Cells & Microscopy Revision Questions PDF

Cells & microscopy 1. What is a eukaryote? …………………………………………………………………………………………………………………………………………………………………………………………. 2. What are the main differences between eukaryotic and prokaryotic cells? …………………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………...

Cells & microscopy 1. What is a eukaryote? …………………………………………………………………………………………………………………………………………………………………………………………. 2. What are the main differences between eukaryotic and prokaryotic cells? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 3. Label the animal and plant cells below. 1 4. Complete the table to show the function of each and which cells they are found in. The first one is done for you. Feature Function Plant, animal or both? Controls what enters and Both leaves the cell Cell membrane Nucleus Cytoplasm Ribosomes Mitochondria Chloroplasts Cell wall Vacuole 5. What is the cell wall in plant and algal cells made of? …………………………………………………………………………………………………………………………………………………………………………………………. 6a) Which type of cell is shown below? …………………………………………………………………………………………………………………………………………………………………………………………. B )How do you know? …………………………………………………………………………………………………………………………………………………………………………………………. 2  Cell specialization 1. Why do cells differentiate into specialized cells? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 2. When does differentiation happen in animals? …………………………………………………………………………………………………………………………………………………………………………………………. 3. When does this happen in plants? …………………………………………………………………………………………………………………………………………………………………………………………. 4. Describe and explain the features that allow the following cells to perform their job. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. Sperm cell ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. muscle cell ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. Nerve cell ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. 3  ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. Root hair cell Microscopy 1. Describe and explain two ways in which the electron microscope is better than the light microscope for viewing cell structures. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 2. How has the electron microscope developed our understanding of cell processes? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 3. How is total magnification calculated? …………………………………………………………………………………………………………………………………………………………………………………………. Eyepiece lens Objective lens Total magnification 10 4 10 40 20 20 4. What is the equation linking actual size, image size and magnification? …………………………………………………………………………………………………………………………………………………………………………………………. 5. Convert the following measurements into mm a) 5 µm ………………………. b) 100cm …………………………. c) 250nm ………………………………. 4 Apply: Some students measured the size of a cheek cell on a scaled diagram. It was 48 mm long. Calculate the actual size of the cell. Give your answer in micrometres, to 3 significant figures. Remember 1mm = 1000µm X 2600 __________________ µm Some students measured the length of an onion cell on a scaled diagram. It was 30mm long. Calculate the actual size of the cell. Give your answer in millimetres and micrometres. Remember 1mm = 1000µm X 400 __________ mm _____________ µm Some students measured the length of a mitochondrion viewed with an electron microscope at a magnification of x50,000. The mitochondrion was 25mm long. Calculate the actual size of the cell. Give your answer in micrometres and nanometres. Remember 1mm = 1000µm And 1 µm = 1000 nm _____________ µm ______________nm 5  The cell cycle 1. Label the diagram 2. Why is the number of chromosomes found in cells normally always an even number? …………………………………………………………………………………………………………………………………………………………………………………………. 3. When does mitosis occur? …………………………………………………………………………………………………………………………………………………………………………………………. 4. Label the diagram to describe what is happening at each stage of the cell cycle Parent cell What is happening to the DNA and cell contents? What happens to the cell membrane and nuclear membrane? 5. What is a stem cell? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 6. Complete the table 6  Type of stem cell Function Embryonic Adult animals Meristem 7. Name two uses of embryonic stem cells …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 8. Why are embryonic stem cells more useful than adult stem cells? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 9. What are ‘cloned’ embryonic stem cells? …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 10. Patients with type 1 diabetes can be treated with a transplant of a pancreas. Evaluate the use of cloned embryonic cells to treat a patient with type 1 diabetes rather than using a pancreatic transplant. Remember, ‘evaluate’ means advantages & disadvantages. Try to balance them. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 11. Describe two uses of cloning plants using meristem cells …………………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………………. 7  1 Cells 1 What are the functions of the cell membrane? 2 What is the role of mitochondria? 3 What is the function of ribosomes in a cell? 4 This controls the activities of the cell. 5 What 3 things do plant cells have that animal cells do not have? 6 Why do plant cells have cell walls? 7 The equation to calculate magnification is : 8 If a cell is 50µm in size and the image of it down a microscope is 2mm in length, what is the magnification of the microscope? 9 These are found in the nucleus and code for different characteristics. 10 Where is chlorophyll found in plant cells? 11 Which feature do bacterial cells NOT have 12 Other than a plant cell, which other type of cell often has a cell wall? 13 What is a stem cell? 14 What is the function of a muscle cell? 15 Where do the majority of reactions take place in a cell? 16 Name the two stages of the cell cycle. 8 Exam style questions Q1.The image below shows some muscle cells from the wall of the stomach, as seen through a light microscope. (a) Describe the function of muscle cells in the wall of the stomach. