CBSE Board Biology Class XII | Sample Paper -1 |
Time: 3 hour
Subject- Biology M.M.-80
All questions are compulsory.
Section – A (1 mark each)
- Who was the first to suggest that codons are triplet?
- Where is sporopollenin found in plants? Give its significance.
- Mention one positive and one negative application of amniocentesis.
- A hemophilic son was born to normal parents. Give the genotype of the parents.
- Give the polarity of the leading and template strands during DNA replication.
- Mention the cause of evolution according Hugo –de-vries.
- Why an AIDS patient does suffers from many other infections?
Section –B (2 mark each)
- The base sequence in one of DNA strand is –
C A T G T A A T C C A G T T C A C T
- Give the base sequence of its complementary strand.
- How are these base links to the pentose sugar?
- Draw a diagram of nucleosome.
- Why rhizobium is called symbiotic ? How does it act as bio fertilizer?
- Mention the factors responsible for the success of green revolution.
- Divergent evolution leads to homologous structures. Explain it with example.
Name four vestigial organs in human and How the support evolution?
- Given above is a lac operon in E.coli. What is the significant role of i gene in switching on or off the operon?
- Red flower Red flower
R r R r
Write the genotype of A, B, C, D
Write the phenotype of A, B, C, D
- Expend ZIFT. Why is it a boon to childless couple? Explain its procedure.
- Draw a labelled diagram of an embryosac of angiospermic flower.
Section—C (3 marks each)
- What is triple fusion? Where and how does it take place? Name the product of triple fusion.
- Write the name and steps A, B, C, D, E, F in the
process given below.
- Name the phenomenon that leads to XO disorder in human. How do human with XO Suffer? Explain .
Explain the Mechanism of sex determination in insect like Drossophila.
- Why in RNA regarded as the first genetic material?
- Write the name, symptoms and causative agents of two helminthic diseases.
- State the views of operin and Haldane on evolution. How does Miller’s experiment support their view?
- Describe the structure and function of anti body with a labelled diagram.
- How does industrial malanism support Darvin’s theory of natural selection? Explain.
Explain pastver’s experiment criticising spontaneous theory.
- Name two diseases each which are transmitted in the following ways.
- Through contaminated food and water.
- Through insect vectors.
- Through air/droplets inhaled.
- Draw a brief sketch of biogas plant with complete labelling.
Long answered — 3×5=15
- Explain the causes, inheritance pattern and symptoms of any two mandalion genetic disorders.
- What is semi conservative DNA replication? How was it experimentally proved and by whom?
Write the function of the following –
- Corpus leutium iii- endometrium v- Frimbrae
- leydig cells iv- germinal epithelium of testes.
- Write short notes on –
- DNA finger printing ii- codominance
Name any five hybrid varieties of crop plants which have been developed in India.