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Question 1

HLPaper 1

Which flower structures are indicated by the letters Y and Z?

Question 2

HLPaper 1

Which graph represents the effect of humidity on the transpiration rate in plants?

Question 3

HLPaper 1

Students investigated the environmental factors needed for germination, using seeds from 20 different plant species. Which factors would prevent germination if they are absent?

Question 4

HLPaper 2

1.

Outline how greenhouse gases interact with radiation and contribute to global warming.

[4]

2.

Outline how plants make use of the different wavelengths of light.

[4]

3.

Explain how organic compounds are transported within plants.

[7]

Question 5

HLPaper 2

1.

Compare and contrast the mode of nutrition of detritivores and saprotrophs.

[2]

2.

Explain how some plant species are able to respond to changes in their abiotic environment and flower at a precise time of the year.

[3]

3.

Outline the extension of the stem in plants.

[2]

Question 6

HLPaper 2

Every cell is surrounded by a cell surface membrane which regulates the movement of materials into and out of the cell.

1.

Discuss alternative models of membrane structure including evidence for or against each model.

[8]

2.

Outline the process used to load organic compounds into phloem sieve tubes.

[3]

Question 7

HLPaper 3

The diagram shows the development of potato plants (Solanum tuberosum) over 14 weeks. New tubers start growing from week 9. These are modified underground stems serving as a starch reserve and bearing buds from which new plants arise.

Scientists planted several potato plants in a greenhouse. The sucrose and amino acids inpotato plant phloem exudates were measured during several weeks.

1.

Describe briefly how scientists obtained leaf phloem sap from the potato plants.

[2]

2.

Suggest reasons for different amounts of sucrose in the leaf phloem sap of the potato plants.

[3]

Question 8

HLPaper 1

How does auxin exert its effect on plant cells?

Question 9

HLPaper 1

Which process is most responsible for movement of water from roots to leaves of a plant on a hot sunny day?

Question 10

HLPaper 1

Agar is a growth medium without nutrients; starch agar is agar with starch added to it. Seed coats were removed from seeds and the seeds were used to set up the following conditions. Which plant embryo was unable to grow?

Topic 9 - Plant biology (HL)

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