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Question
Explain the structure of chromosomes with labelled diagram.
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Solution
Structure of chromosome:
- A typical chromosome consists of two chromatids joined together at the centromere also known as primary constriction.
- Primary constriction consists of a disk shape plate called the kinetochore. During cell division, spindle fibers get attached to the kinetochore.
- Apart from primary constriction, a few chromosomes possess an additional one or two constrictions called secondary constriction.
- At secondary constriction I (nucleolar organizer), nucleolus becomes organized during interphase.
- A satellite body (SAT body) is attached at secondary constriction II, in very few chromosomes.
- Each chromatid in turn contains a long, unbranched, slender, highly coiled double-stranded DNA thread, called chromonema, extending through the length of the chromatid.
- The ends of chromosomes (i.e. chromatids) are known as telomeres.
A: Parts of chromosomes
B: Showing secondary constrictions and details
Structure of Chromosome
RELATED QUESTIONS
Give appropriate biological or technical terms for the following :
The condition in which a pair of chromosomes carries similar alleles of a particular character.
State the difference between:
Chromosome and chromatid:
Choose the correct answer:
Telocentric chromosomes are _________________
(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?
Long answer type question.
Describe the different types of chromosomes.
The centromere is found at the centre of the ______ chromosome.
The loss of one or more chromosomes in ploidy is called ______.
The thin thread-like structures found in the nucleus of each cell are called ______.
