AP Biology : Plant Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #61 : Plant Biology

Which of the following is not true regarding the cork cambium?

Possible Answers:

It is the source of secondary epidermis growth 

It is a type of secondary meristem 

It is located in the periderm

It is the source of secondary xylem and phloem growth

Correct answer:

It is the source of secondary xylem and phloem growth

Explanation:

The cork cambium is a type of secondary meristem tissue found in the periderm. Cork cambium controls lateral growth; specifically, it is the source of secondary epidermis growth.

Example Question #62 : Plant Biology

Which of the following best describes what annual growth rings in trees represent?

Possible Answers:

New vascular cambium growth

New primary xylem growth

New cork cambium growth

New primary phloem growth

Correct answer:

New vascular cambium growth

Explanation:

Cutting into the trunk of a tree to create a horizontal cross section reveals rings, called annual growth rings. These rings show new vascular cambium growth over the course of a year. Differences in growth speed change the size of the growth rings.

Example Question #63 : Plant Biology

Which of the following best describes the location of the receptacle on an angiosperm?

Possible Answers:

Inside the ovary 

At the top of the ovary 

At the top of the stem 

Attached to the anther

Correct answer:

At the top of the stem 

Explanation:

The receptacle is the part of an angiosperm out of which the flower grows; thus, the receptacle is at the top of the stem.

Example Question #64 : Plant Biology

Which of the following is contained in the carpel?

Possible Answers:

Stamen

Flower

Ovules

Anther

Correct answer:

Ovules

Explanation:

The carpel is a part of the female angiosperm reproductive system. The carpel includes the ovary, ovules, style, and stigma. Flowers may have several carpels clustered into a pistil.

Example Question #65 : Plant Biology

Which of the following is produced by stamens in angiosperms?

Possible Answers:

Pollen

Seeds

Sap

Ovules

Correct answer:

Pollen

Explanation:

Stamens are a part of the male reproductive system in angiosperms. Stamens have a filament and an anther, which is attached to the top of the filament. Anthers produce pollen through the process of meiosis.

Example Question #66 : Plant Biology

Which of the following best describes the function of the sepal in angiosperms?

Possible Answers:

Attracts pollinators

Protection of the flower when it is still in the bud

Production of pollen

Houses ovules awaiting fertilization

Correct answer:

Protection of the flower when it is still in the bud

Explanation:

The sepal is a protective structure in angiosperms. When the flower is still in the bud, the sepal offers protection and later supports the bloom.

Example Question #5 : Plant Structures

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

Possible Answers:

Vascular tissue

Vascular cambium

Sclerenchyma

Ground tissue

Dermal tissue

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 #1 : Understanding Water Transport

How do plants transport water against gravity?

Possible Answers:

Active transport

Capillary action

Aquaporins

Water pumps

Passive diffusion

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 #2 : Understanding Water Transport

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 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 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 #67 : Plant Biology

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

Possible Answers:

Desert plants would have larger spines

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

Desert plants would have more seeds than plants in the rainforests

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. 

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