B4 Homeostasis and Response

Transcription

1 B4 Homeostasis and Response 35 Questions Name: Class: Date: Time: Marks: Comments: Page of 20

2 Amylase is an enzyme that digests starch. A student investigated the effect of ph on the activity of amylase. This is the method used.. Mix amylase solution and starch suspension in a boiling tube. 2. Put the boiling tube into a water bath at 25 C. 3. Remove a drop of the mixture every 30 seconds and test it for the presence of starch. 4. Repeat the investigation at different ph values. The table below shows the students results. ph Time when no starch was detected in minutes (a) The student concluded ph 7.25 was the optimum ph for the amylase enzyme. This is not a valid conclusion. Suggest two reasons why.. 2. (2) Page 2 of 20

3 (b) The student did another investigation. This is the method used.. Put amylase solution and starch suspension into a boiling tube. 2. Make the ph Put the boiling tube into a water bath at 25 C. 4. Measure the amount of sugar produced every 30 seconds. The results are shown in the figure below. Calculate the mean rate of sugar produced per minute during the first 5 minutes. Mean rate = units per minute (2) Page 3 of 20

4 (c) Iodine solution is added to a sample taken from the boiling tube after 0 minutes and 60 minutes. Suggest what you would see in these samples. After 0 minutes After 60 minutes (2) (d) The scientist repeated the investigation at 37 C. Draw a line on the figure above to show the results the scientist would get. (2) (e) The same investigation was done at 65 C. How would this affect the results? Explain why. (3) (Total marks) Page 4 of 20

5 2 A person with Type diabetes does not produce enough of the hormone insulin. (a) Where is the hormone insulin produced? Tick one box. Brain Pancreas Pituitary Thyroid () (b) How does insulin travel around the body? () Page 5 of 20

6 (c) The same concentration and volume of glucose solution was given to two people. Person with Type diabetes. Person without Type diabetes. The figure below shows how the blood glucose concentration of these two people changed after they each drank a glucose solution. Look at the figure above. Compare the blood glucose concentrations of the two people. Include similarities and differences in your answer. Page 6 of 20

7 (4) (d) People with diabetes may be asked to control their diet. Explain how this can help to reduce the risk of developing health problems. (3) (Total 9 marks) 3 Neurones pass information around the body. (a) Why are reflex reactions important? () (b) Caffeine is a drug found in coffee. After a person drinks coffee information passes through neurones in the nervous system more quickly. Suggest a hypothesis for the effect of caffeine concentration on reaction time. () Page 7 of 20

8 (c) Two students investigated the effect of caffeine concentration on reaction time. This is the method used.. Student A drinks a cup of coffee. 2. Student B holds a ruler above Student A s hand. 3. Student B drops the ruler. 4. Student A catches the ruler as quickly as she can. 5. The distance the ruler falls is recorded. Suggest how this method could be improved to produce valid results. (6) (Total 8 marks) Page 8 of 20

9 4 People with Type diabetes cannot control the concentration of glucose in their blood. This is because they do not produce the hormone insulin. The same concentration and volume of glucose solution is given to two people. Person with Type diabetes. Person without Type diabetes. Figure shows how the blood glucose concentration of these people changes after they each drink a glucose solution. Figure Page 9 of 20

10 (a) The blood glucose concentration increases at a faster rate in the person with diabetes compared to the person without diabetes. Calculate how much faster the rate of increase in blood glucose concentration is in the person with diabetes. Give the rate of increase for the first 30 minutes after drinking the glucose solution. Give your answer in units / h. Units / h (2) (b) The blood glucose concentration of the person without diabetes starts to change 30 minutes after drinking the glucose solution. Explain why the blood glucose concentration changes. (2) Page 0 of 20

11 (c) People with diabetes should try to keep their blood glucose concentration within the same range as a person without diabetes. Most people with Type diabetes regularly check their blood glucose concentration using a meter, as shown in Figure 2. The meter reading is used to estimate how much insulin they need to inject. Figure 2 Vincente Barcel/Hemera/Thinkstock Figure 3 shows a new system. It is connected to the person all the time. Figure 3 The new system: gives better control of blood glucose concentration reduces the number of times the glucose concentration falls too low. Page of 20

12 Evaluate the two systems as methods for controlling blood glucose concentrations for people with Type diabetes. Give a justified conclusion to your evaluation. (4) (d) How does the body respond if slightly too much insulin is injected into the body. (5) (Total 3 marks) Page 2 of 20

13 5 Hormones are released from glands. (a) Which gland produces hormones to control other glands in the endocrine system? Tick one box. Adrenal Ovary Pituitary Thyroid () Page 3 of 20

14 (b) The figure below shows the level of adrenaline in a man s bloodstream while he was watching a 2-minute film. Calculate the percentage increase in adrenaline after point B. Percentage increase in adrenaline = (2) (c) Suggest why the percentage increase in adrenaline after point B is different from the percentage increase after point A. (2) Page 4 of 20

