| Date | May 2019 | Marks available | 1 | Reference code | 19M.1.HL.TZ1.34 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Identify | Question number | 34 | Adapted from | N/A |
Question
Which statement describes the control of reproduction in flowering plants?
A. Flowering in short-day plants results from changes in gene expression in the shoot apex.
B. Flowering in long-day plants is controlled by the production of auxins in the shoot apex.
C. All flowering plants depend on the duration of periods of light and darkness to regulate the timing of reproduction.
D. Flowering in short-day plants occurs when day length is longer than 12 hours.
Markscheme
A
Examiners report
Although this question attracted almost no comments from teachers, the statistics show that it was problematic. Only 6 % of candidates chose the answer that the examining team considered correct and not surprisingly the discrimination index was very low. Sub-topic 9.4 of the programme includes the Understanding that flowering involves a change of gene expression in the shoot apex. This was answer A. 77 % of candidate instead chose C. Although many plants use periods of darkness to regulate the timing of reproduction, not all do. Plants that are native to areas between the tropics are mostly daylengthneutral, because daylength doesn’t vary enough to be easily detectable by plants.
Syllabus sections
- 18N.1.HL.TZ0.34: The diagram shows results of experiments into flowering in a species of plant. What can be...
- 17M.1.HL.TZ1.33: Which flower structures are indicated by the letters Y and Z?
- 20N.1.HL.TZ0.34: Plants were given four different light treatments to investigate the influence of light on...
- 18M.2.HL.TZ2.1c: Discuss the evidence provided in the bar chart for the hypothesis that plant leaves use up...
- 18M.2.HL.TZ2.1b: Distinguish between plants grown in long days and short days in the mean number of leaves per...
- 18N.2.HL.TZ0.4d.i: Suggest one advantage for the evergreen trees of the boreal forest being pollinated by wind.
- 18N.2.HL.TZ0.4d.ii: Discuss the advantages of the production of seeds enclosed in fruit.
- 18M.2.HL.TZ2.1a.ii: Distinguish between plants grown in long days and short days in the timing of the four stages...
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18M.2.HL.TZ2.1a.i:
Calculate the difference (in mm2) in the mean leaf area of L6 at the start of stage 4 between the leaves of plants grown in long days and short days.
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21N.1.HL.TZ1.34:
The graph shows how the mass of a bean seed from which all water has been removed (dry mass) changes during germination.
What can be deduced from the graph?
A. The plant loses more water during period X than during period Y.
B. During period Y, photosynthesis occurs but not respiration.
C. During period Y, more CO2 is fixed in photosynthesis than is released by cell respiration.
D. The seeds were not exposed to the correct temperature for germination during period X.
- 21M.2.HL.TZ2.3b: An experiment was done to test the hypothesis that temperature affects the rate of...
- 17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
- 22M.1.HL.TZ2.34: Students investigated the environmental factors needed for germination, using seeds from 20...
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17N.2.HL.TZ0.08a:
Plants have widespread influences, from food chains to climate change.
Draw a labelled diagram of the internal structure of a seed.
- 18M.1.HL.TZ1.34: Fruit-eating bats living in protected Brazilian rainforests are attracted out of the forests...
- 17N.1.HL.TZ0.32: Agar is a growth medium without nutrients; starch agar is agar with starch added to it. Seed...
- 17M.1.HL.TZ2.30: Which process is matched with a valid example?
- 19M.3.HL.TZ2.1b.ii: Outline the relationship the bee has with the T. grandiflora flower.
- 19M.3.HL.TZ2.1a: Using the drawing, deduce which plant phylum T. grandiflora belongs to, giving one visible...
- 18N.1.HL.TZ0.33: What is a difference between pollination and fertilization in flowering plants? A. ...
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18M.2.HL.TZ2.1d.ii:
Suggest reasons for the difference in end of day starch concentrations in stage 2 (S2) for the plants grown in long days and short days.
- 18M.2.HL.TZ2.1d.i: For each of the stages, identify whether the starch concentration at the end of the day is...
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21N.2.HL.TZ0.5b:
Explain how some plant species are able to respond to changes in their abiotic environment and flower at a precise time of the year.
- 18M.2.HL.TZ2.1e: Using the data in the bar chart, discuss the evidence for Arabidopsis plants adapting to...
- 18M.2.HL.TZ2.1f: Using all relevant data in this question, deduce with reasons whether Arabidopsis is a long...
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19M.1.HL.TZ1.32:
The image shows a cross-section of a flower.
[Source: © International Baccalaureate Organization 2019]
Where does production of haploid gametes occur?
A. I and II only
B. III and IV only
C. I and III only
D. II and IV only
- 21M.1.HL.TZ1.34: Which method can be used to induce short-day plants to flower out of season? A. Grow them in...
- 16N.2.HL.TZ0.7b: The flowers of angiospermophyta are used for sexual reproduction. Outline three processes...
- 19M.3.HL.TZ2.1b.i: Identify the structure labelled X.
- 19M.3.HL.TZ2.1c: After fertilization, seeds of T. grandiflora form in a small pod. If you were provided with...
- 19M.2.HL.TZ2.4c: Successful sexual reproduction in flowering plants depends on several essential processes....
- 16N.1.HL.TZ0.33: Chrysanthemums are an important commercial flower. As a short-day plant, how can growers...
- 19N.1.HL.TZ0.34: A pollen tube grows down the style to an egg inside the ovary of a flower. What is the next...
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19N.2.HL.TZ0.8a:
Draw a half-view of an animal-pollinated flower.
