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Morgan used Drosophila as experimental m...

Morgan used Drosophila as experimental material because
(a) It cannot be reared and bred under lab conditions
(b) A single mating produce very few offsprings
(c) It has high number of morphologically similar chromosomes
(d) It has a short life span

A

It cannot be reared and bred under lab conditions

B

A single mating produce very few offsprings

C

It has high number of morphologically similar chromosomes

D

It has a short life span

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The correct Answer is:
To solve the question about why Morgan used Drosophila as experimental material, we need to analyze each of the provided options: 1. **Option A: It cannot be reared and bred under lab conditions.** - This statement is incorrect. Drosophila, specifically Drosophila melanogaster (the fruit fly), can be easily reared and bred in laboratory conditions. This characteristic made it a suitable organism for genetic studies. 2. **Option B: A single mating produces very few offspring.** - This statement is also incorrect. In fact, a single mating of Drosophila can produce a large number of offspring. This high fecundity allows researchers to conduct experiments with a substantial sample size. 3. **Option C: It has a high number of morphologically similar chromosomes.** - This statement is misleading. While Drosophila has a manageable number of chromosomes (8 in total), they are not morphologically similar. The chromosomes can be distinguished from one another, which is important for genetic studies. 4. **Option D: It has a short life span.** - This statement is correct. Drosophila has a short life span of about 2 weeks, which allows for rapid generation turnover. This characteristic is advantageous for genetic experiments, as researchers can observe multiple generations in a short period. Based on the analysis, the correct answer is **Option D: It has a short life span.**
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Morgan worked with Drosophila melanogaster because. i) they complete their life cycle in two months. ii) male and female are easily distinguishable. iii) a single mating could produce a large number of progeny flies. iv) it has many types of hereditary variations that can be seen with low power microscopes.

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The main application of osmotic pressure measurement is in the determination of the molar mass of a substance which is either slightly soluble or has a very high molar mass such as proteins, polymers of various types and colloids.This is due to the fact that even a very small concentraion of the solution produces fairly large magnitude of osomotic pressure.In the laboratory the concentrations usually employed are of the order of 10^(-3) to 10^(-4) M.At concentration of 10^(-3) mol dm^(-3) , the magnitude of osmotic pressure of 300 K is : P=10^(-3)xx0.082xx300=0.0246 atm or 0.0246xx1.01325xx10^5=2492.595 Pa At this concentration, the values of other colligative properties such as boiling point elevation and depression in freezing point are too small to be determined experimentally. Further polymers have following two types of molar masses : (A) Number average molar mass (barM_n) , which is given by (undersetisumN_iM_i)/(undersetisumN_i) where N_i is the number of molecules having molar mass M_i . (B) Molar average molar mass (barM_m) , which is given by (undersetisumN_iM_i^2)/(undersetisumN_iM_i) Obviously the former is independent of the individual characteristics of the molecules and gives equal weightage to large and small molecules in the polymer sample.On the other hand later gives more weightage to the heavier molecules.Infact with the help of a colligative property only one type of molar mass of the polymer can be determined. One gram each of polymer A (molar mass=2000) and B(molar mass=6000) is dissolved in water to form one litre solution at 27^@C .The osmotic pressure of this solution will be :

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AAKASH INSTITUTE ENGLISH-PRINCIPLES OF INHERITANCE AND VARIATION-Exercise
  1. Select the odd one out w.r.t chromosomal theory of inheritance

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  2. The term gene for Mendellan factor was coined by

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  3. Morgan used Drosophila as experimental material because (a) It cannot ...

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  4. Who carried out several dihybrid crosses in Drosophila to study genes...

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  5. Female Drosophila is (a) Smaller in size than male (b) Larger in siz...

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  6. Find the odd one out w.r.t complete linkage

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  7. A condition where an individual heterozygous for two pairs of linked g...

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  8. How many linkage groups are present in human male? (a) 24 (b) 23 ...

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  9. What is the recombination percentage between gene y and w in Drosophi...

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  10. Find the incorrect statement w.r.t chromosomal mapping

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  11. Individuals having homomorphic sex-chromosomes produce (a) One type of...

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  12. Holandric genes are present on (a) X-chromosomes (b) Y-chromosomes ...

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  13. Mark the incorrect pair (w.r.t sex determination) (a) ZW-ZZ type - Fi...

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  14. 50% sperms are devoid of sex-chromosomes in (a) Melandrium (b) Mo...

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  15. In the XX-XO type of sex chromosomes in (a) Females produce only o...

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  16. Select the odd one out w.r.t genic balance theory of sex-determinatio...

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  17. Environmental mechanism of sex-determination is seen in

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  18. Select the odd one out w.r.t haemophilia

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  19. Select the correct match

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  20. All sex limited traits, except

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