AQA Applied Biology. New Document 1. Class: Year 12. Date: March minutes. Time: 129 marks. Marks: Comments:

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1 New Document Name: Class: Year 2 AQA Applied Biology Date: March 208 Time: 5 minutes Marks: 29 marks Comments:

2 Q. (a) The table shows some parts of cells and two different types of cell. Complete the table by putting a tick in a box if the structure is present in the type of cell. Cell wall Cell-surface membrane Nucleus White blood cell Bacterial cell The diagram is of a mitochondrion at a magnification of Calculate the actual length of this mitochondrion in micrometres (µm). Show your working. Answer = µm (c) Some scientists support the theory that mitochondria are organelles that evolved from prokaryotic cells. (i) Give one piece of evidence that supports the theory that mitochondria evolved from prokaryotic cells. () What is the advantage to cells of having mitochondria?

3 (Total 7 marks) Q2. Anti-diuretic hormone (ADH) is released into the blood in response to a shortage of water in the body. ADH enters the collecting duct cells in nephrons and causes the increased synthesis of one type of protein molecule. These protein molecules are inserted into the plasma membranes of the collecting duct cells where they act as channels. Only water molecules can pass through these channels, increasing the reabsorption of water from the kidney filtrate. (a) Name the gland which releases ADH. () (i) Explain how the structure of protein molecules allows them to form channels through which only water molecules can pass. Explain how the cells of the collecting duct are able to absorb water from the filtrate through the protein channels in their plasma membranes. (Total 5 marks) Q3. The diagram represents some of the light-independent reactions of photosynthesis.

4 (a) Describe the light-independent reactions of photosynthesis and explain how they allow the continued synthesis of hexose sugars.

5 (6) Describe the role of electron transport chains in the light-dependent reactions of photosynthesis. (6) (c) Explain why the increase in the dry mass of a plant over twelve months is less than the mass of hexose produced over the same period. (3) (Total 5 marks) Q4. (a) (i) Give two products of the light-dependent stage of photosynthesis.. 2.

6 The products of the light-dependent stage are used in the light-independent stage of photosynthesis. What are these products used for? () The graph shows the rate of uptake or release of carbon dioxide by a plant at different light intensities. Explain the rate of carbon dioxide exchange at point X. (Total 5 marks) Q5. A student investigated the effect of different wavelengths of light on the rate of photosynthesis. She used the apparatus shown in Figure. Figure (a) What measurements should the student have taken to determine the rate of photosynthesis?

7 () Other than temperature and ph, give two factors which should be kept constant during this investigation.. 2. (c) The student did not use a buffer to maintain the ph of the solution. Explain what would happen to the ph of the solution during this investigation. (d) Figure 2 shows the student s results. Figure 2 Suggest and explain why the rate of photosynthesis was low between 525 nm and 575 nm wavelengths of light.

8 [Extra space] (Total 7 marks) Q6. Scientists investigated the effects of temperature and light intensity on the rate of photosynthesis in creeping azalea. They investigated the effect of temperature on the net rate of photosynthesis at three different light intensities. They also investigated the effect of temperature on the rate of respiration. The graph shows the results. (a) (i) Name the factors that limited the rate of photosynthesis between X and Y. () Use information from the graph to explain your answer. Use information from the graph to find the gross rate of photosynthesis at 20 C and

9 medium light intensity. Answer () (c) Creeping azalea is a plant which grows on mountains. Scientists predict that in the area where this plant grows the mean summer temperature is likely to rise from 20 C to 23 C. It is also likely to become much cloudier. Describe and explain how these changes are likely to affect the growth of creeping azalea. (3) (Total 7 marks) Q7. (a) During respiration where, exactly, in a cell does each of the following occur? (i) Glycolysis () Electron transfer chain () Without oxygen, less ATP is produced by respiration. Explain why. (Total 4 marks)

