3.2. Osmosis
A subsection of Biology, 0610, through 3. Movement into and out of cells
Listing 10 of 220 questions
For Examiner's Use Explain how water is absorbed by plant roots. Young plants were grown in pots of sand for four weeks. Some plants were watered with distilled water at pH 7.0 (no salts). Most pots were watered with solutions containing different concentrations of salt (sodium chloride) at pH 7.0. The plants were kept at 20 oC. The growth of the plants was measured after four weeks. The growth of the plants is shown in as percentages of the growth of the plants watered with distilled water. concentration of sodium chloride / arbitrary units growth as percentages of the growth of the plants given distilled water For Examiner's Use Describe the results shown in . You will gain credit for using the figures in the graph to support your answer. Explain the difference in growth between the plants watered with low concentrations and those watered with high concentrations of salt solution. For Examiner's Use The pH of soils influences the availability of ions to plants. shows the availability of ions in soils of different pH. 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 availability of each ion magnesium potassium phosphate nitrate iron sulfate Name the ion that is least available in soils of pH 4.0 and in soils of pH 11.0. pH 4.0 pH 11.0 For Examiner's Use Plants grown in soils of pH 10 may show symptoms of deficiency. They are stunted and their leaves are yellow. Explain how deficiencies of magnesium ions and nitrate ions lead to the symptoms described. magnesium ions nitrate ions
0610_w11_qp_33
THEORY
2011
Paper 3, Variant 3
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shows part of the water cycle. water in streams, rivers, lakes and seas atmosphere soil plants P Q R S Using words from the list, identify the processes P, Q, R and S. drainage egestion evaporation photosynthesis rainfall transpiration P Q R S State two ways in which water may leave the body of a mammal. Describe how water in a plant may become water in the cells of an animal. shows apparatus which can be used to measure the rate of water uptake by a plant shoot. stop clock air bubble scale Three sets of this apparatus, using shoots from the same tree, were used at the same time. The experiment was carried out with four different sets of external conditions A, B, C and D. The time for the air bubble to move 10 cm was measured and recorded in Table 8.1. Table 8.1 external conditions time for air bubble to move 10 cm / s shoot 1 shoot 2 shoot 3 A dry, still air at 15 °C B dry, still air at 25 °C C dry, moving air at 25 °C D humid, still air at 15 °C State which shoot took up water most quickly under all conditions. Suggest a difference between the shoots that could explain these results. Suggest why the results under condition D were different from the results under condition A.
0610_w13_qp_23
THEORY
2013
Paper 2, Variant 3
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For Examiner's Use This question is about transport in plants. Two pea plants, D and E, were supplied with substances containing the radioactive isotopes, carbon-14 (14C) or phosphorus-32 (32P), as shown in . A leaf of plant D was exposed to radioactive carbon dioxide. Plant E was placed into a solution containing radioactive phosphate ions. nutrient solution fruit seed growing point flower clear plastic bag with added radioactive carbon dioxide plant D plant E nutrient solution with added radioactive phosphate ions After several hours the plants were analysed for the presence of the radioactive isotopes. Sucrose containing 14C was found throughout plant D. Compounds containing 32P were found throughout plant E. Complete Table 4.1 to show: • the tissue in which each substance is transported; • one possible sink for each substance. Table 4.1 pea plant D E substance transported sucrose phosphate ions transport tissue sink For Examiner's Use State one substance, other than sucrose, that is produced in leaves and translocated to other parts of the plant. Outline how sucrose is produced from carbon dioxide in pea plants. State two uses of sucrose within a pea plant. Explain how ions, such as phosphate ions, are absorbed by plant roots.
0610_w13_qp_32
THEORY
2013
Paper 3, Variant 2
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Chemical fertilisers are used to improve crop productivity. Outline how chemical fertilisers improve the productivity of crops. For Examiner's Use State the conditions necessary for seeds to germinate. Describe the effects of increasing the concentration of sulfuric acid on the growth of roots and shoots of the seedlings. You will gain credit if you use data from in your answer. Acid rain is formed when sulfur dioxide (SO2) and oxides of nitrogen (NOdissolve in rain water. Explain why concentrations of sulfur dioxide in the atmosphere have increased over the last 150 years. Figure 2.1 © T D Etherton & D E Bauman; Biology of Somatotropin in Growth and Lactation of Domestic Animals; Physiological Reviews; Vol.78, No.3; July 1998; http://physrev.physiology.org/content/78/3/745.html. Figure 6.1 © G Fleet et al; Acid rain in the classroom: a student research project; Journal of Biological Education; 1987. For Examiner's Use Describe three effects of acid rain on organisms and their environment.
0610_w13_qp_33
THEORY
2013
Paper 3, Variant 3
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Questions Discovered
220