AP Biology : Plant Functions

Study concepts, example questions & explanations for AP Biology

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1 3 4

Example Question #1 : Understanding Water And Nutrient Transport

Which plant tissue system is similar to the human circulatory system?

Possible Answers:

Vascular cambium

Ground tissue

Vascular tissue

Dermal tissue

Sclerenchyma

Correct answer:

Vascular tissue

Explanation:

A plant's vascular tissues transport nutrients throughout the plant, just as the circulatory system transports nutrients throughout human bodies. While blood is the primary solvent for nutrients in humans, water is the primary solvent for nutrients in plants. Animals, however, use blood pressure to propel nutrients throughout the body while plants use gravity and the cohesive properties of water to transport nutrients.

The two primary types of plant vascular tissue are xylem, which transports water, and phloem, which transports organic molecules like glucose.

Example Question #2 : Plant Functions

How do plants transport water against gravity?

Possible Answers:

Water pumps

Capillary action

Passive diffusion

Aquaporins

Active transport

Correct answer:

Capillary action

Explanation:

Plants do not have the ability to actively transport water to their respective cells. Instead, water undergoes capillary action, which allows it to flow upward against gravity. When the water is located in a very narrow chamber, such as the xylem of a plant, it creates intermolecular interactions with the walls of the chamber. These interactions allow small amounts of the water to "climb" the chamber walls. Due to the cohesion of water, whereby it is attracted to itself, more water molecules follow the "climbing" adhesion molecules. This subsequently allows the adhering molecules to climb higher, and the joint interaction of the adhesion and cohesion eventually allow the water to reach the topmost region of the plant (the leaves). Water is then released from the stomata, furthering the pull of water to the region of low pressure.

Example Question #1 : Plant Biology

Which of the following best describes how water is transported from the roots of a tree to the tallest branches?

Possible Answers:

Transpiration from the tree's leaves causes tension (negative pressure) to increase in the tree's xylem. As water exits the leaves, the cohesion of water molecules pulls more molecules into the roots and upward.

Transpiration from the tree's leaves causes tension (negative pressure) to increase in the tree's phloem. As water exits the leaves, the adhesion of water molecules pulls more molecules into the roots and upward.

Transpiration from the tree's leaves causes tension (negative pressure) to increase in the tree's phloem. As water exits the leaves, the cohesion of water molecules pulls more molecules into the roots and upward.

Transpiration from the tree's leaves causes tension (negative pressure) to increase in the tree's xylem. As water exits the leaves, the adhesion of water molecules pulls more molecules into the roots and upward.

Correct answer:

Transpiration from the tree's leaves causes tension (negative pressure) to increase in the tree's xylem. As water exits the leaves, the cohesion of water molecules pulls more molecules into the roots and upward.

Explanation:

One of water's most distinctive properties is cohesion—that is, the tendency of water molecules to "stick" to one another. In plants, this cohesion results in columns of water that stretch through the plant's xylem (the vascular tissue responsible for transport of water), from the roots all the way to the leaves. During transpiration, water evaporates from plants' leaves. Because of the cohesion of water, whenever water evaporates, more molecules are "pulled" into the roots to maintain the column of water. This is the transpirational pull-cohesion tension theory.

In contrast, adhesion is the tendency of water molecules to "stick" to other substances, such as the walls of a glass. Adhesion is responsible for the curved meniscus of water in a graduated cylinder. Phloem is responsible for sugar and carbohydrate transport in plants, while xylem transports water.

Example Question #1171 : Ap Biology

How would you expect plants in deserts to differ from those in rainforests?

Possible Answers:

Desert plants would have more seeds than plants in the rainforests

Desert plants would have no woody bark due to lack of herbivores

Desert plants would have larger spines

They would have different water retention and utilization strategies

Correct answer:

They would have different water retention and utilization strategies

Explanation:

Desert plants would have different water retention and utilization strategies. They would likely use C4 or CAM photosynthesis. The C4 and CAM pathways are specific adaptations to arid conditions. They allow higher water retention, which is needed in the desert but not the rainforest. Since the main difference between these two environments is the abundance of water, even if the other options were true, they are minor differences in comparison to the need to utilize water differently. 