15 (d) Adrenaline causes changes in the body to prepare for a fight or flight response. What changes in the man s body are caused by adrenaline? (2) (Total 7 marks) 6 The figure below shows how the concentrations of the reproductive hormones in the blood of a woman change over 28 days. (a) Name hormones A and B. A B (2) (b) Use information from the figure above to explain what happens on Day 4. (2) Page 5 of 20

16 (c) In Vitro Fertilisation (IVF) treatment can be used to help women become pregnant. IVF uses some of the hormones shown in the figure above. Explain why IVF increases the chance of some women becoming pregnant. (6) (Total 0 marks) Page 6 of 20

17 7 Our nervous system controls our reactions. Figure shows the part of the nervous system involved in the rapid response to a stimulus. Figure (a) What is this type of rapid response called? Tick one box. Circular action Fast action Forced action Reflex action () Page 7 of 20

18 (b) Features of the nervous system are labelled A, B, C, D and E on Figure. Draw one line from each feature to the correct label from Figure. Feature Label A Effector B Relay neurone C Sensory neurone D E (3) (c) Two students compare their reactions using a ruler. This is the method used.. Student A sits with his elbow on a table top. 2. Student B holds the ruler so the bottom of the ruler is level with the top of student A s thumb. 3. Student B drops the ruler. 4. Student A catches the ruler. 5. Record the drop distance. 6. Repeat steps to 5 four more times. 7. Repeat the whole experiment with student A dropping the ruler and student B catching it. Page 8 of 20

19 Both students are right-handed. The students are testing the hypothesis: the drop distance of the ruler is smaller when a right-handed person uses their right hand to catch the ruler. Student A uses his right hand to catch the ruler. Student B uses her left hand to catch the ruler. Complete the sentence. Use an answer from the box. control dependent independent The drop distance was the variable. () Page 9 of 20

20 (d) The table below shows the students results. Student Drop distance in cm Test Test 2 Test 3 Test 4 Test 5 Student A Student B Figure 2 shows student B s Test 2 result. Figure 2 Use Figure 2 to complete the missing result for Test 2. Write the answer in the table above. () Page 20 of 20

21 (e) What was the resolution of the ruler the students used? Tick one box. 0. cm 0.5 cm cm 0 cm () (f) One of the results in the table above is anomalous. Identify the anomalous result. Give the reason why you chose your answer. (2) Page 2 of 20

22 (g) The students are testing the hypothesis: the drop distance of the ruler is smaller when a right-handed person uses their right hand to catch the ruler. The results in the table above are not a good test of the hypothesis. What is one reason why? Tick one box. The drop distances are very variable The drop distance for Student A is sometimes bigger than the drop distance for Student B The results are for the left and right hands of different people The drop distances are not measured accurately enough () (Total 0 marks) 8 Blood sugar levels in the body are controlled by insulin. (a) How does insulin travel around the body? () Page 22 of 20

23 (b) The table below shows the blood sugar levels for two people after eating a meal. Time after eating in hours Blood sugar levels in mg per 00 cm 3 of blood Person A Person B Use data from the table above to complete the graph in the figure below. Plot the points for person A. The first two points have been plotted for you. Draw a line through all the points. (3) (c) How long after the meal is person B s insulin production at its peak? () Page 23 of 20

24 (d) What is the greatest decrease in the blood sugar level of person B in an hour? Decrease = mg per 00 cm 3 (2) (e) Estimate how long after eating the meal it will take for person B s blood sugar level to return to the level before the meal. Show your working on the figure above. (2) (Total 9 marks) Page 24 of 20

25 9 The nervous system allows humans to respond to their surroundings. The figure below shows two nerve pathways. Nerve pathway A Nerve pathway B (a) Nerve pathway A is 92 cm long. A nerve impulse travels along pathway A at 76.2 m / s. Calculate how long it takes for the nerve impulse to travel the length of the pathway. Use the equation: distance = speed time Time = s (3) (b) Nerve pathways A and B are the same length. The nerve impulse takes longer to travel along pathway A than along pathway B. Use the figure above to explain why. (3) Page 25 of 20

26 (c) Two students compare their reactions using a ruler. This is the method used.. Student A sits with his elbow on a table top. 2. Student B holds the ruler so the bottom of the ruler is level with the top of student A s thumb. 3. Student B drops the ruler. 4. Student A catches the ruler. 5. Record the drop distance. 6. Repeat steps to 5 four more times. 7. Repeat the whole experiment with student A dropping the ruler and student B catching it. Both students are right-handed. Student A uses his right hand to catch the ruler. Student B uses her left hand to catch the ruler. The table below shows the students results. Student Drop distance in mm Test Test 2 Test 3 Test 4 Test 5 Student A right hand Student B left hand What is the range of student A s results? () Page 26 of 20

27 (d) The students are testing the hypothesis: The drop distance of the ruler is smaller when a right-handed person uses their right hand to catch the ruler. The students results in the table above are not a good test of the hypothesis. Suggest what the students should have done to test the hypothesis. (3) Page 27 of 20

