibiting a certain behaviour.
Suppose someone determines the heritability of IQ scores for a given population. The society changes in a way that provides the best possible opportunity for everyone within that population. Will heritability increase, decrease or remain the same?
Heritability will increase.
Heritability estimates how much of a variation is due to a difference in genes. Therefore if the environment is the same for everyone, it cannot account for any differences.
Provide an example that shows that even if a characteristic is highly heritable, a change in environment can alter it.
Keeping a child with the PKU gene on a strict low-phenylalanine diet to prevent mental retardation. (inability to process protein, managed by a low/protein diet)
People believe the human appendix is useless. Will it become smaller over each generation?
No. Usefulness will not cause a structure to change.
If people with smaller appendixes continue to reproduce with each other, eventually appendixes will shrink.
What are two plausible ways for altruistic genes to spread in a population?
- Altruistic genes could spread because the facilitate care for ones kin or favours in others (reciprocal altruism).
- Group selection, especially if the group rejects non-altruistic individuals
How doe the minimalist position differ from the abolitionist position in regards to the use of animals in research?
Minimalist = limiting animal research to studies with little discomfort to the animal with much potential value.
Abolitionist = eliminate all animal testing regardless of the study’s value
describe the reasons biological psychologists conduct much of their research on non human animals.
To study the animal itself.
To understand human evolution (most animals have a short lifespan than us).
Some procedures may be illegal or unethical in humans.
- what are the widely branching structures of a neuron called?
- And what is the long thin structure that carries information to another cell called?
- Dendrites.
2. Axon
Which animal species would have the longest axons?
The longest axons occur in the largest animals e.g. giraffes or elephants.
Identify the four major structures that make up a neuron
- Dendrites
- Soma (cell body)
- Axon
- presynaptic terminal
Which kind of glia cell wraps around the synaptic terminals of axons?
Astrocytes
Identify one major advantage and disadvantage of having a blood-brain barrier.
The blood-brain barrier keeps out viruses (advantage) but also most nutrients (disadvantage)
Which chemicals cross the blood-brain barrier passively?
Small, uncharged molecules pass passively e.g. Oxygen, Carbon dioxide and water and Chemicals that are lipid soluble when they encounter the fats of the membrane
Which chemicals cross the blood-brain barrier by active transport?
Glucose, amino acids, purines, choline, certain vitamins, iron and some hormones
What is the difference between hyperpolarisation and depolarisation?
Hyperpolarisation exaggerates the usual negative charge within a cell. Depolarisation decreases the negative charge within a cell
What is the relationship between the threshold and an action potential?
Depolarisation that passes the threshold produces an action potential.
During the rise of the action potential do sodium ions move into the cell or out of it?
Why?
During the action potential sodium ions enter the cell.
The voltage dependent sodium gates have opened so the sodium can move freely.
Sodium is attracted to the interior of the cell by an electrical and concentration gradient.
As the membrane reaches the peak of the action potential, what brings the membrane down to the resting-potential?
After the peak of the action potential, potassium ions exit the cell, driving the membrane back to its resting potential.
State the all-or-none law.
The size and shape of the action potential are independent of the intensity stimulus that initiated it.
That is, every depolarisation beyond the threshold of excitation produces an action potential of the same amplitude and velocity for a given axon.
Does the all-or-none law apply to dendrites?
why or why not?
No because dendrites do not have action potentials
Suppose a researcher finds that axon A can produce up to 1,000 action potentials per second (at least briefly, with maximum stimulation), but axon B can never produce more that 100 per second (regardless of the strength of the stimulus).
What could we conclude about the refractory periods of the two axons?
Axon A must have a shorter refractory period (about 1ms) whereas Axon B must have a longer refractory period (about 10ms)
In a myleniated axon, how would the action potential be affected if the nodes were much closer together?
How might it be affected if the nodes were much further apart?
If the nodes were closer together the action potential would travel slower.
If they were much further apart the action potential would travel faster IF it could jump from one node to the next - when the distance becomes too great the current cannot diffuse between nodes (jumping) so the action potential stops).
What evidence led Sherrington to conclude that transmission at a synapse is different from transmission along an axon?
he found the velocity through a reflex arc was slower that the velocity of an action potential along an axon therefore some delay must occur between one neuron and and the next.
What is the difference between temporal summation and spatial summation?
Temporal summation = the combined effect of quickly repeated stimulation at a single synapse.
Spatial summation = the combined effect of several nearly simultaneous stimulations at several synapses onto one neuron.
What was Sherrington’s evidence for inhibition in the nervous system?
Sherrington found that a reflex that stimulates a flexor muscle prevents contraction of the extensor muscles of the same limb.
= axons send an excitatory message for the flexor and an inhibitor for the extensor.
What ion gates in the membrane open during an EPSP?
What gates open during and IPSP?
EPSP = sodium gates open
IPSP = potassium or chloride gates open
Can inhibitory messages flow along an axon?
no. Only action potentials propagate along an axon.
Inhibitory (IPSP) messages decay over time and distance
What was Loewi’s evidence that neurotransmission depends on the release of chemicals?
When Loewi stimulated a nerve that increased or decreased a frog’s heart rate, he could draw fluid from around the heart and transfer it to another frogs heart which increased or decreased the second frog’s heart.
Amino acids
acids containing an amine group (NH2)
glutamate
GABA
Glycine
Aspartate
Monoamines
Chemical formed by a change in certain amino acids
indoleamines = serotonin Catecholamines = dopamine, norepinephrine, epinephrine
Acetylcholine
a one member “family”
chemical similar to an Amino Acid but has an N(CH3)3 group instead of NH2
Neuropeptides
chains of amino acids
Endorphins
Substance P
Neuropeptide Y
Purines
a category of chemicals including adenosine & ATP
What does a highly active brain area do to increase its blood supply?
many stimulated neurons release Nitric Oxide (NO) to dilate the blood vessels increasing blood flow.
Catecholamines
dopamine, norepinephrine, epinephrine
When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?
Calcium
how do ionotropic and metabotropic synapses differ in speed and duration of effects
Ionotropic synapses act more quickly and more briefly
what are second messengers, and which type of synapse relies on them?
At metabotropic synapses, the neurotransmitter attaches to its receptor an thereby releases a chemical (the second messenger) within the postsynaptic cell which alters the metabolism or gene expression of the post synaptic cell
