Question 1

Stomate closure in darkened environment,at time zero,with air (0.03% CO₂)or CO₂-free airflow through leaf.(Note: A decrease in conductance indicates inactivation of the proton pump.)

Accepted Answer

This experiment supports only Hypothesis II, which states that proton pumping is necessary for stomatal opening. The fact that there was a decrease in conductance (inactivation of the proton pump) indicates that the lack of COS-free airflow inhibited the proton pump, leading to stomate closure. This experiment does not provide any evidence supporting Hypothesis I, which postulates that elevated levels of COS stimulate stomatal opening.

Question 2

Stomates do not open when exposed to a narrow band of green light.

Accepted Answer

The answer of Stomates do not open when exposed to...

Question 3

Stomates allows carbon dioxide into the leaf and water out of the leaf under normal environmental conditions.

Accepted Answer

Stomates are tiny pores present on the surface of leaves, through which gases such as carbon dioxide and oxygen can diffuse. Stomates also regulate the water content in the leaf by allowing water vapor to evaporate from the leaf into the surrounding air. Therefore, under normal environmental conditions, stomates allow carbon dioxide into the leaf and water out of the leaf.

Question 4

The transpiration rate in plants is increased by

Accepted Answer

All of these choices can increase the rate of transpiration in plants. Wind increases the rate of transpiration by removing the humid air surrounding leaves and replacing it with drier air. Elevated temperature and increased sunlight intensity also increase the rate of transpiration by increasing the rate of evaporation from the leaves.

Question 5

Rhizobium bacteria live in root nodules and

Accepted Answer

Rhizobium bacteria form a symbiotic relationship with legumes and fix atmospheric nitrogen to ammonia which is used by the plant to build organic compounds.

Question 6

Which statement is NOT true about stomata?

Accepted Answer

The statement "The blue light component of sunlight is a signal that can cause stomata to close" is not true. Instead, blue light is a signal that can cause stomata to open.

Question 7

Air with varying amounts of CO₂,within the ranges found in nature,is forced across leaf surfaces and into sub-stomatal cavities; this produces stomatal closure.

Accepted Answer

The statement describes a scenario where CO2 levels affect stomatal closure, which aligns with Hypothesis II, suggesting that CO2 concentration directly influences stomatal behavior.

Question 8

Water moves into the guard cells in response to the movement of K⁺ into the guard cells.

Accepted Answer

K⁺, also known as potassium ions, enter the guard cells causing an increase in osmotic pressure, which results in water moving into the guard cells through osmosis.

Question 9

To secure genuine maple syrup,maple tree trunks are "tapped" with metal spigots that interrupt the flow of sap in late winter prior to spring budding.Which of the following would be true of this process?

Accepted Answer

All the statements are true regarding the process of tapping maple trees for syrup. A) The sucrose in the sap originates from photosynthesis in the leaves. B) The sap does flow out with some pressure, although it's primarily from the xylem, not the phloem. C) The water in the sap indeed comes from soil water absorbed by the tree's roots. D) Only a small part of the tree is tapped to avoid harming the tree, as taking too much sap from a large area could damage or kill it.

Question 10

Which force pushes water into the xylem as osmosis moves water into the root?

Accepted Answer

Root pressure is the force created by the active transport of ions into the root xylem, resulting in a higher solute concentration in the xylem than in the surrounding soil. This generates pressure that pushes water up into the xylem. However, this force is relatively weak and can only push water up a short distance, usually only a few meters at most. The main force that drives water movement in plants is transpiration, the loss of water vapor through the stomata of leaves, which generates negative pressure (or tension) in the xylem, pulling water up from the roots to replace the lost water.

Question 11

Stomate rhythm in wheat under continuous light at 25^$\circ$C.

Accepted Answer

The answer of Stomate rhythm in wheat under continuous light...

Question 12

Sieve tube members are connected by

Accepted Answer

Sieve tube members are specialized cells in plants that form a part of the phloem tissue. They are connected to each other via plasmodesmata, small channels that traverse cell walls, allowing for the flow of nutrients and other substances. Tight junctions are found in animal cells, and are not relevant here. Companion cells are a type of specialized plant cell that aid in the transport of substances in the phloem, but they do not directly connect sieve tubes. Tracheids are a type of water-conducting cell found in xylem tissue, which is separate from phloem.

Question 13

Which of the following hypothesis is supported by the fact that cells of wilting leaves produce abscisic acid,which causes guard cells to close?

Accepted Answer

The answer of Which of the following hypothesis is supported...

Question 14

All of the following statements about the cohesion-tension model are true EXCEPT

Accepted Answer

The cohesion-tension model is a model of how water and minerals are transported in xylem, dependent on the cohesive and adhesive properties of water. Tension created by transpiration in the leaves pulls water along the xylem from the root hairs to the leaves, not the phloem. Option A is true since there is no expenditure of energy in this process.

Question 15

Which hypothesis is supported by the fact that stomates open when exposed to white light,a mixture of all colors of light?

Accepted Answer

Hypothesis I suggests that blue light is necessary for stomatal opening, while Hypothesis II suggests that any light will stimulate stomatal opening. The observation that stomates open when exposed to white light, which contains all colors of light, supports Hypothesis II. It does not provide evidence to support Hypothesis I, as blue light is only one component of white light.

Question 16

Stomate opening after illumination following eight hours in darkness: plant is Xanthium pennsylvanicum.

Accepted Answer

The observation of stomate opening after illumination following eight hours in darkness supports both Hypothesis I (that stomates open in response to light) and Hypothesis II (that stomates are closed in darkness).

Question 17

Which statement is NOT true about the pressure-flow model of phloem transport?