28 (e) Student A s mean reaction time was 0.9 s. Mean reaction time can be calculated using the equation: Calculate the mean reaction time for Student B. Give your answer to two significant figures. Student B s results are repeated here to help you answer the question. Drop distance in mm Test Test 2 Test 3 Test 4 Test 5 Student B left hand Mean reaction time = s (4) (Total 4 marks) Page 28 of 20

29 0 The rate of chemical reactions can be changed by changing the conditions. (a) Methane burns in oxygen to produce carbon dioxide and water. The activation energy for the reaction is 2648 kj / mol. The reaction gives out 88 kj / mol of energy. The figure below shows the reaction profile for this reaction. Complete the reaction profile. Draw arrows to represent: the activation energy the energy given out. (4) (b) What percentage of the activation energy is the energy given out? () (c) Calcium carbonate decomposes when it is heated: The decomposition of calcium carbonate is an endothermic reaction. How would the reaction profile for decomposition of calcium carbonate be different from the reaction profile of methane burning in oxygen? () Page 29 of 20

30 (d) Catalysts are used in chemical reactions in industry. Give two properties of catalysts. For each property, explain why it makes the catalyst useful in industry. (4) (e) Enzymes are biological catalysts. What type of molecule is an enzyme? Tick one box. Carbohydrate Hydrocarbon Lipid Protein () (f) If enzymes are denatured they stop working. Give two ways an enzyme can be denatured.. 2. (2) Page 30 of 20

31 (g) An enzyme called lactase catalyses the reaction that breaks down lactose to smaller molecules. One model used to explain how enzymes affect reactions is called the lock and key model. Use the lock and key model to explain why lactase cannot be used to speed up all chemical reactions. (3) (Total 6 marks) Amylase catalyses the breakdown of starch into sugars. A student investigated the effect of amylase on the reaction at different temperatures. Figure shows the apparatus the student used. Figure Page 3 of 20

32 This is the method used.. Put starch suspension into a test tube. 2. Add amylase solution. 3. Put the test tube in a beaker of water at 5 C. 4. Remove a small sample of the mixture every 30 seconds and put in a spotting tile. 5. Test the sample for starch. 6. Time how long it takes to break down all of the starch in the mixture. 7. Repeat steps 5 at 20 C, 25 C and 30 C. 8. Repeat for each temperature twice more. The table below shows the student s results. Time taken until there was no starch in the sample in minutes Temperature in C Test Test 2 Test 3 Mean (a) One of the results in the table above is anomalous. Draw a ring around the anomalous result. () (b) Calculate the mean for 30 C. () Page 32 of 20

33 (c) Figure 2 shows a graph of the student s results. Figure 2 Use the graph to predict how long it would take to break down all of the starch at 0 C. Time = minutes () (d) The student tested samples of the mixture for starch every 30 seconds. In each test she added one drop of iodine to the sample in the spotting tile. Predict the colour of the samples from the 20 C test at 4.0 minutes and 7.0 minutes. Colour at 4.0 minutes Colour at 7.0 minutes (2) Page 33 of 20

34 (e) The student did a fourth test at 30 C. In this test the starch did not break down, even after 45 minutes. Why did the amylase not break down the starch in this test? Tick one box. The amylase solution and the starch suspension were mixed before the start of the experiment. The amylase solution had been prepared with water at 95 C. The amylase solution had been prepared with water at 20 C. The amylase solution had been stored in the fridge. () (f) The student made the following conclusion about the optimum temperature for amylase to work at. Amylase works fastest at 40 C Her teacher said that this is not a valid conclusion from her results. Describe how the student could change her method to give results that would improve the validity of her conclusion. (6) (Total 2 marks) Page 34 of 20

35 2 The human body is organised to carry out many different functions. (a) Use words from the box to complete Figure by putting the parts of the body in order of size from smallest to largest. The smallest one has been done for you. (2) (b) The stomach is made of different types of tissue. Draw one line from each type of stomach tissue to the correct description. (3) Page 35 of 20

36 (c) Animals can react to their surroundings because they have nervous systems. A student investigated the behaviour of small animals called woodlice. The student set up the investigation as shown in Figure 2. The student covered one half of a Petri dish with black paper to make that side of the Petri dish dark. The other side had no cover. The student put five woodlice into each side of the dish and then put the clear Petri dish lid back on the dish. Figure 2 After 30 minutes, all the woodlice had moved to the dark side of the Petri dish. Page 36 of 20

37 (i) In this investigation, what is the stimulus that the woodlice responded to? () (ii) In this investigation, what is the response that the woodlice made? () (iii) The student concluded that woodlice prefer dark conditions. Give two ways in which the student could improve the investigation to be sure that his conclusion was correct.. 2. (2) (Total 9 marks) 3 This question is about hormones. (a) (i) Hormones carry messages. What type of messenger is a hormone? Draw a ring around the correct answer. chemical electrical environmental () (ii) Which part of the brain secretes hormones? Draw a ring around the correct answer. cerebellum medulla pituitary gland () Page 37 of 20

