Download App

Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance5 Marks
Question
Study the flow chart given below and answer the questions that follow:
  1. S strain into mice mice die.
  2. R strain into mice → mice live.
  3. Heat killed S strain + live R strain into mice → A
  4. Heat killed S strain + DNase + live R strain → into mice B
  1. Name the organism and differentiate between its two strains, R and S, respectively.
  2. Write the results A and B obtained in steps (e) and (d), respectively.
  3. Name the Scientist who performed the steps (a), (b) and (c).
  4. Write the specific conclusion drawn from the step (d).
✓

Answer

  1. Streptococcus pneumoniae:
  1. R-cells are those cells that form rough colonies, without a capsule and are non-virulent, i.e., they did not cause pneumonia.
  2. S-cells are those cells that form smooth colonies, protected by a capsule and are virulent, i.e., they caused the disease, pneumonia.
  3. He showed that DNA is the transforming principle.
  1. A. Mice died of pneumonia. B. Mice lived and did not suffer from pneumonia.
  2. Frederick Griffith performed the steps (a), (b) and (c).
  3. This indicates that DNA is the transforming principle.

When DNase is added to the medium, the DNA of the heat-killed cells gets digested and is unable to carry out the transformation.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Long Answer Type Questions [5M]" from Molecular Basis of Inheritance→Molecular Basis of Inheritance — all question types→BIOLOGY STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

(i) Explain the significance of each of the following features present in plants given below:, (a) In rose-bay plant the stamens ripen before the stigma., (b) In certain species of primrose, the flowers have short stamen and long style., (c) The bisexual flower of mustard exhibits rejection of self-pollen grain., (ii) Explain how autogamy is prevented in castor and papaya plant respectively.
→
In a court of law, two couples X and Y, claim a child Z of blood group O belongs to them. Couple X has man with blood group O and woman with blood group AB. Couple Y has man with blood group A and woman with blood group B. So, a geneticists helped in solving the problem but the judge ordered the= use of more recent and advance techniques and then the child was handed over ultimately to couple Y.
  1. Is it a correct judgement regarding the true/ biological parents of the child? Justify with your knowledge of genetics.
  2. Name the other technique that the judge has ordered for solving this problem.
  3. Indicate the value(s) exhibited by the judge.
→
(i) Define the cross-pollination.
(ii) Give one example each of aluminious, exalbuminous, perispermic seeds.
(iii) Draw a well labelled diagram showing the growth of pollen tube in longitudinal section of pistil.
→
List any two major causes other than anthropogenic causes of the loss of biodiversity.
→
Fill in the blanks,
Species A
Species B
Type of Interaction
Example
+
+
+
-
+
_____
_____
_____
Commensalism
_____
_____
_____
→
Mention any two autosomal genetic disorders with their symptoms.
→
Describe about gastrulation and formation of germinal cartex with the help of a diagram.
→
  1. Following are the responses of different animals to various abiotic factors. Describe each one with the help of an example.
  1. Regulate.
  2. Conform.
  3. Migrate.
  4. Suspend.
  1. If 8 individuals in a population of 80 butterflies die in a week, calculate the death rate of population of butterflies during that period.
→
Suggest some methods to assist infertile couples to have children.
→
Draw a diagrammatic sketch of the sectional view of a typical anatropous ovule.

OR

Draw a labelled diagram of the sectional view of a typical anatropous ovule.

→