Tag: biology

Questions Related to biology

Which one is growth regulator produced by plants?

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

  1. NAA

  2. Zeatin

  3. 2, 4-D

  4. BAP

Show answer
Correct Option: B
Explanation:

Naphthaleneacetic acid (NAA) is a type of synthetic auxin, plant hormone. It is a growth regulator. It acts as rooting agent. Zeatin a type of naturally occurring cytokinin, the plant hormone. It was first discovered in Zea maize. A 2, 4-D is a type of synthetic auxin, plant hormone. It acts as weedicide. BAP (Benzylaminopurine) is a type of synthetic cytokinin, a plant hormone. It is involved in various physiological processes of plants like cell division.

Thus, the correct answer is option B.

Cytokinins which have specific effect in cytokinesis are modified forms of

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

  1. Cytosine

  2. Adenine

  3. Guanine

  4. Thiamine

Show answer
Correct Option: B
Explanation:

Cytokinin is a plant hormone. It has the specific effect in cytokinesis in plants. It is modified form of adenine. Kinetin, zeatin, and 6-benzylaminopurine are adenine type cytokinins. It is adenine molecule that is modified by the addition of 5-carbon sidechains off the 6 position.

Thus, the correct answer is option B.

Plant hormones used for inducing morphogenesis in plant tissue culture is

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

  1. Gibberellins

  2. Ethylene

  3. Cytokinins

  4. ABA

Show answer
Correct Option: C
Explanation:

Morphogenesis is the process of development of shape of an organism. Cytokinins which is present at the site where rapid cell division occurs like root apices, developing shoot buds it helps in plant growth and attaining its shape. So it will help the plant to maintain its shape in tissue culture.

So the correct option is 'Cytokinins'.

State whether the following statements are true or false.
The plant ageing process, senescence, is prevented by cytokinins.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Cytokinin is a plant growth hormone that is basic in nature and is responsible for cell division. This results in cell elongation, growth, and development of plants, they work similar to auxins. Cytokinins are helpful in delaying and stopping the senescence of leaves thus resulting in the process of aging to stop by the mobilization of nutrients in the required part of the plant.

So, the correct statement is 'True'.

Cytokinins helps to produce all except

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

  1. New leaves

  2. Chloroplast in leaves

  3. Lateral short growth and adventitious shoot formation

  4. Rooting on cut stem

Show answer
Correct Option: D
Explanation:

 Cytokinins are plant hormones that cause increased cell division by stimulating the process of mitosis. They help in the production of new leaves, formation of chloroplasts in leaves, lateral shoot growth and adventitious shoot formation. They do not have any role in root formation. So, the correct option is 'Rooting on the cut stem'.

Hormone primarily concern with cell division is

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

  1. IAA

  2. NAA

  3. Cytokinin

  4. Gibberellic acid.

Show answer
Correct Option: C
Explanation:

Cytokinin helps in cytokinesis. Cytokinin induces cell division in the shoots. Cytokinin positively regulates cell cycle along with auxin.

Thus, the correct answer is 'Cytokinin.'

Ageing is retarted by

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

  1. ABA

  2. CKN

  3. GA

  4. C2H4

Show answer
Correct Option: B
Explanation:

Ageing is retarded by the CKN. 

Ageing is the process in which the human being progressively more likely to die. So, Ageing is retarded by CKN.
Hence, option B is correct.

Read the following statements and select the incorrect one.

biology reproductive health stds and infertility gm crops biotechnology

  1. Semen is preserved for artificial insemination by heating

  2. Mating of an animal within the same breed, but having no common ancestors on either side of their pedigree upto 4 - 6 generations is called as outcrossing

  3. Example of interspecific hybridisation is mule

  4. Hinny is a hybrid between the female ass and stallion.

Show answer
Correct Option: A

When a species of an organism cannot form a zygote but the zygote survives, the phenomenon is known as

biology reproductive health stds and infertility gm crops biotechnology

  1. Hybrid vigour

  2. Hybrid sterility

  3. Hybrid zygote

  4. Hybrid fertility

Show answer
Correct Option: B
Explanation:

Hybrid zygotes sometimes develop into adults, such as mules (hybrids between female horses and male donkeys), but the adults fail to develop functional gametes and are sterile. This phenomenon is called as hybrid sterility. Thus, option B is correct. 

Heterosis, also called hybrid vigour, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Plant and animal breeders exploit heterosis by mating two different pure-bred lines that have certain desirable traits. Thus, option A is wrong. 
In some cases, no barriers exist to mating between members of different species. In these cases, the zygote formed is called a hybrid zygote. Thus, option C is wrong. 
Fertility ability of a hybrid is called as hybrid fertility. Thus, option D is wrong.

The ova are released by hormone induction and fertilization by artificial insemination and then embryo is stored at 4$^o$C for several years. This technique is known as

biology reproductive health stds and infertility gm crops biotechnology

  1. Artificial insemination

  2. Embryo transplantation

  3. Super ovulation

  4. Preservation of embryo

Show answer
Correct Option: D
Explanation:

Embryo cryopreservation or preservation of embryo is generally performed as a component of in vitro fertilization which generally also include ovarian stimulation, ovarian hyperstimulation or superovulation, egg retrieval, artifical insemination and embryo transfer.