Tag: biology

Questions Related to biology

Which of the following plays a major role in the formation of a thunderstorm?

  1. Conduction

  2. Convection

  3. Radiation

  4. All of these


Correct Option: B
Explanation:

Convection plays a major role in the formation of a thunderstorm. When warm air rises and meets the cold air, it condenses (releases latent heat). The heat helps fuel the thunderstorm. Then the downdraft forms, bringing cold air and precipitation down to the earth's surface.   

Which of the following are the uses of air?

  1. Generating electricity

  2. Disposal of seeds

  3. Flying of birds

  4. All of the above


Correct Option: D
Explanation:

Air is used in generating electricity for example wind mill is used to generate electricity. 

Dispersal of seeds means transport of seeds away from parent plant. Gravity, wind, ballistic, water and by animals are five modes of seed dispersal. 
Flying of birds as bird use their strong breast muscles to flab their wings and give them the thrust to move through the air and fly.

Mountaineers carry oxygen cylinders with them because:

  1. oxygen supports combustion

  2. air becomes thinner as we go higher

  3. air is dense but lacks oxygen in mountains

  4. none of the above


Correct Option: B
Explanation:

As we go higher and higher the pressure and oxygen decreases, so as due to less oxygen content mountaineers carry oxygen cylinders with them.

Which of the following statements is true regarding the properties of air?

  1. It is a good conductor of electricity.

  2. It is a good conductor of heat.

  3. It is translucent in nature.

  4. None of the above


Correct Option: D
Explanation:
Properties of air are as follows-
$1.$ Air is bad conductor of electricity.
$2.$ Air is bad conductor of heat.
$3.$ Air is not translucent it is transparent.

The power of diffusion is:

  1. more in solids

  2. least in gases

  3. maximum in liquids

  4. maximum in gases


Correct Option: D
Explanation:

The power of diffusion is max in gases because the inter-molecular space between the molecules is highest in gases,

So the particles easily diffuse each other.

Which of the following statement is/are correct ?

  1. At altitudes, the pressure of air is low

  2. At altitudes, density of air is low

  3. At altitudes, cooking takes place slower

  4. At altitudes, water will boil at a temperature greater than $100^{\circ} C$


Correct Option: A,B,C

Ethylene is involved  in .........................

  1. Aerobic respiration

  2. Anaerobic respiration

  3. Climacteric respiration

  4. Fermentation


Correct Option: C
Explanation:

Ethylene is an important natural plant hormone, used in agriculture to force the ripening of fruits. Binding of ethylene to the receptors unleashes a signaling cascade that leads to activation of transcription factors and the turning on of gene expression. The climacteric is a stage of fruit ripening associated with increased ethylene production and a rise in cellular respiration.

The most efficient precursor of ethylene is ................

  1. Adenine

  2. Thiocarbarnate

  3. Zeatin

  4. Methionine


Correct Option: D
Explanation:

Ethylene is a plant hormone which is present in gaseous form. It is formed by the breakdown of methionine, which is in all cells. Thus, methionine is called as the precursor of ethylene hormone. Ethylene hormones helps in the ripening of fruits when sprayed onto it. Ethylene hormone is present mainly in rapidly dividing cells, which is usually in darkness due to the action of methionine, which is the precursor molecule.

Ethylene is a ............

  1. Gaseous hormone

  2. Largest hormone

  3. Liquid-gas mixture

  4. Solid hormone


Correct Option: A
Explanation:

Ethylene is a gas that forms through the breakdown of methionine, which is in all cells. Ethylene has very limited solubility in water and does not accumulate within the cell but diffuses out of the cell and escapes out of the plant. Its effectiveness as a plant hormone is dependent on its rate of production versus its rate of escaping into the atmosphere. Ethylene is produced at a faster rate in rapidly growing and dividing cells, especially in darkness.

Pine apple can made to flower in off season by the application of ................

  1. Zeatin

  2. Ethylene

  3. Short day

  4. Low temperature


Correct Option: B
Explanation:

Ethylene is a simple gaseous PGR. It is synthesised in large amounts by tissues undergoing senescence and ripening fruits. Ethylene is used to initiate flowering and for synchronising fruit-set in pineapples. It also induces flowering in mango. Since ethylene regulates so many physiological processes, it is one of the most widely used PGR in agriculture. The most widely used compound as source of ethylene is ethephon. Ethephon in an aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly. Ethephon hastens fruit ripening in tomatoes and apples and accelerates abscission in flowers and fruits (thinning of cotton, cherry, walnut). It promotes female flowers in cucumbers there by increasing the yield.