Tag: biology

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Multiple choice biology control and co-ordination in plants and animals control of blood glucose hormones in human reproduction testes and ovary

Growth Hormone is secreted by

  1. Pineal Body

  2. Pituitary Gland

  3. Pancreas

  4. Parathyroid Gland
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Growth hormone (GH), also called somatotropin or human growth hormone, peptide hormone secreted by the anterior lobe of the pituitary gland. It stimulates the growth of essentially all tissues of the body, including bone.

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

Delaying aging of leaves and opening of stomata are due to the action of _______

  1. Auxins

  2. Gibberellins

  3. Cytokinins

  4. Abscisic acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A. Auxins are the plant hormones which promote cell enlargement and cell differentiation. It also promote fruit growth. It is responsible for phototropic and geotropic responses of plants.
B. Gibberellins are plant hormones which promote cell enlargement and cell differentiation in the presence of auxins. It help in breaking the dormancy in seeds and buds. It also promote fruit growth. It stimulates elongation of shoots of various plants.
C. Cytokinins are plant hormones which promote cell division in plants. It also helps in breaking the dormancy in seeds and buds. The delay the ageing of leaves. It promotes opening of stomata.
D. Abscisic acid (ABA) is a  plant hormone which functions mainly as a growth inhibitor. It promotes the dormancy in seeds and buds [ this is the opposite of breaking the dormancy. It also promotes closing of stomata. It promotes falling of leaves. 
So, the correct answer is 'Cytokinins'.

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

Cytokinins are known to

  1. Inhibit cytoplasmic movement.

  2. Help in retention of chlorophyll.

  3. Influence water movement.

  4. Promote abscission layer formation.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cytokinins perform several other functions:
- Stimulates cell division.
- Stimulates morphogenesis in tissue culture.
- Stimulates the growth of lateral buds.
- Stimulates leaf expansion.
- Enhance stomatal opening

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

Cytokinin and ethylene have oppsite effect on:-

  1. Leaf senescence

  2. Elogation of stem

  3. Lateral swelling of stem

  4. Winter dormancy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cytokinins are the plant hormones that are responsible for cell division and elongation, their help in the delay of leaf senescence as they transport nutrients to these parts. Ethylene is a gaseous hormone and is responsible for transverse growth as swelling of the stem, It hastens the senescence of leaves due to the evolution of ethylene gas.

So, the correct option is 'Leaf senescence'.

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

Kinetin was first isolated and identified by

  1. Charles Darwin

  2. Boysen and Jansen

  3. Paal

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

Kinetin is a type of cytokinin, a class of plant hormone that promotes cell division. Kinetin was originally isolated by Miller and Skoog et al., as compound from autoclaved herring sperm DNA that had cell division-promoting activity.

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

The chief role of CK is 

  1. To check abscission

  2. To check senescence

  3. To mobilize solutes

  4. To check senescence and to mobilize solutes from one part to other
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cytokinin hormone does the major function of checking senescence and mobilising solutes from one part to another. It promotes the cell division or cytokinesis, in plant roots and shoots.

So, the correct answer is option D.

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

Which of the following contains cytokinin?

  1. Coconut milk

  2. Young kernels of maize

  3. Fruit of cucurbits

  4. Both (A) and (B)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Coconut milk and young kernels of maize contains cytokinin. Cytokinis are a class of plant growth substances that promote cell division, or cytokinesis in plant roots and shoots. It is an adenine derivative.