38 (b) Figure shows the level of a pregnancy hormone over a 40-week pregnancy. This hormone can be detected in a pregnancy test. Figure A woman takes a pregnancy test. In which week of pregnancy is the test most likely to give a positive result? Use information from Figure. Write the correct answer in the box. () Page 38 of 20

39 (c) Figure 2 shows the levels of three other hormones during pregnancy. The baby is usually born at about 40 weeks. Figure 2 Adaptation by kind permission of Biozone International (i) Describe the patterns in the levels of oestrogen and progesterone from 0 to 36 weeks. (4) (ii) Which hormone is likely to stimulate contractions of the uterus (womb) when the baby is born? Use information from Figure 2 to give a reason for your answer. (2) (Total 9 marks) Page 39 of 20

40 4 (a) Control systems help to keep conditions in the human body relatively constant. What is the general name for the processes that keep body conditions relatively constant? Draw a ring around the correct answer. eutrophication homeostasis hydrotropism () (b) The concentration of glucose in the blood is controlled by hormones. Use the correct answer from the box to complete each sentence. glucagon glycerol glycogen kidney liver pancreas When the blood glucose concentration increases, an organ called the releases the hormone insulin. Insulin causes glucose to move from the blood into the cells of the muscles and the. Inside these organs, the glucose is changed into a carbohydrate called, which can be stored. When the blood glucose concentration falls, another hormone is released, which causes the storage carbohydrate to break down into glucose again. This hormone is called. (4) Page 40 of 20

41 (c) A person with Type diabetes does not make enough insulin. The person needs to test their blood at intervals throughout the day. If the concentration of glucose in their blood is too high, the diabetic person needs to inject insulin. (i) Insulin is a protein. It must be injected and cannot be taken by mouth. Explain why. (2) (ii) Apart from injecting insulin, give one other way that a diabetic person could help to control the concentration of glucose in their blood. () Page 4 of 20

42 (d) Pet dogs have been trained to detect if the concentration of glucose in the blood of their diabetic owners is outside the normal healthy range. These dogs are called medical response dogs. The dogs respond in different ways. They may bark, jump up, or stare at their owners.they may even fetch a blood-testing kit. (i) Suggest what stimulus the dogs might be responding to when they behave like this. () (ii) Table shows how the concentration of glucose varied in blood samples from five diabetic people. Measurements were made both before and after getting a medical response dog. Table Mean percentage of blood samples with different concentrations of glucose from the five diabetic people Number of blood samples measured Low glucose Within normal range of glucose High glucose Before getting a dog After getting a dog A survey was made of the effect of a medical response dog on the lives of 6 diabetic people. Table 2 shows how well these diabetic people agreed with each statement in the survey. Table 2 Statement in survey Totally agree Somewhat agree Neither agree Somewhat nor disagree disagree Totally disagree I am more independent since getting my dog. There are disadvantages to having a medical Page 42 of 20

43 response dog. I trust my dog to alert me when my sugar levels are low. I trust my dog to alert me when my sugar levels are high Evaluate how useful medical response dogs are for warning diabetic people that the concentration of glucose in their blood is outside the normal range. Use information from Tables and 2. (5) Page 43 of 20

44 (e) Table 3 shows the concentrations of some substances in the urine of a non-diabetic person and in the urine of a diabetic person. Table 3 Concentration of substance in urine in g per dm 3 Substance Non-diabetic person Diabetic person Protein 0 0 Glucose Urea Sodium ions Compare the results for the non-diabetic person and the diabetic person. Give reasons for any differences. Use your knowledge of how the kidney works. (5) (Total 9 marks) 5 Humans use the nervous system to react to changes in the environment. (a) (i) Which word means a change in the environment? Draw a ring around the correct answer. neurone reflex stimulus () Page 44 of 20

45 (ii) Figure shows a light receptor cell. Use the correct answer from the box to label part A on Figure. chloroplast cytoplasm vacuole () Page 45 of 20

46 (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 46 of 20

47 (ii) 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 This question is about the nervous system. (a) Describe the function of receptors in the skin. (2) Page 47 of 20

48 (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. (4) (ii) Some effectors help to control body temperature. Give one reason why it is important to control body temperature. () (Total 7 marks) Page 48 of 20

49 7 Blood glucose concentration in humans must be kept between 4.4 and 6. mmol per dm 3. Four students, A, B, C and D, tested their blood glucose concentration with glucose testing strips. The diagram shows the results of their tests and the key from the test strip bottle. (a) (i) Which student, A, B, C or D, has diabetes and has eaten a large piece of cake? () (ii) Which student, A, B, C or D, is in most need of eating carbohydrates? () (iii) Which student, A, B, C or D, has a healthy blood glucose concentration? () Page 49 of 20

50 (b) (i) Name the hormone that people with diabetes inject to prevent their blood glucose concentration from becoming too high. () (ii) Blood glucose concentration is monitored in the body. Which organ monitors blood glucose concentration? Draw a ring around the correct answer. brain liver pancreas () (Total 5 marks) 8 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 50 of 20

