Name: BIOLOGY B1. Nerves and Hormones Part 1. Class: Time: Marks: Comments: Page 1 of 66

Transcription

1 BIOLOGY B Nerves and Hormones Part Name: Class: Time: Marks: Comments: Page of 66

2 A student accidentally touches a sharp object. Her hand is immediately pulled away from the object. The diagram shows the structures involved in this response. Use the correct word or phrase from the diagram to complete each sentence. (i) The stimulus is detected by the... () Impulses travel to the central nervous system along a cell called a... () (iii) Impulses travel from the central nervous system to the effector along a cell called a... () (iv) The hand is pulled away from the sharp object by the... () (b) Where in the body are there cells sensitive to: (i) light... sound... () () (iii) changes in position?... () (Total 7 marks) Page 2 of 66

3 2 Information is also passed by impulses in the nervous system. Neurones carry impulses very rapidly. The diagram shows a reflex arc. Label the diagram by adding the names of the neurones. (Total 3 marks) 3 Diagram shows the neurones and parts of the body involved in a response to touching a hot object. Diagram Page 3 of 66

4 A neurone is a nerve cell. Neurones carry impulses around the body. (i) Draw a ring around the correct answer to complete each sentence. Neurone A is a motor neurone. relay neurone. sensory neurone. At point Y there is a tiny gap between two neurones called an effector. a receptor. a synapse. (2) The hand touches a hot object. An impulse travels through the nervous system to the muscle (point X). The muscle moves the hand away from the hot object. What does the muscle do to move the hand away from the hot object? Tick ( ) one box. contract relax stretch () (iii) The action described in part is a reflex action. How can you tell that this action is not a conscious action? Use information from the diagram. () Page 4 of 66

5 (iv) Reflex actions like this are useful. Explain why. (2) (b) Some students investigated the effect of caffeine on a person s reaction time. The students used the following steps.. One student held a ruler just above a second student s hand, as shown in Diagram 2. Diagram 2 2. The student let go of the ruler. The second student caught it as soon as possible, as shown in Diagram 3. Diagram 3 Page 5 of 66

6 3. The students repeated this experiment seven more times. 4. The student catching the ruler then drank a cup of strong coffee. Coffee contains caffeine. 5. Fifteen minutes after drinking the coffee the students repeated steps to 3. Table and Table 2 show the students results. Table Table 2 Distance ruler fell before it was caught in cm Distance ruler fell before it was caught in cm Before drinking coffee After drinking coffee Mean = 8.4 Mean = 2.4 (i) The students used the reading on the ruler as a measure of the reaction time. What do the results show about the effect of caffeine on reaction time? () Look carefully at all the data in Table and Table 2. Using the data in Table and Table 2, give one reason why a scientist may not accept your conclusion in part (b) (i). () Page 6 of 66

7 (iii) How could the students improve their investigation? Suggest two ways (2) (Total 0 marks) 4 The diagram shows a reflex pathway in a human. (b) Label the receptor on the diagram. Label the effector on the diagram. () () (c) (i) Suggest a stimulus to the hand that could start a reflex response.... () Describe the response that this stimulus would cause () Page 7 of 66

8 (d) Put arrows on the diagram to show the direction of the path taken by the nerve impulses. () (Total 5 marks) 5 Humans use the nervous system to react to changes in the environment. (i) Which word means a change in the environment? Draw a ring around the correct answer. neurone reflex stimulus () Figure shows a light receptor cell. Use the correct answer from the box to label part A on Figure. chloroplast cytoplasm vacuole () Page 8 of 66

9 (b) Figure 2 shows a boy riding a bicycle on a sunny day. Stockbyte/Thinkstock (i) Receptors in the boy s body detect changes in the environment. Complete the table to show which organ of the body contains the receptors for each change in the environment. Change in the environment Organ that contains the receptors Sound of traffic from behind him Flashing blue lights of a police car Cooler air temperature in the shadows (3) Page 9 of 66

10 The boy s response to danger is to pull on the bicycle brakes. Which type of effector causes this response? Tick ( ) one box. A gland A muscle A synapse () (Total 6 marks) 6 The nervous system allows humans to react to their surroundings. Sense organs have receptors. Receptors detect changes in the environment. Which word describes a change in the environment? Draw a ring around one answer. an effector a neurone a stimulus () Page 0 of 66

11 (b) The photograph shows a baby. Labels A, B, C, D and E show some of the baby s sense organs. Photo by D. Sharon Pruitt [CC-BY-2.0], via Wikimedia Commons Answer each question by writing one letter, A, B, C, D or E, in each box. (i) Which sense organ has receptors sensitive to light? () Which two sense organs have receptors sensitive to chemicals? and (2) (iii) Which sense organ has receptors sensitive to changes in the baby s position? () Page of 66

12 (c) Information from sense organ A is passed along nerve cells. The information is coordinated to produce a response. Which organ in the body coordinates the information?... () (Total 6 marks) 7 (b) What is the name of the organ which controls the nervous system?... The diagram shows a reflex arc. Label the three neurones. () (c) (d) Snatching your hand from a hot object is an example of a reflex action. Give one other example of a reflex action.... Describe the stages that happen in a reflex action (3) ()... (3) (Total 8 marks) Page 2 of 66