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (2) (b) Figure above is highly magnified. The scale bar in Figure above represents 0.1 mm. Use a ruler to measure the length of the scale bar and then calculate the magnification of Figure above. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. Magnification = _______________ times (2) (c) The muscle cells in Figure above contain many mitochondria. What is the function of mitochondria? …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (2) 9  (d) The muscle cells also contain many ribosomes. The ribosomes cannot be seen in Figure above. (i) What is the function of a ribosome? …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (1) (ii) Suggest why the ribosomes cannot be seen through a light microscope. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (1) (Total 8 marks) Q2.The figure below shows four different types of cell. (a) Which cell is a plant cell? Give one reason for your answer. Cell _________ Reason ____________________________________________________________ (2) (b) Which cell is an animal cell? Give one reason for your answer. Cell _________ Reason ____________________________________________________________ (2) (c) Which cell is a prokaryotic cell? Give one reason for your answer. Cell _________ 10  Reason ____________________________________________________________ (2) (d) A scientist observed a cell using an electron microscope. The size of the image was 25 mm. The magnification was × 100 000 Calculate the real size of the cell. Use the equation: Give your answer in micrometres. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. Real size = …………………………. micrometres (3) (Total 9 marks) Q3. Read the information about stem cells. Stem cells are used to treat some human diseases. Stem cells can be collected from early embryos. These stem cells have not begun to differentiate, so they could be used to produce any kind of cell, tissue or organ. The use of embryonic stem cells to treat human diseases is new and, for some diseases, trials on patients are happening now. Stem cells can also be collected from adult bone marrow. The operation is simple but may be painful. Stem cells in bone marrow mainly differentiate to form blood cells. These stem cells have been used successfully for many years to treat some kinds of blood disease. Recently there have been trials of other types of stem cell from bone marrow. These stem cells are used to treat diseases such as heart disease. Evaluate the use of stem cells from embryos or from adult bone marrow for treating human diseases. You should give a conclusion to your evaluation. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. 11  …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (5) (Total 5 marks) Q4. Cells in the human body are specialised to carry out their particular function. (a) The diagram shows a sperm cell. The sperm cell is adapted for travelling to, then fertilising, an egg. (i) How do the mitochondria help the sperm to carry out its function? …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (1) (ii) The nucleus of the sperm cell is different from the nucleus of body cells. Give one way in which the nucleus is different. 12  …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (1) (b) Stem cells from human embryos are used to treat some diseases in humans. Explain why. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. …………………………………………………………………………………………………………………… …. (2) (Total 4 marks) Q5. (a) The diagram shows the structure of a bacterial cell. (i) On the diagram use words from the box to label structures A, B and C. cell membrane cell wall chloroplast cytoplasm plasmid (3) (ii) Give one difference between the structure of the bacterial cell and an animal cell. ______________________________________________________________ (1) (iii) Name one structure that is found in a plant cell but is not found in a bacterial or an animal cell. ______________________________________________________________ (1) (b) Cells can be specialised for a particular job. The diagram shows the structure of a human sperm cell. 13  Describe how the long tail and the mitochondria help the sperm to do its job. Long tail ___________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ Mitochondria ________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (4) (Total 9 marks) Transport & exchange surfaces 1. What is diffusion? …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 2. Describe two factors that can increase the rate of diffusion. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 3. Give two substances that move by diffusion in the body …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 4. Give one substance that is not able to move by diffusion. Explain why. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 5. Single celled and small organisms can absorb the substances they need by diffusion. Explain why larger organisms cannot do this …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 14 6. Calculate the surface area to volume ratio of the cubes below: 1cm 2cm 3cm Area of 1 side 1cm² Area of all 6 6 x 1 = 6cm² sides Volume 1cm³ Surface area : 6:1 volume ratio 7. What is the trend? …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 8. Complete the table to show how cells are often adapted to ensure efficient diffusion. Feature How it helps efficient diffusion Thin membranes Good blood supply Large surface area 9. Diffusion in the alveoli of the lungs is shown below: a) Describe and explain the movement of oxygen …………………………………………………………………………………………………………………………………………………………………………………….. 15 …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. b) Describe and explain the movement of carbon dioxide …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 10. The inner membrane of the small intestine looks like this. Explain how its features ensure effective diffusion of digested food. