Behaviour
revision
Questions
Answering
questions correctly makes all the difference. Here are some model questions
and answers collected from previous papers and their mark schemes. The
asterisks (*) indicate what a mark was given for on the mark scheme. Those
without asterisks are answers that got full marks, or are copied from books.
4.1
Sense Organs
The
Eye
4.2
Synapses
Describe
how information is transmitted across a neuromuscular junction between the
neurone and the muscle
(Byo4
Feb 96 Section B, 5 marks)
- A nerve
impulse reaches the motor neurone's end plate, causing the membrane to become
more permeable to Ca2+ ions
- Influx of
Ca2+ ions causes synaptic vesicles to fuse with end plate
- Neurotransmitter
(acetylcholine) is released
- This binds
to receptor sites on sarcolemma, causing an influx of Ca+ ions
- Which switch
on the calcium switch, causing muscle contraction
Explain
one way in which drugs might affect this transmission of information
(Byo4
Feb 96 Section B, 2 marks)
- Block/mimic
neurotransmitter
- By binding
to receptor site
4.3
Muscle
What
causes the banding pattern seen in a muscle fibril?
(Byo4
Feb 97 Section B, 3 marks)
- Myosin is
a thick filament and forms the dark regions
- It is surrounded
by thin actin filaments which form the lighter regions
- Partial
overlapping results in a band pattern
How
and why will the banding pattern change when the muscle fibril contracts?
(Byo4
Feb 97 Section B, 4 marks)
- Myosin cross-bridges
use ATP to move
- Causing
actin filaments to slide over it
- So the light
regions shorten
- And the
dark regions stay the same length
Describe
the mechanism which results in the muscle contracting.
(Byo4
Feb 96 Section B, 5 marks)
- Myosin (thick)
filaments surrounded by actin (thin)
- Myosin cross-bridges
use ATP to move
- Causing
actin filaments to slide over it
- When the
Ca2+ switches are activated by calcium
4.5
& 4.6 Behaviour
In
the examples given in (a), (b), and (c), identify the types of behaviour described
in italics. Explain the reason for your answers.
(Byo4
Feb 96 Section B, 12 marks)
(a)
Flies enter the base of traps and crawl up to the undyed area at the top where
they may be killed by fast-acting insecticide. (3 marks)
- Taxis
- Moving directly
towards a stimulus: light at top of trap (or away from gravity)
- Positive
phototaxis (or negative geotaxis)
(b)Young
toads come out of burrows when water is noisily sprinkled on soil, even if
the soil is kept try by a plastic sheet (6 marks)
- Innate response
- Young all
do same so can't be learned
- Involuntary
- Sign stimulus:
- Sound of
rain
(c)
When aphids encounter a chemical produced naturally by aphids to insecticide
sprays they disperse rapidly from the lettuce heart to its outer leaves (3
marks)
- Pheromone
- Chemical
produced by one organism which influences behaviour of others
- Chemotaxis
Describe
the main features of innate behaviour
(Byo4
Feb 97 Section B, 4 marks)
- Genetically
inherited
- Does not
make enormous demands on higher centres of nervous system
- Ensures
'correct' behaviour in young from birth
- Same in
all members of a species
Describe
the main features of imprinting
(Byo4
Feb 97 Section B, 4 marks)
- Simple and
specialised form of learning
- Occurs during
receptive period
- Resistant
to change later
- Based in
CNS
- Involves
young identifying with another organism (normally first thing it sees moving)
- Enables
skill acquisition from parent in a natural situation
Describe
the main features of habituation
(BY04
June 96 Section B, 4 marks)
- Involves
loss of response
- Caused by
continuous repetition of stimulus
- No association
with reward or punishment
- Important
to young especially
- Based in
CNS
- Fairly permanent
Explain
how a rat learns to obtain a food pellet when placed in a Skinner box
(BY04
June 96 Section B, 4 marks)
- Initially
rat presses lever accidentally
- Gets a reward
(food)
- Associates
action with reward
- So learns
to pres lever
With
the help of an example, describe what is meant by classical conditioning
(BY04
June 96 Section B, 4 marks)
- (Based on
work of Pavlov and his dogs)
- Animal is
presented with two stimuli at once
- Has an innate
response to one stimulus
- Learns to
associate the two stimulus
- Eventually
the second stimulus alone brings the same response as the original
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Copyright
© 2000 Simon
the A-Level Man. Full reproduction permission is granted provided the
URL http://start.at/alevel is included.
If you are reproducing, please bear in mind that every third baby born
on Earth is Chinese so maybe you should stop at two (Note: the author has
nothing against Chinese)