N5 Biology Past Paper Q, Study notes of Biology

Download N5 Biology Past Paper Q and more Study notes Biology in PDF only on Docsity! 3 Unit 1 – Cell Biology 1 - Cell structure Questions 1 and 2 refer to the plant cell diagram below. 1. Which of the plant cell components shown above is made from a structural carbohydrate? 2. Which labelled part controls cell activities? 2 - Transport across membranes 2. The diagram below shows a model cell that 3. Which line in the table below shows what was sct up to investigate diffusion through a happens to cells when placed in a hypertonic selectively permeable membrane. solution? Todine is a small, soluble molecule. Animal Cell Plant Cell Starch A swells and bursts becomes turgid suspension Selectively 1 (cloudy white) B becomes turgid swells and bursts permeable lL tedine c shrinks becomes membrane ——P solution ~ s KS plasmolysed (yellow) D becomes becomes plasmolysed plasmolysed Predict the colour changes which would be observed after one hour. Colour change after one hour Starch suspension Todine solution A | remained cloudy white | yellow to blue/black cloudy white to blue/black remained yellow C | remained cloudy white remained yellow D | cloudy white to blue/black | yellow to blue/black (ii) State two properties of simple sugar molecules which allow them to be absorbed from the digestive system into the blood. (b) (i) The plant cell is placed in a hypertonic solution. Describe the appearance of the plant cell after one hour. (ii) explain why the animal cell would stay the same size when it is placed in an isotonic solution. 8. (a) ‘The process of diffusion is important to organisms. From the list below, select a substance which is involved in diffusion and answer the questions which follow. List oxygen glucose carbon dioxide Substance selected (i) Explain why its diffusion is important. (i) Where does its diffusion take place? (b) Cells from the same plant tissue were placed in three different liquids, left for 20 minutes and then examined using a microscope. The following diagrams represent cells from each liquid. Cell A Cell B Cell C Which cell is most likely to have been placed in pure water? Give a reason for your answer. Cell Reason 4. (a) A model cell was made using a visking tubing bag filled with a starch and amino acid solution. It was placed into a beaker of water and left for two hours. starch and amino acid solution \ He (i) Amino acids were detected in the water outside the model cell. model cell What process is responsible for this movement? (ii) Why would no starch be detected in the water outside the model cell? (ii) What would happen to the mass of the model cell during the two hour period? Explain your answer. Mass of model cell Explanation 12 3 - Producing new cells (c) The following is a description of the stages of mitosis. Stage 1 — Chromosomes become visible as pairs of chromatids ¥ Stage 2 y Stage 3 — Pairs of chromatids attach to the spindle near the middle of the cell 4 Stage 4 y Stage 5 — Daughter chromosomes gather at the ends of the cell ¥ Stage 6 — ‘I'he cytoplasm divides Describe stages 2 and 4 in the spaces below. Stage 2 Stage + (d) Daughter cells produced by mitosis each have the same chromosome complement as the original cell. Why is this important? 13 9. (a) The diagrams below show two stages of mitosis in cells. Draw one straight line from each diagram to its correct description. chromosomes shorten and thicken chromosomes line up at the centre of the cell chromatids are pulled to opposite ends of the cell nuclear membrane reforms (6) How does mitosis ensure that the daughter cells will be able to function properly? 14 2. The diagram below represents a breakdown reaction involving an enzyme. A B Which letter identifies the substrate? 17 17. (a) Biological washing powders contain enzymes. Explain how these enzymes work to remove stains. (c) Biological washing powders contain different enzymes. Explain why this is necessary. (6) (i) What term is used to describe the temperature at which an enzyme works best? (ii) Name one factor, other than temperature, which has an effect on the activity of an enzyme. (b) Name the enzyme involved in the synthesis of starch in potato cells. 