13 8 The body controls internal conditions. Use words from the box to complete the sentences about water loss from the body. kidneys liver lungs skin (i) Water is lost in sweat via the... Water is lost in urine via the... (iii) Water is lost in the breath via the... () () () (b) Students investigated body temperature in the class. The bar chart shows the results. Body temperature in C (i) One student used the bar chart to calculate the mean body temperature of the class. The student calculated the mean body temperature as 37.0 C. How did the student use the bar chart to calculate the mean? (2) Page 3 of 66

14 How many students had a body temperature higher than the mean of 37.0 C... () (iii) Body temperature must be kept within a narrow range. Why? () (Total 7 marks) 9 A man is walking along a street. He plans to cross the road at the pelican crossing. Pelican crossings show a flashing green person and bleep when it is safe to cross. State two different ways the man uses: (i) his eyes, to help him cross the road safely; (2) his ears, to help him cross the road safely (2) (b) (i) Eyes, ears and skin contain sense receptors. State the names of two other parts of the body which contain sense receptors.... and... (2) Page 4 of 66

15 What type of sense receptor is in the skin of his feet?... () (Total 7 marks) 0 The diagram shows the nervous pathway which is used to coordinate the knee-jerk reflex. When the person is hit at point P, the lower leg is suddenly raised. (i) Name the type of neurone labelled A.... () On the diagram, draw arrows next to the neurones labelled A and B to show the direction in which an impulse moves in each neurone. () (b) How is information passed across the synapse at C?... () (c) On the diagram, label the effector with the letter X. () (Total 4 marks) Page 5 of 66

16 A dog runs across the road in front of a car. The driver slams her foot on the brakes. (i) Explain how the nervous system brings about this response (4) Explain why alcohol consumption would affect the driver s response () (Total 5 marks) 2 The drawing below shows a light-sensitive (receptor) cell from the eye. The structures labelled A, B and C, can be found in most animal cells. Name the structures labelled A, B and C. A... B... C... (3) Page 6 of 66

17 (b) Describe, as fully as you can, what happens in the nervous system when this receptor cell is stimulated by light (3) (Total 6 marks) 3 The diagram shows a section through the spinal cord. Coordination of a reflex movement of the arm, in response to the hand touching a hot object, involves three neurones. One of these, the relay neurone, is shown in the diagram. Complete the nerve pathway between the receptor and the muscle on the diagram by drawing and labelling: (i) the sensory neurone; the motor neurone. (2) Page 7 of 66

18 (b) The nerve pathway linking the heat receptor in the hand with the arm muscle is about.5 metres in length. It would take the nervous impulse 0.02 seconds to travel this distance along a neurone. However, it takes about 0.5 seconds for the arm to start moving during the reflex response to the heat stimulus. Explain the difference (2) (Total 4 marks) 4 The diagram shows the structures involved in the knee-jerk reflex. When the tendon is struck with the hammer, the receptor is stimulated and the lower leg moves forward. Name the structures labelled A, B and C. A... B... C... (3) Page 8 of 66

19 (b) How is information passed from structure A to structure B? () (c) What is the effector in this response?... () (Total 5 marks) 5 The drawing shows a group of people in a café. Use words from the box to answer the questions. brain eye nose skin tongue Which organ contains receptors that allow a person to: (i) read the newspaper... smell the coffee... (iii) feel how hot the cup is... (iv) taste the coffee?... () () () () Page 9 of 66

20 (c) A cigarette manufacturer increased the amount of nicotine in cigarettes by % between 997 and The manufacturer did not tell the public about this change. (i) Suggest one reason why the manufacturer increased the amount of nicotine in the cigarettes () Suggest one reason why the manufacturer did not tell the public about the change () (Total 6 marks) 6 This question is about the nervous system. Describe the function of receptors in the skin (2) Page 20 of 66

21 (b) A response is caused when information in the nervous system reaches an effector. (i) There are two different types of effector. Complete the table to show: the two different types of effector the response each type of effector makes. Type of effector Response the effector makes 2 (4) Some effectors help to control body temperature. Give one reason why it is important to control body temperature. () (Total 7 marks) Page 2 of 66

22 7 A person accidentally touches a hot pan. Her hand automatically moves away from the pan. The diagram shows the structures involved in this action. Describe fully how the structures shown in the diagram bring about this reflex action (6) Page 22 of 66

23 (b) (i) The nerve pathway in this reflex action is about.5 metres in length. A nerve impulse travels at 75 m s. Use this information to calculate the time taken for this reflex action to occur. Show clearly how you work out your answer. Time intervals... s (2) The actual time interval is longer than the interval you have calculated in part (i). Suggest an explanation for the difference. () (Total 9 marks) 8 The diagram shows the nervous pathway that is used to coordinate the knee-jerk reflex. When the tendon below the knee is tapped with a hammer, the lower leg jerks upwards in a reflex action. Page 23 of 66

24 On the diagram, draw arrows next to the neurones labelled A and B to show the direction in which an impulse moves in each neurone. () (b) How is information passed across the synapse at C?... (c) On the diagram, label the effector with the letter X. () () (d) (i) The nerve pathway linking the stretch receptor with the muscle is about.5 metres in length. A nerve impulse travels at 75 ms. Use this information to calculate the time interval between the stimulus and the response. Time interval... s (2) The actual time interval is longer than the interval you have calculated in part (d)(i). Suggest an explanation for the difference. (2) Page 24 of 66

