This set of Class 12 Biology Chapter 2 Multiple Choice Questions & Answers (MCQs) focuses on “Reproduction in Flowering Plants – Structure of a Pollen Grain”.
1. Pollen grain protoplast is _______
Explanation: Pollen grain protoplasts are uninucleate at the beginning but at the time of liberation it becomes 2 or 3 celled. Pollen grains are the male gametes. They are present inside the pollen sacs.
2. Cytoplasm of the pollen grains are rich in _______
Explanation: The cytoplasm is rich in starch and unsaturated oils. Unsaturated oils protect the cell or rather chromosome from radiation damage. It prevents mutation of the chromosome, ensuring the genes are protected.
3. Wall of pollen grain is called as ________
Explanation: Pollen grains are the male gametes. They’ve a wall like protective covering. Sporoderm is the wall or covering of the pollen grain. It has two layers. Exine-the outer layer and intine-the inner layer.
4. Intine is ____ in nature.
Explanation: Pollen grains are covered by sporoderm which constitute 2 layers, the exine (outer) and intine (inner). Intine is pectocellulosic in nature. At certain places it contains enzymatic proteins.
5. Exine is made up of ____
a) vascular strands
d) meristematic cells
Explanation: Exine forms the outer layer of the pollen grain. It is made of sporopollenin. It basically helps in providing protection. Sporopollenin is chemically inert and is not broken down or degraded by enzymes.
6. Sporopollenin helps preserve pollen grains as microfossils.
Explanation: Sporopollenin is not affected by high temperatures, enzymes, strong acids and strong alkalis. Sporopollenin does indeed preserve the pollen grains like microfossils because of its features.
7. Exine is further differentiated into two parts.
Explanation: Exine possesses proteins for enzymatic and compatibility reactions. Exine is further differentiated into outer ektexine (sexine) and and inner endexine (nexine).
8. Which of the following is a part of the ektexine?
Explanation: Ektexine is a part of the exine which forms the outer covering. Ektexine is further made up of an inner continuous foot layer, a middle discontinuous baculite layer and outermost discontinuous tectum.
9. What is palynology?
a) Study of internal morphology of pollens
b) Study of anthers
c) Study of external morphology of pollens
d) Study of young pollens
Explanation: Palynology is the study of the external morphology of mature pollen grains. Helps experts to identify the species, genus, family, nature, etc.
10. What is exine covered by?
Explanation: The exine is spiny to help attach itself to insects for pollination. This exine is covered by a sticky, yellow, oily covering called pollenkit. Its made up of lipids and carotenoid.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
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