18 4. Enzymes are biological catalysts. The diagram below shows part of an enzyme controlled reaction. Substrate Enzyme Enzyme\Substrate Complex (a) Describe the features of an enzyme which allow it to combine with only one substrate. (b) What happens to an enzyme when it is boiled? (c) Name a factor, other than temperature, which affects enzyme activity. (d) Complete the following word equation for the enzyme catalase. catalase hydrogen peroxide —§ —————» and substrate products 19 (a) Insulin is used to treat people with diabetes. It can be manufactured by genetically-engineered bacteria using the steps described below. A _ Bacteria are grown in a fermenter and produce insulin. B ‘The human insulin gene is isolated. a Plasmids are removed from bacteria. D ~~ Human insulin is purified and used to treat people with diabetes. m The human insulin gene is inserted into a plasmid. ay Altered plasmids are put into bacteria. Arrange the steps into the correct order by putting the appropriate letter into each empty box. 22 The diagram below represents some of the stages of genetic engineering which are used to produce medicines such as insulin for human use. A B Cc Extract . Insert E Join O 4 Next stage Extract (a) Complete the table below to identify the labelled parts of the diagram. Name of structure Letter bacterial cell insulin gene plasmid (6) Describe the next stage needed to produce insulin for use as a medicine. (c) Name another human hormone produced by genetic engineering. (d) State one advantage of genetic engineering. 23 7 - Photosynthesis 5. ‘The diagrams below show four experiments used in an investigation into the conditions needed for hotosynthesis photosynthesis Clear Black plastic plastic bag bag 2 Leaf G Water Cotton wool souked in a chemical that produces carbon dioxide Clear Black plastic plastic bag ag \ 3 4 LE] Cotton wool soaked in a chemical that absorbs carbon dioxide bi / / J ee) The results from which two experiments should be compared to show that light is needed for photosynthesis? A land2 Bland4 C 2and3 D 3and4 7. Acrop of tomatoes was grown ina polytunnel. watcring system polytunnel Which of the following changes would not produce an carlier crop of tomatoes? A Increasing the heating during the day. B Increasing the CO) concentration at night. C Increasing the light intensity at night. D Increasing the CO; concentration during the day. 24 (b) (i) Complete the diagram below to show how the carbohydrate product of photosynthesis is used in a plant. carbon dioxide + -—»| photosynthesis [> oxygen water y is made in the leaves fy OS converted to . an converted to used in respiration to TTT release energy and used to make and stored . cell walls (ii) Name a tissue in the leaves of plants in which photosynthesis takes place. The diagram below shows the green water plant Elodea used in an experiment to investigate photosynthesis. oxygen ° QO . °°? water with a dissolved carbon dioxide a | 9G ° 3 Llodea lamp C4 funnel —4 Describe how the requirements for photosynthesis shown in the diagram are used in photolysis and carbon fixation to produce oxygen and starch. 27 na : : : : AVLUTA 5. (a) ‘The sentences below give some information about photosynthesis. Underline one option in each set of brackets to make the sentences correct. Photosynthesis uses oxygen green plants carbon Hosdeheg sow | ‘ungi |x make their own food. cellulose Some of this food is converted to starch | for making cell walls. 2 (b) Decide if each of the following statements about photosynthesis is True or False, and tick (W) the appropriate box. If the statement is False, write the correct word(s) in the Correction box to replace the word(s) underlined in the statement. Statement True | False Correction The first reaction in photosynthesis is called carbon fixation. Hydrogen is transferred from the first reaction to the second reaction. ADP is used as the energy source for the second reaction in photosynthesis. 28 8 - Respiration 1. Which substance enters animal cells by diffusion and is used to produce ATP? A Carbon dioxide 4. Which of the following stages in respiration would result in the production of 38 molecules B_ Starch of ATP? C Water A Glucose to pyruvic acid B Pyruvic acid to lactic acid D_ Glucose c Pyruyic acid to carbon dioxide and water D_ Glucose to carbon dioxide and water 3. ‘The diagram below shows cnergy transfer within a cell. Compound X + phosphate Energy Cellular processes Energy Compound Y Which line in the table identifies correctly compounds X and Y? xX Y A glucose co, B co, ADP Cc ADP ATP D ATP glucose 29 (6) ATP is formed during respiration and broken down for uses in cells. (i) How many molecules of A’l'P are formed from each glucose molecule during Stage 1 only? Both Stage 1 and Stage 2? (ii) What two molecules are produced when ATP is broken down? and (iii) State one use of the energy released when ATP is broken down. (6) ‘Vhe table below shows how altitude affects the percentage oxygen carried in blood. Altitude (metres) Percentage oxygen carried in blood (%) (sea level) 0 97 2800 91 3700 85 4700 80 Use the data in the table to explain why a runner who lives at an altitude of 2800 metres would fatigue more quickly if racing in an event at +700 metres. 32 (a) Yeast cells have many industrial and commercial uses. The sentences below describe some of the uses of veast cells. Underline one option in each set of brackets to make the following sentences correct. bacteria carbon dioxide . Yeast cellsare; that produce which makes bread fungi oxygen rise. 33  34