10 Q8. (a) The table contains statements about three biological processes. Complete the table with a tick if the statement in the first column is true, for each process. Photosynthesis Anaerobic respiration Aerobic respiration ATP produced Occurs in organelles Electron transport chain involved (3) Write a simple equation to show how ATP is synthesised from ADP. () (c) Give two ways in which the properties of ATP make it a suitable source of energy in biological processes.. 2. (d) Humans synthesise more than their body mass of ATP each day. Explain why it is necessary for them to synthesise such a large amount of ATP. (Total 8 marks) Q9. A student investigated the rate of gas exchange in aerobically respiring seeds using the apparatus shown in the diagram. She carried out two experiments. In Experiment, she put potassium hydroxide solution in the beaker. Potassium hydroxide solution absorbs carbon dioxide.

11 In Experiment 2, she put water in the beaker. (a) Both experiments were carried out at the same temperature. Explain why. (i) The level of coloured liquid in the right-hand side of the manometer tube went down during Experiment. Explain why. (Extra space) (3) The results from both experiments are shown in the table.

12 Answer = cm 3 () Experiment Solution in beaker Fall in volume of coloured liquid in right-hand side of manometer / cm 3 Potassium hydroxide 5 2 Water Use these results to calculate the volume of carbon dioxide produced during Experiment. (c) The student repeated Experiment using seeds which were respiring anaerobically. What would happen to the level of coloured liquid in the right-hand side of the manometer tube? Explain your answer. (Total 8 marks) Q0. In the kidney, ultrafiltration and selective reabsorption are two of the processes involved in the formation of urine. (a) (i) Where does ultrafiltration occur? () Give one component of the blood which is not normally present in the filtrate. () The kidneys remove a substance called creatinine from the blood. The rate of creatinine removal is a measure of the rate of filtration of the blood. In one hour, a person excreted 75 mg of creatinine in his urine. The concentration of creatinine in the blood entering his kidneys was constant at 0.0 mg cm 3. Calculate the rate at which the blood was filtered in cm 3 min. Show your working.

13 Filtration rate = cm 3 min (c) Reabsorption of glucose takes place in the proximal tubule. Explain how the cells of the proximal tubule are adapted for this function. (Total 6 marks) Q. The diagram shows the outer layers of three different cells, A, B and C. (a) What is the evidence from the diagram that (i) cell B is an animal cell, () cell C is a prokaryotic cell? ()

14 Explain how you would calculate the magnification of cell C. () (c) Cell A is a plant cell. Name a polysaccharide which may be found in cell A but would not be found in the animal cell. () (d) Penicillin is an antibiotic. It prevents the formation of bacterial cell walls. As a result, bacterial cells that have been treated with penicillin swell and burst as water enters. (i) Explain how water enters a bacterial cell. Suggest why penicillin has no effect on plant cells. () (Total 7 marks) Q2. Three processes are involved in the formation of urine in a mammalian kidney. These are ultrafiltration, selective reabsorption and concentration. The diagram shows where these processes take place in a nephron. (a) Describe how ultrafiltration produces glomerular filtrate.

15 (Extra space) (5) Some people who have diabetes do not secrete insulin. Explain how a lack of insulin affects reabsorption of glucose in the kidneys of a person who does not secrete insulin. (Extra space) (4) (c) Some desert mammals have long loops of Henle and secrete large amounts of antidiuretic hormone (ADH). Explain how these two features are adaptations to living in desert conditions.

16 (Extra space) (6) (Total 5 marks) Q3. (a) The graph shows changes in the concentration of glucose in a person s blood following a meal. Changes in the concentration of glucose are controlled by the hormones glucagon and insulin. Write the letters X and Y on the graph to show X a time when glucagon secretion would be high; Y a time when insulin secretion would be high. () S Many diabetics require regular injections of insulin. Describe how bacteria can be genetically modified to produce human insulin.

17 (4) (Total 5 marks) Q4. Homeostatic mechanisms maintain a constant environment in the body. (a) The graph shows changes in plasma glucose concentration that occurred in a person who went without food for some time. Use evidence from the graph to explain the role of negative feedback in the control of plasma glucose concentration.

