Tag: chemical coordination in plants

Questions Related to chemical coordination in plants

Which one prevents over-ripening of banana and browning of cut fruits?

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. Gibberellic Acid

  2. Indole-3 Acetic Acid

  3. Ascorbic Acid

  4. Abscisic Acid

Show answer
Correct Option: C
Explanation:

Lemon juice helps keep the apple from browning, because it is full of ascorbic acid (Vitamin C) and it has a low (acidic) pH level. Ascorbic acid works because oxygen will react with it before it will react with the polyphenol oxidase. However, once the ascorbic acid gets used up, the oxygen will start reacting with the enzyme and browning will occur. Lemon juice's low pH level also helps prevent browning. Polyphenol oxidase works best when the pH level is between 5.0 and 7.0. However, below a pH level of 3.0, the enzyme becomes inactivated. The pH of lemon juice is in the 2.0 range, making it very effective against browning.

Abscisic acid controls

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. Cell elogation and cell wall formation

  2. Shoot elogation

  3. Leaf fall and dormancy

  4. Cell division

Show answer
Correct Option: C
Explanation:

Abscissic acid regulates abscission (the shedding of leaves, flowers and fruits from the living plant) and dormancy. It acts as general plant growth inhibitor and also inhibit plant metabolism. It inhibits closure of stomata in epidermis, and increase tolerance of plant to various kinds of stresses, and therefore called as stress hormone.
ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand dessication and other factors favourable for growth.

Thus, the correct answer is option C.

State whether the following statements are true or false.
Dormancy of winter buds in temperate trees is caused by abscisic acid.

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Abscisic acid is the hormones also called as stress hormones as they function in stress conditions. They are also known as dormant as they induce dormancy in buds. It mostly induced bud dormancy at the start of the winter season. They are generally growth hormone which inhibits growth normally.

So, the correct statement is 'True'.

State whether the following statements are true or false.
Dormancy of plants occurs in relation to abscisic acid.

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Dormancy is the period when the physiological activities of the plant slow down for some time. Abscisic acid is a stress hormone that is responsible for the protection of plants in drought conditions. They are generally growth inhibitors and are also called as dormants. They are mainly responsible for the bud dormancy at the time of winter season and also cause seed dormancy and protect it from desiccation.

So, the correct statement is 'True'.

Choose the correct answer from the alternatives given.
Which of the following plant hormones is associated with the closure of the stomata in a plant under water stress?

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. Abscisic acid

  2. Auxin

  3. Cytokinin

  4. Ethylene

Show answer
Correct Option: A
Explanation:

Abscisic acid inhibits seed germination and stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone.

So, the correct option is 'Abscisic acid'. 

Leaf abscission is caused by

biology chemical coordination in plants abscisic acid fruit plants: structure and function

  1. ABA

  2. cytokinin

  3. auxin

  4. gibberellin

Show answer
Correct Option: A
Explanation:

A plant will abscise apart either to discard a membrane that is no longer necessary, such as a leaf during autumn or a flower following fertilization or for the purpose of reproduction. Most deciduous plants drop their leaves by abscission before winter, whereas evergreen plants continuously abscise their leaves.

So, the correct option is 'ABA'.

Match the following.

A. IAA (i) Herring sperm DNA
B. ABA (ii) Bolting
C. Ethylene (iii) Stomatal closure
D. GA (iv) Weed-free lawns
E. Cytokinins (v) Ripening of fruits
biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. A-(iv), B-(iii), C-(v), D-(ii), E-(i)

  2. A-(v), B-(iii), C-(iv), D-(ii), E-(i)

  3. A-(iv), B-(i), C-(iv), D-(iii), E-(ii)

  4. A-(v), B-(iii), C-(ii), D-(i), E-(iv)

Show answer
Correct Option: A
Explanation:

IAA is an auxin but has potential role of herbicide and weedicide. ABA is stress inducing plant growth regular. It can induce closure of stomata, Ethylene on other hand increases climactic rate and hence used for fruit ripening, GA or gibberlic acid are known to cause bolting in crucifers. Cytokinins were first isolated from Herring sperm DNA.

Thus, the correct answer is 'A-(iv), B-(iii), C-(v), D-(ii), E-(i).'

Which of the following is a plant hormone?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Insulin

  2. Thyroxin

  3. Oestrogen

  4. Cytokinin

Show answer
Correct Option: D
Explanation:

Insulin is secreted by Islets of Langerhans of the pancreas and serves to lower the blood glucose level by stimulating the uptake of glucose by cells, specifically muscle cells, liver cells and adipose tissues cells. 

Thyroxine is a thyroid hormone which targets all tissues and stimulates metabolic rate, growth and development. 
Oestrogen is the female sex hormone secreted by developing follicles in the ovary. It serves to stimulate the growth of the uterus and the vagina, is necessary for egg maturation as well as for the development of the secondary sex characteristics in females. Thus, options A, B and C are incorrect as these hormones are animal hormones. 
Cytokinins are the plant growth hormones that regulate the cell division in root and shoot of the plant both in vivo and in-vitro.
So, the correct answer is 'Cytokinin' 

Which one is paired incorrectly?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Auxin - Isolated from human urine

  2. Zeatin - Isolated from corn kernels and coconut milk

  3. Gibberellins - Isolated from fungus G. fujikori

  4. Abscisic acid - Isolated from ripened oranges

Show answer
Correct Option: D
Explanation:

Kogl et al. (1931) isolated auxin from human urine called heteroauxin which was identified as indole-3-acetic acid (IAA).
Zeatin is a cytokinin-like substance isolated and crystallised by Letham (1963-65) from milky endosperm of corn (Zea mays). It also occurs in coconut milk.
Yabuta and Sumiki (1938) isolated a chemical substance from the cultural filtrate of fungus Gibberella fujikuroi in crystalline form and named it gibberellic acid.
Cousins (1910) found that ripe oranges produced a volatile substance that hastened ripening of unriped bananas nearby. With the help of gas chromatography, it was found that the ripening causing volatile substance was ethylene.
So, the correct answer is 'Abscisic acid - Isolated from ripened oranges'.

To speed up the malting process in brewing industry the growth hormone used is ____________.

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. auxin

  2. gibberellin

  3. kinetin

  4. ethylene.

Show answer
Correct Option: B
Explanation:

Gibberellins are used to speed up the malting process in brewing industry. They increase the yield of malt from barley grains.