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Contents Knowledge Retrieval Practice Shade in each level of the circle as you feel more confident and ready for your exam. How to use this book...

Contents Knowledge Retrieval Practice Shade in each level of the circle as you feel more confident and ready for your exam. How to use this book iv B1 Cell biology 2 B6 Organisation in plants 60 B11 Photosynthesis 118 B16 Reproduction 180 Knowledge Knowledge Knowledge Knowledge Retrieval Retrieval Retrieval Retrieval Practice Practice Practice Practice B2 Cell transport 12 B7 The spread of diseases 72 B12 Respiration 130 B17 Evolution 194 Knowledge Knowledge Knowledge Knowledge Retrieval Retrieval Retrieval Retrieval Practice Practice Practice Practice B3 Cell division 24 B8 Preventing and treating disease 84 B13 Nervous system & homeostasis 142 B18 Adaptation 208 Knowledge Knowledge Knowledge Knowledge Retrieval Retrieval Retrieval Retrieval Practice Practice Practice Practice B4 Organisation in animals 34 B9 Monoclonal antibodies 96 B14 Hormonal coordination 156 B19 Organising an ecosystem 220 Knowledge Knowledge Knowledge Knowledge Retrieval Retrieval Retrieval Retrieval Practice Practice Practice Practice B5 Enzymes 46 B10 Non-communicable diseases 106 B15 Variation 168 B20 Humans and biodiversity 232 Knowledge Knowledge Knowledge Knowledge Retrieval Retrieval Retrieval Retrieval Practice Practice Practice Practice ii For answers and more practice questions visit Even more practice and interactive iii www.oxfordrevise.com/scienceanswers revision quizzes are available on  Knowledge B4 B4 Organisation in animals There are five levels of organisation in living Digestive system Blood vessels organisms: The structure of each blood vessel relates to its functions. pancreas mouth cells basic building blocks makes enzymes: where food is chewed Vessel Function Structure Diagram amylase, lipase, and protease thick, muscular, and elastic walls thick small lumen salivary glands liver make saliva containing carries blood away from the heart the walls can stretch and wall thick layer of muscle makes bile artery groups of cells that the enzyme amylase (high pressure) withstand high pressure and elastic fibres tissues have similar structures gall bladder small lumen and functions stores bile – bile is alkaline to neutralise oesophagus have valves to stop blood flowing large lumen carries food to relatively hydrochloric acid carries blood to the heart the wrong way thin wall often has groups of tissues working the stomach vein from the stomach, (low pressure) thin walls valves organs together to perform a and emulsifies fat to large lumen specific function form small droplets with a large surface stomach churns food one cell thick – short diffusion area releases protease – distance for substances to move wall one tiny vessel small intestine carries blood to tissues with narrow groups of organs organ systems working together where digested digests proteins releases hydrochloric capillary and cells between the blood and tissues cell thick lumen food is absorbed (e.g., oxygen into cells and carbon into the blood acid – kills pathogens connects arteries and veins dioxide out) rectum large intestine very narrow lumen organ systems work where water and stores faeces organisms together, forming an minerals are absorbed anus organism into the blood expels faeces The heart Double circulatory system The heart is the organ that pumps blood around your body. It is The human circulatory system is described as Lungs made from cardiac muscle tissue, which is supplied with oxygen a double circulatory system because blood When breathing in, air moves deoxygenated blood in by the coronary artery. passes through the heart twice for every circuit 1 into the body through the around the body: oxygenated pulmonary artery aorta mouth and nose blood out bronchiole takes deoxygenated carries oxygenated the right ventricle pumps blood to the lungs 2 down the trachea branch of blood to the lungs blood around the body where gas exchange takes place trachea pulmonary 3 into the bronchi pulmonary vein the left ventricle pumps blood around the branch of artery bronchi vena cava brings oxygenated rest of the body. pulmonary 4 through the bronchioles vein brings blood from the deoxygenated lungs 5 into the alveoli (air sacs). blood into the pulmonary left atrium vein alveoli heart Oxygen then diffuses into the blood in pulmonary lungs artery the network of capillaries over the right atrium left ventricle surface of the alveoli. right ventricle pumps blood around the body pumps blood to network of the lungs vena cava capillaries over aorta the surface of the alveoli Heart rate is controlled by a group of cells in the right atrium that generate