51 Describe how the water content of the blood is controlled. (Total 6 marks) 9 (a) Diagram shows the neurones and parts of the body involved in a response to touching a hot object. Page 5 of 20

52 Diagram 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) Page 52 of 20

53 (ii) 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 (a) (ii) is a reflex action. How can you tell that this action is not a conscious action? Use information from the diagram. () (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. Page 53 of 20

54 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 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. Page 54 of 20

55 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? () (ii) 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 55 of 20

56 (iii) How could the students improve their investigation? Suggest two ways.. 2. (2) (Total 0 marks) 20 The diagram below shows the pathway for a simple reflex action. (a) 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 () (ii) Draw a ring around the correct answer to complete the sentence. a chemical. Information passes across the gap as an electrical impulse. pressure. () Page 56 of 20

57 (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) 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. (a) What type of neurone is neurone X? () (b) Describe how information passes from the relay neurone to neurone X. Use the diagram to help you. (3) Page 57 of 20

58 (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) 22 Phenylketonuria (PKU) is an inherited condition. PKU makes people ill. (a) PKU is caused by a recessive allele. (i) What is an allele? () (ii) What is meant by recessive? () Page 58 of 20

59 (b) The diagram below shows the inheritance of PKU in one family. (i) Give one piece of evidence from the diagram that PKU is caused by a recessive allele. () (ii) Persons 6 and 7 are planning to have another child. Use a genetic diagram to find the probability that the new child will have PKU. Use the following symbols in your answer: N = the dominant allele for not having PKU n = the recessive allele for PKU. Probability = (4) (c) Persons 6 and 7 wish to avoid having another child with PKU. A genetic counsellor advises that they could produce several embryos by IVF treatment. (i) During IVF treatment, each fertilised egg cell forms an embryo by cell division. Name this type of cell division. () Page 59 of 20

60 (ii) An embryo screening technique could be used to find the genotype of each embryo. An unaffected embryo could then be placed in person 7 s uterus. The screening technique is carried out on a cell from an embryo after just three cell divisions of the fertilised egg. How many cells will there be in an embryo after the fertilised egg has divided three times? () (iii) During embryo screening, a technician tests the genetic material of the embryo to find out which alleles are present. The genetic material is made up of large molecules of a chemical substance. Name this chemical substance. () (d) Some people have ethical objections to embryo screening. (i) Give one ethical objection to embryo screening. () (ii) Give one reason in favour of embryo screening. () (Total 2 marks) Page 60 of 20

61 23 The diagram shows the position of two glands, A and B, in a woman. (a) (i) Name glands A and B. A B (2) (ii) Gland A produces the hormone Follicle Stimulating Hormone (FSH). FSH controls changes in gland B. How does FSH move from gland A to gland B? () Page 6 of 20

62 (b) (i) A woman is not able to become pregnant. The woman does not produce mature eggs. The woman decides to have In Vitro Fertilisation (IVF) treatment. Which two hormones will help the woman produce and release mature eggs? Tick ( ) one box. FSH and Luteinising Hormone (LH) FSH and oestrogen Luteinising Hormone (LH) and oestrogen () (ii) Giving these hormones to the woman helps her to produce several mature eggs. Doctors collect the mature eggs from the woman in an operation. Describe how the mature eggs are used in IVF treatment so that the woman may become pregnant. (3) (iii) IVF clinics have been set a target to reduce multiple births. At least 76% of IVF treatments should result in single babies and a maximum of 24% of treatments should result in multiple births. Suggest one reason why the clinics have been set this target to reduce multiple births. () Page 62 of 20

63 (c) Two clinics, R and S, used IVF treatment on women in Doctors at each clinic used the results of the treatments to predict the success rate of treatments in The table shows the information. Total number of IVF treatments in 2007 Number of IVF treatments resulting in pregnancy in 2007 Predicted percentage success rate in 2008 Clinic R Clinic S (i) Compare the success rates of the two clinics in () (ii) The range of the predicted success rate in 2008 for clinic R is much smaller than the range of the predicted success rate for clinic S. Suggest why. (2) (Total marks) Page 63 of 20

64 24 The diagram shows some of the stages in IVF (in vitro fertilisation). (a) Use words from the box to name structures A, B, C and D. egg embryo fertilised egg ovary sperm Structure A Structure B Structure C Structure D (4) (b) What do doctors do next with structure D? (2) Page 64 of 20

65 (c) The table gives statistics for an IVF clinic. Age of women treated Below 35 years years years years Number of women treated Number of women who produced one baby Number of women who produced twins Number of women who produced triplets (i) About what proportion of the treated women aged years produced one or more babies? Draw a ring around your answer. one quarter one third half () (ii) This clinic does not give IVF treatment to women over 42 years of age. Use data from the table to explain why. (2) (iii) The committee which regulates IVF treatment now advises that only one embryo is used in each treatment. Suggest one reason for this. () (Total 0 marks) Page 65 of 20

