Tag: biology

Quizzes (1160) Questions (12174)

Questions Related to biology

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Photosynthesis in CAM-plants in minimal because of the limited amount of _________________.

  1. $CO _{2}$ fixed at night
  2. $O _{2}$ fixed at night
  3. $O _{2}$ fixed at day light
  4. $CO _{2}$ fixed at day light
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CAM plants fix CO2 at night to minimize water loss. The total amount of photosynthesis is limited by the amount of CO2 they can fix during the night, which is stored as organic acids.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

  1. Increasing atmospheric $CO _{2}$ concentration up to $0.05$% can enhance $CO _{2}$ fixation rate
  2. $C _{3}$ plants respond to higher temperatures with enhanced photosynthesis while $C _{4}$ plants have much lower temperature optimum
  3. Tomato is a greenhouse crop which can be grown in $CO _{2}$ - enriched atmosphere for higher yield

  4. None of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

What would happen if green plants disappear from earth?

  1. Only herbivores die

  2. Only carnivores die

  3. No one dies

  4. Both herbivores and carnivores die
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Green plants are the sources of food and energy for all organisms. If all green plants disappear from the earth, all the herbivores will die due to the absence of food and so will the carnivores.

So, the correct answer is option D.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

The classical experiments on growth were performed by

  1. Lamarck and Boysen Jensen

  2. Boysen Jensen and Darwin

  3. Darwin and Lamarck

  4. Lamarck and Darwin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Charles Darwin and Francis showed  the presence of the phototropic stimulus at the tip of the plant and that the apical region communicates with the cell of elongation zone. The Danish plant physiologist Boysen-Jensen experimentally showed that the apex cells communicate with the the cell of elongation zone via chemical passing down from the tip of the coleoptile. Lamarck gave the theory of inheritance of acquired characters that explains evolution as the inheritance of acquired characters under influence of needs as posed as changing environmental conditions. Thus, the correct answer is option B.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Ultrafiltration theory for permeability of cell membrane was put forth by

  1. Traube

  2. Ruhland

  3. Sachs

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

W. Ruhland (1912) and Hoffman (1925) put forth the ultrafiltration theory and describe that small pores are found on the membrane of the molecules, which are small in size than pores of the membrane are only passed through membranes.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Meaningful girdling (ringing) experiment cannot be done on sugarcane because

  1. Phloem is present inside the xylem.

  2. It can not tolerate the injury.

  3. Vascular bundles are scattered.

  4. Plants are very delicate.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Monocots have scattered vascular bundles, while dicots have a continuous ring arrangement of vascular bundles. In a dicot stem, after a few years of growth, phloem is present as a single continuous layer or sheet on the outer side as a constituent of bark. 
  • It can be easily removed because it is present as a continuous sheet. In a similar manner phloem cannot be removed in a monocot stem, because of the scattered arrangement, some of the vascular bundles might be present near the surface and some embedded deep inside. 
  • Removing phloem from each of the bundles individually is not possible. The girdling experiment is used to identify the tissue through which food is conducted. In this experiment, a ring of phloem is removed from the woody plant. 
  • Hence girdling experiments cannot be performed on a monocot stem-like sugarcane.
Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

A small mesophytic twig with green leaves is dipped into water in a big beaker under sunlight. It demonstrates

  1. Photosynthesis

  2. Respiration

  3. Transpiration

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There will be loss of water through the leaves if the beaker is kept covered. Otherwise direct evaporation of water from free surface will also happen. The purpose of this experiment is to demonstrate transpiration, which is loss of water through leaves of plants in vapour form.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Who proposed the retention pressure theory for the permeability of the membrane?

  1. Traube

  2. Overton

  3. Cocking

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Traube (1867) proposed his ''Haftdruck'' or retention pressure theory. According to this theory, the permeation of solutes through a membrane depended on their relative affinity towards the membrane substance as compared to that of water.

Multiple choice biology the leaf mechanism of absorption mineral absorption significance of transpiration

Which of the following is the significance of photosynthesis?

  1. Balance of carbon dioxide and oxygen

  2. Balance of nitrogen in the environment

  3. Provides food

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

In the atmosphere, plants prepare food due to photosynthesis and release oxygen and animals release carbon dioxide by respiration. Animals inhale oxygen released by plants and plants use carbon dioxide for the process of photosynthesis. Hence balance of carbon dioxide and oxygen is maintained by photosynthesis. Plants use energy from sunlight to turn water and carbon dioxide into an energy-rich sugar called glucose.which is stored as starch inside the plant body. Plants provide food in the form of carbohydrates(glucose and starch).

So, the correct answer is 'Both A and C'.