18 (5) How does maintaining a constant body temperature allow metabolic reactions in cells to proceed with maximum efficiency? (5) (Total 0 marks) Q5. Resource A A glucometer is a device used to measure blood glucose concentration. A person uses a test strip that goes into the glucometer. They put a drop of blood onto the test strip. There are substances on the test strip that produce a colour change with glucose. The higher the concentration of glucose, the deeper the colour produced. The glucometer measures the depth of colour produced and converts this into a glucose concentration. A new test strip is used for each blood test. Figure glucometer and test strip

19 The following equations show how the substances on the test strip produce a colour change. Glucose + oxygen gluconic acid + hydrogen peroxide Hydrogen peroxide + dye with colour A dye with colour B + water Non-diabetics have no glucose in their urine. Diabetics have glucose in their urine if their blood glucose concentration rises above about 70 mg 00 cm 3. Before the glucometer was available, diabetics used test strips to measure the concentration of glucose in their urine as a means of measuring their blood glucose concentration. When testing urine, the colour of the test strip is compared against a colour chart which gives a glucose concentration range for the colour produced. Resource B There are two types of diabetes: type and type 2. People with type diabetes do not produce enough insulin. People with type 2 diabetes do produce insulin but have cells which do not respond to insulin. Doctors use a glucose tolerance test to help diagnose people with diabetes. They start each test after a person has not eaten overnight. They measure a person s blood glucose concentration. The person then drinks a solution containing 75 g of glucose. The doctors measure the person s blood glucose concentration 2 hours later. During the test, the person remains at rest. Figure shows three diagnoses that can be made from the results of the test. Figure 2 glucose tolerance test results and diagnoses Blood glucose concentration after 2 hours Diagnosis Comments / mg 00 cm 3 0 Non-diabetic Low risk for future diabetes Between 40 and 200 Pre-diabetic High risk for future diabetes. Some doctors recommend that the upper value should be lowered to 80 mg 00 cm Diabetic Confirm by doing a second test

20 A researcher monitored the mean blood glucose concentration of a non-diabetic, a pre-diabetic and a diabetic after they had each eaten a midday meal. His results are shown in Figure 3. Figure 3 A laboratory worker suspected she had type 2 diabetes but did not have a glucometer. Instead she added a drop of her blood to a test strip and used a colour chart to estimate her blood glucose concentration as 40 mg 00 cm 3. Is it valid to conclude that she did have type 2 diabetes? Use this information, and Resource A and Resource B, to explain your answer. (Extra space) (Total 3 marks) Q6. The diagram shows the structure of the cell-surface membrane of a cell.

21 (a) Name A and B. A B (i) C is a protein with a carbohydrate attached to it. This carbohydrate is formed by joining monosaccharides together. Name the type of reaction that joins monosaccharides together. Name the type of reaction that joins monosaccharides together. () Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus contains protein. Name one organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus. Organelle Description of role (Total 5 marks) Q7. The diagram shows a section through the heart. The main blood vessels are labelled A, B, C and D.

22 (a) Write a letter, A, B, C or D, in the box to represent the correct blood vessel. (i) Which blood vessel carries oxygenated blood away from the heart? () (i) Which blood vessel carries deoxygenated blood to the heart? () Explain how the highest blood pressure is produced in the left ventricle. () (c) Some babies are born with a hole between the right and the left ventricles. These babies are unable to get enough oxygen to their tissues. Suggest why.

