Physiology Practice Questions Part 2
1. After fertilization, the _____ develops into a seed and the _____ develops into a fruit.
(a) ovule . . . ovary(b) pollen grain . . . ovule
(c) ovary . . . ovule
(d) egg . . . ovule
2. Plants growing in harsh environments such as deserts, sand dunes, and arctic tundra often reproduce vegetatively. This is because
(a) there are few animals available to pollinate them.(b) they are members of plant families that only reproduce asexually.
(c) fruits would freeze or dry out in these environments.
(d) vegetative reproduction is not as risky as making seeds.
3. In contrast to animals, plants exhibit ______ and _____.
(a) determinate growth . . . persistent morphogenesis(b) indeterminate growth . . . are not capable of morphogenesis throughout their
lifespan
(c) indeterminate growth . . . persistent morphogenesis
(d) growth . . . morphogenesis
4. Which of the following seedlings will probably bend toward the light?
(a) tip covered with a cap made of black plastic(b) tip separated from base by a gelatin block
(c) tip separated from base by aluminum foil
(d) tip cut off and place a block of agar over half of the cut portion; the side with the
agar block will bend towards the light
5. In shoots, branching is inhibited by _____ from the tip of a growing shoot, but this effect is countered by _____ from the roots.
(a) cytokinins . . . auxins(b) gibberellins . . . ethylene
(c) auxins . . . cytokinins
(d) gibberellins . . . abscisic acid
6. As leaf lettuce matures, the basal edible leaves suddenly send up a tall flowering shoot. After the plant bolts like this, it no longer produces broad, tasty leaves. Suppose you wanted to prevent bolting so that you could harvest lettuce longer. You might look for some way to interfere with the effects of
(a) abscisic acid. (b) gibberellins.(c) cytokinins. (d) ethylene.
7. Seeds of many desert plants will not germinate until a heavy rain washes away their
(a) phytochrome. (b) abscisic acid.(c) gibberellins. (d) auxins.
8. The abscission layer
(a) causes a shoot to bend toward light.(b) secretes cytokinin.
(c) is the location of the biological clock in a plant.
(d) is where a leaf separates from a stem.
9. When a plant structure such as a leaf is injured, it produces ______, which may cause the part to age and drop off.
(a) cytokinins (b) ethylene(c) auxins (d) abscisic acid
10. Once a flower is pollinated, changes occur that make it less attractive to insects. Its petals, for example, shrivel and fall off. Pollination must
(a) increase the output of cytokinins in the flower.(b) block the flow of auxins from the roots.(c) trigger the release of ethylene in the flower.
(d) increase the formation of phytochrome, which sets the biological clock.
11. In the autumn, the amount of ____ increases and the amount of ____ decreases in fruit and leaf stalks, causing a plant to drop fruit and leaves.
(a) ethylene . . . auxin(b) gibberellin . . . abscisic acid
(c) cytokinin . . . abscisic acid
(d) auxin . . . ethylene
12. Plant hormones act by affecting the activities of
(a) genes. (b) genes and enzymes.(c) enzymes. (d) genes, membranes, and enzymes.
13. _______ appear to be responsible for gravitropism.
(a) Statoliths (b) phytochromes(c) Gibberellins (d) Cytokinins
14. A rapid loss of water in specialized cells in the sensitive plant Mimosa pudica causes
(a) the plant to bend toward light.(b) stomatal opening so photosynthesis can begin.
(c) stress that results in the production of PR proteins.
(d) leaves to droop.
15. A biological cycle with a period of about 24 hours is called
(a) thigmotropism. (b) a circadian rhythm.(c) photoperiod. (d) abscission.
16. An Rajasthani hunter was worried about being attacked by grizzly tigers, so he left the lights in his cabin on all the time. Plants near the cabin flowered a month early. Which of the following best explains this?
(a) They must have been long-night plants.(b) The lights must have emitted far-red light.
(c) They must have been long-day plants.
(d) They must have been short-day plants.
17. Most plants flower when
(a) the soil reaches a certain temperature.(b) the days are of right length.
(c) a certain number of days have passed since they last flowered.
(d) the nights are of right length.
18. A certain short-day plant flowers when days are less than 12 hours long. Which of the following would cause it to flower?
(a) a 9-hour night and 15-hour day with 1 minute of darkness after 7 hour.(b) an 8-hr day and 16-hour night with a flash of white light after 8 hr.
(c) a 13-hour night and 11-hour day with 1 minute of darkness after 6 hr.
(d) a 12-hour day and 12-hour night with a flash of red light after 6 hr.
19. A chemical change in a substance called phytochrome
(a) causes a plant to bend toward light.(b) triggers fruit drop.
(c) enables a plant to respond to the presence of light.
(d) is responsible for gravitropism.
20. Which of the following tissues produces voluntary body movements?
(a) smooth muscle (b) simple cuboidal epithelium(c) cardiac muscle (d) skeletal muscle
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