Biology

Plant Transport and Physiology

2,012 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice biology biology : an introduction introduction to organization of life signs of life what is living?

Stomata can be related to which of the following activity

  1. Locomotion

  2. Excretion

  3. Movement

  4. Reproduction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stomata are pores found on the surface ie. epidermis of the leaf. These are used for the exchange of gases and releasing water by the process of transpiration. In some plants, calcium salts are also excreted through these pores. So the correct option is B "excretion".

Multiple choice biology anatomy of flowering plants theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Heaping of earth around base of stem in Potato is meant for.

  1. Preventing exposure of roots

  2. Providing extra support to delicate stem

  3. Inducing development of more auxiliary shoots

  4. Making more water available
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heaping soil around the base of the potato stem, known as earthing up, encourages the development of more underground stems (stolons) from the axillary buds, which then swell to form tubers.

Multiple choice biology anatomy of flowering plants theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Choose the correct answers from the alternatives given.
Which of the following functions is not shared by both the root system and the shoot system of a plant?

  1. Absorb water

  2. Transport water

  3. Transport inorganic nutrients

  4. Transport organic nutrients
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The root system forms the underground system of the plant that absorbs water from the soil along with various organic and inorganic nutrients. It exerts the root pressure due to which the absorbed water is transported to the shoot system.

The shoot system forms the upper part of the plant part. It transports the absorbed water and nutrients to different plant parts.
Hence, the correct answer is 'Absorb water'.

Multiple choice biology anatomy of flowering plants theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Choose the correct answers from the alternatives given :
Plant roots function to

  1. anchor the plant

  2. store the products of photosynthesis

  3. produce hormones that stimulate stem growth

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Root is the most important organ of a plant which generally lies below the soil in the vascular plants.

The main functions of the root are:
a. It anchors the plants in soil and thus provides mechanical support to plants to stand upright.
b. Photosynthesis products are usually stored in roots. eg. Raddish, carrots etc.
c. Roots synthesize certain hormone that helps in the growth of the plant.

So the correct answer is "All of the above"

Multiple choice biology anatomy of flowering plants theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Choose the correct answers from the alternatives given.
When a leaf trace extends from a vascular bundle in a dicot stem, what would be the arrangement of vascular tissues in the veins of the leaf

  1. Xylem would be on top and the phloem on the bottom

  2. Phloem would be on top and the xylem on the bottom

  3. Xylem would encircle the phloem

  4. Phloem would encircle the xylem
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vascular bundles are scattered in the spongy parenchyma. These can be seen in the veins and the midrib of the leaves. The dicot leaves possess reticulate venation in which veins form a network. The xylem forms the top layer and phloem is present at the bottom in the arrangement of the vascular tissues. The veins vary in thickness in the reticulate venation.

Hence, the correct answer is 'Xylem would be on top and the phloem on the bottom'.

Multiple choice biology selection and evolution theory of natural selection natural selection evidence for evolution

State whether the following statements are true or false .
Osmosis is concerned with the movement of water only and cannot directly affect the movement of dissolved substances into the roots and through the plant.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Osmosis is the movement of solvent from its higher concentration to its lower concentration across a semipermeable membrane. It does not affect the solute particles and does not facilitate their movements. Thus osmosis does not affect the movement of dissolved substances into roots and through the plant.


So the correct answer is 'True'

Multiple choice biology selection and evolution theory of natural selection natural selection evidence for evolution

State whether the following statements are true or false .
Transpiration takes place only through stomata in terrestrial plants.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transpiration can vary according to the type of structure involved. It is of four types:

1. Stomatal transpiration: Occurs through stomata. It is responsible for 50-97% of total transpiration.
2. Cuticular transpiration: Occurs through cuticle (a waxy layer that covers the epidermis of leaves and stems). Contributes 3-10% of the total transpiration.
3. Lenticular transpiration: Occurs through lenticels (aerating pores in the cork of woody stems). insignificant contribution to water loss.
4. Bark transpiration: Occurs through the bark of woody stem. Contributes to 1% of total transpiration.
So, the given statement is false.

Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

When a plant cell is placed in pure water, it?

  1. Expands until the osmotic pressure reaches that of water

  2. Becomes less turgid until the osmotic potential reaches that of pure water

  3. Becomes more turgid until the pressure potential of cell reaches its osmotic potential

  4. Becomes more turgid until the osmotic potential reaches that of pure water
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Plant cells are enclosed by a rigid cell wall. When the plant cell is placed in a hypotonic solution, it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting. The plant cell is said to have become "turgid" i.e. swollen and hard. The pressure inside the cell rises until this internal pressure is equal to the pressure outside. This liquid or hydrostatic pressure called the turgor pressure prevents further net intake of water.
So the correct answer is 'becomes more turgid until the pressure potential of the cell reaches its osmotic potential'.
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

In a plant cell, O.P. is equal to?

