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प्रश्न
Answer the following question in your own words.
What is meant by ‘chromosome’?
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 |
Choose the correct answer:
Thick short chromosomes can be observed at (in mitosis) ___________
Choose the correct answer:
Chromosomes largely consist of _______________
Give a reason for the following:
Gametes must be produced by meiosis for sexual reproduction.
Identify the stages of meiosven below and label them.
Explain the Term Chromosomes
Name the following:
The part of the cell associated with heredity.
Give Technical Terms
The stage at which the formation of chiasmata occurs.
State the Location: Polytene chromosome
Multiple Choice Question
Chromosomal aberrations are caused by:
With the help of a neat labelled diagram, describe the structure of chromosome.
Describe the structure of sex chromosomes with the help of labelled diagram.
The centromere is found at the centre of the ______ chromosome.
The loss of one or more chromosomes in ploidy is called ______.
______ is a sudden permanent heritable change that can occur in the gene, in the chromosome or chromosome number.
Which of the following type of chromosomes has only one telomere?
The two non-sister chromatids of a paired chromosome are attached to each other at ______ during the process of crossing over.