electrical impulses, acting as a pacemaker. head and body Artificial pacemakers can be used to control irregular heartbeats. The circulatory system Key terms Make sure you can write a definition for these key terms. red blood cells – bind to oxygen and transport it around the body blood is a tissue plasma – transports substances and blood cells around the body made up of four alveoli amylase aorta artery atrium bronchi bronchiole capillary cardiac platelets – form blood clots to create barriers to infections main components coronary double circulatory system lipase organ organ system plasma platelet white blood cells – part of the immune system to defend the body against pathogens protease pulmonary tissue vein vena cava ventricle 34 B4 Organisation in animals B4 Knowledge 35  KO4Retrieval Exam-style questions Now go back and use the questions below to check your knowledge from previous chapters. B4 Learn the answers to the questions below, then cover the answers column with a piece of paper and write as many as you can. Check and repeat. Previous questions Answers sugars can be absorbed when the concentration B4 questions Answers Put paper here What is the purpose of active transport in the small 1 of sugar in the small intestine is lower than the intestine? concentration of sugar in the blood patient’s cells are used to create an early embryo 1 Name the five levels of organisation. cells ➞ tissues ➞ organs ➞ organ systems ➞ organisms 2 What is therapeutic cloning? clone of themselves – stem cells from the embryo can Put paper here then be used to treat the patient’s medical conditions Put paper here 2 What is a tissue? group of cells with similar structures and functions undifferentiated cell that can differentiate into one or 3 What is a stem cell? more specialised cell types group of tissues working together to perform a 3 What is an organ? Give one disadvantage of using plant meristems to no genetic variation, so, for example, an entire cloned specific function 4 clone plants. crop could be destroyed by a disease Put paper here produces bile, which neutralises hydrochloric acid movement of particles against a concentration 4 What is the function of the liver in digestion? from the stomach and emulsifies fat to form small 5 What is active transport? gradient – from a dilute solution to a more droplets with a large surface area concentrated solution – using energy from respiration lubrication to help swallowing – contains amylase to 5 What is the function of saliva in digestion? break down starch Put paper here 6 Name three enzymes produced in the pancreas. amylase, protease, lipase Required Practical Skills 7 Name the four main components of blood. red blood cells, white blood cells, plasma, platelets Practise answering questions on the required practicals using the example below. You need to be able to apply your skills and knowledge to other practicals too. form blood clots – prevent the loss of blood and stop 8 What is the function of platelets? Put paper here wounds becoming infected Food tests Worked Example Practice bi-concave disc shape – large surface area-to- There are different ways to test A student wanted to test a sample for the 1 A student picked up volume ratio for diffusion of oxygen for four different compounds presence of protein using Biuret reagent. solution A and added it to 9 Describe three adaptations of a red blood cell. found in food: Write a risk assessment for this activity. a sample of food. Solution contains haemoglobin – binds to oxygen no nucleus – more space for oxygen A was blue and turned ethanol test for lipids Answer: purple after adding to the Put paper here (fats) – colour change from engulf pathogens Write down general safety practices in labs: food. Name solution A, and 10 How do white blood cells protect the body? colourless to cloudy if produce antitoxins to neutralise toxins, or antibodies wear goggle to protect your eyes identify the food present in present the sample. Name the substances transported in the blood Benedict’s test for sugars – wash hands at the end of the practical 11 hormones, proteins, urea, carbon dioxide, glucose 2 Benedict’s test for sugar plasma. colour change from blue to clear up any spills quickly red if present requires the solution to Put paper here blood passes through the heart twice for every circuit do not eat any of the food be heated. One way to do iodine test for starch around the body – deoxygenated blood is pumped Write down what things could hurt you in this is heating the test tube Why is the human circulatory system a double (carbohydrates) – colour 12 from the right side of the heart to the lungs, and the the practical, and how they could hurt you: in a beaker of water using circulatory system? change from brown to blue- oxygenated blood that returns is pumped from the left a Bunsen burner. Give black if present Biuret reagent – irritant side of the heart to the body an alternative method of Biuret reagent test for glass – can break heating the solution. Put paper here carries blood away from the heart under high protein – colour change from pipette – can poke you in the eyes How does the structure of an artery relate to its 13 pressure – has a small lumen and thick, elasticated blue to purple if present. 