All AP Biology Resources
Example Questions
Example Question #2 : Plant Functions
How do plants transport water against gravity?
Aquaporins
Passive diffusion
Capillary action
Active transport
Water pumps
Capillary action
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?
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.
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 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 cohesion of water molecules pulls more molecules into the roots and upward.
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 #3 : Plant Functions
How would you expect plants in deserts to differ from those in rainforests?
Desert plants would have no woody bark due to lack of herbivores
They would have different water retention and utilization strategies
Desert plants would have more seeds than plants in the rainforests
Desert plants would have larger spines
They would have different water retention and utilization strategies
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 __________.
diploid . . . seed
diploid . . . endosperm
haploid . . . fruit
haploid . . . endosperm
diploid . . . fruit
diploid . . . endosperm
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 #1 : Plant Functions
Which of the following is true of the sporophyte of a plant?
It produce zygotes, which grow into sporophytes
It produce seeds, which grow into gametophytes
It produces spores, which grow into gametophytes
It produce zygotes, which grow into gametophytes
None of these
It produces spores, which grow into gametophytes
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 #2 : Plant Functions
Pollination is a process in which pollen is transferred between which of the following two structures of an angiosperm?
From the stamen to the ovary
From the pollen tube to the ovary
From the anther to the stigma
From the stigma to the anther
From the anther to the stigma
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?
All of these
Wind
Water
Another organism
All of these
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 #3 : Plant Functions
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?
Niether; diecious plants do not produce pollen
Only female gingko plants
Both male and female gingko plants
All male gingko plants and some female gingko plants
Only male gingko plants
Only male gingko plants
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 #72 : Plant Biology
Which of the following techniques could be used to determine if a species of plant requires potassium?
Use autoradiography to find potassium in leaf tissues
Analyze root contents for potassium
Measure how fast radioactive potassium enters the plant
Measure the amount of potassium in a sample of plants
Grow a sample of plants in a potassium-rich environment and another sample in a potassium-deprived environment
Grow a sample of plants in a potassium-rich environment and another sample in a potassium-deprived environment
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.
Example Question #11 : Plant Functions
Which of the following nutrients is most likely to be abundant in soil?
Carbon
Phosphorus
Oxygen
Hydrogen
Iron
Iron
There are many necessary nutrients involved in plant development. The nutrients are used in different quantities and are grouped accordingly in two categories: micronutrients and macronutrients. Micronutrients, such as iron, are important to healthy plant growth but are used in small quantities. Macronutrients, such as oxygen, carbon, hydrogen, and phosphorus, are also used for healthy plant growth but are used in the greatest quantities.
As a result, the macronutrients are more likely to become depleted in the soil as the plant absorbs them, while the micronutrients remain abundant. Iron, as a micronutrient, is more likely to be abundant in soil than any of the macronutrients.
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