This set of Class 12 Biology Chapter 1 Multiple Choice Questions & Answers (MCQs) focuses on “Pre-Fertilisation Events in Sexual Reproduction”.
1. What are the 2 main pre fertilization events?
a) Gamete transfer and fertilization
b) Gamete transfer and gametogenesis
c) Gametogenesis and fertilization
d) Gametogenesis and cell division
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Explanation: Gametogenesis refers to the formation of the gametes. In sexual reproduction formation of gametes is very important since an offspring is formed only after the fusion of the gametes. Gamete transfer refers to bringing the 2 gametes together.
2. Gametes are diploid.
a) False
b) True
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Explanation: Gametes are haploid. In gametogenesis, during the fusion of 2 gametes (male + female), 2 haploids make a diploid. The nucleus of the 2 gametes fuses which makes the zygote or egg diploid.
3. The male gamete is called as ___________
a) Antherozoid
b) Egg
c) Isogametes
d) Fucus
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Explanation: Male gamete is called antherozoid or sperm. They are called so in heterogametes. The two gametes produced are morphologically distinct types. The female gamete is called egg or ovum.
4. What are the male organs in a flowering plant called?
a) Carpels
b) Petals
c) Ovary
d) Stamen
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Explanation: Stamens are the male organs of a flower. Flowers maybe unisexual (either staminate or pistillate). In staminate plants only the male part, that is the stamen, is present and in the pistillate plants only the female part is present (ovaries). In bisexual plants, both are present.
5. Cucurbits and coconuts are examples of _______
a) Polycious
b) Dioecious
c) Trioecious
d) Monoecious
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Explanation: A plant having both reproductive organs in the same plant is known as monoecious plants. It may also be known as homothallic conditions. Dioecious plants are those which have only one reproductive organ, also known as unisexual plants. Another word for dioecious plants is heterothallic.
6. Which of the following is an example of a unisexual organism?
a) Earthworm
b) Cockroach
c) Tapeworm
d) Leech
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Explanation: Cockroach is an example of a unisexual organism, which means it can produce only one type of gamete, either male or female. Leech, tapeworm and earthworm are bisexual organisms, organisms that can produce both gametes.
7. Gametes in all ____ species are of 2 types.
a) Heterogametic
b) Homogametic
c) Mongametic
d) Polygametic
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Explanation: All heterogametic species can produce 2 types of gametes, male and female, their sex chromosomes are unidentical. Homogametic species the sex chromosomes are identical.
8. What are the cells in diploid organisms that undergo meiosis called?
a) mitocytes
b) meiocytes
c) polygametes
d) gametes
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Explanation: Meiocytes are cells in diploid organisms that undergo meiosis. Meiosis is the process of producing 4 haploid cells from a single cell that has been divided twice. The haploid cell then becomes diploid after its fusion with the other sex gamete.
9. Which structure in the plant carries the male organ?
a) sperm
b) ovule
c) pollen grain
d) spores
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Explanation: The pollen grains carry the male organ. Mostly the male organs are the motile gamete while the female organ is stationary. It is necessary for the male organs to be small and light for easy propagation by the environmental agents.
10. What is shown in the following image?
a) Ovaries
b) Stamen
c) Anther
d) Filament
View Answer
Explanation: The above picture shows ovaries in the flower. Ovaries are the female reproductive organ in the plant. It is stationary. Plants that are unisexual with the female part are known as pistillate flowers.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
To practice all chapters and topics of class 12 Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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- Check Class 12 - Biology Books
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- Practice Class 12 - Mathematics MCQs