66 25 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. (a) 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) Page 66 of 20

67 26 Diabetes is a disease in which the concentration of glucose in a person s blood may rise to fatally high levels. Insulin controls the concentration of glucose in the blood. (a) Where is insulin produced? Draw a ring around one answer. gall bladder liver pancreas () (b) People with diabetes may control their blood glucose by injecting insulin. (i) If insulin is taken by mouth, it is digested in the stomach. What type of substance is insulin? Draw a ring around one answer. carbohydrate fat protein () (ii) Apart from using insulin, give one other way people with diabetes may reduce their blood glucose. () Page 67 of 20

68 (c) The bar chart shows the number of people with diabetes in different age groups in the UK. Age in years (i) Describe how the number of males with diabetes changes between the ages of 0 44 years and 75 years and over. (3) Page 68 of 20

69 (ii) Compare the number of males and females with diabetes: between the ages of 0 and 64 years over the age of 65 years. (2) (Total 8 marks) 27 Penguins live mainly in the Antarctic. Penguins eat mainly fish. Photograph shows a penguin swimming underwater. Photograph raywoo/istock Page 69 of 20

70 (a) Use information from Photograph to suggest three ways the penguin is adapted for catching fish (3) (b) The Antarctic winter is very cold. In the winter some species of penguin huddle together as shown in Photograph 2. Photograph 2 Fuse Suggest how the behaviour shown in Photograph 2 helps the penguins to survive the Antarctic winter. (3) Page 70 of 20

71 (c) A student did an investigation to model the behaviour of the penguins shown in Photograph 2. The diagram shows the apparatus the student used. The student: held seven similar test tubes together with elastic bands as shown in the diagram stood a similar eighth tube in a test tube rack filled each of the eight tubes with hot water to the same level measured the temperature of the water in tubes A, B and C every 2 minutes for 20 minutes. Page 7 of 20

72 The table shows the student s results. Time in Minutes Temperature in C Tube A Tube B Tube C (i) Give two variables that were controlled in the investigation.. 2. (2) (ii) Describe the patterns the data shows. (2) Page 72 of 20

73 (iii) How far does the data from the model support the suggestion you made in part (b)? (2) (d) Describe how blood vessels help control human body temperature. (4) Page 73 of 20

74 (e) Penguins control their body temperature in similar ways to humans. Scientists investigated changes in body temperature of penguins when the penguins were diving to catch fish. (i) Graph shows the relationship between the temperature of the muscles moving a penguin s wings and diving. The shaded areas show when the penguin was diving. Graph Time Reprinted from Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 35, P.J. Ponganis,R.P. Van Dam,D.H. Levenson,T. Knower,K.V. Ponganis,G. Marshall, Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice, pp , copyright 2003, with permission from Elsevier Suggest an explanation for the changes in temperature inside the muscles moving the penguin s wings. (3) Page 74 of 20

75 (ii) Graph 2 shows the relationship between the temperature inside a penguin s foot and diving. The shaded areas show when the penguin was diving. Graph 2 Time Reprinted from Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 35, P.J. Ponganis,R.P. Van Dam,D.H. Levenson,T. Knower,K.V. Ponganis,G. Marshall, Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice, pp , copyright 2003, with permission from Elsevier Suggest an explanation for the changes in temperature inside the penguin s foot as it dives. (3) (Total 22 marks) Page 75 of 20

76 28 The number of cases of Type 2 diabetes in the UK is increasing rapidly. (a) Describe how insulin and glucagon help control the blood sugar concentration in a healthy person. (6) (b) What is Type 2 diabetes? () Page 76 of 20

77 (c) Body mass index (BMI) is a person s body weight divided by the square of his or her height. (i) Graph shows the relationship between BMI and the percentage probability of developing Type 2 diabetes. Graph Percentage probability of developing Type 2 diabetes Suggest an explanation for the relationship between BMI and the risk of developing Type 2 diabetes. (2) Page 77 of 20

78 (ii) Graph 2 shows changes in the number of new cases of Type 2 diabetes in the UK. Graph 2 Year Suggest explanations for the trend shown by the data in Graph 2. (3) (Total 2 marks) 29 One factor that may affect body mass is metabolic rate. (a) (i) What is meant by metabolic rate? () Page 78 of 20

79 (ii) Metabolic rate is affected by the amount of activity a person does. Give two other factors that may affect a person s metabolic rate.. 2. (2) Page 79 of 20

80 (b) Predicted early death is the number of years that a person will die before the mean age of death for the whole population. The predicted early death of a person is affected by their body mass. Scientists have calculated the effect of body mass on predicted early death. The graph shows the results of the scientists calculations. Ideal body mass The number of times above or below ideal body mass is given by the equation: In the UK the mean age of death for women is 82. A woman has a body mass of 70 kg. The woman s ideal body mass is 56 kg. (i) Use the information from the graph to predict the age of this woman when she dies. Age at death = years (2) Page 80 of 20

