12th Grade > Biology
GROWTH & REPRODUCTION IN PLANTS AND ANIMALS MCQs
Plant Growth And Development, Reproduction In Animals, Sexual Reproduction In Flowering Plants
Total Questions : 111
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Answer: Option D. -> No fertilisation
:
D
In sexual reproduction, one male gamete and one female gamete fuse to form the zygote and this process is called fertilisation. The zygote undergoes several cell divisions to form a new individual. The new individuals (offsprings) formed are genetically and morphologically different from the parents.. Hence, sexual reproduction accounts for variation.
:
D
In sexual reproduction, one male gamete and one female gamete fuse to form the zygote and this process is called fertilisation. The zygote undergoes several cell divisions to form a new individual. The new individuals (offsprings) formed are genetically and morphologically different from the parents.. Hence, sexual reproduction accounts for variation.
Answer: Option B. -> Angiosperms
:
B
Angiosperms include about 250,000 species and are the most recently and highly evolved plants on Earth. Genetic variation is easily possible only in the case of sexual reproduction as it involves the fusion of genetically unique male and female gametes. And since variations and adaptations are the primary drivers for evolution, this has led to angiosperms becoming highly evolved plants.
:
B
Angiosperms include about 250,000 species and are the most recently and highly evolved plants on Earth. Genetic variation is easily possible only in the case of sexual reproduction as it involves the fusion of genetically unique male and female gametes. And since variations and adaptations are the primary drivers for evolution, this has led to angiosperms becoming highly evolved plants.
Answer: Option B. -> Sporogenous cells, pollen mother cells, pollen grains
:
B
Sporogenous tissue undergoes mitosis and forms pollen mother cells (PMC) ormitocytes. These mitocytesundergo meiosis and formhaploid microspores(meiocytes) that ultimately mature andformpollen grains that are also termedmeiospores.
:
B
Sporogenous tissue undergoes mitosis and forms pollen mother cells (PMC) ormitocytes. These mitocytesundergo meiosis and formhaploid microspores(meiocytes) that ultimately mature andformpollen grains that are also termedmeiospores.
Answer: Option B. -> Apomixis is similar to self pollination and can lead to stagnation of species
:
B
In many plants, the normal process of sexual reproduction is substituted by an asexual process and as a result seeds are produced without fertilisation. This phenomenon of substituting the usual sexual process by asexual methods is known as Apomixis and plants which show this condition are called apomictic plants. Self-pollination and apomixis lead to no genetic recombination and produce pure lines similar to the parent plant.
:
B
In many plants, the normal process of sexual reproduction is substituted by an asexual process and as a result seeds are produced without fertilisation. This phenomenon of substituting the usual sexual process by asexual methods is known as Apomixis and plants which show this condition are called apomictic plants. Self-pollination and apomixis lead to no genetic recombination and produce pure lines similar to the parent plant.
Answer: Option A. -> (i) 80 & (ii) 20
:
A
Total megaspores produced by 20 ovules = 20 × 4 = 80.
In each tetrad only one is functional megaspore.
Therefore, the no. of functional megaspores = 20.
:
A
Total megaspores produced by 20 ovules = 20 × 4 = 80.
In each tetrad only one is functional megaspore.
Therefore, the no. of functional megaspores = 20.
Answer: Option D. -> Endosperm
:
D
Fertilisation in angiosperms involves two important events - synagamy and triple fusion. In syngamy, the egg (n) and the sperm (n) fuse in the embryo sac to form a diploid zygote which develops into an embryo and in triple fusion, another sperm (n) released in the embryo sac fuses with central nucleus (2n) to form triploid primary endosperm nucleus which develops into an endosperm. Microspore and megaspore are the haploid spores which further develop or become gametophytes in flowering plants.
:
D
Fertilisation in angiosperms involves two important events - synagamy and triple fusion. In syngamy, the egg (n) and the sperm (n) fuse in the embryo sac to form a diploid zygote which develops into an embryo and in triple fusion, another sperm (n) released in the embryo sac fuses with central nucleus (2n) to form triploid primary endosperm nucleus which develops into an endosperm. Microspore and megaspore are the haploid spores which further develop or become gametophytes in flowering plants.
Answer: Option C. -> (i)-Thalamus, (ii)-Mesocarp, (iii)-Endocarp, (iv)-Seed
:
C
Apple is afalse fruit where the entire fruit develops from the thalamus. Thefruit wall is differentiated intoouter epicarp, middle mesocarp andinner endocarp. Inner to the endocarp is the ovary which houses the seeds.
:
C
Apple is afalse fruit where the entire fruit develops from the thalamus. Thefruit wall is differentiated intoouter epicarp, middle mesocarp andinner endocarp. Inner to the endocarp is the ovary which houses the seeds.
Answer: Option A. -> Virus-free clones
:
A
Polyembryony is the formation of more than one embryo from a single fertilised ovum or in a single seed. Polyembryony is of great significance in horticulture and plant breeding.We know that in vegetative propagation new plants obtained can be considered as a clone of the parent plant. Similar to this polyembryony also produces uniform seedlings of the parental type. The clones formed are also free from diseases. In fact polyembryony is the only practical approach to raise virus-free clones.
:
A
Polyembryony is the formation of more than one embryo from a single fertilised ovum or in a single seed. Polyembryony is of great significance in horticulture and plant breeding.We know that in vegetative propagation new plants obtained can be considered as a clone of the parent plant. Similar to this polyembryony also produces uniform seedlings of the parental type. The clones formed are also free from diseases. In fact polyembryony is the only practical approach to raise virus-free clones.
Answer: Option A. -> True
:
A
The living differentiated cells that by now have lost the capacity to divide can regain the capacity of division under certain conditions. This phenomenon is termed as dedifferentiation.
:
A
The living differentiated cells that by now have lost the capacity to divide can regain the capacity of division under certain conditions. This phenomenon is termed as dedifferentiation.