Question 1

A newly bred plant that takes up 100 times the normal amount of cadmium from soil is most likely to be useful for

Accepted Answer

A plant that takes up 100 times the normal amount of cadmium from soil is likely useful in phytoremediation, which is the use of plants to clean up polluted soil. Cadmium is a toxic heavy metal that can accumulate in soil and cause harm to both plants and animals. The newly bred plant would be able to absorb a large amount of cadmium from contaminated soil, thereby reducing the concentration of the metal in the soil and making it less toxic.

Question 2

If plants that absorb 50 times the normal amount of soil manganese are not susceptible to a particular fungal blight, the best conclusion is that this fungus is unable to infect plants that _______ manganese.

Accepted Answer

The passage states that plants that absorb 50 times the normal amount of soil manganese are not susceptible to the fungal blight, suggesting that the plants' ability to hyperaccumulate manganese is related to their resistance to the fungus. Therefore, the best choice is B, which describes plants that hyperaccumulate manganese. The other choices do not provide a clear connection between manganese absorption and fungal resistance.

Question 3

Cropland soils in arid environments often become infertile due to increases in the concentration of _______ after too many cycles of irrigation and evaporation.

Accepted Answer

Irrigation in arid environments can lead to the buildup of salt in the soil due to evaporation, which can eventually render the soil infertile. Nitrate buildup can also occur, but salt buildup is the more common issue in arid croplands. The other options are not relevant to the process of soil infertility in arid croplands.

Question 4

Canavanine is a secondary metabolite used in a plant's defense against _______.

Accepted Answer

The answer of Canavanine is a secondary metabolite used in...

Question 5

Chaperonins are especially important in plants subjected to

Accepted Answer

Chaperonins are primarily involved in protein folding and stabilization. High temperatures can denature proteins, making proper folding and stabilization impossible. Therefore, chaperonins are essential in helping plants cope with high temperatures.

Question 6

Which element is not a heavy metal?

Accepted Answer

Sodium is not a heavy metal. Heavy metals are typically defined as those with a density exceeding 5 g/cm³, and sodium (at room temperature and pressure) has a density of only 0.97 g/cm³. Cadmium, zinc, nickel, and arsenic are all heavy metals.

Question 7

A scientist looking for soil high in cadmium would most likely be successful by locating plants that _______ cadmium.

Accepted Answer

Plants that hyperaccumulate cadmium are able to absorb and store high levels of cadmium in their tissues. Therefore, a scientist looking for soil high in cadmium would have the best success by locating these types of plants. Options A, B, and E are unlikely to lead to soil high in cadmium as they involve plants actively expelling, secreting, or avoiding cadmium. Option C, chelating cadmium, could potentially lead to higher concentrations of cadmium in plants, but this would still not be as effective as locating plants that hyperaccumulate cadmium.

Question 8

Many induced plant defenses are triggered by infection or herbivory.But plants also have _______ defenses already in place before such damage occurs.

Accepted Answer

The answer of Many induced plant defenses are triggered by...

Question 9

The use of hyperaccumulating plants to clean up contaminated soils is called

Accepted Answer

The use of hyperaccumulating plants to clean up contaminated soils is called phytoremediation. Soil washing involves physically removing contaminants from soil, superfunding is a government funding program for cleaning up hazardous waste sites, replenishing involves adding nutrients to soil, and leaching involves removing nutrients from soil.

Question 10

Which adaptation would not be useful for a plant growing with its roots submerged in salt water?

Accepted Answer

Reduced activity of transporters that move NaCl into the vacuole would not be useful for a plant in salt water because it would limit the plant's ability to sequester salt away from the cytoplasm, potentially leading to toxic levels of salt within the cells.

Question 11

There is currently an urgent need for the development of _______ strains that are resistant to a fungal infection called rust.

Accepted Answer

The answer of There is currently an urgent need for...

Question 12

Systemic acquired resistance can be very specific (for example, protecting a plant against RNA viruses).It can also be much more general, for example, involving _______, which induces genes to produce various pathogen fighting proteins and can even be modified to carry an airborne warning signal to other plants.

Accepted Answer

The answer of Systemic acquired resistance can be very specific...

Question 13

Halophytes that grow in coastal ocean water commonly have high ion concentrations in

Accepted Answer

Halophytes that grow in coastal ocean water have adapted to the high salt content by accumulating ions in their leaf cell vacuoles. This helps to maintain a lower concentration of salt in the cytoplasm, which would otherwise be detrimental to the plant's metabolic processes.

Question 14

Which statement about heavy metal tolerance in plants is false?

Accepted Answer

This statement is false. Most heavy metal-tolerant plants actually accumulate heavy metals in their tissues, but they have mechanisms to prevent those metals from damaging their cells. Some plants may also excrete excess heavy metals, but exclusion is not the primary method of tolerance.

Question 15

Heavy irrigation of crops in arid environments is most likely to result in

Accepted Answer

Heavy irrigation of crops in arid environments can result in the accumulation of salt in the soil. As water evaporates in arid environments, the salt in the soil becomes concentrated. If the irrigation water contains salt, the salt concentration in the soil can become too high for crops to grow, leading to decreased yields and even crop failure. This process is known as salinization.

Question 16

Plants that grow in saline environments often secrete salt through

Accepted Answer

Plants that grow in saline environments often have specialized structures called salt glands that secrete excess salt. This helps them survive in areas with high salt concentration.

Question 17

Which label refers to plants having adaptations for dealing with excess salt?

Accepted Answer

Halophytes are plants that have adapted to survive in high salinity environments. They have special adaptations such as the ability to excrete salt, store salt in vacuoles, and have specialized root systems to take up water and exclude salt. Xerophytes are plants adapted to arid environments, hydrophytes are plants adapted to aquatic environments, succulents are plants adapted to store water, and hypersensitive species are plants that can exhibit a exaggerated response to biotic or abiotic stressors.

Question 18

Halophytes

Accepted Answer

Halophytes are plants that are adapted to grow in highly saline environments. As a result, they have evolved to have lower water potentials compared to other plants, which helps them to extract water from their salty surroundings.

Answer: A 
 Halophytes may have higher levels of abscisic acid (ABA) in their vacuoles, which helps them to regulate water uptake and maintain water balance under salt stress.

Answer: D 
 Halophytes often have lower root-to-shoot ratios compared to other plants, as they allocate more resources towards shoot growth for maximizing photosynthesis in harsh environments.

Overall, options C and E are incorrect because they both describe extremes that are not representative of all halophytes.

Question 19

Which property is least likely to be found in a hyperaccumulator?

Accepted Answer

Hyperaccumulators store metal ions in vacuoles, not in the cytoplasm of leaf cells. The other properties listed (A, C, D, E) are commonly found in hyperaccumulators.

Question 20

Hyperaccumulated metals are most likely to be stored in

Accepted Answer

Vacuoles are responsible for storing various substances, including excess or toxic nutrients, such as hyperaccumulated metals, in plant cells. Therefore, hyperaccumulated metals are most likely to be stored in vacuoles.

Quiz 38: Plant Responses to Environmental Challenges