81 (ii) The woman could live longer by changing her lifestyle. Give two changes she should make.. 2. (2) (Total 7 marks) 30 Type diabetes develops when the body does not produce enough insulin. (a) Which organ produces insulin? () (b) One treatment for diabetes is to inject insulin. The table gives the properties of four different types of insulin, A, B, C and D. Type of insulin Time taken for the insulin to begin to work in minutes Time taken for insulin to reach maximum concentration in the blood in minutes Time when insulin is no longer effective in hours A B C D (i) Some people with diabetes need to inject insulin just before a meal to stop a big increase in blood sugar concentration. Which type of insulin, A, B, C or D, should these people with diabetes inject just before a meal? Give the reason for your answer. (2) Page 8 of 20

82 (ii) A person with diabetes is told to inject type B insulin immediately after breakfast at The person with diabetes is told to then inject a second type of insulin at lunchtime at The second type of insulin should keep the blood sugar level under control for the rest of the 24 hours. Which type of insulin, A, C or D, should this person with diabetes inject at lunchtime? Give the reason for your answer. (2) (iii) Apart from injecting insulin, give one other way in which Type diabetes can be controlled. () (Total 6 marks) Page 82 of 20

83 3 The pancreas and the liver are both involved in the control of the concentration of glucose in the blood. The liver has two veins: the hepatic portal vein taking blood from the small intestine to the liver the hepatic vein taking blood from the liver back towards the heart. Scientists measured the concentration of glucose in samples of blood taken from the hepatic portal vein and the hepatic vein. The samples were taken hour and 6 hours after a meal. Graph shows the concentration of glucose in the two blood vessels hour after the meal. Graph Blood vessel (a) The concentration of glucose in the blood of the two vessels is different. Explain why. (3) Page 83 of 20

84 (b) Graph 2 shows the concentration of glucose in the two blood vessels 6 hours after the meal. Graph 2 Blood vessel (i) The concentration of glucose in the blood in the hepatic portal vein hour after the meal is different from the concentration after 6 hours. Why? () Page 84 of 20

85 (ii) The person does not eat any more food during the next 6 hours after the meal. However, 6 hours after the meal, the concentration of glucose in the blood in the hepatic vein is higher than the concentration of glucose in the blood in the hepatic portal vein. Explain why. (3) (Total 7 marks) 32 The human body produces many hormones. (a) (i) What is a hormone? () (ii) Name an organ that produces a hormone. () (iii) How are hormones transported to their target organs? () Page 85 of 20

86 (b) Describe how the hormones FSH, oestrogen and LH are involved in the control of the menstrual cycle. (3) (Total 6 marks) 33 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. Page 86 of 20

87 (a) 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. () (c) Describe what happens at the synapse during this reflex. (3) (Total 7 marks) 34 The diagram shows the structures involved in a reflex action. (a) On the diagram, name the structures labelled W, X and Y. (3) Page 87 of 20

88 (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. (2) (Total 5 marks) Page 88 of 20

89 35 The diagram shows an intra-uterine contraceptive device (IUCD). The IUCD is put inside the uterus (womb). The IUCD contains a hormone. The hormone diffuses directly into the uterus. The supply of hormone in the IUCD lasts for about five years. The hormone works by: causing the cervix to produce a thick plug of mucus causing the lining of the uterus to become very thin. For every 000 women using the IUCD for one year about 2 women become pregnant. There are about 0 pregnancies for every 000 women using the contraceptive pill for one year. Evaluate the use of the IUCD compared with the contraceptive pill. Use the information in this question and your own knowledge and understanding. Remember to give a conclusion to your evaluation. Page 89 of 20

90 (4) (Total 4 marks) Page 90 of 20

91 Mark schemes (a) any two from: same result at ph 7 and 7.5 or could be any ph between 7 and 7.5 or not tested at ph 7.25 or need to test at smaller ph intervals (between 7 and 7.5) accuracy of result only to nearest 0.5 minutes no repeats difficult to determine end point (colour) 2 (b) 2.7 / (units per minute) allow 0.52 with no working shown for 2 marks allow mark for 0.52 or 0.56 (c) (d) (e) (after 0 minutes) solution goes black (after 60 minutes) solution stays the same or does not go black or goes slightly orange steeper curve levels off at.8 units and before 45 minutes no / little sugar produced allow a correct description of what the graph would look like (because at 65 C) the enzyme will be denatured allow (because) the enzyme s shape will be changed or (because) the active site is damaged Page 9 of 20

92 (so) will no longer fit the starch or (so) will not be able to catalyse the reaction [] 2 (a) pancreas (b) (in the) blood(stream) allow in the (blood) plasma ignore dissolved or in solution (c) any two from: concentration rises and falls in both people concentration is higher at start / always in person with diabetes concentration rises higher in person with diabetes allow correct use of figures 2 plus any two from: concentration rises more rapidly in person with diabetes concentration stays high for longer in person with diabetes concentration does not return to starting level during test in person with diabetes, yet concentration returns to starting concentration by 90 minutes in person without diabetes concentration goes below starting concentration only in person without diabetes 2 (d) reduce carbohydrate / glucose / sugar in diet (so) blood glucose concentration does not increase as much (so) there is reduced named effect (of prolonged high blood glucose) allow reduced short or long term consequences such as tiredness or increase urination or thirst or eye / kidney / nerve / heart disease [9] 3 (a) fast reaction to reduce / protect from harm allow named examples Page 92 of 20

