This Biology quiz is called 'Biology - Plant Sensitivity and Control' and it has been written by teachers to help you if you are studying the subject at high school. Playing educational quizzes is a user-friendly way to learn if you are in the 9th or 10th grade - aged 14 to 16.
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In high school science, one topic studied is how organisms use nerves and hormones. This quiz looks in particular at how plants use hormones for both sensitivity and control.
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We all recognize the main parts of a plant but have you ever wondered how the stem of a plant knows to grow upwards and how the roots know that they should grow downwards?
One of the characteristics of life on earth is sensitivity to the surroundings. In the case of animals how they react to external stimuli is easy to see, however, it is not always so obvious for plants. Plants don't have a nervous system or muscles but they do have hormones which they use to give them sensitivity to their surroundings. The sensitivity granted by the hormones enables plants to grow towards light and makes their roots push down into the soil.
Certain plants living in areas where conditions mean that there are few nutrients have developed carnivorous habits. Not like the giant 'man-eating' plants of science fiction stories - they only eat insects. You probably know about the venus fly trap which has small hairs on its 'traps' that detect insects and close the trap, but there are others such as the sundew and pitcher plants. These plants have evolved to trap flies and other insects. They secrete digestive juices that slowly break down the insects into the nutrients that the plant needs. These are then absorbed by the plant cells and transported in the sap to where they are needed.
As well as for sensitivity, plants also use hormones to control their biological processes. Growth of plants is controlled by hormones but plants also use them to control their formation of flowers, stems and leaves, and for their shedding of leaves.
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1.
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Phototropism is caused by a hormone. What is phototropism? |
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| [ ] |
When old photographs are ruined by bacteria |
| [ ] |
Skin darkening in response to sunlight |
| [ ] |
Plant leaves losing their green color when there isn't much sunlight |
| [ ] |
Plants growing towards the light |
|
|
|
2.
|
Gravitropism (geotropism) is also caused by a hormone. What is gravitropism? |
|
| [ ] |
Roots growing downwards, shoots growing upwards |
| [ ] |
Shoots growing upwards only |
| [ ] |
A plant disease |
| [ ] |
Plants growing away from the light |
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3.
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Which of the following options applies to the plant hormones, auxins? |
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| [ ] |
Auxins are found only in the leaf cells of plants |
| [ ] |
Auxins respond only to light |
| [ ] |
Auxins are made in the growing tips and spread throughout the plant |
| [ ] |
Auxins respond only to gravity |
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4.
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Which of these combinations describes the tropisms of shoots correctly? |
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| [ ] |
Positively phototropic and positively geotropic |
| [ ] |
Negatively phototropic but positively geotropic |
| [ ] |
Positively phototropic but negatively geotropic |
| [ ] |
Negatively phototropic and negatively geotropic |
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5.
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Which of these combinations describes the tropisms of roots correctly? |
|
| [ ] |
Positively phototropic and positively geotropic |
| [ ] |
Negatively phototropic but positively geotropic |
| [ ] |
Positively phototropic but negatively geotropic |
| [ ] |
Negatively phototropic and negatively geotropic |
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6.
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What are the three main external stimuli to which plants respond? |
|
| [ ] |
Light, water, sound |
| [ ] |
Water, gravity, touch |
| [ ] |
Gravity, heat, light |
| [ ] |
Light, water, gravity |
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7.
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The ripening of fruit is a response to hormones. Certain hormones can be sprayed on plants to make the fruit all ripen at the same time. Which of the following is not a disadvantage with this? |
|
| [ ] |
There will be too much to pick all at once |
| [ ] |
It is easier for commercial fruit growing companies to pick fruit in one go |
| [ ] |
The fruits ripened in this way do not all have the same color |
| [ ] |
The fruits will continue to ripen after they have ben picked |
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8.
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If a plant pot with a seedling is placed on its side with a bright light at 45 degrees to the pot and higher, what will happen? |
|
| [ ] |
The whole plant will continue to grow horizontally but the leaves will be at 45 degrees to the stem |
| [ ] |
The stem will grow downwards and the roots will continue to grow horizontally |
| [ ] |
The stem will grow upwards at 90 degrees and the roots will continue to grow horizontally |
| [ ] |
The stem will grow upwards at about 45 degrees and the roots will grow downwards |
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9.
|
What happens in a plant shoot that makes it grow towards the light? |
|
| [ ] |
The warmth of the light attracts the hormone auxin so the shoot bends in the direction of the light |
| [ ] |
The auxin on the lit side of the plant shoot is destroyed by the light, making that side grow less than the other |
| [ ] |
There is less auxin on the shaded part of the plant shoot so that side grows more |
| [ ] |
The cells on the light side of the shoot shrivel up so that side gets shorter and the shoot bends over towards the light |
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10.