Example Question #21 : Plant Biology

Double fertilization in angiosperms results in a __________ zygote and a triploid __________.

Possible Answers:

diploid . . . endosperm

diploid . . . seed

diploid . . . fruit

haploid . . . fruit

haploid . . . endosperm

Correct answer:

diploid . . . endosperm

Explanation:

Double fertilization is the process by which two sperm cells are introduced to the ovule. One sperm () fertilizes the egg (), creating a zygote(). The other sperm combines with the two polar nuclei (), forming the endosperm () that will nourish the embryo.

Example Question #3 : Plant Functions

Which of the following is true of the sporophyte of a plant?

Possible Answers:

It produce seeds, which grow into gametophytes

It produce zygotes, which grow into sporophytes

It produces spores, which grow into gametophytes

It produce zygotes, which grow into gametophytes

None of these

Correct answer:

It produces spores, which grow into gametophytes

Explanation:

The sporophyte produces spores, which grow into gametophytes. The gametophyte produces both ovules and pollen, which unite to form a zygote. The zygote grows into the next sporophyte. The plant life cycle continues to alternate between these stages. In flowering plants, the gametophyte stage has been greatly reduced compared to the sporophyte stage.

Example Question #1 : Understanding Plant Reproduction

Pollination is a process in which pollen is transferred between which of the following two structures of an angiosperm?

Possible Answers:

From the stigma to the anther

From the stamen to the ovary 

From the pollen tube to the ovary 

From the anther to the stigma

Correct answer:

From the anther to the stigma

Explanation:

Pollination is the process in angiosperms through which pollen is transferred from the male anther to the female stigma. Pollination can be either abiotic (i.e. by the wind) or biotic (i.e. by an animal). This process precedes fertilization.

Example Question #1 : Plant Functions

Which of the following can be best described as a method of pollination?

Possible Answers:

All of these

Wind

Another organism

Water

Correct answer:

All of these

Explanation:

Pollination is defined as the transfer of pollen from the male anther to the female stigma of an angiosperm. There are abiotic and biotic methods of pollinations. Abiotic pollination includes wind and water while in biotic pollination another organism facilitates pollination.

Example Question #1 : Understanding Plant Reproduction

Diecious plants (such as Gingko biloba) have separate sexes rather than having both male and female parts on a single plant.

Given that ginkgo is diecious, which plants would you expect to produce pollen?

Possible Answers:

Only male gingko plants

Only female gingko plants

Both male and female gingko plants

All male gingko plants and some female gingko plants

Niether; diecious plants do not produce pollen

Correct answer:

Only male gingko plants

Explanation:

Pollen is the male part of the plant, and thus is only produced by male ginkgo plants. Females have ovules with a fleshy, fruit-like outer layer and rely on the males plants for pollination. (Ginkgo is a gymnosperm and thus technically not a flowering/fruit-producing plant.)

Example Question #1 : Plant Functions

Which of the following techniques could be used to determine if a species of plant requires potassium?

Possible Answers:

Use autoradiography to find potassium in leaf tissues

Analyze root contents for potassium

Grow a sample of plants in a potassium-rich environment and another sample in a potassium-deprived environment

Measure the amount of potassium in a sample of plants

Measure how fast radioactive potassium enters the plant

Correct answer:

Grow a sample of plants in a potassium-rich environment and another sample in a potassium-deprived environment

Explanation:

In hypothesis-based scientific inquiry, the experiment must have an experimental group and a control group. In this case, growing plants with potassium would be the experimental group and growing plants without potassium would be the control group. Maintaining all other experimental variables, this method would allow the researcher to determine whether the plant species requires potassium. If the plants in the potassium-deprived environment die, but the plants in the potassium-rich environment survive, we can conclude that potassium is necessary for this species to survive.

The presence of potassium in the plant, leaves, or roots does not indicate it is a required nutrient. This simply indicates that the plant is capable of absorbing potassium, but does not show a dependency on potassium. Also, the movement of potassium into the plant does not indicate it is a required nutrient.

← Previous 1 3 4
Learning Tools by Varsity Tutors