Advertisements
Advertisements
Question
During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring. What are the processes through which these events take place?
Advertisements
Solution
During gametogenesis, the chromosomal number is reduced by half and then regained through fertilisation.
APPEARS IN
RELATED QUESTIONS
Explain the development of a secondary oocyte (ovum) in a human female from the embryonic stage upto its ovulation. Name the hormones involved in this process.
Briefly describe the process of spermatogenesis.
Implantation of embryo occurs in ______.
______ type of reproduction occurs without fusion of gametes.
In case of sexual reproduction, newborn show similarities about characters. Explain this statement with suitable examples.
Explain the structure of secondary oocyte.
What is gamete formation?
Answer the following type of question Assertion (A) and Reason (R).
(A) - Head of the sperm consists of acrosome and mitochondria.
(R) - Acrosome contains spiral rows of mitochondria.
Give a schematic representation of spermatogenesis and oogenesis in humans.
Expand the acronym.
LH
The immature male germ cells differentiates into ______ at the end of meiosis I.
______ undergoes 2nd meiotic division during spermatogenesis.
The human male gamete is usually about ______ in length.
Which of the following contains a fluid filled cavity called antrum?
How many functional sperms and how many ova will be formed by a primary spermatocyte and a primary oocyte.
Gray crescent is the area ______.
In oogenesis haploid egg is fertilised by sperm at which stage?
Select the correct sequence of stages of spermatogenesis in a human male ______.
Read the following and answer from given below:
Oogenesis is the process of the formation of an ovum in the ovaries. It consists of three phases: multiplication, growth, and maturation. Oogenesis is controlled by hormones GnRH, LH, FSH. GnRH secreted by the hypothalamus stimulates the anterior lobe of the pituitary gland to secrete LH and FSH.
Which cell division is involved in the formation of secondary oocytes?
The number of chromosome groups at the equatorial plate in metaphase-I of meiosis in a plant with 2n = 50 shall be:
In human females, meiosis II is not completed until:
What is the difference between a primary oocyte and a secondary oocyte?
Draw a neat and labelled diagram of spermatogenesis.
Meiotic division of the secondary oocyte completed ______.
The diagram given below shows the various steps in spermatogenesis.
- Name the parts labelled '1', '2' and '3'.
- Name the process by which part '3' changes to part '4'.
Draw a labelled diagram of a section through the ovary.
Match List - I with List - IІ.
| List - I | List - II |
| A. Head | I. Enzymes |
| B. Middle piece | II. Sperm motility |
| C. Acrosome | ΙII. Energy |
| D. Tail | IV. Genetic material |
Choose the correct answer from the options given below:
