Plus Two Botany Model Question Papers Paper 3

Plus Two Botany Model Question Papers Paper 3 is part of Plus Two Botany Previous Year Question Papers and Answers. Here we have given Plus Two Botany Model Question Papers Paper 3

Plus Two Botany Model Question Papers Paper 3

Time: 1 Hours
Cool off time : 10 Minutes

General Instructions to candidates:

• There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hrs.
• Your are not allowed to write your answers nor to discuss anything with others during the ‘cool off,time’.
• Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
• Read questions carefully before you answering.
• All questions are compulsory and only internal choice is allowed.
• When you select a question, all the sub-questions must be answered from the same question’itself.                  ,
• Calculations, figures and graphs should be shown in the answer sheet itself.
• Malayalam version of the questions is also provided.
• Give equations wherever necessary.
• Electronic devices except non programmable calculators are not allowed in the Examination Hall.

Answer all questions. Each question carried 1 score.

Question 1.
Bv observinq the relationship of the first, fill in the blanks.
Unisexual male flower : Staminate
Unisexual female flower : ………………

Question 2.
Johny, a plus two student is from a tribal colony with lower level of vitamins, minerals and protein deficiency. He wishes to be a plant breeder to help the public by producing new crops with high levels of vitamins, minerals, protein etc. Identify the phenomenon.

Question 3.
After syngamy and triple fusion in embryosac, embryo will be diploid and endosperm will be…………….

Question 4.
In some seeds the nucellus may be persistent. Such nucellus is called
a. Endosperm
b. Scutellum
c. Plumule
d. Perisperm

Answer any 10 questions. Each question j carried 2 score.

Question 5.
Raju is searching blight resistant plants for his crossing experiments. Unfortunately no such varieties are available.
a. Suggest a process to create such plants.
b. Justify your suggested method.

Question 6.
Given below is a table which shows the interspecific interaction. ‘ + ’ sign indicates beneficial, sign indicates detrimental and ‘0’ indicates neutral.
a. Fill in the blanks.
Species A        Species B     Interaction
–                             –               Competition
0                            –                …………………
+                            –                …………………
b. Name the interactions where one species is benefited and the other is detrimental.

Question 7.
Given below are 3 gametes a, b and c. a and b gametes undergoes fusion.

a. Identify the fusion.
b. Give the explanation for the identification.

Question 8.
Industrial effluents and domestic sewage seriously affect fresh water bodies. For protecting aquatic life Govt, of India recently declared an animal as national aquatic animal.
a. Identify the animal.
b. Distinguish biomagnification from eutrophication.

Question 9.
Copy the picture given below and mark the following:

a. Connective tissue
b. Endothecium
c. Tapetum
d. Sporogenous tissue

Question 10.
Ram singh is a conventional wheat breeder. One of the promising wheat varieties is found to be susceptible to leaf rust. , What breeding steps will be adopt to make his original promising variety resistant to leaf rust?

Question 11.
Consider pond as an ecosystem showing the number of individuals in the following ‘ categories.
Carnivores – 2500,
Producers – 15000,
Herbivores – 5000
a. Draw the pyramid of numbers in this ecosystem.
b. Comment on the energy flow in the ecosystem.

Question 12.
Meena, an environmental activist, noticed a gradual decline in the population of birds in the open agricultural fields near her place. She has heard of the excessive use of pesticides like DDT around that area.
a. What might have led to the decline of bird population in that area?
b. Name the process that has caused this phenomenon.

Question 13.
The regeneration of whole plants from any part of the plant grown under sterile conditions is called tissue culture.
a. The general term of the part of the plant taken out for tissue culture is …………
b. The capacity to generate a whole plant from any plant cell is………….

Question 14.
In summer we use air conditioners and in winter we use heaters. Here homeostasis is accomplished by artificial means. Explain four ways by which other living organisms cope with the situation.

Question 15.
Match the Column A with B:
A                        B
1. Bulbil             a. Bulbophyllum
2. Offset            b. Sponge
3. Gemmules   c. Water hyacinth
4. Leaf buds     d. Agave

Question 16.
In a debate one of the speaker reported like this. “Continuous inbreeding leads to inbreeding depression”. If so define the following:
a. Outcross
b. Cross breeding

Answer any 2 questions. Each question carried 3 score.