25 (e) A group of students wanted to find out how the speed of the hammer affected the distance the lower leg moved. The diagram shows how the experiment was set up. Each trial was recorded on a video. A frame was taken every 33 milliseconds. The video was then played using single-frame advance. The number of frames for the hammer to move to the knee was found. The faster the speed, the smaller was the number of frames. The video was also used to find the distance moved by the toe. In each trial, the experimenter held the hammer 20 cm from the subject s knee and then hit the subject s tendon. For each trial the experimenter used the hammer at a different speed. The table shows some of the results. Trial number Distance hammer moved to knee in cm Number of frames it took the hammer to move to the knee Distance moved by toe in cm (i) What variable did the experimenter control in this experiment? () Page 25 of 66

26 Give two advantages of using a video to measure the time it took for the hammer to move to hit the tendon (2) (iii) One of the results seems to be anomalous. Draw a ring around the anomalous result in the table. Suggest one reason why the anomalous result may have happened. (2) (iv) Draw a conclusion from the results of the experiment. (2) (v) Suggest one way in which the precision of the experiment could have been improved. () (Total 5 marks) Page 26 of 66

27 9 The diagram shows the structures involved in a reflex action. On the diagram, name the structures labelled W, X and Y. (3) (b) The control of blood sugar level is an example of an action controlled by hormones. Give two ways in which a reflex action is different from an action controlled by hormones (2) (Total 5 marks) Page 27 of 66

28 20 The photograph shows a new-born baby. By SCA Svenska Cellulosa Aktiebolaget [CC-BY-2.0], via Wikimedia Commons New-born babies have reflex actions. The reflex actions help new-born babies to survive. Draw a line from each reflex action to the way in which it helps the baby to survive. Reflex action How the reflex action helps the baby If milk goes down the baby s windpipe the baby coughs If the mother touches the palm of the baby s hand, the baby clenches its fist. If the mother strokes the baby s mouth, the baby begins to suck. If a bright light shines on the baby, the baby s eyes shut. Helps the baby to hold on to the mother Prevents the baby from choking Helps to protect some of the baby s receptors Helps the baby to crawl Helps the baby to feed (4) Page 28 of 66

29 (b) Which two of the following may be effectors in reflex actions? Tick ( ) two boxes. Brain Glands Motor neurones Muscles Sensory neurones (2) (Total 6 marks) 2 The diagram below shows how a nerve impulse passing along a relay neurone causes an impulse to be sent along another type of neurone, neurone X. What type of neurone is neurone X?... () Page 29 of 66

30 (b) Describe how information passes from the relay neurone to neurone X. Use the diagram to help you (3) (c) Scientists investigated the effect of two toxins on the way in which information passes across synapses. The table below shows the results. Toxin Curare Strychnine Effect at the synapse Decreases the effect of the chemical on neurone X Increases the amount of the chemical made in the relay neurone Describe the effect of each of the toxins on the response by muscles. Curare Strychnine (2) (Total 6 marks) Page 30 of 66

31 22 The diagram shows the nervous pathway used to coordinate the knee-jerk reflex. When the person is hit at point P, the lower leg is suddenly raised. Name neurones A, B and C. A... B... C... (3) (b) The receptor in the muscle in the leg is sensitive to a stimulus. Suggest the stimulus.... () Page 3 of 66

32 (c) Describe what happens at the synapse during this reflex (3) (Total 7 marks) 23 Diagram shows cells from the light-sensitive layer in the eye. Diagram (b) On Diagram, add labels to name part A and part B of the light-sensitive cell. There is a junction between the connecting neurone and the neurone carrying the impulse to the brain. (2) (i) What name is given to the junction? () Page 32 of 66

33 In what form is information passed across the junction? () (c) Diagram 2 shows a bee flying towards a man s eye. In the blink reflex, light from the bee reaches the light-sensitive cell in the eye. The muscles in the eyelid shut the man s eye before the bee hits the eye. Describe the pathway taken by the nerve impulse in the blink reflex. (4) (Total 8 marks) 24 A man hurt his head in an accident. Doctors found that he could not remember anything that had happened on the day of the accident. (i) Name the part of the brain concerned with memory. () Page 33 of 66

34 Name one method the doctors could use to find out how much the brain was damaged. () (b) The doctors were worried that the man might also have injured his spine. They touched different areas of his skin with a sharp point. They asked him to tell them each time if he could feel the sharp point. (i) Explain how the information about the sharp point touching the skin reaches the man s brain. (6) The doctors found that the man could feel the sharp point when the point touched his arms but not when the point touched his legs. Suggest what this information could tell the doctors about the damage to the man s spinal cord. Explain your answer. (2) (Total 0 marks) Page 34 of 66

35 25 The diagram below shows the pathway for a simple reflex action. What type of neurone is neurone X? Draw a ring around the correct answer. motor neurone relay neurone sensory neurone () (b) There is a gap between neurone X and neurone Y. (i) What word is used to describe a gap between two neurones? Draw a ring around the correct answer. effector receptor synapse () Draw a ring around the correct answer to complete the sentence. Information passes across the gap as a chemical. an electrical impulse. pressure. () (c) Describe what happens to the muscle when it receives an impulse from neurone Z. How does this reflex action help the body? What happens to the muscle How this helps the body (2) (Total 5 marks) Page 35 of 66

36 26 The diagram shows the structures involved in the knee-jerk reflex. When the person is hit at point P, the lower leg is suddenly raised. Name the structures labelled A, B and C. A... B... C... (3) (b) How is information passed across a synapse? () (c) What is the effector in this response?... () (Total 5 marks) 27 In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Homeostasis keeps conditions in the body relatively constant. The amount of water in the body is controlled by homeostasis. Kidney function is controlled by a gland in the brain. Page 36 of 66