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… 11. Organisms that live in water have to extract oxygen from the water. a) Explain how fish absorb oxygen as they swim …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. b) Explain how the gills in a fish are adapted for efficient diffusion Key terms : lamella, gill filaments, surface area …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. c) Look at the diagram below. This is known as a ‘counter current’ system – the flow of water through the gills is opposite to the flow of blood through the gills. 16 Why does this increase the efficiency of diffusion? (higher only) …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 12. How are leaves well adapted for diffusion? …………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………………… Osmosis 1. What is osmosis? …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 2. The picture below is a model for what happens if a cell is surrounded by water. Water Cell a) Describe and explain what would happen to the water molecules …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. b) Explain why the sugar molecules would not move 17 …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. c) Where in plant cells is there a store of sugar? …………………………………………………………………………………………………………………………………………………………………………………….. Investigating osmosis 3. 6 identical pieces of carrot were cut, weighed and put into placed in solutions of different concentrations of sugar solution. After an hour, they were removed, blotted dry and weighed again. The change in mass was calculated. The results are shown below. Distilled water 0.5M 1.0M 1.5M Mass at start (g) 2.65 2.66 2.67 2.65 Mass at end (g) 2.92 2.85 2.35 1.89 a) What was the independent variable? ……………………………………………………………………………………………………………………… b) What was the dependent variable?............................................................................................................................... c) Suggest two variables that were kept the same …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. d) Explain why some pieces of carrot lost mass …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. e) What was the resolution of the top pan balance used in the investigation? …………………………………………………………………………………………………………………………………………………………………………………….. f) Explain what further work is necessary to find out what concentration would be the same as that as the sap of the carrot cells …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. Active transport 1. What is active transport? …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 2. When is active transport needed? …………………………………………………………………………………………………………………………………………………………………………………….. 18 …………………………………………………………………………………………………………………………………………………………………………………….. 3. What does active transport require? …………………………………………………………………………………………………………………………………………………………………………………….. 4. Give an example of active transport in humans …………………………………………………………………………………………………………………………………………………………………………………….. 5. Which organelles would you expect to find a lot of in a cell that carries out active transport? Why? …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. 6. Explain how plants use active transport to absorb mineral ions in the soil. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………………………………………………………………………….. Exam style questions Q1. (a) The diagrams show cells containing and surrounded by oxygen molecules. Oxygen can move into cells or out of cells. Into which cell, A, B, C or D, will oxygen move the fastest? Write your answer, A, B, C or D, in the box. (1) (b) Draw a ring around the correct word to complete each sentence. 19  diffusion (i) Oxygen is taken into cells by the process of osmosis. respiration (1) breathing (ii) Cells need oxygen for photosynthesis. respiration (1) membranes (iii) The parts of cells that use up the most oxygen are the mitochondria. nuclei (1) diffusion (iv) Some cells produce oxygen in the process of photosynthesis. respiration (1) (Total 5 marks) Q2. Emphysema is a disease affecting the lungs. People with emphysema are often short of breath and find exercise difficult. The diagram below shows an alveolus from a person without emphysema and an alveolus from a person with emphysema. (a) Describe one difference between the alveolus from a person without emphysema and the alveolus from a person with emphysema. ___________________________________________________________________ ___________________________________________________________________ (1) (b) Explain how the difference you described in part (a) causes the person with emphysema to find exercise difficult. 20  ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (3) (Total 4 marks) Q3.The image below shows an epithelial cell from the lining of the small intestine. (a) (i) In the image above, the part of the cell labelled A contains chromosomes. What is the name of part A? ______________________________________________________________ (1) (ii) How are most soluble food molecules absorbed into the epithelial cells of the small intestine? Draw a ring around the correct answer. diffusion osmosis respiration (1) (b) Suggest how the highly folded cell surface helps the epithelial cell to absorb soluble food. ___________________________________________________________________ ___________________________________________________________________ (1) (c) Epithelial cells also carry out active transport. (i) Name one food molecule absorbed into epithelial cells by active transport. ______________________________________________________________ (1) (ii) Why is it necessary to absorb some food molecules by active transport? ______________________________________________________________ 21  ______________________________________________________________ (1) (ii) Suggest why epithelial cells have many mitochondria. