- Summary list for 9.3 Growth in plants
- Mindmaps
- Exam style question about auxin
- Model answer
- Exam style question on micropropagation.
- Model answer
- Exam style question on flowering and day length
- Model answer
- Multiple choice questions
- 9.3 Plant growth 1/1
Summary list for 9.3 Growth in plants
Meristems and growth
- Plant meristems are undifferentiated cells which allow indeterminate growth (ie: plants continue to grow when adult.)
- Mitosis and cell division in the shoot apex provide cells needed for the stem to get longer and for the development of leaves.
Hormonal control of shoot growth
- Plant hormones (ie: auxin) control growth in the shoot apex.
- Auxin efflux pumps can create auxin concentration gradients
- Plant shoots respond to the environment by tropisms.
- Concentration gradients of auxin in plant tissue influence the rate of cell growth by changing the pattern of gene expression.
Skills
- Micropropagation of plants using tissue from the shoot apex grown on nutrient agar gels in the presence of growth hormones can be used for rapid production of new varieties, of virus-free strains of existing varieties and for propagation of orchids and other rare species.
Mindmaps
These diagram summaries cover the main sections of topic 9.3 Growth in plants.
Study them and draw your own list or concept map, from memory if you can.
Try to turn the simple mindmap into the detailed mindmap from memory.
Exam style question about auxin
Explaining the effect of auxin on plant growth is an important skill from this topic.
Answer the question below, on a piece of paper, then check your answer against the model answer below.
Describe the role of auxin in phototropism in growing shoots [5]
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Click the + icon to see a model answer.
Multiple choice questions
This is a self marking quiz containing questions covering the topic outlined above.
Try the questions to check your understanding.
START QUIZ!
Which of the statements best describes apical meristems?
The apex is the tip (apical) Lateral is at the side, lateral meristems are found where branches or leaves form on the stem. Apical meristems are found at root tips and shoot tips
The microscope image below shows the tip of an onion root.
What are the characteristic of the cells which form the meristem?
They are small undifferentiated cells, doing rapid mitosis, found just behind the tip of the root.
At the very tip, there are some larger cells which form the root cap. This area is tough and prevents damage to the meristem behind it as the root pushes through the soil.
What is the name of the plant hormone which causes this unusual plant growth towards a window?
Auxin is the plant hormone which causes phototropism.
What is the difference between mitosis and cell division?
Mitosis divides the nucleus and then cell division occurs dividing the cytoplasm.
Cell elongation is also important for the growth of the shoot but it noes not provide new cells.
Name the response shown by the plants in the image below which causes them to grow towards the light?
Phototropism is the growth of a plant, towards or away from a source of light, in response to the light.
Plant shoots often grow towards light so they can maximise their photosynthesis.
Which of the following suggestions is a potential application of micropropagation?
As all the plants produced by micropropagation are genetically identical there will be no increase in the genetic variety in the gene pool. The procedure produces many small plants which may have a beneficial characteristic, e.g. drought tolerance, or resistant to pests, but existing plants are not changed using this process.
Which is the best description of micropropagation?
Micropropagation uses plant tissue from the shoot apex to create clones of the original plant.
The movement of auxin within a growing shoot is important for phototropism.
Which of the following mechanisms is thought to move auxin from cell to cell in a growing shoot?
Auxin efflux pumps move auxin away from light and towards the shady part of a growing shoot.
The graph below shows the results of an experiment to test four concentrations of auxin on the growth of some seedlings.
Which of the following statements is the best explanation of the results?
Be careful interpreting the scale.
The y-axis is potentially confusing. 2.5 means that the shoots grow 2.5 times more than the control group.
Drag and drop activities
Test your ability to construct biological explanations using the drag and drop questions below.
The role of the meristem in plant growth.
Drag and drop the correct term into the gap to outline growth in flowering plants.
hormones mitosis environmental determinate indeterminate meiosis types expression totipotent flower different
Angiosperm growth is , meristematic cells divide by and produce new organs continually.
Meristems are , depending upon the growth pattern of the plant, the same meristematic cells can produce organs. For example, the stem apical meristem can produce stem, leaf or primordia (embryonic organs) and all of the cell that the organ requires.
The development of the plant is controlled by plant that alter gene in the differentiating cells by responding to conditions such as the length of the day.
Explanation: Angiosperm grwth patterns are controlled by hormones and are responses to environmental influences.
Everyone needs a bit of fun while they revise. Try this Growth in plants card matching game.
Can you reach the leader board?
How much of Growth in plants 9.3 HL have you understood?
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