37 Describe how the water content of the blood is controlled (Total 6 marks) Page 37 of 66

38 Mark schemes (i) receptor (iii) (iv) sensory neurone motor neurone muscle (b) (i) eye(s) allow retina ignore sight (iii) ear(s) ignore hearing do not allow ear drum ear(s) ignore balance [7] 2 top left label sensory credit afferent do not accept receptor bottom right label connector or relay credit intermediate bottom left label motor or effector credit efferent [3] 3 (i) sensory neurone a synapse Page 38 of 66

39 (iii) (iv) contract not connected to brain / coordinated only by spinal cord automatic / rapid (response) allow no thinking / faster / less time protects body from danger / from damage / from burning (b) (i) caffeine decreases reaction time accept caffeine speeds up / quicker reactions (iii) the two sets of results overlap (considerably) allow use of appropriate numbers eg 5 of the after results overlap with the before results allow wide spread of results allow it was just one person or it was a small sample accept use of one pair of results only if meaning is clear accept use of one pair of overlapping results any two sensible suggestions: eg more repetitions perform investigation on several other people use other (measured) amounts of coffee use different / more time intervals other suggested measure of reaction time eg computer-generated light flash + time measurement use pure caffeine or caffeine tablets 2 [0] 4 (b) label drawn to the hand may be labelled as a accept the receptor identified as the hand label drawn to the muscle may be labelled as b accept the effector identified as the muscle (c) (i) sharp point or heat accept specific examples such as pain, bee sting, cut, burning do not accept touch by itself Page 39 of 66

40 move the hand (or arm) away from stimulus or muscle in the arm contracts do not credit reference to impulse reaching brain unless it is clear that this is in addition to the reflex act do not credit reflex action already given (d) an arrow on the sensory fibre from hand to spine award one mark for both arrows in the correct direction and note the arrows may be drawn separately from the printed neurone an arrow on the motor fibre from spine to muscle do not credit if the impulse travels to the muscle via the brain but a one way journey to the brain will be neutral [5] 5 (i) stimulus cytoplasm (b) (i) ear(s) in this order only eye(s) accept retina skin ignore extra detail A muscle [6] 6 a stimulus (b) (i) A Page 40 of 66

41 C either order D (iii) E (c) brain allow spinal cord / CNS / central nervous system do not allow spine [6] 7 brain (b) receptor or sensory or afferent connector or relay 3 effector or motor or efferent (c) any one from blink (of eye) accept a violent movement of a limb from pain or sharp object knee jerk do not credit snatch from cold object or any temperature reference e.g. boiling water accept sneezing, coughing, choking, vomitting, pupil closing or reflex Page 4 of 66

42 (d) danger or a signal detected (by nerve) or impulse sent goes to or through spine accept impulse by-passes the brain do not award mark if brain mentioned do not credit message to spine a very rapid response occurs or then to effector or muscle or motor accept no thinking time is needed [8] 8 (i) skin (iii) kidneys accept kidney lungs accept lung (b) (i) multiply temperature by number of students at that temperature and add them up allow (36.8 5) + (36.9 3) + (37.0 6) + (37. 7) + (37.2 3) allow 888 divide by number of students allow divide by 24 (iii) 0 / ten so enzymes work (well) ignore death / overheating / hypothermia allow body reactions work (well) [7] Page 42 of 66

43 9 (i) any two from see the (green) light or sign or man for seeing where to go to avoid objects see cars (that are stopped) answer must show that the person sees something 2 any two from hear the bleeps or noise to listen for traffic or danger for balance answer must show that the person hears something 2 (b) (i) nose credit smell tongue credit taste but not mouth credit temperature sensor any one from do not accept sensory receptors or neurone touch pain credit nerves pressure temperature credit heat do not accept cold [7] 0 (i) sensory / afferent on diagram: arrow (next to neurone A) pointing towards spinal cord and arrow (next to neurone B) pointing towards muscle Page 43 of 66

44 (b) (c) chemical (released) or neurotransmitter or by diffusion on diagram: accept correct named example of a neurotransmitter X labelling muscle or motor end plate do not accept on stretch receptor [4] (i) eyes as sense organs/detector/receptors in eye, electrical signals (impulses), to co-ordinator, then to leg muscles/effector for mark each 4 affects the nervous system and slows down the reactions for mark [5] 2 A cell membrane B cytoplasm C nucleus each for mark 3 (b) (nerve) impulse sent along nerve fibre to brain each for mark 3 [6] Page 44 of 66

45 3 sensory neurone correctly drawn and labelled from receptor + via dorsal root + cell body in ganglion + synapse to relay neurone motor neurone correctly drawn and labelled to muscle + via ventral root + same shape as relay neurone + synapse with relay neurone OR correct pathways for both neurones given (ie without synapse or cell bodies) and labelled, or correctly drawn but unlabelled = mark for this part) (b) any two from: reference to synapses / gaps between neurones extra time for release / movement of chemical extra time for development of muscle tone / tension 2 [4] 4 A sensory (neurone) ignore nerve B motor (neurone) ignore nerve C spinal cord / central nervous system / grey matter Page 45 of 66

46 (b) by chemical / substance allow transmitter (c) muscle allow extensor ignore muscle names [5] 5 (i) eye (iii) (iv) nose skin tongue (c) (i) eg to ensure more people addicted to cigarettes / make cigarettes more addictive eg people might not buy the brand [6] 6 detect changes in surroundings or detect stimuli allow any named stimulus for skin convert information to impulse allow send impulse to sensory neurones / brain Page 46 of 66

