Cell physiology: diffusion — KCSE Biology
KCSE Biology · 88 practice questions · 3 syllabus objectives
What You'll Learn
Key learning outcomes for this topic, aligned to the KNEC KCSE syllabus.
Define diffusion and state factors affecting its rate
Describe experiments to demonstrate diffusion
Cell physiology: diffusion
Sample Questions
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In the study of cellular processes, understanding the mechanisms of gaseous exchange is crucial for appreciating how organisms interact with their environment. The following questions explore the specific structures and adaptations that facilitate this vital function in a given organism. (a) Identify the surface used for gaseous exchange in Paramecium. (1 mark) (b) State one adaptation of this surface that makes it efficient for gaseous exchange. (1 mark)
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In the study of cellular processes, understanding the movement of substances across membranes is crucial. This involves examining the principles that govern the rate of diffusion, influenced by various factors such as molecular mass and temperature. (a) State Graham's law of diffusion. (2 marks) (b) Using Graham's law, explain why ammonia gas (molar mass 17) diffuses faster than hydrogen chloride gas (molar mass 36.5). (2 marks)
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In the study of plant biology, understanding the mechanisms that facilitate the exchange of gases is crucial. Consider the various structures that enable this process in terrestrial plants and their specific locations within the plant system. (a) Identify three structures used for gaseous exchange in terrestrial plants. (3 marks) (b) For each structure, state the part of the plant where it is found. (3 marks)
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In the context of cellular respiration, the exchange of gases between blood capillaries and body cells is crucial for maintaining metabolic processes. Consider the roles of specific gases involved in this vital physiological function. (a) Name the gas that diffuses from the blood capillaries to the body cells during respiration. (1 mark) (b) Name the gas that diffuses from the body cells to the blood capillaries. (1 mark) (c) Explain why these gases move in these directions. (2 marks)
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