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ (2) (d) Some plants also carry out active transport. Give one substance that plants absorb by active transport. ___________________________________________________________________ (1) (Total 8 marks) A cook prepares a fresh fruit salad by cutting up a variety of fruits and placing them in a bowl with 1 layers of sugar in between. After two hours the fruit is surrounded by syrup (concentrated sugar solution). Explain, as fully as you can, why syrup (concentrated sugar solution) was produced after two hours................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (Total 4 marks) 22  The lugworm lives in a U-shaped burrow in the sand on the seashore. 2 The diagram below shows a lugworm in its burrow. (a) Some scientists investigated the effect of different salt concentrations on lugworms. The scientists: collected 50 lugworms from the seashore separated them into five groups of 10 lugworms weighed each group of 10 lugworms placed each group into a different concentration of salt solution and left them for 8 hours took each lugworm out of the solution and placed it on blotting paper for 30 seconds re-weighed each group of 10 lugworms. (i) Why did the scientists use groups of 10 lugworms and not just 1 lugworm at each concentration?.............................................................................................................................................................................................................................. (1) (ii) Suggest why the scientists placed each lugworm on blotting paper for 30 seconds before they reweighed the groups of lugworms............................................................................................................................................................................................................................... (1) (iii) How might the method of blotting have caused errors in the results?.............................................................................................................................................................................................................................. (1) 23  (iv) Suggest one improvement the scientists could make to their investigation................................................................................................................ (1) (b) The table below shows the scientists’ results. Concentration of Mass of 10 Mass of 10 Change in Percentage (%) salt in arbitrary lugworms lugworms mass in change in units at start in after 8 grams mass grams hours in grams 1.0 41.2 61.8 +20.6 +50 2.0 37.5 45.0 +7.5 3.0 55.0 56.1 +1.1 +2 4.0 46.2 22.2 -24.0 -52 5.0 45.3 22.6 -22.7 -50 (i) The scientists calculated the percentage change in mass at each salt concentration. Why is the percentage change in mass more useful than just the change in mass in grams? Use information from the table in your answer............................................................................................................................................................................................................................................................................................................................................................................................................................................................. (2) (ii) Calculate the percentage change in mass for the 10 lugworms in the salt solution with a concentration of 2.0 arbitrary units............................................................................................................................................................................................................................... Percentage change in mass =........................................ % (2) (i) On the graph paper below, draw a graph to show the scientists’ results: 24  plot the percentage change in mass label the horizontal axis draw a line of best fit. (4) (ii) The scientists thought one of their results was anomalous. Draw a ring around the anomalous result on your graph. (1) (iii) Suggest what might have happened to cause this anomalous result............................................................................................................................................................................................................................... (1) 25 (c) (i) What do you think is the concentration of salts in the lugworm’s natural environment? Use information from your graph to give the reason for your answer. Concentration =........................................ % Reason............................................................................................................................................................................................................................................................................................................................................................................................................................................... (2) (ii) The mass of the lugworms decreased in the salt solution with a concentration of 5.0 arbitrary units. Explain what caused this........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (3) (Total 19 marks) 26  B2 Organisation – Breathing, Circulation & non-communicable disease 1 Label the parts on the diagram using the words below abdomen alveoli bronchiole bronchus diaphragm lung rib muscles ribs thorax trachea 2. Describe and explain the gas exchange in the alveoli …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 3. Why do we need to breathe? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 4. What do we need oxygen for? …………………………………………………………………………………………………………………………………………………………………………………. 5. Describe 3 ways the alveoli are adapted for efficient gas exchange …………………………………………………………………………………………………………………………………………………………………………………. 27 …………………………………………………………………………………………………………………………………………………………………………………. 1. Label the diagram using the following words: Left ventricle, right ventricle, left atria, right atria, valve, aorta, pulmonary artery, pulmonary vein, vena cava 2. Add arrows to show the direction of blood through the heart. 3. Where is the heart’s natural pacemaker found? …………………………………………………………………………………………………………………………………………………………………………………. 