47 (b) (i) muscle contract(ion) gland release / secrete / produce chemical / hormone / enzyme mark for each effector mark for each response response must match type of effector (if given) ignore examples ignore relax(ation) / movement for contraction do not allow expansion for muscles 4 any one from: (maintain temperature at which) enzymes work best so chemical reactions are fast(est) prevent damage to cells / enzymes allow prevent enzymes being denatured (by temperature being too high) [7] 7 stimulus / heat detected by temperature receptors in skin impulses travel along sensory neurone to spinal cord / CNS chemical transmission across synapse via relay neurone impulses to muscle / effector via motor neurone muscle / effector contracts, moving the hand away (b) (i) 0.02 s correct answer gains 2 marks if answer incorrect, evidence of.5 / 75 gains mark 2 Page 47 of 66

48 impulse slowed down because of time taken for diffusion of the chemical across the synapse [9] 8 towards spinal cord by A and away from spinal cord by B (b) by chemicals (c) muscle labelled X (d) (i).5 75 = 0.02 s correct answer with or without working gains 2 marks impulse is slowed down at synapse because of time taken for diffusion of the chemical (across the synapse) award up to 2 marks for any other feasible suggestion (e) (i) distance moved by hammer permanent record of results provides means of measuring the very short time the hammer moved (iii) circle around distance in trial 5 eg hammer did not hit tendon fully (iv) increasing the speed of hammer increases the distance the toe moved up to a maximum of 0 cm (v) eg reduce grid size to eg cm award mark for any feasible suggestion [5] Page 48 of 66

49 9 Y - spinal cord / central nervous system / CNS do not accept spine ignore nerve / nervous system / coordinator ignore grey / white matter W - receptor / nerve ending ignore sensory / neurone / stimulus X - effector / muscle allow gland (b) any two from: eg accept reverse argument for each marking point reflex action quicker effect of reflex action over shorter period hormone involves blood system and reflex involves neurones / nerve cells ignore nervous system / nerves reflex involves impulses and hormone involves chemicals reflex action affects only one part of the body ignore involves brain ignore outside / inside stimuli 2 [5] Page 49 of 66

50 20 all four correct = 4 marks three correct = 3 marks two correct = 2 marks one correct = mark extra line from a statement cancels the mark 4 (b) glands muscles mark for each correct tick each extra box ticked cancels mark [6] Page 50 of 66

51 2 motor allow efferent / postsynaptic allow another relay (neurone) (b) (c) release of chemical (from relay neurone) allow ecf for motor neurone from allow release of neurotransmitter / named example chemical crosses gap / junction / synapse allow diffuses across allow chemical moves to X chemical attaches to X / motor / next neurone (causing impulse) (curare) decrease / no contraction accept (muscle) relaxes (strychnine) increase / more contraction if no other mark awarded allow mark for (curare) decrease / no response and (strychnine) increase / more response [6] 22 ignore nerve / neuron(e) throughout A sensory accept afferent B motor accept efferent C relay accept intermediate (b) stretch allow pressure / pull / tension (in muscle) allow a hit at (point) P ignore pain Page 5 of 66

52 (c) any three from: chemical (release) accept neurotransmitter / acetylcholine diffuses (across the gap / synapse) transmits impulse / information (across synapse) allow transmits signal / message between neurones / nerve cells / named if named, must be either sensory / A to relay / C or relay / C to motor / B allow to the next neurone 3 [7] 23 A cytoplasm in this order only B (cell) membrane do not accept (cell) wall (b) (i) synapse (as) chemical accept neurotransmitter or named ignore references to how the chemical is passed do not accept electrical (c) (from light-sensitive cell to connecting neurone) to sensory neurone ignore references to synapses accept nerve cell for neuron(e) throughout penalise nerve for neurone once only (sensory neurone) to brain / CNS allow (sensory neurone) to relay neurone / spinal cord (brain / CNS) to motor neurone allow (relay neurone / spinal cord) to motor neurone Page 52 of 66

53 (motor neurone) to (eyelid) muscle ignore effector [8] 24 (i) cerebral cortex accept cerebrum / cerebral hemisphere MRI (scan) allow CAT / CT scan do not accept MIR or electrode stimulation allow electrical stimulation (b) (i) sharp point stimulates (pain) receptor (in the skin) must be in correct order to send (nerve) impulse ignore information and messages via sensory neurone to spinal cord do not accept spine, ignore CNS crosses synapse allow synapse in any correct context to other (relay) neurones / to brain do not accept motor neurone allow explanation in a flow diagram damage must be between arms and legs / below arms accept below the waist since information from nerves in arms still reaches the brain / information from the legs doesn t reach the brain [0] 25 sensory neurone Page 53 of 66

54 (b) (i) synapse a chemical (c) (What happens to the muscle) mark both parts of the question together any one from: contraction / contracts gets shorter ignore relaxation / relaxes / tenses (How this helps the body) idea of protection for body (from damage / pain) eg moves finger / arm away (from pin / stimulus / source of pain) [5] 26 A sensory (neurone) ignore nerve B motor (neurone) ignore nerve C spinal cord / central nervous system / white matter accept grey matter (b) by chemical / substance allow transmitter (c) muscle allow extensor ignore muscle names [5] Page 54 of 66

