CHERRY HILL TUITION AQA BIOLOGY A2 PAPER 22

Transcription

1 8 4 (a) The tabe contains statements about three stages of respiration. Compete the tabe with a tick if the statement in the first coumn is true for each stage of respiration in an anima. Occurs in mitochondria Carbon dioxide produced Gycoysis Link reaction Krebs cyce NAD is reduced (3 marks) 4 (b) The foowing reaction occurs in the Krebs cyce. Succinate Enzyme Fumarate A scientist investigated the effect of the enzyme inhibitor maonate on this reaction. The structure of maonate is very simiar to the structure of succinate. The scientist added maonate and the respiratory substrate, pyruvate, to a suspension of isoated mitochondria. She aso bubbed oxygen through the suspension. 4 (b) (i) Expain why the scientist did not use gucose as the respiratory substrate for these isoated mitochondria. (08) 1 WMP/Jun13/BIOL4

2 9 4 (b) (ii) Expain how maonate inhibits the formation of fumarate from succinate. 4 (b) (iii) The scientist measured the uptake of oxygen by the mitochondria during the investigation. The uptake of oxygen decreased when maonate was added. Expain why. 9 Turn over for the next question Turn over (09) 2 WMP/Jun13/BIOL4

3 10 5 Scientists investigated the effect of iron deficiency on the production of triose phosphate in sugar beet pants. They grew the pants under the same conditions with their roots in a iquid growth medium containing a the necessary nutrients. Ten days before the experiments, they transferred haf the pants to a iquid growth medium containing no iron. The scientists measured the concentration of triose phosphate produced in these pants and in the contro pants: at the end of 6 hours in the dark then for 16 hours in the ight. Their resuts are shown in the graph Mean concentration of triose phosphate / arbitrary units 20 Contro pants Time after ight switched on / hours Iron-deficient pants 5 (a) (i) The experiments were carried out at a high carbon dioxide concentration. Expain why. (1 mark) 5 (a) (ii) Expain why it was important to grow the pants under the same conditions up to ten days before the experiment. (1 mark) (10) 3 WMP/Jun13/BIOL4

4 6 3 Urea from anima waste can be used as a fertiiser. Some bacteria in the soi secrete the enzyme urease which hydroyses urea into ammonia. Some of this ammonia is reeased into the atmosphere. NBPT is an inhibitor of urease and can be added to urea fertiiser to reduce the oss of ammonia to the atmosphere. 3 (a) A moecue of NBPT has a simiar structure to a moecue of urea. Use this information to suggest how NBPT inhibits the enzyme urease. Scientists investigated the effect of NBPT on the reease of ammonia from urea fertiiser added to the soi. A contro experiment was carried out. This invoved adding urea fertiiser ony. The graph shows their resuts Urea fertiiser and NBPT 1000 Urea fertiiser 800 Ammonia reeased to atmosphere / mg day Time after appication of fertiiser / days (06) 4

5 7 3 (b) (i) Describe how NBPT affected the oss of ammonia from urea fertiiser. (1 mark) 3 (b) (ii) Suggest an expanation for the increase in mass of ammonia reeased over the first four days in the contro experiment. 3 (c) Suggest how the addition of NBPT to urea fertiiser coud resut in increased growth of crop pants. (3 marks) 8 Turn over (07) 5

6 8 4 The young of frogs and toads are caed tadpoes. Ecoogists investigated the effect of predation on three species of tadpoe. They set up four artificia pond communities. Each community contained 200 spadefoot toad tadpoes 300 spring peeper frog tadpoes 300 southern toad tadpoes. The ecoogists then added a different number of newts to each pond. Newts are predators. Figure 1 shows the effect of increasing the number of newts on the percentage surviva of the tadpoes of each species. Percentage surviva of tadpoes Figure 1 Spadefoot toad Springpeeper peeper frog Southern toad Number of predatory newts per pond 4 (a) (i) Describe the effect of an increase in the number of newts on the percentage surviva of the tadpoes of each of the toad species. (08) 6

7 9 4 (a) (ii) Suggest an expanation for the effect of an increase in the number of newts on the percentage surviva of the tadpoes of spring peeper frogs. Figure 2 shows how the masses of the tadpoes were affected in each pond during the investigation. Figure 2 Spadefoot toad Springpeeper peeper frog Southern toad Mean mass of tadpoes in pond Number of predatory newts per pond 4 (b) Using the information provided in Figure 1 expain the resuts obtained in Figure 2. 6 Turn over (09) 7

8 10 5 Scientists investigated the effects of temperature and ight intensity on the rate of photosynthesis in creeping azaea. They investigated the effect of temperature on the net rate of photosynthesis at three different ight intensities. They aso investigated the effect of temperature on the rate of respiration. The graph shows the resuts High ight intensity Net rate of photosynthesis measured as uptake of carbon dioxide / mg g 1 h 1 ( ) 2 1 X Y Low ight intensity Medium ight intensity Rate of respiration measured as production of carbon dioxide / mg g 1 h 1 ( ) Respiration Temperature / C (a) (i) Name the factors that imited the rate of photosynthesis between X and Y. (1 mark) 5 (a) (ii) Use information from the graph to expain your answer. (10) 8

9 11 5 (b) Use information from the graph to find the gross rate of photosynthesis at 20 C and medium ight intensity. Answer... (1 mark) 5 (c) Creeping azaea is a pant which grows on mountains. Scientists predict that in the area where this pant grows the mean summer temperature is ikey to rise from 20 C to 23 C. It is aso ikey to become much coudier. Describe and expain how these changes are ikey to affect the growth of creeping azaea. (3 marks) 7 Turn over (11) 9

10 12 6 (a) A student measured the rate of aerobic respiration of a woodouse using the apparatus shown in the diagram. 3-way tap Syringe containing air Ruer Capiary tubing Drop of cooured iquid Woodouse Wire gauze Potassium hydroxide to absorb carbon dioxide Water bath 6 (a) (i) The student cosed the tap. After thirty minutes the drop of cooured iquid had moved to the eft. Expain why the drop of cooured iquid moved to the eft. (3 marks) (12) 10

11 13 6 (a) (ii) What measurements shoud the student have taken to cacuate the rate of aerobic respiration in mm 3 of oxygen g 1 h 1? (3 marks) 6 (b) DNP inhibits respiration by preventing a proton gradient being maintained across membranes. When DNP was added to isoated mitochondria the foowing changes were observed ess ATP was produced more heat was produced the uptake of oxygen remained constant. Expain how DNP caused these changes. (3 marks) 9 Turn over (13) 11

12 18 8 (a) Rather than use chemica pesticides or bioogica agents, farmers often use an integrated system of chemica pesticides and bioogica agents to contro agricutura pests. Expain the advantages of using an integrated system to contro agricutura pests. (6 marks) (18) 12 WMP/Jun13/BIOL4

13 19 8 (b) Nitrate from fertiiser appied to crops may enter ponds and akes. Expain how nitrate may cause the death of fish in fresh water. (5 marks) Question 8 continues on the next page Turn over (19) 13 WMP/Jun13/BIOL4

14 20 8 (c) Expain how the intensive rearing of domestic ivestock increases net productivity. (4 marks) 15 END OF QUESTIONS Copyright 2013 AQA and its icensors. A rights reserved. (20) 14 WMP/Jun13/BIOL4