Question
The nervous system coordinates the responses of animals to changes in their environment.
(a) Fig. 2.1 shows the arrangement of the nervous system in a mammal.
Complete Fig. 2.1 by writing the names of the missing parts of the mammalian nervous system
in the boxes.
(b) Fig. 2.2 is a flow chart that shows how an involuntary action is controlled.
(i) State the structure found at X.
(ii) State the type of involuntary action shown by the flow chart. [1]
(iii) State two ways in which a voluntary action differs from an involuntary action.
1
2
(c) Fig. 2.3 shows three pots of seedlings that have been kept in different conditions.
(i) State the conditions in which pots P and Q were kept.
P
Q [1]
(ii) State the name of the growth response shown by the seedlings in pot R. [2]
(iii) Explain the advantage to the seedlings of this growth response. [2]
(iv) Auxins control the growth responses of seedlings.
Explain how auxins control the growth response of the seedlings in pot R
Answer/Explanation
Ans
2 (a) central (nervous system) ;
peripheral (nervous system) ;
spinal cord ;
(b) (i) sensory neurone ;
(ii) simple reflex /reflex ;
(iii) slower/ takes more time ;
needs thought/uses (higher centres of) the brain/ conscious control ;
learnt/ not inherited/ not innate/ needs training/AW ;
not automatic ;
response is not always the same to the stimulus ;
(c) (i) either
pot P – (uniform) light AND pot Q – no light/dark / covered (up) ;
or
pot P – (uniform) with/ plus, magnesium AND pot Q – no magnesium ;
(ii) positive ;
(photo)tropism/(photo)tropic ;
(iii) idea that leaves / seedlings / plants / chloroplasts, get more light ;
more (light) energy, absorbed/ trapped/AW ;
more photosynthesis ;
more, growth/ biomass / glucose/ starch/AW ;
(iv) (auxins) made/produced, in (shoot), tip/ apex ;
pass /move/ diffuse/ spread (down the stem) ;
auxins collect in the side, in the dark / away from light ;
greater (cell) elongation on side in the dark ;
AVP ; e.g. absorption of water (by osmosis)/ stretching of cell walls /
phototropin(s)/ plants detect or sense light/ref to turgor pressure
Question
A neurone is a type of specialised animal cell.
(a) (i) Neurones develop from unspecialised cells.
State the name of these unspecialised cells.
……………………………………………………………………………………………………………………………….
Answer/Explanation
Ans:
stem (cells) ;
Question
(ii) All animal cells have some common features.
State two structural features common to all animal cells.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
Answer/Explanation
Ans:
nucleus / nucleolus / nuclear membrane ;
cell membrane ;
cytoplasm ;
ribosomes ;
mitochondria ;
endoplasmic reticulum / ER ;
vesicle / vacuole ;.
AVP ;
Question
(iii) Most neurones are longer than other types of animal cell.
Suggest why most neurones are very long.
………………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………………
Answer/Explanation
Ans:
(transmit impulses) from one (distant) part of the body to another / AW;
so (impulse) is fast / AW ;
Question
(b) Some neurones connect to effector organs.
(i) State the name of the type of neurone that connects to an effector organ.
…………………………………………………………………………………………………………………………….
Answer/Explanation
Ans:
motor (neurones) ;
Question
(ii) State one example of an effector organ.
……………………………………………………………………………………………………………………………………..
Answer/Explanation
Ans:
muscle ;
gland ;
(c) Fig. 4.1 shows parts of two neurones. The area in the dashed circle has been magnified.
Question
(i) Complete Table 4.1. One row has been done for you.
