2017_Photosynthesis_Respiration_STQ_QP

2017 Photosynthesis and Respiration STQ 2017 / H2 / AJC PRELIM / P2 Q61In anaerobic respiration in yeast, the pyruvate molecules are broken down to produce ethanol and carbon dioxide. The release of carbon dioxide can be used to investigate the rate of anaerobic respiration. Fig. 6.1 shows an experiment which was set up to find the rate of anaerobic respiration. Fig. 6.1The meniscus moves down the tube as carbon dioxide is released. Table 6.1 shows the distance moved by the meniscus from the start point. This was recorded every 10 minutes. Table 6.1Time/ min0102030405060708090Distance travelled by meniscus from start point/ mm012591421457398 (a)The rate of anaerobic respiration can be calculated by using the rate of movement of the meniscus.Calculate the rate of anaerobic respiration between 70 and 80 minutes. You will lose marks if you do not show your working. [2(b)This experiment was repeated three more times. Each time, the glucose (a monosaccharide) was replaced with a different disaccharide sugar:

Maltose – a disaccharide of glucose and glucoseSucrose – a disaccharide of glucose and fructoseLactose – a disaccharide of glucose and galactose. Tables 6.2 (a), (b) and (c) show the results of these experiments. Table 6.2 (a): Using maltoseTime/ min0102030405060708090Distance travelled by meniscus from start point/ mm00000236912Table 6.2 (b): Using sucroseTime/ min0102030405060708090Distance travelled by meniscus from start point/ mm000131122374861Table 6.2 (c): Using lactoseTime/ min0102030405060708090Distance travelled by meniscus from start point/ mm0000000000With reference to the information provided in Tables 6.2 (a), (b) and (c) and your biological knowledge:(i)Describe the difference in the results for maltose and sucrose, and suggest one explanation for this difference, [2

(ii)Suggest two explanations for the results for lactose. [2(c)An electron micrograph of yeast, Candida albicans, is shown in Fig. 6.2. Fig. 6.2(i)On Fig. 6.2, label site of i.Glycolysisii.Oxidative phosphorylation[2(ii)State one visible structure of mitochondria from Fig. 6.2 and describe how it supports mitochondria’s function. [1

(ii)Besides location, compare between oxidative phosphorylation and photophosphorylation. [4] [Total: 13 marks]

2017 / H2 / CJC PRELIM / P2 Q62Microalgae have been extensively studied for various purposes, such as the production of biomass as a source of valuable chemicals of health foods and for wastewater treatment. Recently, microalgal photosynthesis was considered to be an effective means to reduce the emission of carbon dioxide, a major greenhouse gas, in the atmosphere. Light is the most important factor affecting microalgal photosynthesis kinetics. In general, most microalgal mass culture systems are limited by light, because light is easily absorbed and scattered by the microalgal cells. Therefore, u