23 (Total 5 marks) Q8. The diagram shows a carrot. A group of students investigated the effect of sucrose concentration on the length of cylinders cut from a carrot. (a) The students used a cork borer to cut cylinders from the carrot. Describe how the students should cut these cylinders to make sure that this was a fair test and would produce reliable results. They measured the initial length of each cylinder then placed the cylinders into test tubes containing different concentrations of sucrose solution. Bungs were placed in the tubes and the tubes were left overnight. Explain why the bungs were placed in the tubes. (c) The students then measured the final lengths of the carrot cylinders. Their results are shown in the table. Concentration of sucrose / mol dm

24 (i) The students used these results to find the concentration of sucrose that has the same water potential as the carrot cylinders. Describe how they could have done this. Was it important in this investigation that the carrot cylinders had the same initial length? Explain your answer. () (Total 7 marks)

25 Mark schemes Q. (a) White blood cell Bacteria cell 2.80 (μm);; Answer in range scores 2 marks If length incorrect but divided by , allow mark 2 2 (c) (i) Circular DNA / smaller/70s ribosomes / no introns / no histones/proteins associated with DNA; Ignore reference to plasmids. Able to respire aerobically; 2. So make (more) ATP/ release (more) energy; Reject producing energy unqualified 2 [7] Q2. (a) Pituitary; Ignore any reference to lobe / hypothalamus. (i) (Each) protein has a tertiary structure; Gives specific / correct shape / size to (inside of) channel / pore; 2 More negative / lower WP (inside tubule cells); accept Ψ symbol / down a WP gradient Water enters / moves by diffusion / osmosis; ignore water concentration, etc. 2 [5] Q3. (a) 5C / RuBP combines with CO 2 ; 2 to form 3C compound / TP / GP; 3 using ATP; 4 and reduced NADP / eq; 5 2 molecules of 3C compound / TP / GP form hexose; 6 all RuBP is regenerated;

26 7 0 molecules of 3C / TP / GP form 6 molecules of 5C / RuBP; 6 max electron transport chain accepts excited electrons; 2 from chlorophyll / photosystem; 3 electrons lose energy along chain; 4 ATP produced; 5 from ADP and Pi; 6 reduced NADP formed; 7 when electrons (from transport chain) and H + combine with NADP; 8 H + from photolysis; 6 max (c) some hexose / biomass / eq. used in respiration; growth cancels this point 2 CO 2 produced (is lost to air); 3 some parts of the plant are eaten / some parts lost to decomposers / in leaf fall; 3 [5] Q4. (a) (i) Reduced NADP; Accept NADPH/ ATP; Accept oxygen/o 2 (To incorporate carbon dioxide) to make sugars/glucose/fructose; Accept to fix carbon dioxide Accept correct biochemical answers Accept provide energy to make sugars Change (in CO 2 exchange) due to photosynthesis; Plants carry out photosynthesis and respiration; At X (rates of) respiration and photosynthesis same; 2 max [5] Q5. (a) Oxygen production / concentration and time.

27 Accept: oxygen volume / concentration Reject: oxygen uptake Neutral: reference to carbon dioxide uptake. Intensity of light; Accept: distance from light 2. Amount / number / mass / species of algae / photosynthesising cells; 3. Carbon dioxide (concentration / partial pressure); 4. Time. 2 max (c). (ph) increases; Neutral: becomes more alkaline / less acidic 2. As (more) carbon dioxide removed (for photosynthesis). 2 (d). Less absorption / (more) reflection (of these wavelengths of light); Reject: no absorption or cannot absorb unless in context of green light. Note: no green light absorbed or green light reflected = 2 marks. 2. (Light required) for light dependent (reaction) / photolysis Accept: for excitation / removal of electrons (from chlorophyll) 3. (Represents) green light / colour of chlorophyll. 2 max [7] Q6. (a) (i) Temperature and light; Increase in temperature causes increase in rate of photosynthesis / uptake of carbon dioxide; Increase in light / more / medium / high light (intensity) causes increase in rate of photosynthesis / uptake of carbon dioxide; (mg g hr ) Accept answers in range (c). Growth will decrease (at higher temperature); 2. Rate of respiration will increase at higher temperature; 3. Photosynthesis decreases as limited by light / as there is less light; Ignore references to effect of temperature on rate of photosynthesis 2 3 [7]

