Biology

Plant Transport and Physiology

1,834 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 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

The plant cells central vacuole

  1. Provides the plant cell with support

  2. Stores nutrients and cellular waste products

  3. Is a reservoir for water

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
In plant cells, there is a centrally located large vacuole. This vacuole serves as the reservoir of water and sometimes wastes. It also provides the plant cell with structural support and also reserves nutrients.

So, the correct answer is 'all of the above'.
Multiple choice biology structural organization in living organisms structure of a plant cell levels of organisation in plants plant and animal cell

Plant cells need a protective cell wall around their cells because

  1. they are far more important than the animal cells

  2. they cannot move and protect themselves from the extreme weather conditions

  3. they are prokaryotic cells

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Eukaryotic cells, in addition to the nucleus, have many membrane-bound organelles like the mitochondria, endoplasmic reticulum, Golgi bodies etc. Such membrane-bound organelles are absent in the Prokaryotic cells

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

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

Water enters from the soil into the root hairs due to

  1. Turgor pressure of root hair

  2. Osmotic pressure of root hair

  3. Suction pressure

  4. Diffusion pressure
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Suction pressure is same as DPD (Diffusion Pressure Deficit). Water moves in a plant due to suction pressure or DPD from a region of lower DPD to a region of higher DPD.

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

When the mesophyll cells lose water, their DPD will

  1. Increase

  2. Decrease

  3. Remain constant

  4. None of the above is applicable
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When the mesophyll cells lose water the concentration of solutes will increase. Consequently, the OP will increase concomitantly, there will be a drop in turgor and TP will decrease. These changes will increase the DPD. Water moves from lower DPD to higher DPD, thus, water will gain entry into the cells, whose DPD has increased.

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

In a plant cell the diffusion pressure deficit is zero when it is 

  1. Plasmolysed.

  2. Turgid.

  3. Flaccid.

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

Diffusion Pressure Deficit = osmotic pressure - wall pressure. Wall pressure is the same as Turgor pressure. When a cell is placed in a hypotonic solution water enters the cell. Hence its osmotic pressure decreases and the turgor pressure increases. In a fully turgid cell the turgor pressure becomes equal to the osmotic pressure. Hence the Diffusion Pressure Deficit becomes zero in a turgid cell. Thus the correct answer is option B.

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

Root hair absorb water from soil due to

  1. Osmotic pressure

  2. Turgor pressure

  3. Suction pressure

  4. Root pressure
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Suction pressure is the decrease in the diffusion pressure of solution over its pure state due to the presence of solute particles in it. The concentration of solute is higher in root hair cells as compared to soil water. So suction pressure builds up and water is drawn towards root hair cells. These water molecules are transported to different parts of the plant. So, the correct answer is 'Suction pressure'.

Multiple choice biology respiration in organism do plants breathe? plant respiration respiration-plants

Leaves of the plant have tiny pores for exchange of oxygen and carbon dioxide. These small pores are known as

  1. Nodule

  2. Stomata

  3. Radicle

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In plants, the stoma is a tiny opening found on the under-surface of leaves. These pores provide the passage for the entry of the air and the exchange of gases. They are also useful during transpiration for the escape of water vapour into the atmosphere.

So the correct option is 'Stomata'

Multiple choice biology respiration in organism do plants breathe? plant respiration respiration-plants

Plants take in .......... from the air and give out ..........

  1. Oxygen, Carbon dioxide

  2. Carbon dioxide, Oxygen

  3. Oxygen, Nitrogen

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plants perform photosynthesis to obtain the light energy from direct sunlight and convert it into chemical energy. This process utilizes carbon dioxide, water and sunlight to produce carbohydrates and oxygen. It acts as a counterbalance to respiration by utilizing the carbon dioxide generated by all breathing organisms and giving out the oxygen back to the atmosphere. 

So the correct option is ' Carbon Dioxide, Oxygen'