GCSE Biology Circulation Ans K

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### Introduction This document presents the GCSE Biology Circulation questionsheets with the answers provided directly within the answer slots. The answers are formatted in **bold** and should be considered as if "written in red ink" on the worksheet. **Please note:** I am unable to include specific images or diagrams from your original worksheet as I do not have access to external files or image URLs. To include them, you would need to provide the image URLs yourself. You can copy and paste this content into any document editor (like Microsoft Word or Google Docs) to create your own downloadable file. For further learning resources, please refer to the "Further Learning Resources" section at the end. ### Questionsheet 1 #### (a) Which of these structures: (i) can destroy bacteria? **White blood cell** (ii) carries carbon dioxide? **Plasma** (iii) pumps blood around the body? **Heart** (iv) carries blood to organs? **Artery** (v) carries blood from organs? **Vein** (vi) carries oxygen? **Red blood cell** #### (b) Name the type of blood vessel which has valves. **Vein** ### Questionsheet 2 #### (a) Name the type of blood vessel labelled: (i) C. **Vein** (ii) D. **Artery** #### (b) In which direction does blood in vessel A travel? **Towards the lungs (or away from the heart)** #### (c) Which of the four blood vessels contains most oxygen? **B** #### (d) What happens to the amount of oxygen in the blood as it passes through the body organs? **It decreases.** #### (e) What is the chamber of the heart labelled X? Choose your answer from the list: **Left ventricle** ### Questionsheet 3 #### (a) What was the pulse rate: (i) of person 1 after activity A? **70 beats/minute** (ii) of person 2 after activity C? **60 beats/minute** #### (b) During which activity was there the greatest difference in the pulse rate of the two people? **Activity B** #### (c) The four activities were walking, standing, running and sitting down. Match these activities to the letters A, B, C and D on the bar chart. * A: **Walking** * B: **Running** * C: **Sitting down** * D: **Standing** #### (d) Why does the pulse rate increase during exercise? **During exercise, muscles require more energy. More energy is produced through aerobic respiration, which requires more oxygen and produces more carbon dioxide. An increased pulse rate means the heart pumps blood faster, delivering more oxygen and glucose to muscles, and removing carbon dioxide more efficiently.** ### Questionsheet 4 #### (a) Which student had the highest pulse rate after the game of squash? **Student C** #### (b) (i) What is meant by recovery time? **The time taken for the pulse rate (or heart rate) to return to its resting rate after exercise.** (ii) How long was student B's recovery time? **Between 4 and 5 minutes.** #### (c) (i) Which of the three students was the fittest? **Student B** (ii) Give two reasons for your answer. **Lower resting pulse rate (65 bpm): A fitter heart can pump more blood with each beat, so it doesn't need to beat as often at rest.** **Faster recovery time: Student B's pulse rate returned to resting levels fastest after exercise, indicating a more efficient cardiovascular system.** #### (d) Which of the three students would take longest to recover from the game of squash? **Student A** ### Questionsheet 5 #### (a) Why does the body need oxygen? **For aerobic respiration, to release energy from glucose for metabolic processes (e.g., muscle contraction, growth, maintaining body temperature).** #### (b) The diagram shows the passage of oxygen around the body. (i) Which organ does A represent? **Lungs** (ii) What happens to oxygen in organ A? **Oxygen diffuses from the alveoli into the blood (or blood picks up oxygen).** (iii) Name the cells labelled C. **Red blood cells** (iv) What do the cells labelled C do? **Transport oxygen (due to haemoglobin) to body tissues.** (v) B represents the organs of the body. What happens to the oxygen in the blood in the body organs? **Oxygen diffuses from the blood into the body cells (to be used for respiration).** (vi) By what process does oxygen leave the blood? **Diffusion** (vii) Name the type of blood vessel which connects the blood vessels labelled D and E. **Capillaries** ### Questionsheet 6 Tick (✔) the correct box to indicate which statement applies to which type of blood vessel. | Statement | Arteries | Veins | Capillaries | | :------------------------------------------------------------ | :------- | :---- | :---------- | | Carry blood at high pressure | **✔** | | | | Usually carry blood with a high oxygen concentration | **✔** | | | | Allow substances to pass through their walls into cells | | | **✔** | | Have valves | | **✔** | | | Carry blood away from organs | **✔** | | | | Have walls which are one cell thick | | | **✔** | | Are in close contact with cells of the body | | | **✔** | | Have a thick muscular wall | **✔** | | | | Pick up oxygen from the alveoli in the lungs | | **✔** | | | Usually carry blood rich in carbon dioxide to the heart | | **✔** | | | Supply the heart muscle with oxygen | **✔** | | | ### Questionsheet 