Polytene chromosomes, Biology

Assignment Help:

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


Related Discussions:- Polytene chromosomes

Define tuberculosis, Define tuberculosis Tuberculosis (TB) is still a p...

Define tuberculosis Tuberculosis (TB) is still a problem in the United States, even though the incidence continues to decline in most of the country. Treatment of TB can be div

Why d scientists pick hydrogen as the basis for mri scanning, Why d scienti...

Why d scientists pick hydrogen as the basis for MRI scanning? Name of the human body that do not appear in an MRI scan. Explain thermal stratification? How does thermal stratifi

Trihybrid cross between two true-breeding homozygous, Which of the followin...

Which of the following statements is true regarding a trihybrid cross between two true-breeding homozygous individuals with contrasting phenotypes? Which of the following statement

Action of natural selection in changing environments, Directional or progre...

Directional or progressive selection is the mode of selection associated with environmental change. We said earlier that in an unchanging environment stabilising selection removes

Explain the process of nucleotide catabolism, Question 1 Write a short not...

Question 1 Write a short note on the following Free Energy Cori cycle Fermentation Pentose phosphate pathway Transamination Allosteric Regulation Qu

Dinoflagellates, Dinoflagellates are single-celled to colonial protistans ...

Dinoflagellates are single-celled to colonial protistans characterized by the two flagella, one girdling cell and the other trailing the cell. Some of the dinoflagellates exist in

What is the water cycle, Q. What is the water cycle? The water cycle re...

Q. What is the water cycle? The water cycle represents the recycling and circulation of water in nature. The Liquid water on the planet surface is heated by the sun and turns i

Importance of intestinal bacterial synthesis - vitamin k, Define Importance...

Define Importance of Intestinal Bacterial Synthesis as a Source of Vitamin K? Intestinal microflora synthesizes large amounts of menaquinones, which are potentially available a

Explain the recommended dietary allowance for nicotinic acid, Explain the R...

Explain the Recommended Dietary Allowance for nicotinic acid? There are various factors and which niacin requirements depend. These are energy Utilization, body size and dietar

What are the micronutrients, What are the Micronutrients   All the micr...

What are the Micronutrients   All the micronutrients except molybdenum, boron and chlorine are available more in acid soils. These elements may limit plant growth either becaus

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd