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प्रश्न
State how does meiosis maintains chromosome number in a species.
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उत्तर
The gametes are formed by meiosis. During meiosis the number of chromosomes is reduced to half i.e. the gametes contain haploid number of chromosomes. The male and female gametes fuse to form a diploid zygote. In this way meiosis maintains chromosome number in a species.
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संबंधित प्रश्न
Synthesis phase in the cell cycle is called so, because of the synthesis of more:
A. RNA
B. RNA and proteins
C. DNA
D. Glucose
State the exact location of the Centromere
Chromosomes get aligned at the centre of the cell during:
A. Metaphase
B. Anaphase
C. Prophase
D. Telophase
Give appropriate biological or technical terms for the following :
The condition in which a pair of chromosomes carries similar alleles of a particular character.
What are genes?
Given below is a schematic diagram of a portion of DNA.
- How many strands are shown in the diagram?
- How many nucleotides have been shown in each strand?
- Name the parts numbered 1, 2, 3, 4 and 5 respectively.
- Name the DNA unit constituted by the parts 1, 2, 3 collectively.
Choose the best option out of the four alternatives a, b, c and d
Question 1:
The number of chromosomes in a certain type of cell division is halved. This kind of cell
division occurs in.
(a) Only testis
(b) Only ovary
(c) Both ovary and testis
(d) All body cells
Humans have 46 chromosomes. Their sperms and eggs will have ______ chromosomes each.
Mention whether the following statement is (T) Or (F). Give reason in support of your answer.
The unfertilized human egg has half the number of chromosomes of the body cells.
Choose the correct answer:
During mitosis which of the following disintegrate ___________
Mention the contribution of the scientist given below in the study of chromosome:
Balbiani
Choose the correct answer:
A 'V' shaped chromosomes has to _____________
Give Reasons for the following
The meiosis is called reductional division
Differentiate between
Gametic meiosis and Zygotic meiosis.
(i) Draw a neat labeled diagram to show the metaphase stage of mitosis in an animal cell having ‘6’ chromosome.
(ii) How many daughter cells are formed at the end of mitosis and at the end of meiosis?
(iii) With reference to cell division explain the following terms:
(Chromatid, Centromere, Haploid).
(iv) Name the type of cell division that occurs during:
1. Growth of shoot 2. Formation of pollen grains.
3. Repair of worn out tissues.
Multiple Choice Question:
How many chromosomes are found in a cell of humans?
Complete the following sentence with appropriate word:
The chromosomal theory of inheritance was proposed by ____________in 1902.
What is allosome?
Identify the odd one:-
The sex of the newborn child is a matter of chance and neither of the parents may be considered responsible for it. What would be the possible fusion of gametes to determine the sex of the child?