55 27 Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5, and apply a best-fit approach to the marking. 0 marks No relevant content. Level ( 2 marks) There is a brief description of kidney function including a mention of pituitary gland or hormones but roles may be confused. Level 2 (3 4 marks) There is a clear description of kidney function in relation to fluctuations in blood water levels and the roles of the pituitary gland or hormone is mentioned with correct role. Level 3 (5 6 marks) There is a clear and detailed scientific description of kidney function in relation to fluctuations in blood water levels and of the roles of the pituitary gland and ADH. examples of biology points made in the response: if water content too low, ADH released from pituitary gland into the blood (causing) kidney reabsorbs more water more concentrated / small volume urine produced if water content too high, ADH lowered / not produced less water reabsorbed by kidney more dilute / larger volume urine produced full marks may be awarded for detailed description of either water loss or gain [6] Page 55 of 66

56 Examiner reports Although the phrase from the diagram was emboldened many candidates ignored this and gave answers such as gland. (i) (iii) (iv) Two thirds of the candidates correctly chose receptor. Unsuccessful candidates mainly chose sharp object or sensory neurone. Three quarters of the candidates correctly chose sensory neurone. Unsuccessful candidates mainly chose receptor or motor neurone. Two thirds of the candidates correctly chose motor neurone. Unsuccessful candidates mainly chose sensory neurone. Over half of the candidates correctly chose muscle. Many candidates ignored the diagram and wrote effector. Unsuccessful candidates mainly chose brain or spinal cord. (b) (i) The large majority of the candidates correctly chose eye. Unsuccessful candidates mainly did not name an organ, but rather gave vision or sight. (iii) Nearly all of the candidates correctly chose ear. Unsuccessful candidates mainly did not name an organ, but rather gave hearing. Only a tenth of the candidates correctly chose ear. Unsuccessful candidates mainly gave brain or muscle. 2 Foundation Tier this qeustion involved labelling the neurones involved in a reflex arc. Examiners reported that responses to this question varied greatly from centre to centre. In some centres, it was common to see all three labels correct, whereas in other centres all three labels were often left blank. Higher Tier Most confusion occurred when labelling the nerves in this question. Candidates often knew the names of the neurones but did not appreciate the direction of the reflex arc. Hence, connector/relay was the most commonly named correct neurone. It was pleasing to see that all bar one or two candidates used the more modern names for the neurones. Page 56 of 66

57 4 Foundation Tier This question worked extremely well as a discriminator. The more able candidates had a clear grasp of the reflex arc and understood, crucially, that it only involves the brain as a secondary aspect. Hence the more able could avoid mention of the brain in part (c) and in their drawings in part (d). Many candidates were unclear about the technical terms receptor and effector. Higher Tier This question worked extremely well as a discriminator. Large numbers of candidates clearly had a grasp of the reflex arc and understood, crucially, that it only involves the brain as a secondary aspect. Hence the more able were able to avoid mention of the brain in part (c) and in their drawings in part (d). A minority of candidates was unclear about the technical terms receptor and effector. 5 (i) The majority of students correctly identified stimulus from the list, although the two distractors were chosen by a significant minority of students. Some students merely drew a ring around their answer in the box. Provided the answer line was left blank, this was accepted by the examiners. However where an answer was written on the answer line in the figure, this took precedence. A number of students concocted hybrid words such as chloroplasm or cytoplast, probably as a result of poor copying. Unfortunately, as it was unclear which term was intended and no mark could be awarded in these cases. (b) (i) Although most students correctly identified the ears and the eyes for the first two stimuli, the third answer proved a little more problematic. Despite this, almost threequarters of students gained all three marks. A number of students did not name organs and offered answers such as hearing and sight. These were ignored if they were appropriate and the correct answer was also given. A considerable number of students thought that a synapse is an effector although the majority correctly identified muscle. Page 57 of 66

58 6 Almost as many students gave the incorrect response of an effector as gave the correct answer of a stimulus to describe a change in the environment. (b) (i) and Were completed more successfully. A high proportion of students identified A (eye) as the organ sensitive to light and D (nose) and C (tongue) as being sensitive to chemicals. (iii) Was less well done, with almost as many choosing B (skin) as being sensitive to changes in the baby s position as chose the correct response E (ear). Throughout part (b) a number of students wrote the various names of the organs in the boxes. These were not credited, as they contravened the rubric of the questions. When directed to use letters in their responses, students must use letters if they hope to be awarded marks. (c) Was completed correctly by the great majority of students, who gave brain. Although not strictly correct, spinal cord was accepted here as the distinction between the two parts of the central nervous system is beyond the scope of the specification. Although the central nervous system was accepted it was only very rarely seen. Reference to the spinal column was not accepted. 7 Foundation Tier Most candidates were able to identify the brain as being the organ responsible for controlling the nervous system. Responses to the part which required candidates to label the neurones on the diagram varied greatly from centre to centre. It was quite common to see this section left blank. Of those who did attempt it, the relay or connector neurone was the least well known, and many candidates had the receptor and motor neurones reversed. In part (c) reflex actions were often confused with conditioned or learned responses. It was common to see goalkeeping quoted as an example of a reflex action. Many candidates suggested a suitable stimulus, such as when you sit on a drawing pin, but failed to go on to state what the response would be. In attempting to describe the stages of a reflex action, the great majority of candidates showed that they had failed to appreciate the most important aspect, namely that the brain is not involved, in order to produce a more rapid response. Higher Tier Part was well answered. In part (b) sensor was the best known neurone with some confusion between receptor and effector. Candidates responses included the full range of names given on the mark scheme. In part (c) blinking or knee jerk were the most common correct answers. Other answers usually neglected the violent motion idea. Many answers made references to insect bites or stings and breaking a fall. Page 58 of 66

