Advertisements
Advertisements
प्रश्न
Name two main processes of sexual reproduction
उत्तर
Two main processes of sexual reproduction:
(1) Meiosis: It is a process of cell division in which the chromosome number is reduced to half to form haploid gametes (2n→n).
(2) Fertilisation: The union of the haploid male gamete with the haploid female gamete to form the diploid zygote is called fertilisation. By fertilisation, the chromosome number again becomes diploid (2n).
APPEARS IN
संबंधित प्रश्न
Write one difference between asexual and sexual mode of reproduction.
How does reproduction help in providing stability to populations of species?
A zygote is formed as a result of fertilisation.
Differentiate between internal fertilization and external fertilization.
Which species is likely to have better chances of survival - the one reproducing asexually or the one reproducing sexually? Justify your answer.
Name two animals which reproduce sexually.
Name the male and female gametes in animals.
Define sexual reproduction.
What are gametes?
Describe the various steps involved in the sexual reproduction in animals. Draw labelled diagrams to show the fertilisation of an ovum (or egg) by a sperm to form a zygote
Characters that are transmitted from parents to offspring during sexual reproduction show :
(a) only similarities with parents
(b) only variations with parents
(c) both similarities and variations with parents
(d) neither similarities nor variations with parents
The number of chromosomes in parents and offsprings of a particular species remains constant due to :
(a) doubling of chromosomes after zygote formation
(b) halving of chromosomes during gamete formation
(c) doubling of chromosomes after gamete formation
(d) halving of chromosomes after gamete formation
The offsprings formed as a result of sexual reproduction exhibit more variations because ______
Distinguish between the following pair of terms:
Sexual reproduction and asexual reproduction.
Differentiate between the following:
Sperm and Ovum
Mention the common method of reproduction in Amoeba.
Mention the common method of reproduction in Flatworm.
Mention the changes which occur during adolescence in humans.
Adolesecence is considered a critical stage in the life of boys and girls. Explain this statement.
“The chromosomes number of the sexually reproducing parents and their offspring is the same.” Justify this statement.
Explain why variations are observed in the offsprings of sexually reproducing organisms?
What are seasonal breeders? Give an example.
Answer in one sentence.
Outline the path of sperm upto the urethra.
Give an account of external genitalia in human females.
Write an account of the seminal vesicle and bulbourethral gland in the male reproductive system.
Animals which give birth to young ones directly are named as ______.
What are the different stages of sexual reproduction?
Choose the correct statement from the following:
Name an organism where cell division is itself a mode of reproduction.
Animals giving birth to young ones: ______
The end of vegetative phase in plants which marks the beginning of the reproductive phase can be easily seen in the higher plants when they come to ______.
______ is the first stage of sexual reproduction.
______ lay thousands and sometimes millions of small, soft eggs in water.
Reproduction is essentially a phenomenon that is not for survival of an individual but for the stability of a species. Justify.
Sexual reproduction is characterized by ______
Which is a better mode of reproduction, sexual or asexual? Why?
Explain how stability of the DNA of the species is ensured in sexually reproducing organisms.