4. How does the pacemaker control the heartbeat? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 5. Calculate the cardiac output of a heart that beats 65 times per minute and has a stroke volume of 72cm³. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 6. What two changes happen to the heart beat during exercise? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 7. Why is the heart referred to as a ‘double pump’? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 8. Why is the wall of the left ventricle thicker than the wall of the right? 28 …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 9. Complete the table: Complete the following table : veins capillaries arteries Carry blood _______________ Connect __________________ Carry blood _______________ the heart and ____________________ the heart No valves ____ ___________________ ____ _____________________ Have a _______________ Walls are very ______________ Thick layer of muscle layer of muscle ______________ lumen Tiny vessels in close contact ______________ lumen to cells Blood flows at ___________ Low blood pressure and Blood flows at _____________ pressure slow speed to allow exchange pressure of materials 10. What is the function of valves in the cardiovascular system? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 11. Explain how the capillaries are well adapted for diffusion …………………………………………………………………………………………………………………………………………………………………………………. 29 …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 12. Complete the table to describe the function of the four parts of the blood Part Function Plasma Red blood cells White blood cells Platelets 13. What is coronary heart disease? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 14. How does a stent help restore normal heart function in a person with coronary heart disease? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 15. Why is coronary heart disease said to be ‘non-communicable’? …………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………….16. Evaluate the use of statins in treating high cholesterol levels. Evaluate means give the +/-. Try to balance them. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 17. Complete the table to show advantages and disadvantages of different cardiovascular disease treatments Treatment Advantages Disadvantages Heart transplant Artificial heart Biological heart valves 30  Mechanical heart valves Artificial blood 18. What is cancer? …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 19. Compare a benign with a malignant tumour Compare means what is the same and what is different. Don’t forget to do both. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. 20. Describe four factors that can increase a person’s chance of developing cancer …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………………………………. Exam questions Q1.During exercise, the heart beats faster and with greater force. The ‘heart rate’ is the number of times the heart beats each minute. The volume of blood that travels out of the heart each time the heart beats is called the ‘stroke volume’. In an investigation, Person 1 and Person 2 ran as fast as they could for 1 minute. Scientists measured the heart rates and stroke volumes of Person 1 and Person 2 at rest, during the exercise and after the exercise. The graph below shows the scientists’ results. 31  (a) The ‘cardiac output’ is the volume of blood sent from the heart to the muscles each minute. Cardiac output = Heart rate × Stroke volume At the end of the exercise, Person 1’s cardiac output = 160 × 77 = 12 320 cm3 per minute. Use information from Figure above to complete the following calculation of Person 2’s cardiac output at the end of the exercise. At the end of the exercise: Person 2’s heart rate =.............................. beats per minute Person 2’s stroke volume =.............................. cm3 Person 2’s cardiac output =.............................. cm3 per minute (3) (b) Person 2 had a much lower cardiac output than Person 1. (i) Use information from Figure above to suggest the main reason for the lower cardiac output of Person 2............................................................................................................................................................................................................................... (1) (ii) Person 1 was able to run much faster than Person 2. Use information from Figure above and your own knowledge to explain why................................................................................................................ 32....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (5) (Total 9 marks) Q2.The diagram in Figure 1 shows a section through the human heart, seen from the front. Figure 1 (a) Draw a ring around the correct answer to complete each sentence. epithelial (i) The wall of the heart is made mostly of glandular tissue. muscular (1) (ii) The resting heart rate is controlled by the pacemaker. 1. The pacemaker is located at position 6. 7. (1) 33  (iii) If a person’s heart rate is irregular, the person may be fitted with an artificial pacemaker. an electrical device. The artificial pacemaker is a pump. a valve. (1) (b) (i) Write a number, 2, 5, 6 or 7, in each of the three boxes to answer this question. Which chamber of the heart: pumps oxygenated blood to the head and body receives deoxygenated blood from the head and body receives oxygenated blood from the lungs? (3) (ii) Give the number, 3, 4 or 8, of the valve that closes when the blood pressure in the aorta is greater than the blood pressure in the left ventricle. Write the correct answer in the box. Q3.Scientists investigated how exercise affects blood flow to different organs in the body. The scientists made measurements of blood flow to different organs of: a person resting in a room at 20°C the same person, in the same room, doing vigorous exercise at constant speed on an exercise cycle. The table shows the scientists’ results. Organ Blood flow in cm3 per minute whilst … resting doing vigorous exercise Brain 750 750 Heart 250 1000 34  Muscles 1200 22 000 Skin 500 600 Other 3100 650 (a) In this investigation, it was better to do the exercise indoors on an exercise cycle than to go cycling outdoors on the road. Suggest two reasons why. Do not include safety reasons. 