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प्रश्न
“First meiotic division is the reduction division” what does the word ‘reduction’ refer to in this statement?
उत्तर
In this statement, reduction means that the number of chromosomes are reduced to half i.e. out of the 23 pairs of chromosomes in humans, only single set of chromosomes are passed on to the sex cells.
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संबंधित प्रश्न
Chromosomes get aligned at the centre of the cell during:
A. Metaphase
B. Anaphase
C. Prophase
D. Telophase
Correct the following statement if there is any mistake:
Genes are specific sequences of bases on a chromosome .
Match the events given in column A with the phase in mitotic cell division in column B.
| Column ‘A’ | Column ‘B’ | ||
| 1. | Chromosomes get arranged in a horizontal plane at the equator. |
a. | Anaphase |
| 2. | Daughter chromosomes move to the opposite poles of a spindle |
b. | Prophase |
| 3. | Chromosomes become visible as fine, long threads. |
c. | Telophase |
| 4. | Chromosomes lose their distinctiveness and gradually become transformed into a chromatin network. |
d. | Metaphase |
Answer the following question in your own words.
What is meant by ‘chromosome’?
Choose the correct answer:
In an interphase cell chromosome are as _____________
Label the lettered parts of the given figure and answer the following questions:
(i) What does this diagram represent?
(ii) What is the importance of'd'?
(iii) What are the 'staining' properties of 'b' and 'c'?
(iv) Who gave the term used for this structure today?
(v) What is a?
(vi) Is 'e' present in all chromosomes?
Choose the correct answer:
A 'V' shaped chromosomes has to _____________
What is the importance of meiosis?
Identify the stages of meiosven below and label them.
Give Technical Terms
The stage at which chromosomes occurs reach the opposite poles.
Complete the following sentence with appropriate word :
Polytene chromosomes are found in _________ of fly larvae.
Duplicated chromosomes are joined at a point termed ______.
Give Reason:
The Law of independent assortment holds good for the gene pairs that occur in different pairs of chromosomes.
Identify the odd one:-
The thin thread-like structures found in the nucleus of each cell are called ______.
Define the following term:
Chromosome
In the human male, a sperm contains autosomes and ______.
Distinguish between the following pair:
Karyotype and Karyokinesis
