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प्रश्न
Answer the following question in your own words.
What is meant by ‘chromosome’?
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उत्तर
The structure in the nucleus of cells that carries the hereditary characteristics is called the chromosome. It is made up mainly of nucleic acids and proteins. During cell division chromosomes can be clearly seen under the compound microscope. ‘Genes’ which contain the information about hereditary characteristics in coded form are located on chromosomes. Each species has a specific number of chromosomes.
Each chromosome is made up of DNA and it appears dumbell-shaped midway during cell division. There is a constricted region on each chromosome. It is called the ‘Primary constriction’ or ‘Centromere’. This divides the chromosome into two parts. Each part is called an ‘arm’. The centromere has a specific position in each chromosome.
Organization of chromosome
APPEARS IN
संबंधित प्रश्न
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 |
Fill in the blank
The _______ (s) are surrounded by radiating rays called aster
Choose the correct answer:
Centromere is related to ________
Mention the contribution of the scientist given below in the study of chromosome:
Strasburger
Mention the contribution of the scientist given below in the study of chromosome:
Waldeyer
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?
The number of chromosomes in a certain type of cell division is halved. This kind of cell division occurs in ______.
Give Reasons for the following
The meiosis is called reductional division
Give Reasons for the following
Chromosomes are the carriers of heredity.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Chromosomes other than sex-chromosomes are autonomous.
Name the following:
The number of chromosomes present in human gametes.
Complete the following sentence with appropriate word:
The number of chromosomes in humans is ________.
Compare X chromosome and Y chromosome.
Describe the structure of sex chromosomes with the help of labelled diagram.
The region of the chromosome where the spindle fibres get attached during cell division ______
The thin thread-like structures found in the nucleus of each cell are called ______.
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?
Which of the following type of chromosomes has only one telomere?
Define Aneuploidy.
