6.1. Photosynthesis
A subsection of Biology, 0610, through 6. Plant nutrition
Listing 10 of 307 questions
For Examiner's Use Many growers of crops in glasshouses use carbon dioxide enrichment to improve yields. Explain the advantages of carbon dioxide enrichment of glasshouses. shows the carbon dioxide concentrations inside three glasshouses, D, E and F, on a hot day with bright sunlight. • Glasshouses D and E received carbon dioxide enrichment and were ventilated by opening the windows. • Glasshouse F did not receive any extra carbon dioxide and the windows were closed. The carbon dioxide concentrations in the glasshouses and in the atmosphere were measured. The concentration in the atmosphere was 0.039 %. D concentration of CO2 = 0.041 % CO2 E concentration of CO2 = 0.070 % F concentration of CO2 = 0.020 % CO2 The rate of uptake of carbon dioxide by the crop plants was measured in grams of carbon dioxide absorbed per square metre of glasshouse per hour. These results are shown in Table 3.1. Table 3.1 glasshouse rate of uptake of carbon dioxide by crop plants / g per m2 per hour D 2.5 E 5.7 F 1.0 For Examiner's Use Suggest why it may not be cost effective to maintain a high concentration of carbon dioxide in glasshouse E compared to the concentration of carbon dioxide in the atmosphere. Concentrations of carbon dioxide in all three glasshouses in increased at night. State why this happened. Explain why it is important to ventilate glasshouses by opening the windows.
0610_s12_qp_33
THEORY
2012
Paper 3, Variant 3
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For Examiner's Use Sulfur dioxide is a pollutant gas produced when some types of fossil fuel are burnt. Describe three undesirable effects of sulfur dioxide pollution. Sulfur dioxide in the air can affect a type of organism called a lichen. shows the numbers of three types of lichen, K, L and M, growing near to an industrial site that releases sulfur dioxide. distance from industrial site / km number of each lichen per 20 m2 lichen K lichen L lichen M State which type of lichen grows closest to the industrial site. State which types of lichen you would expect to find growing 5 km from the industrial site. For Examiner's Use Explain which type of lichen is most affected by the sulfur dioxide. Calculate how many lichen plants you would expect to find in a 20 m2 area at 10 km from the industrial site. Show your working. lichen plants
0610_s13_qp_23
THEORY
2013
Paper 2, Variant 3
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shows the carbon cycle. P, Q, R, S and T each represent a part of the carbon cycle. P R T Q S photosynthesis respiration respiration respiration death carbonisation carbonisation death feeding combustion Complete Table 6.1 by identifying P, Q, R and S and the name of one example of a carbon compound found in each. T has been completed for you. Table 6.1 letter part of cycle carbon compound found in each part P Q R S T fossil fuels, e.g. natural gas methane Photosynthesis is a very important process in the carbon cycle. Explain how the process of photosynthesis converts carbon compounds from P to carbon compounds in Q. The rate of photosynthesis varies as a result of changes in environmental factors. State one environmental factor and explain how it can affect the rate of photosynthesis. Copyright Acknowledgements: Question 2 Figure 2.1 © Xue-Yan Liu, Hua-Yun Xiao, Cong-Qiang Liu, Hong-Wei Xiao, Yan-Li Wang; Assessment of atmospheric sulphur with the epilithic moss Haplocladium microphyllum: Evidences from tissue sulphur and d34S analysis. Environmental Pollution; Elsevier; 2009. Question 4 Figure 4.1 © Biodisc; Cross-section of a Lily anther showing the second meiotic division (Lilium), a monocot. LM X65; Visuals Unlimited; 2011. Question 4 Figure 4.2 © Anurag Dhyani; LILIES and Related Plants, 2011-2012. Phenology of Lilium polyphyllum in Garhwal Himalaya, India; RHS Lily Group; 2011. Environmental factors can be controlled in glasshouses. Describe how three environmental factors are controlled in a glasshouse to improve crop yield. factor 1: how is it controlled: factor 2: how is it controlled: factor 3: how is it controlled:
0610_s14_qp_33
THEORY
2014
Paper 3, Variant 3
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A student carried out an investigation to find the effect of carbon dioxide concentration on the rate of photosynthesis of an aquatic plant. The apparatus that the student used is shown in . The student was advised to use a light meter positioned at the same distance from the lamp as the pond plant. The student counted the number of bubbles produced by the cut end of the stem. water-bath thermometer pond plant movable lamp cm ruler dilute sodium hydrogencarbonate solution stop watch Explain why the student included the following in the apparatus. The beaker of water and the thermometer. The light meter and the ruler. The results obtained by the student are shown in . 0.00 0.05 0.10 0.15 0.20 0.25 carbon dioxide concentration / % 0.30 0.35 0.40 0.45 0.50 rate of photosynthesis / number of bubbles per minute X Y Describe the student’s results. You will gain credit if you use data from in your answer. State the factor that is limiting the rate of photosynthesis in region X of the graph. Suggest and explain the reasons for the shape of the graph in region Y. Counting bubbles may not be the best way to measure the rate of photosynthesis. The volume of the bubbles is not always exactly the same. Suggest and explain one alternative way of measuring the gas given off to solve this problem. shows the carbon dioxide concentration in the atmosphere as determined at Mauna Loa in Hawaii between 1959 and 2013. year concentration of carbon dioxide in the atmosphere / parts per million mean value range of values Explain why the concentration of carbon dioxide has increased between 1959 and 2013. Global warming is largely due to this increase in atmospheric carbon dioxide. Explain how increases in atmospheric carbon dioxide concentrations contribute to global warming.
0610_s15_qp_31
THEORY
2015
Paper 3, Variant 1
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Researchers in Michigan investigated the rate of photosynthesis in leaves of big-tooth aspen trees, Populus grandidentata, by placing some of the growing leaves inside transparent boxes. The researchers measured the uptake of carbon dioxide by the leaves over a range of temperatures from 10–40 °C. They carried out their measurements at two different concentrations of carbon dioxide: H – 325 ppm carbon dioxide which is close to the concentration in the atmosphere; J – 1935 ppm carbon dioxide which is a very high concentration. The results are shown in . uptake of carbon dioxide / mg m–2 min–1 temperature / °C J H Describe how the results for the aspen leaves in batch J differ from the results for the aspen leaves in batch H. Use data from in your answer. Explain why the rate of photosynthesis in the leaves in batch J: increases with an increase in temperature from 15 °C to 35 °C decreases at temperatures above 35 °C. Use the results in to suggest and explain the likely effect on plant growth of an increase in carbon dioxide concentration in the atmosphere as a result of the combustion of fossil fuels.
0610_s15_qp_33
THEORY
2015
Paper 3, Variant 3
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Questions Discovered
307