3 When testing a sample function? Write down how you can prevent these walls that can stretch for protein in a test tube, You need to be able to identify hurting you: a student found that the carries blood back to the heart at low pressure – and describe the correct method, top of the sample tested How does the structure of a vein relate to its wash hands after touching Biuret 14 doesn’t need thick, elasticated walls, but has valves to and results, for each test. positive whereas the function? reagent, do not eat in the lab, and if prevent blood flowing the wrong way Put paper here ingested or it gets into the eyes inform bottom did not. Give the How does the structure of a capillary relate to its carries blood to cells and tissues – has a one-cell-thick the teacher immediately reason for this result. 15 function? wall to provide a short diffusion distance if glass is broken inform a teacher immediately List the structures air passes through when mouth/nose ➞ trachea ➞ bronchi ➞ bronchioles ➞ 16 point pipettes downwards breathing in. alveoli 36 B4 Organisation in animals B4 Retrieval 37  Practice Paper 1 B4 Exam-style questions 01.4 Explain how the structures in the chest cavity cause the changes in 01 The events that occur during one breath – one inhalation and one lung volume shown between 0 s and 1 s. [4 marks] ! Exam Tip exhalation – are known as one respiratory cycle. Figure 1 shows change in the volume of the lungs in one respiratory An ‘explain’ question, wants cycle. The data were taken when the person was resting. to know why things are happening. Figure 1 0.5 change in lung volume in dm3 0.4 0.3 ! Exam Tip 01.5 A doctor measured another person’s resting respiratory cycle. This person had 25 respiratory cycles per minute. ! Exam Tip Draw lines on the graph to 0.2 help you work it out! Suggest and explain one possible cause of this difference. [2 marks] ‘Suggest and explain’ means you need to say what you 0.1 think will happen and why. 0.0 0 1 2 3 time in s 02 A student carried out a number of food tests on an unknown sample. 01.1 Use Figure 1 to determine the volume of air taken in when the Their results are shown in Table 1. person inhales. [1 mark] Table 1 Reagent used Result dm 3 iodine yellow–orange Benedict’s solution blue 01.2 The person’s total lung volume after inhalation was 6.00 dm3. Biuret reagent purple Calculate their total lung volume after exhalation. [2 marks] ethanol cloudy white layer formed 02.1 Suggest and explain one safety precaution that the student should have taken when using the Biuret reagent. [2 marks] ! Exam Tip dm3 The question has asked for a specific safety precaution 01.3 Calculate how many respiratory cycles will take place in one minute. when using Biuret reagent, so Give your answer to two significant figures. [3 marks] a general safety measure isn’t going to get the marks! 02.2 Identify which of the following statements is a correct description of the student’s findings. Tick one box. [1 mark] per minute The food sample contains starch, protein, and fat. The food sample contains starch and sugar. The food sample contains fat and protein. The food sample contains fat and sugar. 38 B4 Organisation in animals For answers and more practice questions visit Even more practice and interactive B4 Practice 39 www.oxfordrevise.com/scienceanswers revision quizzes are available on  B4 02.3 Identify which foodstuff is most likely to be the food sample the 04 Figure 3 shows some organs Figure 3 student tested. from the digestive system. Tick one box. [1 mark] 04.1 Identify organs A and C from Figure 3. [2 marks] a chocolate bar 04.2 Identify the organ from Figure 3 that is responsible a meat burger for absorbing water from A undigested food. [1 mark] B spaghetti 04.3 The stomach is made up of a number of tissues. Draw a carrot one line from each type of stomach tissue to C 02.4 Many people with diabetes have to follow a strict diet to control its function. [3 marks] their blood glucose levels. ! Exam Tip D Explain why using Benedict’s solution to test foods for glucose may Think about which food not be helpful to a diabetic. [2 marks] diabetics need to control their intake of. Stomach tissue Function churns the food and digestive juices of the stomach together ! Exam Tip muscular