SystemsIB MYP Sciences: Topic test

20 questions, 54 marks

IB MYP Sciences

Systems topic test

Total 54 marks

Name

Class

Date

1
A marine biologist in Hawaii studies seaweed growing on a coral reef. In bright sunlight, tiny bubbles of gas form on the seaweed's fronds.
(a)
Which gas is in the bubbles?
[1 mark]
AOxygen
BCarbon dioxide
CHydrogen
DNitrogen
(b)
Which substance does the seaweed use as a raw material, together with water, to make glucose?
[1 mark]
AOxygen
BGlucose
CCarbon dioxide
DStarch
(c)
Write the word equation for the process that makes the bubbles, and name the part of the cell where it takes place.
[2 marks]
Total for question 1: 4 marks
2
A cyclist in Bogotá rides at a steady pace for two hours along a mountain road. Her leg muscle cells release energy from glucose using oxygen delivered by her blood.
(a)
In which part of the muscle cell does aerobic respiration take place?
[1 mark]
ANucleus
BChloroplast
CCell wall
DMitochondria
(b)
Which equation summarises aerobic respiration?
[1 mark]
Acarbon dioxide + water → glucose + oxygen
Bglucose + oxygen → carbon dioxide + water
Cglucose → lactic acid
Dglucose → ethanol + carbon dioxide
(c)
State two uses of the energy released by respiration in the cyclist's body.
[2 marks]
Total for question 2: 4 marks
3
A grower in Almería, Spain, grows peppers in a large polytunnel. She records how fast the leaves photosynthesise under different conditions. The temperature is kept at 25 °C and the carbon dioxide concentration is 0.04%. As the light intensity is raised, the rate of photosynthesis is 4 arbitrary units at light intensity 20, 8 units at 40, and 12 units at 60. It then stays at 12 units at light intensities 80 and 100. When she raises the carbon dioxide concentration to 0.10% at light intensity 100, the rate rises to 24 units.
(a)
Describe three ways in which the structure of a pepper leaf helps it to carry out photosynthesis.
[3 marks]
(b)
Explain the grower's results.
[4 marks]
Total for question 3: 7 marks
4
A company in Antofagasta, Chile, grows microscopic algae in large open tanks. The algae photosynthesise quickly and are harvested to make a food supplement and a biofuel. The company pumps in waste carbon dioxide from a nearby power station to help the algae grow. A student at a local school wants to know whether adding more carbon dioxide always makes algae photosynthesise faster. In the school laboratory she has pondweed, a lamp, sodium hydrogencarbonate (which dissolves to release carbon dioxide into water), beakers, a ruler and a stopwatch.
(a)
Design an investigation using pondweed to test the student's idea. Include a hypothesis with a reason, the variables, the method and a safety precaution.
[6 marks]
(b)
Evaluate the company's use of waste carbon dioxide from the power station to grow algae for food and fuel, and reach a justified conclusion.
[6 marks]
Total for question 4: 12 marks
5
A brewery in Prague makes beer by adding yeast to a sugary liquid in large sealed tanks. The yeast respire the sugar and make alcohol.
(a)
Which two substances does yeast produce when it respires anaerobically?
[1 mark]
ALactic acid and water
BEthanol and carbon dioxide
CCarbon dioxide and water
DGlucose and oxygen
(b)
Why do the brewers keep air out of the sealed tanks?
[1 mark]
ASo the yeast respire aerobically
BSo the yeast can photosynthesise
CSo that no carbon dioxide forms
DSo the yeast respire anaerobically and make ethanol
(c)
Compare the energy released per glucose molecule in anaerobic respiration in yeast with that in aerobic respiration, and explain the difference.
[2 marks]
Total for question 5: 4 marks
6
A sealed glass bottle garden in a school in Perth contains small plants growing in soil. It has been sealed for many years and the plants still grow well. Light enters through the glass, and drops of water collect on the inside of the glass.
(a)
Which process happens in the plant cells only when light is available?
[1 mark]
AAerobic respiration
BAnaerobic respiration
CPhotosynthesis
DRelease of carbon dioxide
(b)
Which statement compares photosynthesis and aerobic respiration correctly?
[1 mark]
APhotosynthesis stores energy from light in glucose, but respiration releases energy from glucose
BPhotosynthesis releases energy and respiration stores energy
CBoth processes use oxygen
DBoth processes take place only in chloroplasts
(c)
Explain how the gases in the sealed bottle garden stay in balance.
[2 marks]
Total for question 6: 4 marks
7
At a swimming championship in Sydney, a scientist studies two swimmers. One swims 1500 m at a steady pace, taking about 15 minutes. The other swims 50 m at full speed, taking about 25 seconds. The muscles of both swimmers need energy for contraction.
(a)
Write the balanced symbol equation for aerobic respiration, and state where in the muscle cells it takes place.
[3 marks]
(b)
Compare how the muscles of the two swimmers get their energy.
[4 marks]
Total for question 7: 7 marks
8
A school in Tashkent runs a project on renewable fuels. Students count the bubbles of gas given off by pondweed in one minute at different temperatures, with the same light intensity and carbon dioxide supply each time. The numbers of bubbles per minute were 6 at 10 °C, 14 at 20 °C, 25 at 30 °C, 12 at 40 °C and 1 at 50 °C. The students also study how yeast ferments sugar from crops to make bioethanol, a fuel that is mixed with petrol, and debate whether farmland should be used for fuel crops instead of food.
(a)
Describe the trend in the pondweed results, explain it, and evaluate the investigation.
[6 marks]
(b)
Evaluate the use of farmland to grow crops for bioethanol instead of food, and reach a justified conclusion.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).