28 Q7. (a) (i) Cytoplasm; Accept - cytosol Inner membrane of mitochondrion Icristae; Reject crista/ particle Oxygen is the termina/ acceptor; (No) electron transfer chain / proton transfer / no oxidative phosphorylation; Accept ETC abbreviation Which produces most of the ATP (in aerobic respiration); Only glycolysis takes place; Pyruvate used to make lactate; Accept lactic acid Only produces (net) 2 ATP (per molecule of glucose); Accept only 4 ATP are made 2 max [4] Q8. (a) Photosynthesis Anaerobic respiration Aerobic respiration ATP produced Occurs in organelles Electron transport chain involved mark per column Mark ticks only. Ignore anything else if different symbols such as crosses are used as well. If crosses are used instead of ticks allow cross as equivalent to a tick. Reject tick with a line through 3 ADP + P i ATP; Both sides correct, but allow other recognised symbols or words for phosphate ion. Reject P unless in a circle. Accept = as equivalent to arrow Accept reversible arrow Ignore any reference to kj / water (c). Energy released in small / suitable amounts;

29 2. Soluble; 3. Involves a single / simple reaction;. In context of release, not storage. Ignore producing energy / manageable amounts. 2. Reject "broken down easily / readily". Reject "quickly / easily resynthesised". 2 max (d). ATP cannot be stored / is an immediate source of energy; 2. ATP only releases a small amount of energy at a time; 2 [8] Q9. (a). Affects enzymes; respiration involves enzymes = two marks 2. Affects respiration; Ignore reference to controlling a variable Or 3. Affects volume / pressure of gases; Mark point 4 can only be awarded if mark point 3 has been credited 4. Affects readings; (i). Oxygen taken up / used (by seeds); Reject air is taken up for mark point 4; 2. Carbon dioxide (given out) is absorbed by solution / potassium hydroxide; 3. Decrease in volume / pressure (inside flask); Reference to vacuum negates mark point 3 (c). Remains the same; 2. No oxygen uptake / used; Any reference to carbon dioxide not being produced disqualifies mark point 2 2 max 3 2 [8] Q0. (a) (i) Renal capsule / Bowman s capsule / glomerulus / basement membrane; blood cells / platelets / proteins / named plasma protein;

30 75 divided by 60 / 75 divided by 0.0; Answer 25; (Correct answer gains two marks) (c) (Many) mitochondria provide ATP / energy for active transport; (Many) carrier proteins for active transport / channel proteins for facilitated diffusion; Microvilli / brush border provide large surface area (for absorption); 2 max [6] Q. (a) (i) no cell wall / only has (plasma) membrane; has capsule / slime layer; (c) correct approach which makes use of scalebar; ignore reference to units. cellulose / starch / amylose / amylopectin; (d) (i) water potential lower / more negative in cell; (water enters by) osmosis; 2 plant cell wall made of a different substance / cellulose / penicillin does not affect cellulose; [7] Q2. (a). Blood pressure / hydrostatic pressure; 2. Small molecules / named example; 3. Pass through basement membrane / basement membrane acts as filter; 4. Protein too large to go through / large so stays behind; 5. Presence of pores in capillaries / presence of podocytes;. High concentration of glucose in blood; 2. High concentration in tubule / in filtrate; 3. Reabsorbed by facilitated diffusion / active transport; 4. Requires proteins / carriers; 5. These are working at maximum rate / are saturated; 6. Not all glucose is reabsorbed / some is lost in urine; 5 4 max (c) For general principle, applied to either example:. More water (from filtrate) reabsorbed / returned to blood / less lost in urine; 2. By osmosis;