Table 4.1
| etter from Fig. 4.1 | name | description |
| component of the cell that releases energy during aerobic respiration | ||
| H | neurotransmitters | chemicals that transmit signals from one neurone to the next neurone |
| the gap between two neurones | ||
| the sac in which neurotransmitters are transported to the cell membrane | ||
| the molecules that the neurotransmitters bind to | ||
| the structure that controls the activities in the cell |
Answer/Explanation
Ans:
| etter from Fig. 4.1 | name | description |
| E | mitochondrion / mitochondria ; | component of the cell that releases energy during aerobic respiration |
| H | neurotransmitters | chemicals that transmit signals from one neurone to the next neurone |
| J | synapse ; | the gap between two neurones |
| F/G | vesicle ; | the sac in which neurotransmitters are transported to the cell membrane |
| K | receptors ; | the molecules that the neurotransmitters bind to |
| M | nucleus ; | the structure that controls the activities in the cell Question(ii) State where in the body the neurones in Fig. 4.1 would be found. Answer/ExplanationAns: brain / spinal cord / central nervous system / CNS ; Question(d) Describe how neurotransmitters move across the gap between two neurones. Answer/ExplanationAns: diffusion ; Question(e) Nerves and hormones coordinate the functions of the body. Answer/ExplanationAns: nerves faster / hormones slower ;
|
Question
Reflexes are simple responses that protect the body.
(a) The letters A to G show the components involved in a reflex action.
A stimulus
B motor neurone
C sensory neurone
D receptor cell
E response
F relay neurone
G effector
Put the letters into the correct sequence involved in a reflex action. Two have been done for
you.
[1]
(b) Impulses travel along neurones.
Describe how impulses pass from one neurone to another neurone across a synapse.
…………………………………………………………………………………………………………………………………
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(c) Drugs such as heroin affect the nervous system. When users stop taking heroin they may
experience withdrawal symptoms.
(i) Outline the short-term effects of heroin on the body.
………………………………………………………………………………………………………………………….
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………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………. [3]
(ii) State two withdrawal symptoms that heroin users may experience.
………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………. [2]
(iii) Suggest why heroin abuse may increase criminal activity.
………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………. [1]
Answer/Explanation
Ans:
Question
(a) Fig. 3.1 shows a piece of apparatus used to measure reaction time. As soon as the bulb lights up, the student being tested presses the switch. The reaction time, in seconds, is then displayed on the timer.
Ten students each have one attempt on the timer.
The results of the investigation are shown in Fig. 3.2.
The average reaction time for the boys is 0.18 s.
Calculate the average reaction time for the girls. Show your working.
average reaction time for the girls ………………………………………………. s [2]
Answer/Explanation
Ans: 0.16;;
but (0.18 + 0.15 + 0.15 + 0.16 + 0.16) / 5;
(b) Fig. 3.3 shows the pathway for a simple reflex action.
(i) Complete the diagram by writing the correct words in the boxes.
Answer/Explanation
Ans: receptor / sensor; effector;
(ii) Blinking is a reflex action. Fig. 3.4 shows what is happening as an eye blinks and then opens again.
Suggest one reason why this reflex action is important to the body.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[1]
Answer/Explanation
Ans: protection of eye surface / cornea (from dust / injury / AVP);
protection of retina from bright light;
maintaining eye surface moist with tears AW;
(c) Heroin is a powerful drug.
(i) Describe what is meant by the term drug.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
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………………………………………………………………………………………………………………………[2]
Answer/Explanation
Ans: any substance taken into the body; that modifies chemical reactions in the body / alters the metabolism;
(ii) Suggest how heroin could affect reaction time.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[1]
Answer/Explanation
Ans: (heroin is a depressant so could)
slow down the transmission of impulses / AW;
or increase reaction time;
(iii) There are many problems caused by people using heroin.
Describe three examples of these problems.
1 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
3 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[3]
Answer/Explanation
Ans:
addiction, withdrawal symptoms, risk of overdosing, risk of
death,
infection from shared needles, damage to veins,
risk of HIV, risk of hepatitis C,
criminal behaviour, theft, imprisonment,
loss of inhibitions, aggression, violence, more prone to
accidents, poor judgement of behaviour, euphoria, mental
health problems,
social problems, family breakdown, loss of job, loss of home,
poor ability to work,
emotional problems / AW ( e.g. lack of self-esteem),
physical health problems, heart attacks, liver damage, brain or
neurone damage, respiratory failure, strokes,
d) An antibiotic is an example of a drug that can be used as a medicine.
Describe how antibiotics are useful to the human body.
…………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………..[1]
[Total: 12]
Answer/Explanation
Ans: destroy / kill / inhibit bacteria;