Tag: mechanism of absorption

Questions Related to mechanism of absorption

Generally stomata found on the lower surface of leaf. Thus, approximate percentage of transpiration through abaxial surface is

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. 47 %

  2. 57 %

  3. 67 %

  4. 97 %

Show answer
Correct Option: D
Explanation:

Stomata are usually confined in more number on the lower sides of the leaves. The lower surface is called as abaxial surface and the upper surface is called as the adaxial surface. Hence, maximum percentage i.e., 80- 95% of transpiration occurs from the lower surface.

Which one is the driving force for the process of passive absorption of water in roots?

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Root pressure

  2. Transpiration in leaves

  3. Activity of aquaporins

  4. Increase in imbibition pressure in root cells

Show answer
Correct Option: B
Explanation:

Passive absorption is absorption by the pull from transpiration without the active involvement of root cells, The shoots and leaves of the plant experience transpiration due to evaporation of water from their surface.

So, the answer is, "Transpiration in leaves".

Transpiration ratio is the ratio of moles of H$ _{2}$O transpired / moles of CO$ _{2}$ fixed. This ratio is measure of

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. The efficiency of guard cells on stomatal movement.

  2. Effectiveness of stomata is maximizing photosynthesis, while minimizing water loss.

  3. Distinguishing a xerophyte from a glycophyte.

  4. Stomatal pore size of the leaves.

Show answer
Correct Option: B
Explanation:

Water is required to generate the reducing power, which is used to reduce carbon dioxide during photosynthesis. The water molecules are split up and oxygen released as a by-product. The protons are used to synthesize reducing power. Now all the water that is absorbed is never used up. In fact, the water that is actually used is a small fraction of water that is absorbed. Hence, transpiration ratio is calculated to find out the effectiveness of stomata in maximizing photosynthesis and minimizing loss of water.

Water moves up against gravity and even for a tree of $20$m height, the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is ____________.

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Cohesive forces

  2. Adhesive forces

  3. Transpiration pull

  4. Root pressure

Show answer
Correct Option: C
Explanation:

According to transpiration pull theory, due to transpiration, the water column inside the plant comes under tension. This is called 'transpiration pull'. On account of this tension, the water column is pulled up passively from below to top of the plant(almost like a rope). A tension of one atmosphere is sufficient to pull water to a height of about $20$ meters.

So, the correct answer is 'Transpiration pull'

Choose the correct answers from the alternatives given.
Which of the following forces is responsible for moving water up to the tops of the tallest trees?

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Atmospheric pressure

  2. Root pressure

  3. Guttation

  4. Transpiration

Show answer
Correct Option: D
Explanation:

Loss of water from the leaves causes water stress to develop from the top of the trees which forces more and more water to rise from the roots to the leaves. The column of the water is maintained due to cohesion and adhesion forces and the water moves up due to transpiration pull.

Hence,the correct answer is 'Transpiration'.

Choose the correct answers from the alternatives given.
What is the action spectrum of transpiration?

botany the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Blue and infra red

  2. Green and ultraviolet

  3. Orange and red

  4. Blue and red

Show answer
Correct Option: D
Explanation:

An action spectrum is a graph of the rate of a physiological activity plotted against the wavelengths of light. it shows which wavelengths of light is most effectively used in a specific reaction. In photosynthesis, chlorophyll is much more efficient at the blue and red wavelengths of light to carry out photosynthesis. Since transpiration is indirectly related to photosynthesis, its action spectrum would be similar to photosynthesis.

Hence, the correct answer is 'Blue and red'.

Oxygen is returned to the atmosphere mainly by __________.

biology the leaf mechanism of absorption mineral absorption significance of transpiration

  1. burning of fossil fuel

  2. respiration

  3. photosynthesis

  4. fungi

Show answer
Correct Option: C
Explanation:

Photosynthesis is a process that converts $CO _2$ into organic compounds and starch (carbohydrate) using energy from sunlight. $O _2$ is also released during this process.

Oxygen we breathe is obtained from ________

biology the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Respiration

  2. Guttation

  3. Photosynthesis

  4. All of the above

Show answer
Correct Option: C
Explanation:

$CO _{2} + H _{2}O \underset {chlorophyll}{\xrightarrow {light}} sugar + oxygen (O _{2})$
Oxygen is a product of photosynthesis.

Carbohydrates, the most abundant biomolecules on earth are produced by

biology the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Some bacteria, algae and green plants

  2. Fungi, algae and green plants

  3. All bacteria, fungi and algae

  4. Viruses, fungi and bacteria

Show answer
Correct Option: A
Explanation:

Carbohydrate synthesis occurs through photosynthesis Chloroplasts are the green plastids which occur in all the green parts of the plants. They are the actual site of photosynthesis. 

Cyanobacteria and other photosynthetic bacteria do not possess chloroplasts. However, the photosynthetic pigments of these organisms are located on thylakoids which lie freely in the cytoplasm.
The algae also contain the chloroplasts to perform the photosynthesis.
Fungi are either saprophytic, symbiotic or parasitic organisms. Viruses are parasitic.
Hence, the correct answer is 'Some bacteria, algae and green plants'.

Photosynthesis is essential for survival of

biology the leaf mechanism of absorption mineral absorption significance of transpiration

  1. Animals

  2. Plants

  3. Most of the organisms

  4. All of the above

Show answer
Correct Option: D
Explanation:
Photosynthesis is plants taking in water, carbon dioxide, and light to make sugar and oxygen. This is important because all living things need oxygen to survive. All producers make oxygen and sugar for the secondary consumers and then the carnivores eat animals that eat the plants. If there is not enough producers to make the sugar and oxygen that all living things need then all living things will die out. Without producers CO2 couldn't be taken in by the plants to be turned back into oxygen that all animals need for survival. Also, without producers, herbivores wouldn't have anything to eat and they would all die leaving carnivores without food to eat and all life forms wouldn't be on Earth. Photosynthesis happens in the Chloroplast of the plant's organelle, if the Chloroplast wasn't in the plant Photosynthesis couldn't happen. If there was no sunlight for the plant to absorb then Photosynthesis couldn't happen. If living things didn't breathe out CO2 then the plants would die and living things would have no way of getting oxygen. These are the reasons why Photosynthesis is important to plants and all loving things on the planet.

So, the correct option is 'Option D'.