tissue Be careful – there is one spare 03 Gluten is a form of protein found in some grains, for example, wheat. covers the inside and outside function! glandular tissue of the stomach 03.1 Describe the structure of a protein. [1 mark] sends impulses to other areas 03.2 Coeliac disease is a disease of the digestive system. It damages ! Exam Tip of the body epithelial tissue the lining of the small intestine when foods that contain gluten For this question coeliac ! Exam Tip are eaten, resulting in a patient having a reduced number of villi. produces the digestive juices disease is used as an example. Your answer must relate to This causes a number of symptoms such as abdominal bloating You may not have covered this fat digestion, not to any other and pain. A healthy person has on average 25 to 30 villi per µm2. 04.4 Explain how the pancreas and the gall bladder work together to in class, but this is getting you functions! Calculate the density of the villi in the small intestine of a coeliac increase the efficiency of fat digestion. [6 marks] used to applying what you patient who has 50 000 villi in 7200 µm2 of small intestine. [2 marks] know to new situations for the exam. 05 Figure 4 represents cross-sectional areas through the three main 03.3 Figure 2 compares a section of the small intestine of a person with coeliac disease with a person who does not have coeliac disease. types of blood vessel. Figure 2 Figure 4 normal villi villi affected by coeliac disease ! Exam Tip A B C There is a clear difference in the picture. Think about how this difference may relate to the function of the digestive system. 05.1 Identify which blood vessel in Figure 4 represents an artery. [1 mark] ! Exam Tip coeliac disease Use Figure 4 to help with this normal villi 05.2 Explain one way arteries are adapted for their function. [2 marks] question! Use the information in the question and your own knowledge to 05.3 Blood in the arteries is usually bright red because it is full of oxygen. suggest why a child with coeliac disease may not grow as tall as Identify the artery where this is not true. [1 mark] their peers. [4 marks] aorta vena cava pulmonary artery coronary artery 40 B4 Organisation in animals For answers and more practice questions visit Even more practice and interactive B4 Practice 41 www.oxfordrevise.com/scienceanswers revision quizzes are available on  B4 05.4 Give a reason for your answer to 05.3. [1 mark] 08.1 Explain how a red blood cell is adapted to perform its function. [6 marks] 05.5 Describe two reasons why it is important that blood is transported to every cell in the body. [2 marks] 08.2 Using Table 2, calculate the percentage change between the number of red blood cells present in a person living at 2000 m ! Exam Tip 06 A student was provided with an unknown food sample and the above sea level, and 4000 m above sea level. [2 marks] Percentage change is how following apparatus: different they are from each 08.3 As altitude increases, the amount of oxygen in the air decreases. test tubes (in a test-tube rack) Benedict’s solution Using information in Table 2, explain how differences in a person’s other as a percentage. water bath Biuret reagent ! Exam Tips blood composition enable them to live at different iodine ethanol This is a great practice altitudes. [3 marks] The food sample had been ground into a powder using a pestle and question. mortar. Explain how the student could test the food sample for the Remember, don’t use all of 09 Figure 6 shows a section of blood vessels in the upper arm. presence of starch, sugar, fats, and protein. [6 marks] your sample in one go, clearly Figure 6 lay out what observations blood flow blood flow 07 Figure 5 shows a cross-section through the human heart. would mean positive or negative results, and don’t muscle cells Figure 5 forget your safety precautions. B X A Y A ! Exam Tip The first thing you should do C when you see a diagram of a Z heart is mark down your right (on the left-hand side) and left (on the right-hand side). B Z X Y 09.1 Name the blood vessel represented by label Z. [1 mark] magnification: × 0.75 09.2 Describe two ways structure Z is adapted to maximise the rate of 07.1 Identify which label is pointing to the left atrium. [1 mark] diffusion of carbon dioxide. [2 marks] 07.2 Name the blood vessels labelled A and B. [2 marks] 09.3 Identify which arrow shows the direction of transport of carbon dioxide. [1 mark] 07.3 Identify and describe the function of part Z. [2 marks] 10 Figure 7 shows the Figure 7 07.4 Humans have a double circulatory system. Describe what changes in blood this means. [2 marks] 140 pressure of a person blood vessel A at rest. Their blood ! 