31 3. From collecting duct / from end of second convoluted tubule; 4. Due to longer loop of Henle; For loop of Henle, maximum 2 marks: 5. Sodium / chloride ions absorbed from filtrate in ascending limb; 6. Gradient established in medulla / concentration of ions increases down medulla; For ADH, maximum 2 marks: 7. Acts on collecting duct / distal convoluted tubule / second convoluted tubule; 8. Makes cells more permeable / inserts aquaporins in plasma membranes; Note: to score full marks, candidates must make one specific statement about Loop of Henle and one about ADH. 6 max [5] Q3. (a) On graph: X where glucose level is below norm AND Y where glucose level is above norm; EITHER. Use m-rna + reverse transcriptase to produce gene / (c)-dna; 2. Restriction enzyme to cut open plasmid; 3. Add sticky ends (to insulin gene and to plasmid); OR Allow:. Cut out insulin gene / cut open plasmid with restriction enzyme; 2. Use same restriction enzyme on second DNA; 3. Reference to (complementary) sticky ends; 4. Use ligase to join 2 DNA molecules; 5. Modified plasmid taken up by bacteria; max 4 [5] Q4. Quality of Communication The answers to all sections of this question require the use of continuous prose. Quality of language should be considered in crediting points in the scheme. In order to gain credit, answers should be expressed logically and unambiguously, using scientific terminology where appropriate. (a). Deviation of a value from norm initiates corrective mechanisms; 2. fluctuations in plasma glucose concentration detected by hypothalmus / islet cells in pancreas; 3. initial decrease, no food given (in plasma glucose) stimulates (increased) secretion of glucagon; 4. increases (in plasma glucose) stimulate (increased) secretion of insulin from β cells as secretors; 5. correct ref. to interconversion of glycogen / glucose / increased / decreased uptake of glucose by cells (as appropriate) / correct ref to change in membrane permeability; 5

32 . Body temp. / 37 C is optimum temp for enzymes; 2. excess heat denatures enzymes / alters tertiary structure / alters shape of active site / enzyme so substrate cannot bind / eq; 3. reactions cease / slowed; 4. too little reduces kinetic energy of molecules / moleculesmove more slowly; 5. fewer collisions / fewer ES complexes formed 5 [0] Q5.. Diabetics have (blood glucose) concentration greater than 40 mg cm 3 / than her estimate / estimate suggests she is pre-diabetic; 2. Colour change is subjective / blood on test strip masks colour change; 3. Concentration given as a range / estimation is not reliable; 4. May not have fasted; 5. May not have had a drink with 75 g glucose; 6. Only one test carried out; No mark for valid or not valid [3] Q6. (a). A: phospholipid (layer);. Reject hydrophobic / hydrophilic phospholipid 2. B: pore / channel / pump / carrier / transmembrane / intrinsic / transport protein; 2. Ignore unqualified reference to protein (i) Condensation (reaction); 2 Organelle named; Function in protein production / secretion; Function must be for organelle named Incorrect organelle = 0 eg. Golgi (apparatus);. Accept smooth endoplasmic reticulum 2. Package / process proteins; OR 3. Rough endoplasmic reticulum / ribosomes; 3. Accept alternative correct functions of rough endoplasmic reticulum. ER / RER is insufficient 3. Accept folding polypeptide / protein

33 4. Make polypeptide / protein / forming peptide bonds; OR 5. Mitochondria; 6. Release of energy / make ATP; 6. Reject produce / make energy 6. Accept produce energy in the form of ATP OR 7. Vesicles; 8. Secretion / transport of protein; 2 [5] Q7. (a) (i) C; A; Ignore name of vessel Ignore name of vessel Strongest/stronger contractions; Accept most muscle in wall / thickest/thicker muscular wall A comparative statement is needed Answer must be in context of producing force and not resisting it (c). Blood flows from left ventricle to right ventricle/ mixing of oxygenated and deoxygenated blood; 2. Lower volume of (oxygenated) blood leaves left ventricle/flows into aorta/c OR Lower pressure in blood leaving left ventricle/flowing into aorta/c OR Less oxygen in blood leaving left ventricle/aorta/c; 2 [5] Q8. (a) Lengthways / down the root; Through one tissue only / through same part / same proportion of tissues; 2 To prevent the water from evaporating / prevent evaporation; Changing the concentrations / water potential (of solution); 2 (c) (i) Plot data on a graph;

34 Find (sucrose concentration) from the graph where the ratio is ; 2 No, because the results are given as a ratio / as a proportion of initial length; [7]