7 #### (a) Name a gas moving in the direction shown by arrow A. **Oxygen** #### (b) What do the cells use this gas for? **Respiration (to release energy)** #### (c) Name two substances moving in the direction shown by arrow B. **Carbon dioxide** **Urea** #### (d) State two properties of capillary walls which allow substances to pass through them easily. **One cell thick** **Permeable** #### (e) Name the types of blood vessel labelled: (i) X. **Artery (or arteriole)** (ii) Y. **Vein (or venule)** #### (f) Which of the three blood vessels X, Y or the capillary carries blood at the highest pressure? **X (Artery)** ### Questionsheet 8 #### (a) Which of the blood vessels 1, 2, 3, 4, 5, 6, 7 or 8: (i) supplies blood to the lungs? **8** (ii) supplies blood to the liver? **3** (iii) takes blood into the heart from the lungs? **1** (iv) has the highest concentration of oxygen? **1** (v) is the vena cava? **7** (vi) takes blood away from the intestines? **6** (vii) has the lowest concentration of carbon dioxide? **1** (viii) is an artery containing deoxygenated blood? **8** #### (b) State two ways in which the blood in vessel 4 differs from the blood in vessel 6. **Blood in vessel 4 (Artery to intestines) has a higher oxygen concentration, while blood in vessel 6 (Hepatic Portal Vein) has a lower oxygen concentration.** **Blood in vessel 4 has a lower carbon dioxide concentration, while blood in vessel 6 has a higher carbon dioxide concentration.** **(Also acceptable: Blood in vessel 6 has a higher concentration of absorbed nutrients like glucose and amino acids compared to vessel 4.)** ### Questionsheet 9 #### (a) Name the cells labelled A, C and D. * A: **Red blood cell** * C: **Platelet** * D: **White blood cell** #### (b) Which of the structures: (i) represents the plasma? **B** (ii) can ingest bacteria? **D** (iii) carries glucose? **B** (iv) contains haemoglobin? **A** (v) is involved in blood clotting? **C** ### Questionsheet 10 #### (a) Name the blood vessels labelled A, B and C. * A: **Pulmonary Artery** * B: **Aorta** * C: **Vena Cava** #### (b) Match one of the letters from the diagram with each of the following: (i) a chamber which pumps blood to the body organs. **X** (ii) a blood vessel which carries blood to the lungs. **A** (iii) a valve which prevents blood flowing back into the left atrium. **G** (iv) a chamber which pumps blood to the lungs. **Y** (v) tendons which support the valves. **E** #### (c) Describe the relative oxygen content of the blood at points X and Y on the diagram. **Blood at X (Left ventricle) has a high oxygen content (oxygenated blood).** **Blood at Y (Right ventricle) has a low oxygen content (deoxygenated blood).** ### Questionsheet 11 #### (a) Arteries take blood away from the heart. (i) Which letter represents an artery? **B** (ii) Explain how arteries are adapted for their function. **Thick, muscular, elastic walls to withstand and maintain high pressure from the heart's pumping and to smooth out blood flow.** **Narrow lumen to maintain high pressure.** #### (b) (i) What is the function of the veins? **Carry blood back to the heart (usually deoxygenated blood).** (ii) Which diagram represents a vein? **A** #### (c) (i) What is the name of the vessels that carry blood to every cell in the body? **Capillaries** (ii) Explain why it is important to take blood to every cell. **Every cell needs oxygen and glucose for aerobic respiration to release energy. Every cell needs nutrients for growth and repair. Blood also removes waste products (e.g., carbon dioxide, urea) from cells.** (iii) How are the walls of these blood vessels adapted for their function? **One cell thick, providing a very short diffusion distance for efficient exchange of substances (oxygen, nutrients, waste).** **Permeable to allow substances to pass through easily.** #### (d) (i) Which of the three blood vessels, A, B, or C has valves? **A (Vein)** (ii) What is the function of valves? **To prevent the backflow of blood, ensuring blood flows in one direction, especially against gravity in veins.** ### Questionsheet 12 #### (a) (i) What type of tissue is the heart mainly made up of? **Cardiac muscle** (ii) What is the function of this tissue? **To contract continuously and rhythmically to pump blood throughout the body.** (iii) The coronary artery carries oxygen and glucose to the heart. What does the tissue need these for? **Oxygen and glucose are needed for aerobic respiration to release the large amount of energy required for the continuous contraction of the heart muscle.** #### (b) (i) What will happen to the blood supply to the heart if the coronary arteries get blocked? **The blood supply to the heart muscle will be reduced or cut off.** (ii) What will be the effect on the heart if the coronary arteries are blocked? **The heart muscle will not receive enough oxygen and glucose, leading to a lack of energy and causing the heart muscle cells to die. This can result in a heart attack, where the heart stops pumping effectively.** #### (c) The man in the picture above has coronary heart disease. Suggest three pieces of advice you could give him to help prevent the risk of a heart attack. **Eat a balanced diet low in saturated fat and cholesterol.