  1. T.P. $-$ D. P.D.
  2. D. P. D. $-$ T.P.
  3. T.P. $-$ D.P.
  4. D. P.D. $+$ T.P.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
When a plant cell is placed in hypotonic solution, water enters into a cell by osmosis and as a result turgor pressure develops. The cell membrane gets stretched and osmotic pressure of cell decreases. As cell absorbs more and more water its TP increases and OP decreases. When a cell is fully turgid, its OP is equal to TP and DPD is zero. The turgid cell cannot absorb any more water. Thus, with reference to a plant cell, the DPD can be described as actual thirst of the cell for water and can be expressed as DPD=OP-TP. When DPD is zero, entry of water will stop. Thus it is DPD that tends to equate and represents water absorbing ability of a cell, it is also called suction force (SF) or suction pressure (SP). 
Therefore, the correct answer is option D. 
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

The percentage of water in a typical plant cell is about 

  1. 10%

  2. 20%

  3. 50%

  4. 80%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Plants are made up of water, organic and inorganic substances. Water makes the majority of the volume of the plant cell. Water comprises of 80-90 percent of the plant's total weight. Water is used to support the cell structure, for metabolic functions, to carry the nutrients and for photosynthesis. 

Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

A plant cell placed in pure water will

  1. Swell up and become turgid

  2. Swell up and burst

  3. Lose water and become flaccid

  4. Shrink and die
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plant cells have a strong cell wall surrounding them. When they take up water by osmosis they start to swell, but the cell wall prevents them from bursting. As a result, the plant cells become “turgid” when they swell up and become turgid.

Thus, the correct answer is option (A). 

Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

Choose the correct answers from the alternatives given.
When a plant cell is placed in pure water, it will

  1. Become rigid because of turgor pressure

  2. Lose water and wilt

  3. Swell and burst

  4. Alter its cell wall composition so that it becomes impermeable to water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pure water is a hypotonic solution that causes endosmosis. The water diffuses into the cell causing the cytoplasm to build up pressure against the wall. This pressure is called turgor pressure that causes rigidity of the cell and the cell does not burst. This turgor pressure is responsible for the enlargement and extension of the cells during growth.

Hence, the correct answer is 'Become rigid because of turgor pressure'.

Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

The cellulosic cell wall is essential for plant cell because 
(a) It gives shape to the cell.
(b) It gives protection to the cells.
(c) It is able to withstand high temperature, high wind speed and atmospheric moisture.
(d) It is involved in the recognition of substances required for the cells.

  1. a, b, and d

  2. a, c and d

  3. b, c and d

  4. a, b and c
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cellulosic cell wall provides structural shape (a), protection (b), and mechanical strength to withstand environmental stressors (c). While it is involved in some signaling, option (d) is less standard than the primary structural roles listed in (a, b, c).

Multiple choice biology chemical coordination in plants ethylene plant hormones plants and animal hormones

State whether the following statements are true or false.
Ethylene evolution is highest when the fruit is unripe but diminishes as the fruit matures.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethylene is a gaseous hormone that promotes transverse growth but inhibits lateral growth. They are produced by the amino acid methionine. It was found that ripened fruits produce this hormone, so when the ripened fruits are placed together with unripe fruits, the unripe fruits will get ripened due to the release of this gas. Ethylene evolution is highest at the time of ripening but it diminishes when the fruit matures and the evolution of gas got reduced.

So, the correct statement is 'True'.

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which of the following is not correct about $DPD$?

  1. Its the loss of diffusion pressure
  2. Maximum valu of $DPD$ is equal to $OP$
  3. $DPD$ of pure $H _{2}O$ is zero
  4. Increase in $TP$ of a cell decreases $DPD$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The term diffusion pressure deficit (DPD) is the reduction in the diffusion pressure of water in solution or cell over its pure state due to presence of solutes in it and forces opposing diffusion. Diffusion pressure of water is maximum and its theoretical value is 1236 atm. DPD of a solution is equal to its osmotic pressure i.e. DPD = OP(of solution). DPD of a cell is influence by both osmotic pressure and wall pressure (turgor pressure) which opposes the endosmotic entry of water, i.e. DPD = OP - Wall pressure. DPD is directly proportional to the concentration of the solution. DPD decreases with dilution of solution. The actual pressure with which cell absorbs water is called "suction pressure".

So the correct option is 'DPD of pure H$ _2$O is zero'.