59 In part (d) only good candidates managed to score the full three marks, with far too many references to messages rather than impulses, and descriptions of pathways involving the brain. However, candidates usually included the three points: stimulus, sending of information and response. 8 Almost all students knew the correct organs for water losses in sweat and breath. Fewer students were confident with the organ through which urine is lost, with about a quarter suggesting the liver. (b) (i) This part proved to be difficult for most students. The most common responses revolved around adding up the five temperatures for which recordings were made, then dividing by five. Other students developed this further, suggesting that all seven values on the scale should be added, then divided by seven. Of course in both cases, the mean value would be 37.0 C, so students believed they had done the right thing. Other students explained how to determine the median value, writing all the figures down in order and choosing the middle one and some identified the mode, 37. C and suggested it should be rounded to the nearest whole number. Only those students who were able to see that the bars on the graph needed to be broken down into the temperatures of the individual participants before adding them up were rewarded with the first mark. Some gained this by showing the calculations required and others gave the correct value, 888. The second mark required realisation that the mean could only be calculated if the derived figure was divided by the number of students, or 24. It was more common for students to gain this mark, even if their method of determining the initial temperature sum was incorrect. Surprisingly a few students showed calculations that were far away from the mean stated in the question, adding the five temperatures on the axis and dividing by 24, only to arrive at a mean of 7.7 C. It is clear that these students had not paid sufficient attention to the information or they may have realised that their calculations were flawed. (iii) A surprising number of students were unable to read the two correct bars from the graph and add their values. It was clear that those who arrived at 3 had only read the value for one of the bars, perhaps having misread the scale or the question. Any reference to enzymes was infrequent, and a number of these were spoiled by the enzymes being killed. Allowing the body to function properly was insufficient to gain this mark, a reference to (chemical) reactions in the body was required. Commonly students answered in terms of overheating, being too cold, getting ill or dying. Other ideas which did not gain credit were everyone has a similar body temperature and temperature has to be kept in a narrow range. A few students suggested that it was important that all the participants in the class had to have similar temperatures to make the calculations easier. 9 This proved to be a good opening question for most candidates and produced generally high scores. In, concerning crossing the road, it was common to see maximum marks achieved. However, a number of weaker students produced answers that were so vague and generalised that it was impossible to give them credit. Page 59 of 66

60 The majority of candidates could identify the nose as another part of the body containing a sense receptor but many gave the mouth as their second choice instead of stating, more specifically, the tongue. Approximately half of the candidates correctly identified a sense receptor in the skin of the feet, usually quoting touch sensors. 0 This question was also well answered, with many candidates scoring all four of the marking points. However, it would serve candidates better if their labelling on diagrams were clearer, as there were many small X s amongst the motor end plates which could have easily been missed by examiners. Candidates should be encouraged to label in the traditional way, drawing their X off the diagram and using a label line, the end of which should touch the relevant structure. Some candidates put their X between the muscle and the skin surface; with no line it was unclear what they intended, and a mark could not be awarded. Large numbers of candidates now know the stimulus receptor co-ordinator effector - response pattern, but many have difficulty in applying it to a novel situation. Impulses often went straight from the eye to the spinal cord and were frequently electronic. Messages abounded. 3 This question was answered very poorly by the vast majority of candidates. In part most candidates had little idea of the shapes of the sensory and motor neurones, nor how they connected the receptor and the muscle to the relay neurone. Their passage via the dorsal and ventral roots of the spinal nerve also appeared entirely optional. This should have been a simple drawing demonstrating recall. The outcome contrasted markedly with performance in previous examinations where candidates had been expected to label the same structures on a given diagram. Only the ablest candidates understood in part (b), that the delay in coordination of the reflex response was due to the time taken for the transmitter substance to diffuse across each of the synapses. Many candidates stated that extra time was required to send the impulse to the brain. Others demonstrated mathematical weakness by stating that the time for the impulse to travel from the arm to the spinal cord and back again was seconds. Page 60 of 66

61 4 Answers to this question were disappointing. Although the knee jerk reflex involves only two neurones, the fact that the receptor and the muscle were both labelled should have enabled candidates to identify the two neurones. In part the sensory neuron was correctly identified much more frequently than the motor neuron. Common errors in identifying C were synapse and reflex arc. A surprising number got all three correct responses in entirely the wrong sequence. In part (b) some reference to a chemical or a transmitter was required but most candidates answered in terms of a relay neuron or a synapse. In part (c) only 50% of the candidates correctly identified the muscle. The most common incorrect responses were: hammer, tendon, knee and leg moves. 5 In part most candidates were able to identify all four organs. However significant numbers hedged their bets with answers such as brain or another additional organ, thereby losing the mark. In part (c)(i) the vast majority of correct answers used the term addiction, with the occasional hooked. Incomplete responses usually referred to the manufacturer selling more cigarettes or making more money, but missed the addiction aspect. Some candidates thought this would reduce the number of cigarettes smoked, and a few suggested it would help people stop smoking. Very occasionally candidates suggested it would decrease the addiction. Weaker candidates tended to give muddled answers in part (c) such as buying more because they knew they were addictive. Some wrote in terms of stopping smoking and others about the risk of cancer due to nicotine. Many included comments about making more money. Page 6 of 66

