Tag: chemical coordination in plants

Questions Related to chemical coordination in plants

Read the given statements and identify the  plant hormones X,Y and Z
i) Hormone Y includes flowering in mango
ii) Hormone X promotes root growth and root hair formation
iii) Hormone Z inhibits the speed germination,increases the tolerance of the plant to various stresses ,play important role in speed development, maturation and dormancy.

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. Y : ABA X : ausin Z : GA

  2. Z : GA X : Auxin Z :C2H4

  3. Y : Auxin X : C2H4 Z : GA

  4. Y : C2H4 X : C2H4 Z : ABA

Show answer
Correct Option: A

Match List I with List II and select the correct answer using the codes given the lists.

List-I List-II
a. Increase in wall elongation $1$. Gibberellins
b. Bolting and flowering $2$. Auxins
c. Cell division $3$. Absicsic acid
d. Dormancy $4$. Cytokinins
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-$2$, B-$1$, C-$3$, D-$4$

  2. A-$2$, B-$1$, C-$4$, D-$3$

  3. A-$1$, B-$2$, C-$4$, D-$3$

  4. A-$1$, B-$2$, C-$3$, D-$4$

Show answer
Correct Option: A

The substance that triggers the fall of mature leaves and fruits from plants 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. Abscisic acid

  4. Cytokinin

Show answer
Correct Option: C
Explanation:

Phytohormones are important plant growth regulators. The phytohormones, like auxins and gibberellins (GA), have positive growth-promoting effects whereas abscisic acid (ABA) and ethylene have growth inhibiting effects. Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. It triggers fall of mature leaves and fruits from plants. Hence, it is called abscisic acid because of the formation of abscission layer which is responsible for fall of mature leaves and fruits from plants.  But like other PGRs, abscisic acid also has other wide-ranging effects on plant growth and development. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA 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. ABA plays an important role in seed development, maturation and dormancy. By inducing dormancy, ABA helps seeds to withstand desiccation and other factors unfavorable for growth. In most situations, ABA acts as an antagonist to GAs.

Choose the correct answer from the alternatives given.
Which of the following statements about plant hormones is not true?

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. Each naturally occurring hormone has a specific chemical structure

  2. Hormones are among the principal internal regulators of plant growth

  3. Responses to plant hormones may be observed in nearly any part of a plant

  4. All known growth regulators of plant activities are chemicals produced naturally in plants

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Correct Option: D
Explanation:

Cytokinins have specific effects on cytokinesis and were discovered as kinetin (a modified form of adenine, a purine) from the autoclaved herring sperm DNA. Kinetin does not occur naturally in plants.

So, the correct option is 'All known growth regulators of plant activities are chemicals produced naturally in plants'.

Choose the correct answer from the alternatives given.
Plant hormones

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. interact with one another

  2. are influenced by environmental cues

  3. are active in plant embryos within seeds

  4. all of the above

Show answer
Correct Option: D
Explanation:

Plant hormones can work in combination and are dependent on the environmental cues or signals to act. They are also active in plant embryos within the seed such as Gibberellic acid.

So, the correct option is 'all of the above'.

Choose the correct answer from the alternatives given.
The mitotically active and hormone producing cells are:

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. xylem

  2. meristem

  3. phloem

  4. cortex

Show answer
Correct Option: B
Explanation:

Meristem is the actively dividing cells at the root and shoots apices that are mitotically active.

So, the correct option is 'meristem'.

Choose the correct answer from the alternatives given.
The plant hormone that causes cell elongation 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. citric acid

  2. indole 3-acetic acid

  3. ethylene

  4. abscisic acid

Show answer
Correct Option: B
Explanation:

Plant cells elongate irreversibly only when load-bearing bonds in the walls are cleaved. Auxin causes the elongation of stem and coleoptile cells by promoting wall loosening via cleavage of these bonds. This process may be coupled with the intercalation of new cell wall polymers.

So, the correct option is 'indole 3-acetic acid'.

Find the odd man out:

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. Abscisic acid

  3. Thyroxine

  4. Gibberellin

Show answer
Correct Option: C
Explanation:

  • Auxin is a plant hormone that is produced in the tip of the stem that works in elongation.
  •  Auxin helps the plant to move to the darker side, the cell grows larger than corresponding cells present on the lighter side of the plant.
So, the correct option is 'Auxin'.

Which of the following hormones contains nitrogen?

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. Cytokinin

  3. Gibberelins

  4. Both 1 and 2

Show answer
Correct Option: D
Explanation:

Auxin and cytokinin both contain nitrogen in their structure. 

So the correct option is "Both 1 & 2". 

Two plant hormones which regulate growth of plant are?

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. Cytokinin and Auxin

  2. Abscisic acid and Auxin

  3. Auxin and Gibberellin

  4. All of these

Show answer
Correct Option: A