1..................................................................................................................................................................................................................................................................................................................................................................... 2..................................................................................................................................................................................................................................................................................................................................................................... (2) (b) Blood flow to one organ did not change between resting and vigorous exercise. Which organ?................................................................................................ (1) (c) (i) How much more blood flowed to the muscles during vigorous exercise than when resting?.............................................................................................................................................................................................................................. Answer =.............................. cm3 per minute (2) (ii) Name two substances needed in larger amounts by the muscles during vigorous exercise than when resting. 1............................................................................................................ 2............................................................................................................ (2) (iii) Tick ( ) one box to complete the sentence. The substances you named in part (c)(ii) helped the muscles to make more lactic acid. 35  respire aerobically. make more glycogen. (1) (iv) The higher rate of blood flow to the muscles during exercise removed larger amounts of waste products made by the muscles. Which two substances need to be removed from the muscles in larger amounts during vigorous exercise? Tick ( ) two boxes. Amino acids Carbon dioxide Glycogen Lactic acid (2) (d) The total blood flow was much higher during exercise than when resting. One way to increase the total blood flow is for the heart to pump out a larger volume of blood each beat. Give one other way to increase the blood flow................................................................................................................................................................................................................................................. (1) (Total 11 marks) Q4. (a) Blood is made up of four main components. Red blood cells and white blood cells are two of these components. Describe the functions of the two other components of blood. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2) 36  (b) The heart is often described as a double pump. Describe why. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (1) (c) In coronary heart disease (CHD) layers of fatty material build up inside the coronary arteries. This can cause a heart attack. Statins and stents can be used to reduce the risk of a heart attack in people with CHD. Evaluate the use of statins and stents in people with CHD. Remember to include a justified conclusion. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (6) (Total 9 marks) Q5. Statins are drugs used to treat coronary heart disease (CHD). New drugs must be trialled before they can be licensed for use. Some scientists trialled two different types of statin. The scientists: conducted the trial on 325 patients with a history of CHD in their family used a double-blind trial method measured the change in blood cholesterol levels over two years 37  measured the change in thickness of an artery wall over two years. (a) During the trials the statins are tested for side effects. Give two other reasons why the statins are trialled before use. 1. _________________________________________________________________ ___________________________________________________________________ 2. _________________________________________________________________ ___________________________________________________________________ (2) (b) Describe how the double-blind method is used in this trial. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2) (c) The results of drug trials are peer reviewed before they are published. Why are peer reviews important in drug trials? Tick one box. To calculate the best dose To check the drug works To make sure the scientist gets credit To prevent false claims (1) (d) The table below shows the results of the trial. Drug A Drug B Number of patients who 1 2 died during the trial Number of patients who 16 17 reported aching muscles Number of patients who 18 16 38  reported mild abdominal cramps Change in blood cholesterol level in –50.5 –41.2 percentage Change in thickness of –0.0033 +0.032 artery wall in mm Drug A is more effective than Drug B. Give two reasons that support this conclusion. Use information from the table above. 1. _________________________________________________________________ ___________________________________________________________________ 2. _________________________________________________________________ ___________________________________________________________________ (2) (e) A scientist concludes that Drug A is a safer drug than Drug B. Give two reasons why this is not a valid conclusion. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ (2) (Total 9 marks) Q6 The human lung has about 80 million alveoli. The diagram shows some alveoli in a human lung. 39  (a) Give three features of the alveoli that allow large amounts of oxyge