Biologi

Explanation 1 mark

State the function of the ribosomes in a cell.

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Explanation 1 mark

Name the blood vessel that carries oxygenated blood from the lungs back to the heart.

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Explanation 2 marks

State two properties of enzymes.

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Explanation 2 marks

Name the two products formed when a fat (lipid) is completely digested.

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Explanation 2 marks

State two functions of bile in the digestion of food.

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Explanation 2 marks

State two structural differences between a typical plant cell and a typical animal cell.

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Explanation 2 marks

State two structural differences between an artery and a vein.

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Explanation 2 marks

Explain briefly why active transport requires energy.

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Explanation 2 marks

Explain briefly why a person breathes faster and more deeply during vigorous exercise.

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Explanation 3 marks

Describe briefly the role of the kidney in removing waste from the blood.

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Explanation 3 marks

State three ways in which the small intestine is adapted for the efficient absorption of digested food.

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Explanation 3 marks

Describe briefly the pathway taken by a nerve impulse in a reflex arc when a person's hand touches a hot object and is pulled away.

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Explanation 3 marks

Describe briefly how the body brings the blood glucose concentration back to normal after it has risen too high following a meal.

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Explanation 3 marks

Explain the difference between anabolism and catabolism as the two types of metabolism.

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Explanation 3 marks

Describe briefly three ways in which a red blood cell is adapted for transporting oxygen.

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Explanation 4 marks

Explain why having many more mitochondria in his muscle cells is an advantage to an endurance athlete such as Aiman.

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Explanation 4 marks

Explain how soaking the chicken in papaya juice makes the meat softer.

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Explanation 5 marks

Explain the effect of temperature on the rate of the enzyme-catalysed reaction shown by the results.

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Explanation 6 marks

Compare how humans and insects such as the grasshopper obtain oxygen for respiration.

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Explanation 1 mark

State a suitable hypothesis for this experiment.

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Explanation 1 mark

State the responding variable in this experiment.

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Explanation 1 mark

State one precaution the student should take when carrying out this test.

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Explanation 1 mark

State one constant (fixed) variable in this experiment.

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Explanation 1 mark

State the manipulated variable in this experiment.

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Explanation 2 marks

State two constant (fixed) variables in this experiment.

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Explanation 2 marks

Calculate the rate of decolourisation (per second) at each temperature, taking the rate as 1 divided by the time.

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Explanation 2 marks

State two observations you would expect at the end of the two hours.

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Explanation 2 marks

State two observations you would expect if the solution contains protein.

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Explanation 2 marks

State the operational definition of the vitamin C content in this experiment, and explain what a smaller volume of juice would mean.

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Explanation 2 marks

Calculate the percentage increase in her breathing rate caused by the exercise, and state the responding variable.

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Explanation 2 marks

State two observations you would expect if the food sample contains fat.

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Explanation 3 marks

State the expected observation for each flask, explain why flask B is included, and make an inference from the results.

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Explanation 3 marks

Calculate the rate at which the milk cleared (per second) at each temperature, taking the rate as 1 divided by the time, and state the relationship...

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Explanation 3 marks

Calculate the percentage germination at each temperature, state the relationship shown, and suggest one way to improve the reliability of the exper...

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Explanation 6 marks

State the trend shown by the results and make an inference to explain it.

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Explanation 6 marks

State the manipulated variable, the responding variable and one constant variable in this experiment, and name the gas released.

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Explanation 6 marks

Construct a table showing the rate of fermentation (bubbles per minute) for each temperature, and state the operational definition of the rate of f...

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Evaluation 10 marks

Plan a complete experiment to investigate the effect of glucose concentration on the rate of fermentation of yeast. Your plan should include a prob...

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Explanation 1 mark

State the manipulated variable in this experiment.

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Explanation 2 marks

State the two observations you would expect when iodine solution is added to the tested leaf.

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Explanation 2 marks

State two observations you would expect for the cells mounted in the concentrated salt solution.

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Explanation 2 marks

Calculate the rate of water loss in grams per minute, and state why the cut end was sealed.

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Explanation 2 marks

State the relationship between temperature and the amount of pigment released, and make an inference.

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Explanation 2 marks

State the relationship between air movement and the rate of transpiration shown by these results, and give a reason.

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Explanation 3 marks

Calculate the rate of photosynthesis (bubbles per minute) at each concentration, state the relationship shown, and give the operational definition ...

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Explanation 3 marks

Calculate the rate of bubble movement (mm per minute) in each condition, state which condition gave the highest rate, and give a reason for that co...

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Explanation 3 marks

State which leaf surface loses water faster, make an inference to explain the difference, and state how the rate of water loss is shown in this exp...

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Explanation 3 marks

Calculate the percentage change in mass of each bag, state the relationship shown, and classify the distilled water surrounding the 0.8 mol dm⁻³ ba...

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Explanation 5 marks

State the manipulated variable, the responding variable and one constant variable in this experiment.

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Explanation 5 marks

State the operational definition of osmosis in this experiment and identify the concentration of sucrose solution that is isotonic to the potato ce...

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Explanation 6 marks

Make an inference to explain the change in mass in each solution, and classify the 0.0 mol dm⁻³ and 0.8 mol dm⁻³ solutions by type.

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Explanation 6 marks

Construct a table showing the percentage change in mass of the potato strip for each concentration, and state the trend it shows.

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Evaluation 10 marks

Plan a complete experiment using Visking (partially permeable) tubing to investigate how the concentration of sucrose solution affects osmosis. You...

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Explanation 1 mark

Name the process by which water moves across a partially permeable membrane from a dilute solution to a more concentrated solution.

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Explanation 1 mark

State one function of the large central vacuole in a plant cell.

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Explanation 2 marks

State two ways in which a leaf is adapted for photosynthesis.

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Explanation 2 marks

Explain briefly why the stomata of a leaf close on a hot, dry, sunny afternoon.

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Explanation 3 marks

Describe briefly what happens during fertilisation in a flowering plant after a pollen grain has landed on the stigma.

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Explanation 3 marks

Describe briefly how water travels from the soil to the leaves of a tall tree.

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Explanation 4 marks

Explain how the three marked regions along the root tip contribute to the growth of the root.

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Explanation 5 marks

Explain the differences between primary growth and secondary growth in the trees grown at the nursery.

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Explanation 6 marks

Explain how auxin causes the oat coleoptile that is lit from one side only to bend towards the light.

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Evaluation 7 marks

Evaluate whether using the synthetic auxin rooting powder is a suitable way for the nursery to produce strong seedlings for sale.

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Explanation 2 marks

Explain briefly why a food chain in the mangrove rarely has more than four or five trophic levels.

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Explanation 2 marks

Explain briefly what happens to a plant cell when it is placed in a concentrated salt solution.

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Explanation 2 marks

State two roles of decomposers such as bacteria and fungi in the mangrove ecosystem.

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Explanation 4 marks

Explain why the leaves of mangrove trees and desert plants share similar adaptations, even though the two habitats appear very different.

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Explanation 4 marks

Explain the impact on the ecosystem of clearing the mangrove forest to build prawn-farming ponds.

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Explanation 6 marks

Compare the mangrove trees and their adaptations in Zone I with those in Zone II.

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Evaluation 8 marks

Discuss the steps that could be taken to protect the remaining mangrove forest, and judge which approach would be most effective.

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