Question 17.
Three different flowers are given to you in the practical class.
i. Maize
ii. Vallisneria
iii. Rose
You are asked to group them based on pollinating agents. Describe the adaptations of each flower related with the agents of pollination.

Question 18.
Population interactions may be beneficial or not. Write any three interactions in detail.

Question 19.
Resistance is the ability to prevent the pathogen from causing disease.
1. Elucidate the steps in breeding for disease resistance.
2. Cite two examples for virus resistant plants.

Answers

Answer 1.
Pistillate.

Answer 2.
Biofortification: Breeding of crops for higher levels of nutritional quality.

Answer 3.
Triploid.

Answer 4.
d. Perisperm

Answer 5.
a. Mutation breeding
b. A new character can be created by mutation through the changes in the genotype of plants.

Answer 6.
a.
–              –                  – Competition
–             0                  – Ammensalism
+            0                  – Commensalism
b. Parasitism

Answer 7.
a. Isogamy
b. Two identical gametes take place in sexual reproduction.

Answer 8.
a. Gangetic Dolphin.
b. Eutrophication : Natural ageing of a lake by nutrient enrichment of its water.
Biomagnification : To the increases in concentration of the toxicant at successive trophic level.

Answer 9.

Answer 10.

1. Collection of variability.
2. Evaluation & selection of parents.
3. Hybridisation among the selected pa-rents.
4. Selection and testing of superior combinants.
5. Testing, releasing and commercialization of new characters.

Answer 11.
a.

b. Energy flow is unidirectional. The . amount of energy flow decreases with successive trophic level.

Answer 12.
a. High concentration of DDT disturbs calcium metabolism in bird which causes thinning of egg shell and their . premature breaking eventually causing decline in bird population,
b. Biomagnification.

Answer 13.
a. Explant
b. Totipotency

Answer 14.

1. Migration: It is the movement of organism from one place to another region and return when the stressful period is over.
2. Suspend: Organism like bacteria and fungi produce thick walled spores and tide over unfavourable condition.
3. Hibernation (winter sleep): It is the period of dormacy during winter, eg., cold blooded animals like frog.
4. Aestivation (summer sleep): It is the period of dormancy during summer.

Answer 15.

1. Bulbil           d. Agave
2. Offset           c. Water hyacinth
3. Gemmules  b. Sponge
4. Leaf buds    a. Bulbophyllum

Answer 16.
a. The breeding of the unrelated animals of same breed is called out-crossing. The offspring of such a mating is known as an out-cross. It is the best breeding method for animals that are below average in productivity.
b. Out-breeding is the breeding of the unrelated animals, which may be between individuals of the same breed but having no common ancestors for 4-6 generations (out¬crossing) or between different breeds (cross-breeding) or different species (interspecific hybrid i-sation).

Answer 17.
i. Maize – Anemophily – Wind pollination. Numerous pollen grains, pollen is dry and light, stigma is feathery.
ii. Vallisneria – Hydrophily – Water pollination.In vallisneria pollination by water, male flower occur in clusters when mature it detached and reach to the surface of water.
iii. Rose – Entamophily – Insect pollination. Flowers large, colourful, fragrant and rich in nactar.

Answer 18.
a. Predation : It is a kind of interaction between species in which one individual kills another for food, eg., prey is deer and predator is tiger.
Amensalism : In this, one population inhibits the arowth and development of other population.
Mutualism : In which both the species benefit, eg., Lichens (between a fungus and algae), mycorrhizae (between funai and the mots of hiaher plants).

Answer 19.
a.

1. The various sequential steps are:
   • Screening germplasm for resistance sources.
   • Hybridisation of selected parents
   • Selection and evaluation of the hybrids.
   • Testing and release of new varieties.
2. Crop – Chilli
   • Variety – Pusa Sadabahar
     Disease – Chilly mosaic virus, leaf curl
   • Crop – Tomato
     Variety – Bolseno
     Disease – Tomato mosaic virus

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