120 08 Table 2 shows the number of red blood cells present in people Exam Tip pressure was measured living at different altitudes above sea level. blood pressure in mmHg in an artery and a vein at 100 Thinking about how structure Table 2 the same time. 80 relates to function might give Height above sea Mean number of red blood cells 10.1 Identify which line on you a clue here. level in m in millions per mm3 of blood the graph represents 60 0 4.9 a vein. Explain your 40 1000 5.5 answer. [3 marks] 2000 6.2 20 blood vessel B 3000 6.8 0 4000 7.2 0.0 2.5 5.0 7.5 10.0 12.5 15.0 time in s 5000 7.6 42 B4 Organisation in animals For answers and more practice questions visit Even more practice and interactive B4 Practice 43 www.oxfordrevise.com/scienceanswers revision quizzes are available on  B4 10.2 Explain how a vein is adapted to transporting blood back 12.4 Suggest one reason why the student would not be told to observe to the heart. [4 marks] ! Exam Tip their own blood cells in the classroom. [1 mark] 10.3 Draw a line on Figure 7 to suggest the pressure you would find in Measuring the number of 13 The best light microscopes produce magnifications of around a capillary. [1 mark] beats in 15 seconds then ×2000. Transmission electron microscopes (TEMs) have much better multiplying by four will give a 10.4 Calculate the person’s heart rate. [2 marks] resolution, producing magnifications of around ×2 000 000. more accurate result. 13.1 Define the term resolution. [1 mark] 11.1 Explain why a household plant will start to wilt if you don’t water it for several days. [4 marks] 13.2 The smallest object that can be viewed through a light microscope ! Exam Tip is 200 nm in size. Calculate the smallest object that can be viewed ‘Compare’ means you need 11.2 Plants also need a supply of minerals to remain healthy, for through a transmission electron microscope. [3 marks] to give the things that are example, nitrates. Nitrates are taken in through the roots. Figure 8 the same and things that are shows the change over time in the mass uptake of nitrate ions for ! Exam Tip 13.3 Evaluate and compare the use of light and electron microscopes to different. root cells with and without access to oxygen. observe sperm cells. [6 marks] Give the story of the lines, talk Figure 8 about both lines, use figures 14 Figure 9 shows the typical lengths of some different structures. 600 from the graph to show where any changes take place, and Figure 9 mass uptake of nitrate ions in arbitrary units with oxygen 500 describe the shape of the graph. giant minke eukaryotic prokaryotic a small redwood whale human apple wasp ant cells cells viruses DNA molecule 400 300 without oxygen 100 m 10 m 1m 10 cm 1 cm 1 mm 100 μm 10 μm 1 μm 100 nm 10 nm 1 nm 200 14.1 Deduce the difference in order of magnitude between an ant and a human. [1 mark] 100 14.2 Explain why humans need lungs whereas ants do not. [2 marks] 0 0 60 120 180 240 300 14.3 The resolution of a light microscope is 800 nm. Identify the time in seconds smallest structure from Figure 9 that can be viewed using the light microscope. [2 marks] ! Exam Tip Describe the trends shown in the mass uptake of 14.4 An angstrom (Å) is a unit of length used to measure small distances. This may be a new unit to nitrate ions. [4 marks] 1 Å = 1 × 10−10 m. you, but don’t let that distract 11.3 Calculate the percentage difference in the mass of nitrate uptake for you or put you off. Just treat Hydrogen atoms have a diameter of 1 Å. Calculate how many roots with and without access to oxygen after 210 seconds. [2 marks] it like you would any other hydrogen atoms, placed end to end, would be the same width calculation question. as a virus cell. [3 marks] 11.4 Explain why the plant had taken up a greater mass of nitrate ions at 210 seconds when a supply of oxygen was present. [4 marks] 12 A student wanted to observe some of his own cells in the classroom. He was told to use skin cells from the back of his hand. He used a piece of clear sticky tape to remove some dead cells, which he placed on a microscope slide. ! Exam Tip 12.1 Describe how the student should use the microscope to observe This may be very similar to a the slide. [3 marks] practical you’ve done in class, but it is slightly changed so you 12.2 Draw a labelled diagram of the cell the student would expect to can practise applying what you view through the microscope. [4 marks] know to new situations. 12.3 Name one additional structure the student would be able to see if he observed the skin cells using an electron microscope. Give the ! Exam Tip function of this structure. [2 marks] Remember this is an animal cell, not a plant cell! 44 B4 Organisation in animals For answers and more practice questions visit Even more practice and interactive B4 Practice 45 www.oxfordrevise.com/scienceanswers revision quizzes are available on