Polytene chromosomes, Biology

POLYTENE CHROMOSOMES

  1. First seen by Balbiani in salivary glands of larva of Chironomus insect (belongs to order Diptera). Later on such chromosomes observed in several other insects (Drosophila).
  2. Polytene name proposed by Koller.
  3. Polytene Chromosomes composed of many Chromonema (512 to several thousands).
  4. In stained preparation, polytene Chromosomes appear striped with alternate dark and light bands. Dark band have high amount of histone.
  5. Several puffy and swollen areas are seen on polytene Chromosomes. These called Balbiani rings or puffs.
  6. Balbiani rings are site of rapid. m-RNA synthesis.
  7. Ecdyson hormone (moulting hormone) of insects stimulates formation of balbiani rings.
  8. Polytene chromosomes concerned with metamorphosis in insects.

2054_polytene chromosomes.png

Posted Date: 10/8/2012 3:12:54 AM | Location : United States







Related Discussions:- Polytene chromosomes, Assignment Help, Ask Question on Polytene chromosomes, Get Answer, Expert's Help, Polytene chromosomes Discussions

Write discussion on Polytene chromosomes
Your posts are moderated
Related Questions

Q. How is the yolk sac formed? What is the function of the yolk sac? The yolk sac is formed from the covering of the vitellus by few cells originated from the primitive gut.

What is Isonietric Exercise in dynamic auscultation ? Can be carried out by doing handgrip exercise which is sustained over 20-30 second. It results in transient increase in SV

Q. What is the treatment process of mitral stenosis? Presence of symptoms or any complications is an indication for treatment. Apart from penicillin prophylaxis no other treatm

Explain Difficult Feeding and Poor Growth to recognition of congenital heart disease? Difficult Feeding and Poor Growth: The parent of an infant with CHD may complain that the

Why is the human placenta referred to as haemochorial type? Name the hormone it secretes to facilitate parturition.

Define functions of Organic Phosphorus? It is involved in the following reactions/components: a) Structural component of nucleic acids: It is important component of DNA and

Describe the uses of pupil Variation in the size, shape or reaction usually indicates some form of disease, disorder or use of medication. The pupil is usually dilated by the u

Hepatitis A/B  A combination vaccine containing the same antigenic components as  Engerix-B and pediatric  Havrix (Twinrix - GlaxoSmithKline) is available for patients >18 year

Define Dietary habits factor for obesity? You are aware that a positive energy balance is one of the major contributory factors for obesity. Some people are in the habit of eat