Accepted Answer

The pressure-flow model does not involve water being actively transported into phloem. Instead, water moves passively into the phloem due to the concentration gradient created by the active transport of sugar from source areas.

Question 18

Researchers discover that guard cells of the lady slipper orchid lack chloroplasts; yet the guard cells regularly open and close.

Accepted Answer

This supports only Hypothesis II because it suggests that guard cell function is not dependent on the presence of chloroplasts, contradicting Hypothesis I. However, it supports Hypothesis II by suggesting that other mechanisms, such as ion pumping, may be involved in regulating the opening and closing of guard cells.

Question 19

In the pressure-flow model of phloem transport,the sink is normally

Accepted Answer

In the pressure-flow model of phloem transport, the sink is the region where the sugars are actively utilized or stored, such as the roots, developing fruits, or growing shoot tips. Therefore, option B, the roots, would be the best choice.

Question 20

How did the scientist Marcello Malpighi,in 1679,discover the role of phloem?

Accepted Answer

Malpighi discovered the role of phloem by observing the effects of girdling a tree, which involves removing a ring of bark. This interrupts the phloem and shows its role in transporting nutrients.

Quiz 25: Flowering Plants: Nutrition and Transport

Stomate closure in darkened environment,at time zero,with air (0.03% CO₂) or CO₂-free airflow through leaf.(Note: A decrease in conductance indicates inactivation of the proton pump.)

Stomates do not open when exposed to a narrow band of green light.

Stomates allows carbon dioxide into the leaf and water out of the leaf under normal environmental conditions.

The transpiration rate in plants is increased by

Rhizobium bacteria live in root nodules and

Which statement is NOT true about stomata?

Air with varying amounts of CO₂,within the ranges found in nature,is forced across leaf surfaces and into sub-stomatal cavities; this produces stomatal closure.

Water moves into the guard cells in response to the movement of K⁺ into the guard cells.

To secure genuine maple syrup,maple tree trunks are "tapped" with metal spigots that interrupt the flow of sap in late winter prior to spring budding.Which of the following would be true of this process?

Which force pushes water into the xylem as osmosis moves water into the root?

Stomate rhythm in wheat under continuous light at 25^$\circ$C. $Stomate rhythm in wheat under continuous light at 25<sup> \circ </sup>C. A) Supports both Hypothesis I and II. B) Supports only Hypothesis I. C) Supports only Hypothesis II. D) Supports neither hypothesis.$

Sieve tube members are connected by

Which of the following hypothesis is supported by the fact that cells of wilting leaves produce abscisic acid,which causes guard cells to close?

All of the following statements about the cohesion-tension model are true EXCEPT

Which hypothesis is supported by the fact that stomates open when exposed to white light,a mixture of all colors of light?

Stomate opening after illumination following eight hours in darkness: plant is Xanthium pennsylvanicum.

Which statement is NOT true about the pressure-flow model of phloem transport?

Researchers discover that guard cells of the lady slipper orchid lack chloroplasts; yet the guard cells regularly open and close.

In the pressure-flow model of phloem transport,the sink is normally

How did the scientist Marcello Malpighi,in 1679,discover the role of phloem?

Quiz 25: Flowering Plants: Nutrition and Transport

Stomate closure in darkened environment,at time zero,with air (0.03% CO2) or CO2-free airflow through leaf.(Note: A decrease in conductance indicates inactivation of the proton pump.)

Stomates do not open when exposed to a narrow band of green light.

Stomates allows carbon dioxide into the leaf and water out of the leaf under normal environmental conditions.

The transpiration rate in plants is increased by

Rhizobium bacteria live in root nodules and

Which statement is NOT true about stomata?

Air with varying amounts of CO2,within the ranges found in nature,is forced across leaf surfaces and into sub-stomatal cavities; this produces stomatal closure.

Water moves into the guard cells in response to the movement of K+ into the guard cells.

To secure genuine maple syrup,maple tree trunks are "tapped" with metal spigots that interrupt the flow of sap in late winter prior to spring budding.Which of the following would be true of this process?

Which force pushes water into the xylem as osmosis moves water into the root?

Stomate rhythm in wheat under continuous light at 25 ∘\circ∘ C.

Sieve tube members are connected by

Which of the following hypothesis is supported by the fact that cells of wilting leaves produce abscisic acid,which causes guard cells to close?

All of the following statements about the cohesion-tension model are true EXCEPT

Which hypothesis is supported by the fact that stomates open when exposed to white light,a mixture of all colors of light?

Stomate opening after illumination following eight hours in darkness: plant is Xanthium pennsylvanicum.

Which statement is NOT true about the pressure-flow model of phloem transport?

Researchers discover that guard cells of the lady slipper orchid lack chloroplasts; yet the guard cells regularly open and close.

In the pressure-flow model of phloem transport,the sink is normally

How did the scientist Marcello Malpighi,in 1679,discover the role of phloem?

Stomate closure in darkened environment,at time zero,with air (0.03% CO₂) or CO₂-free airflow through leaf.(Note: A decrease in conductance indicates inactivation of the proton pump.)

Air with varying amounts of CO₂,within the ranges found in nature,is forced across leaf surfaces and into sub-stomatal cavities; this produces stomatal closure.

Water moves into the guard cells in response to the movement of K⁺ into the guard cells.

Stomate rhythm in wheat under continuous light at 25^$\circ$C. $Stomate rhythm in wheat under continuous light at 25<sup> \circ </sup>C. A) Supports both Hypothesis I and II. B) Supports only Hypothesis I. C) Supports only Hypothesis II. D) Supports neither hypothesis.$