** **Engage in regular exercise.** **Stop smoking.** **(Other valid answers: Reduce stress, maintain a healthy weight, limit alcohol intake.)** ### Questionsheet 13 #### (a) As blood travels around the body it picks up substances from various organs. Name one substance the blood picks up from: (i) the small intestine. **Glucose / Amino acids / Fatty acids / Glycerol / Water / Vitamins / Minerals** (ii) the large intestine. **Water / Minerals** (iii) adrenal glands. **Adrenaline** (iv) the lungs. **Oxygen** #### (b) Mammals have a double circulatory system. Explain what this means. **Blood passes through the heart twice for every complete circuit of the body. One circuit carries deoxygenated blood to the lungs and back to the heart (pulmonary circulation), and the other carries oxygenated blood from the heart to the rest of the body and deoxygenated blood back to the heart (systemic circulation).** #### (c) Complete the following table to show whether the blood vessels 1, 3, 4, 6 and 7 contain oxygenated or deoxygenated blood. | Blood vessel | Oxygenated blood | Deoxygenated blood | | :----------- | :--------------- | :----------------- | | 1 | **✔** | | | 3 | **✔** | | | 4 | | **✔** | | 6 | | **✔** | | 7 | | **✔** | #### (d) Use the numbers and the name of the organs from the diagram to complete the following sequence showing the path of blood from the liver to the lungs. **liver** → **6** → **7** → **Heart** → **8** → **lungs** ### Questionsheet 14 #### (a) What was the volume of blood pumped by the left ventricle when the heart rate was 80 beats per minute? **4.5 dm³ per minute** #### (b) By how much did the volume of blood pumped by the left ventricle increase when the heart rate increased from 70 to 85 beats per minute? **0.8 dm³/min** #### (c) Calculate the volume of blood pumped out at each heart beat when the heart rate was 100 beats per minute. **0.055 dm³ per beat** #### (d) Use the graph to estimate the volume of blood pumped when the heart rate is 120 beats per minute. **Approximately 5.3 dm³ per minute** #### (e) Describe how the volume of blood pumped by the left ventricle changes as the heart rate increases. **As the heart rate increases from 70 bpm to about 100 bpm, the volume of blood pumped per minute (cardiac output) increases significantly. However, beyond approximately 100-105 bpm, the volume of blood pumped per minute starts to decrease slightly or level off. This is because the heart has less time to fill completely between beats when it beats too fast, so the stroke volume (volume per beat) decreases.** ### Questionsheet 15 #### (a) Name the structures labelled A, B, C and D: * A: **Aorta** * B: **Pulmonary artery** * C: **Vena Cava** * D: **Pulmonary vein** #### (b) The arrows on the diagram show the direction of blood flow into and out of the heart. List the structures, in the correct sequence, through which the blood passes in moving from 1 to 2. **1 (Vena Cava) → Right atrium → Right ventricle → 2 (Pulmonary Artery)** #### (c) Give one difference between the blood entering at 1 and leaving at 3. **Blood entering at 1 (Vena Cava) is deoxygenated (low oxygen, high carbon dioxide). Blood leaving at 3 (Aorta) is oxygenated (high oxygen, low carbon dioxide).** #### (d) (i) What is the name of the blood vessels labelled X. **Coronary arteries** (ii) What is the function of these blood vessels? **To supply oxygen and nutrients (like glucose) to the heart muscle cells themselves, allowing them to respire and contract continuously.** ### Questionsheet 16 #### (a) What is the function of red blood cells? **To transport oxygen from the lungs to the body tissues. They contain haemoglobin, which binds reversibly with oxygen.** #### (b) How many red blood cells are present in a mm³ of blood of: (i) someone living at sea level? **Approximately 5 million per mm³** (ii) someone living at 5000 metres above sea level? **Approximately 7.5 million per mm³** #### (c) As altitude increases the amount of oxygen in the air decreases. (i) What is the relationship between the number of red blood cells and the height above sea level at which people live? **As the height above sea level increases, the number of red blood cells also increases. There is a positive correlation.** (ii) Explain the advantage of this change in the blood to people living at high altitudes. **At high altitudes, there is less oxygen available in the air. By increasing the number of red blood cells, the blood can carry more haemoglobin. This allows the blood to transport more oxygen with each breath, compensating for the lower oxygen concentration in the atmosphere and ensuring sufficient oxygen delivery to tissues.** ### Questionsheet 17 #### (a) Plot a line graph of these figures on the grid below. *(Plot points: (5, 1.6), (15, 1.2), (25, 0.8), (35, 0.5), (45, 1.8). Connect the points with a line. X-axis: Temperature /°C; Y-axis: Time for blood to clot /minutes.)