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Some students did an experiment on plant shoots. They cut off the tips of the shoots on 10 seedlings, covered the tips of 10 more with kitchen foil and left 10 seedlings as they were as a control. The seedlings were then placed in a large box with a hole cut in one side. Which of the following would describe their results? |
|
| [ ] |
All the seedlings died |
| [ ] |
The seedlings that had their tips covered with kitchen foil died; the others grew normally |
| [ ] |
The seedlings that had their tips cut off stayed the same; the ones covered in kitchen foil bent away from the hole in the side of the box and the other seedlings grew normally. |
| [ ] |
The seedlings that had their tips cut off stayed the same; the ones covered in kitchen foil grew taller than the others and stayed straight; the other seedlings grew towards the hole in the side of the box |
|
|
|
1.
|
Phototropism is caused by a hormone. What is phototropism? |
|
| [ ] |
When old photographs are ruined by bacteria |
| [ ] |
Skin darkening in response to sunlight |
| [ ] |
Plant leaves losing their green color when there isn't much sunlight |
| [x] |
Plants growing towards the light |
|
|
|
2.
|
Gravitropism (geotropism) is also caused by a hormone. What is gravitropism? |
|
| [x] |
Roots growing downwards, shoots growing upwards |
| [ ] |
Shoots growing upwards only |
| [ ] |
A plant disease |
| [ ] |
Plants growing away from the light |
|
|
|
3.
|
Which of the following options applies to the plant hormones, auxins? |
|
| [ ] |
Auxins are found only in the leaf cells of plants |
| [ ] |
Auxins respond only to light |
| [x] |
Auxins are made in the growing tips and spread throughout the plant |
| [ ] |
Auxins respond only to gravity |
|
|
|
4.
|
Which of these combinations describes the tropisms of shoots correctly? |
|
| [ ] |
Positively phototropic and positively geotropic |
| [ ] |
Negatively phototropic but positively geotropic |
| [x] |
Positively phototropic but negatively geotropic |
| [ ] |
Negatively phototropic and negatively geotropic |
|
|
|
5.
|
Which of these combinations describes the tropisms of roots correctly? |
|
| [ ] |
Positively phototropic and positively geotropic |
| [x] |
Negatively phototropic but positively geotropic |
| [ ] |
Positively phototropic but negatively geotropic |
| [ ] |
Negatively phototropic and negatively geotropic |
|
|
|
6.
|
What are the three main external stimuli to which plants respond? |
|
| [ ] |
Light, water, sound |
| [ ] |
Water, gravity, touch |
| [ ] |
Gravity, heat, light |
| [x] |
Light, water, gravity |
|
|
|
7.
|
The ripening of fruit is a response to hormones. Certain hormones can be sprayed on plants to make the fruit all ripen at the same time. Which of the following is not a disadvantage with this? |
|
| [ ] |
There will be too much to pick all at once |
| [x] |
It is easier for commercial fruit growing companies to pick fruit in one go |
| [ ] |
The fruits ripened in this way do not all have the same color |
| [ ] |
The fruits will continue to ripen after they have ben picked |
|
|
|
8.
|
If a plant pot with a seedling is placed on its side with a bright light at 45 degrees to the pot and higher, what will happen? |
|
| [ ] |
The whole plant will continue to grow horizontally but the leaves will be at 45 degrees to the stem |
| [ ] |
The stem will grow downwards and the roots will continue to grow horizontally |
| [ ] |
The stem will grow upwards at 90 degrees and the roots will continue to grow horizontally |
| [x] |
The stem will grow upwards at about 45 degrees and the roots will grow downwards |
|
|
|
9.
|
What happens in a plant shoot that makes it grow towards the light? |
|
| [ ] |
The warmth of the light attracts the hormone auxin so the shoot bends in the direction of the light |
| [x] |
The auxin on the lit side of the plant shoot is destroyed by the light, making that side grow less than the other |
| [ ] |
There is less auxin on the shaded part of the plant shoot so that side grows more |
| [ ] |
The cells on the light side of the shoot shrivel up so that side gets shorter and the shoot bends over towards the light |
|
|
|
10.
|
Some students did an experiment on plant shoots. They cut off the tips of the shoots on 10 seedlings, covered the tips of 10 more with kitchen foil and left 10 seedlings as they were as a control. The seedlings were then placed in a large box with a hole cut in one side. Which of the following would describe their results? |
|
| [ ] |
All the seedlings died |
| [ ] |
The seedlings that had their tips covered with kitchen foil died; the others grew normally |
| [ ] |
The seedlings that had their tips cut off stayed the same; the ones covered in kitchen foil bent away from the hole in the side of the box and the other seedlings grew normally. |
| [x] |
The seedlings that had their tips cut off stayed the same; the ones covered in kitchen foil grew taller than the others and stayed straight; the other seedlings grew towards the hole in the side of the box |
|
|