62 6 This question asked about receptors in the skin, rather than receptors in general. Thus students who qualified the first point with inappropriate stimuli, such as light or sound, were not credited with the mark. Furthermore it should be noted that the skin does not detect temperature, but rather changes in temperature, although in a list of otherwise correct stimuli, this inaccuracy was ignored. Anthropomorphic answers had the receptors feeling, thinking and deciding whilst others suggested that the receptors were themselves effectors in bringing about the response. In terms of the second marking point, although many described the role of receptors in sending impulses or the barely acceptable signals, many others reverted to the inadequate messages, additionally these impulses were often sent directly to muscles, rather than the brain / spinal cord or via sensory neurones. (b) (i) Many students had learned this part of the specification well and the format of the question allowed them to gain four marks in a fairly straightforward way. The question identified that there are two types of effector, thus answers that identified a specific muscle or gland were not awarded the marks in the first column. Many thought that hormones or specific examples of hormones were effectors and that glands were responses. There were many instances of neurone, synapse or spinal cord in the effector column with equally wrong matching words in the response column. The response column often contained examples of simple reflex actions. The mark scheme was applied strictly: thus specific examples of effectors were ignored unless preceded by the correct general term. The relaxation of muscles was ignored, whilst expansion of muscles negated any other words written in that part of the table. Many students were unable to offer any suggestions whatsoever and left the table blank. Perhaps a little more attention to the mark allocation here might have prompted some of these to at least have a go at answers, rather than give up so many marks without effort. A significant proportion of students could offer no more than the need to avoid body temperature becoming too high or too low, thus doing little more than restating the question. Better answers, perhaps from students who had studied other units, referred to the possible denaturation of enzymes, although a considerable number of these lost the mark by describing denaturation as a result of low temperatures, whilst others appeared to believe that enzymes work at only one specific temperature. Page 62 of 66

63 9 Many students described actions rather than naming structures; a significant number were triggered to remember words associated with neurone, sensory, motor and relay and these were then scattered amongst the labels. There were lots of wild guesses ovary, vein, womb, lungs, wrinkles, x-ray. Many focussed on the drawing pin and not where the label was pointing. However, many students identified the muscle but used a variety of spellings: musel, mucel, mucle, mussle. Very few students identified the spinal cord. (b) The answers given suffered from a lack of comparison; many students had a good knowledge of the differences between hormones and reflex actions but could not bring the correct information into comparisons; eg Reflex actions are quick but hormones work over a long period of time. Many weaker students resorted to describing pain as a major difference. It was common for just a description of a reflex action to be given. Many students stated that hormones work inside the body and reflexes don t. There was a widespread belief that reflexes are triggered by an external stimulus and hormones just happen on their own. 20 (b) This question provided no difficulty for the vast majority of candidates. What errors occurred were usually as a result of not making the connections clear. Effector is a term that is not understood by the majority of candidates. Only a minority of candidates correctly chose both glands and muscles. The majority of candidates chose options that included either or both of sensory neurones and motor neurones. Page 63 of 66

64 2 22 (b) (c) (b) (c) The link to the relay neurone and the arrow showing the direction of the impulse resulted in a high proportion of students correctly identifying the motor (neurone). The small percentage of students who did not give the correct answer usually offered sensory. Although another relay neurone would have been accepted, the examiners were not aware of any student giving this response. Students are expected to know that information crosses the synapse in the form of chemicals. It was hoped that students would interpret the diagrams in the figure and so gain further marks. Neither the release of the chemical from the relay neurone, nor its attachment to neurone X are expected specification knowledge, however the diagrams clearly showed both of these stages in transmission. Better students recognised that the chemical started off in the relay neurone, some referred to vesicles, exocytosis and to neurotransmitters released. Only the best students went further to describe the chemical attaching to neurone X, again some using terms such as receptors in their answer, showing that they had revised this area of the specification far beyond the requirements. A minority of students had the chemical and electrical parts of the process reversed, describing chemicals passing down the neurones and turning into an electrical impulse to cross the synapse. Students are expected to know that muscles respond by contraction. Relatively few students offered this term in either part of their answer, thus limiting themselves to just one of the two marks for describing a weaker or no response (for curare) and a stronger response (for strychnine). Students are not expected to have any knowledge of ideas about how these responses are created, so the examiners accepted a wide range of possible alternative terms, such as slower / faster or decreased / increased response. However a number of students denied themselves any opportunity of the marks by not answering the question. Instead of referring to responses by the muscles, they discussed the decreased or increased impulse in neurone X. Most students knew the names of the three neurones; a greater problem was applying the names to the correct structures. The most common error was to transpose sensory with motor and thus gain only one of the three marks available for C as the relay neurone. Students struggled with this question, with pressure being the most common acceptable response. Vague references to the indirect stimulus, kick or knock on the knee / leg were not accepted but if this was linked to the precise position P the mark was given. A wide range of unexpected answers, including heat, reference to sharp pins and even bright light was given, as students presumably recalled other stimuli, they had studied. Most students referred to a chemical crossing the synapse, with a few going further than is required with neurotransmitter. Perhaps prompted by part, some described the chemical as passing from one neurone to another or moving between neurones. Better students were able to add further detail, referring to the chemical diffusing across the synapse, although only rarely was it clear that the chemical is a means of transmitting information across the synapse. However, there were some excellent answers here and it was quite clear to examiners that many students had made a concerted effort to learn the events at a synapse. Page 64 of 66