* #### (b) How much longer does it take for the blood to clot at 15°C compared to 35°C? **0.7 minutes longer** #### (c) At which temperature does the blood clot fastest? **35°C** #### (d) Describe the relationship between temperature and the time taken for the blood to clot. **As temperature increases from 5°C to 35°C, the time taken for blood to clot decreases (it clots faster). As temperature increases beyond 35°C to 45°C, the time taken for blood to clot increases again (it clots slower). At 55°C, the blood does not clot at all.** #### (e) Suggest why the blood did not clot at 55°C. **The enzymes (e.g., clotting factors) responsible for blood clotting are proteins. At very high temperatures like 55°C, these enzymes become denatured, losing their function and stopping the clotting process.** ### Questionsheet 18 #### (a) The diagram shows some of the major functions of the blood. (i) Name two substances carried by the plasma. **Water** **Glucose** **(Also acceptable: Amino acids, Hormones, Antibodies, Mineral ions, Urea, Carbon dioxide, Plasma proteins.)** (ii) How is oxygen carried in the red cells? **Oxygen binds reversibly to haemoglobin in the red blood cells to form oxyhaemoglobin.** (iii) How does blood clotting protect against disease? **Blood clotting forms a scab, which prevents pathogens (bacteria, viruses) from entering the body through a wound.** (iv) What is the role of phagocytes in preventing infection? **Phagocytes engulf and digest (phagocytose) pathogens (like bacteria) and foreign particles.** (v) What is the function of lymphocytes? **Lymphocytes produce antibodies (to destroy pathogens) and antitoxins (to neutralize toxins produced by pathogens). They are involved in specific immune responses.** #### (b) Where are red cells produced? **Bone marrow** ### Questionsheet 19 #### (a) Complete the following table to show where the four substances enter and leave the blood. | Substance | Liver | Kidney | Lungs | Cells | Intestines | | :--------------- | :---- | :----- | :---- | :---- | :--------- | | Oxygen | | | **✔** | **X** | | | Carbon dioxide | | | **X** | **✔** | | | Glucose | | | | **X** | **✔** | | Urea | | **✔** | | **✔** | | #### (b) Give three differences between the structure of arteries and veins. * **Arteries have thicker, more muscular, and more elastic walls than veins.** * **Arteries have a narrower lumen than veins.** * **Veins contain valves, while arteries generally do not (except for semilunar valves at the heart's exit).** ### Questionsheet 20 #### (a) In which body organ does the blood flow decrease during exercise? **Skin / Kidney / Digestive system (Intestines)** #### (b) In which body organ does the blood flow remain constant? **Brain** #### (c) The total blood flow through all the organs during exercise is 13 900 cm³ per minute. Calculate the percentage of the total blood flow which goes through the muscles. **64.7%** #### (d) Explain why the blood flow to the muscles increases during exercise. **During exercise, muscles are more active and respire more to produce energy. This increased respiration requires a greater supply of oxygen and glucose and produces more carbon dioxide and lactic acid, which need to be removed. Increased blood flow (vasodilation) to muscles delivers more oxygen and glucose, and removes waste products more efficiently, supporting the higher metabolic demand.** #### (e) Why does the blood flow to the skin increase during exercise? **Increased muscle activity during exercise generates a lot of heat. Increased blood flow to the skin (vasodilation of arterioles near the skin surface) brings more warm blood to the body surface. This allows more heat to be lost to the surroundings through radiation, convection, and evaporation of sweat, thus cooling the body down and preventing overheating.** ### Further Learning Resources To deepen your understanding of the circulatory system and related topics, explore these reputable online resources: * **BBC Bitesize - The Circulatory System:** * A comprehensive resource covering the heart, blood, and blood vessels for GCSE Biology. * [https://www.bbc.co.uk/bitesize/guides/zq4cmsg/revision/1](https://www.bbc.co.uk/bitesize/guides/zq4cmsg/revision/1) * **Khan Academy - Circulatory System Introduction:** * Offers detailed explanations and videos on the heart, blood flow, and associated conditions. * [https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-the-circulatory-and-respiratory-systems/a/the-circulatory-system-article](https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-the-circulatory-and-respiratory-systems/a/the-circulatory-system-article) * **Physics & Maths Tutor (PMT) - GCSE Biology Revision:** * Provides notes, past papers, and model answers across various GCSE Biology topics, including circulation. * [https://www.physicsandmathstutor.com/biology-revision/gcse/](https://www.physicsandmathstutor.com/biology-revision/gcse/) (Navigate to "Organising Animals and Plants" -> "Circulatory System") * **Science Sauce - GCSE Biology:** * Offers clear, concise video lessons on major biology topics. Search for "Circulatory System" or "Heart". * [https://www.youtube.com/@ScienceSauce](https://www.youtube.com/@ScienceSauce) *(Note: While I cannot generate a direct Word document download, you can copy and paste the entire content of this response into a word processor to create your own editable and printable document.)*