This set of Tough Life Sciences Questions and Answers focuses on “Embryonic Development”.
1. The process which begins after the fertilization is known as ____________
Explanation: Embryogenesis is the process of multiplication of cells by mitosis and formation of tissues and organs of a living baby. It starts once the egg has been fertilized.
2. The nucleus of the sperm cell is highly condensed and transcriptionally inactive.
Explanation: In the nucleus of the sperm cell normal histones are replaced by a special class of packaging proteins known as protamins which makes the nucleus transcriptionally inactive.
3. Name the type of fertilization where placenta formation does not occur.
Explanation: Ovoviviparous is the condition where fertilization is internal but there is no placenta formation. Example: dog and fishes.
4. Which of the following fertilization category is found in mammals?
Explanation: In viviparous, fertilization is internal and nourishment is provided through placenta by the uterine wall of the mother.
5. Mark the one, which is NOT an egg laying animal?
Explanation: Egg laying animals fall under the category of oviparous. Here fertilization can be internal or external. Fishes are not oviparous but ovoviviparous, they are not egg laying animals.
6. Which of the following is Alecithal?
Explanation: Animals have been categorized according to the amount of yolk in the egg. Alecithal are those organisms which have no yolk in their egg, e.g. mammals.
7. On the type of yolk distribution, which of the following is Telolecithal?
Explanation: On the basis of yolk distribution, the egg has been divided into three types, i.e., isolecithal, telolecithal, and centrolecithal. Telolecithal are those in which heavy yolk is present at a vegetal pole and less yolk at the animal pole, e.g. amphibians.
8. Name the type of eggs which do not have any protective covers?
b) Cleidoic eggs
d) Noncleidoic eggs
Explanation: Noncleidoic eggs laid in Water or develop inside the mother’s body. These eggs do not have any protective covering around them, e.g., amphibians, fishes, and mammals.
9. Which of the following organism has cleidoic eggs?
Explanation: Cleidoic eggs are those which laid on land and have a leathery coat around them for the prevention of its dessication e.g., birds, and reptiles.
10. Which of the following has discoidal cleavage?
Explanation: When the cleavage takes place in the form of a disc-like flat layer above the yolk in the animal pole, it is called discoidal cleavage. Discoidal cleavage is found in bird’s eggs.
Sanfoundry Global Education & Learning Series – Life Sciences.
To practice tough questions and answers on all areas of Life Sciences, here is complete set of 1000+ Multiple Choice Questions and Answers.