93 (b) (c) higher caffeine concentration causes shorter reaction time. allow converse ignore faster / slower reaction time Level 3 (5 6 marks): A coherent method is described with relevant detail, which demonstrates a broad understanding of the relevant scientific techniques and procedures. The steps in the method are logically ordered. The method would lead to the collection of valid results. Level 2 (3 4 marks): The bulk of a method is described with mostly relevant detail, which demonstrates a reasonable understanding of the relevant techniques and procedures. The method may not be in a completely logical sequence and may be missing some detail. Level ( 2 marks): Discrete relevant points are made which demonstrate some understanding of the relevant scientific techniques and procedures. They may lack a logical structure and would not lead to the production of valid results. 0 marks: No relevant content. Indicative content use decaffeinated coffee as control control volume of coffee blind trial or do not tell students which coffee they are drinking left for standard time between drink and test at least 0 minutes control start position of ruler control other factors such as light in the room same person for different concentrations repeat for each caffeine concentration use a range of caffeine concentrations start with lowest concentration of caffeine use caffeine solution instead of coffee to control for other ingredients repeat investigation with more people and calculate means 6 [8] 4 (a) (76 28) 2 96 (units / h) allow 96 (units / h) with no working shown for 2 marks allow.6 units / min for mark allow answer in range of (units / h) for mark (b) increased blood glucose concentration causes insulin release from pancreas Page 93 of 20

94 which stimulates cells to absorb glucose / sugar from the blood, so blood glucose concentration decreases (c) any three from: at least one advantage and one disadvantage of the system(s) must be given for full marks allow responses phrased in terms of the meter and injection systems advantages of the new system: better control so reduces risk of future health problems allow fewer low / high blood glucose periods so safer no need to estimate dose of insulin less chance of giving too much / little insulin system works automatically / continuously so no need to test / inject disadvantages of the new system: (d) system is always attached so may restrict activities allow pump is difficult to hide pump has to be carried somewhere allow risk of discomfort pump will need re-filling risk of infection or risk of tissue damage (at injection site) line might come out accept new system more expensive qualified conclusion: a statement as to which system is better with reference to at least one advantage and one disadvantage for example, the new system is better because although it is more expensive, it works automatically blood glucose concentration goes too low blood glucose concentration detected by pancreas pancreas releases glucagon (glucagon causes) cells to convert to glycogen into glucose 3 glucose released into blood [3] Page 94 of 20

95 5 (a) Pituitary (b) = 50 (%) (c) the level in the blood is already higher than it was before point A levels hadn t returned to normal yet (before the next scare) allow he had already been scared so he was expecting the second scare (d) increased oxygen to brain / muscles increased glucose to brain / muscles [7] 6 (a) A FSH allow follicle stimulating hormone B Progesterone (b) LH peaks allow luteinising hormone which causes an egg to be released. Page 95 of 20

96 (c) Level 3 (5 6 marks): A detailed and coherent explanation is given, which logically links the role of different hormones to their use in IVF and a clear explanation of how IVF increases the chance of a successful pregnancy. Level 2 (3 4 marks): An attempt is made to link the role of hormones to their use in IVF. The logic used in explaining how IVF increases the chance of a successful pregnancy may not be clear or linked to the hormones. Level ( 2 marks): Discrete relevant points made. The logic may be unclear and links may not be made. 0 marks: No relevant content Indicative content Identification of hormones used in IVF: FSH LH. Role of hormones in IVF: FSH causes eggs to mature LH causes the eggs to be released. Effect on chance of successful pregnancy: high levels of hormones cause many eggs to be matured and released sperm and eggs are collected and eggs are fertilised (so increased probability of fertilisation) fertilised eggs are given time to develop into a small ball of cells some are transferred into the mother (uterus), to increase the probability of one successfully implanting. 6 [0] 7 (a) Reflex action (b) Feature Label extra lines from the left negate the mark 3 Page 96 of 20

97 (c) dependent (d) 7.0 allow answers in range cm (e) 0.5 cm (f) 23.5 does not fit the pattern or at least 5 cm higher than the other values (g) The results are for the left and right hands of different people [0] 8 (a) in the blood(stream) allow plasma ignore dissolved or in solution (b) all three plots correct accept two correct plots for mark 2 suitable line drawn (c) hour (d) identification of steepest part of graph and correct readings taken = 45 (e) line on graph showing extrapolation for person B correct value read from graph (at 30 mg per 00 cm 3 ) allow mark for a value of hours if no extrapolation shown 2 [9] 9 (a) 0.92 = 76.2 time Page 97 of 20