Question
Write short notes on the followings : (a) Predation (b) Competition
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Read the following and answer any four questions from (i) to (v) given below: Plants having foreign genes in their genome through genetic engineering are called transgenic plants. Genes can be incorporated either through a vector or through direct introduction of DNA. Bt cotton is a genetically modified organism which is pest resistant. It contain gene cry I Ac and cry II Ab of Bacillus thuringiensis. It is used to control lepidopterans, coleopterans and dipterans. Bt cotton can resist cotton bollworm and produce higher yields. Cry gene produces cry protein or Bt toxin. It is an endotoxin which remains as protoxin in plants and converted to active toxin after getting ingested by the insects. Alkaline pH of the insect gut solubilises the protein crystals, the activated toxin creates pores to the mid guts wall of the insects which cause them to death.
- Bt cotton crops are:
- Fungal resistant.
- Insect resistant.
- Drought resistant.
- All of these.
- Cotton bollwonns are killed by the protein encoded by the gene:
- cry I Ac
- cry I Ab
- cry I Ab
- Both (a) and (c).
- Which of the following is not an advantage of GM crops?
- GM plants enhance nutritional value of food.
- GM plants are more tolerant to abiotic stresses.
- GM plants have helped to reduce post harvest losses.
- GM plants can cause gene transfer to non-target plant species.
- Bacillus thuringiensis is a:
- Air borne bacteria.
- Soil borne bacteria.
- Soil borne fungus.
- Food borne bacteria.
- Assertion: Cotton bollworms are killed by ingesting the leaves of the transgenic plant.
Reason: Bt toxin binds with the midgut wall of the insect and make pores in them.
- Both assertion and reason are true and reason is the correct explanation of assertion.
- Both assertion and reason are true but reason is not the correct explanation of assertion.
- Assertion is true but reason is false.
- Both assertion and reason are false.
In the given flow diagram, the replication of retrovirus in a host is shown. Observe and answer the following questions,
- Fill in (1) and (2).
- Why is the virus called retrovirus?
- Can the infected cell survive while viruses are being replicated and released?
Identify a, b and c in the table given below:
| S. No. | Pattern of inheritance | Monohybrid F1 phenotypic expression |
| (i) | Co–dominance | a |
| (ii) | b | The progeny resembled only one of the parents. |
| (iii) | Incomplete dominance | c |
Explain how xerarch succession progresses from serie to mesic condition and forms a stable climax community. You may use a flow chart.
Match the items of column A with those given in column B.
| S. No | Column A | S. No | Column B |
| (i) | Eli Lilly | (a) | Cotton bollworm |
| (ii) | Pest resistance | (b) | Meloidegyne incognitia |
| (iii) | Crylab | (c) | Golden Rice |
| (iv) | CryIAC | (d) | Humulin |
| (v) | RNAi | (e) | Corn borer |
| (vi) | Vitamin A | (f) | Bt cotton |
Define an operon. giving an example, explain an Inducible operon.
- With labelled diagrams, depict the stages in embryo development in a dicotyledonous plant.
- Endosperm development precedes embryo development. Why?
(a) Write the name of primates existing on earth about 15 million years ago. Write its important characteristics also?
(b) (i) From where did the animals similar to human being meet?
(ii) In which sequence were neanderthal, homohabilis and homo erectus evolved on earth?
(iii) When did modern man evolve on this planet?
(b) (i) From where did the animals similar to human being meet?
(ii) In which sequence were neanderthal, homohabilis and homo erectus evolved on earth?
(iii) When did modern man evolve on this planet?
List three strategies that a bisexual chasmogamous flower can evolve to prevent self pollination (autogamy).
Placenta acts as an endocrine gland. Explain.