Plus Two Botany Model Question Papers Paper 4

Plus Two Botany Model Question Papers Paper 4 is part of Plus Two Botany Previous Year Question Papers and Answers. Here we have given Plus Two Botany Model Question Papers Paper 4

Plus Two Botany Model Question Papers Paper 4

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.

(Questions 1 to 2): Answer all questions. Each question carries 1 score.

Question 1.
A unisexual flower having no andreorecium is called
a. Dithecous
b. Dioecious
c. Monoecious
d. Pistillate

Question 2.
In honey bees and some lizards female gamete undergoes development to form new oroanisms without fertilization This
phenomenon is called…………

(Questions 3 to 15): Answer any eleven quesions from the following. Each questions carries 2 scores.

Question 3.
In human beings, certain diseases are caused due to genetic disorders.
a. Name the method that allows the correction of a aene defect that has been diagnosed in a child or embryo.
b. How this method has been used for treatina ADA (Adenosine deaminase) deficiency?

Question 4.
A novel strategy to prevent nematode infestation is based on ‘ RNA interference’.
a. Explain RNA interference.
b. Can you suggest, how it can be used for producing nematode resistant plant?

Question 5.
Species diversity decreases from equator towards poles. Ecologists proposed various hypothesis. Suggest two hypothesis for this phenomenon.

Question 6.
Match the following

A                         B
Zoospores      Hydra
Conidia          Sponges
Bud                Chlamydomonas
Gemmules    Penicillium

Question 7.
The gradual and fairly predictable changes in the species composition in an area is called ecological succession.
a. Name the pioneer species in the primary succession in water.
b. Give the sequence of events and climax community in the hydrarch succession.

Question 8.
Infection by nematodes cause threat to t cultivation and yield loss of tobacco plants. A strateav has been developed at RNA level to control this infestation.
a. Name the process.
b. Explain how this process works at the molecular level.

Question 9.
In maize, the chromosome number present in the meiocvte is 20. Give the number of chromosomes present in the following:
a. Maize pollen
b. Maize endosperm

Question 10.
The gradual change in the species composition of a given area leading to the formation of climax community is called ecological succession. In a rocky area,
a. What is the expected type of pioneer species?
b. How this pioneer species leads to the establishment of a stable climax community?

Question 11.
During a .study tour teacher showed the primary colonisers on the banks of the river ‘Nila’.
a. Identify the succession and justify your answer.
b. List the different stages of the identified succession.

Question 12.
Jaya read in a biotechnology book that alien DNA can be introduced into host cell by micro injection and biolistics. Explain these methods.

Question 13.
Sophie was born with a genetic disorder – ADA deficiency.
a. What is ADA deficiency?
b. Can you suggest methods to treat this ADA deficiency?

Question 14.
An article in the newspaper reports that ‘Refrigerants like Chlorofluorocarbons (CFCs) pose threat to the environment’. How CFCs are harmful to the environment?

Question 15.
Genetically Modified Organism (GMO) is always a debatable topic among scientists, academicians and public. State any four usefulness of GMOs.

Question 16.
Interspecific interaction from the interaction of populations of two different species. If we assign + for beneficial, – for detrimental and 0 for neutral interactions, copy and complete the following chart.

Question 17.
A newspaper report read like this. “Conventional agricultural products like cereals, pulses and other seeds may not be able to meet the demand of food according to the increase in population. So focus has to be shifted to alternate food sources like SCPs.
a. What are SCPs? ”
b. Give one example of SCPs.
c. What are the advantages of SCPs?

Question 18.
Restriction endonucleases are the enzymes used to cut the DNA molecules.
a. Give the general term of the specific sequences where these enzymes cut the DNA.
b. Name the enzyme that joints the foreign DNA and vector DNA.
c. Give any two procedures to introduce the recombinant DNA into the host cell.

Answers

Answer 1.
d. Pistillate

Answer 2.
Parthenogenesis.

Answer 3.
a. Gene therapy.
b. ADA deficiency can be treated using bone marrow transplantation or by enzyme therapy. In gene therapy, lymphocytes from the blood of the patient are grown in a culture outside the body. A functional ADA cDNA is then introduced into lymphocytes and return back to patient.

Answer 4.
a. RNA interference (RNAi) is the phenomenon of inhibiting activity of a gene through production of sense RNA and anti-sense RNA
b. The nematode specific genes introduced into the host plant using vectors. The introduction of DNA, it produce both sense and anti sense RNA in the host cells. These two DNA’s it form double stranded RNA that initiated RNA which silenced the specific mRNA of the nematode. Thus parasite could not survive in the host.

Answer 5.

1. Tropical regions have relatively more constant and predictable climate.
2. Tropical regions remained undisturbed for millions of years which results in greater diversification.
3. Availability of more solar energy con-tribute much productivity at tropical regions.

Answer 6.
A                     B
Zoospores     Chlamydomonas
Conidia          Penicillium
Bud                 Penicillium
Gemmules     Sponges

Answer 7.
a. Phytoplanktons
b.

1. Phytoplanktons
2. Submerged stage
3. Floating stage
4. Reed swamp stage
5. Sedge meadow stage
6. Woodland stage
7. Climax forest stage.

Answer 8.
a. RNA interference.
b. RNA interference (RNA) is the phenomenon of inhibiting activity of a gene through production of sense RNA and anti-sense RNA.

Answer 9.
a. 10
b. 30

Answer 10.
a. Lichen, ie., crustose lichen is the pioneer species.
b. Crustose lichen stage → Foliose lichen stage → moss stage → herb stage → shrub stage → forest stage.
Forest stage is a stable climax community.

Answer 11.
a. Hydarch succession.
b.

1. Phytoplanktons
2. Submerged stage
3. Floating stage
4. Reed swamp,stage
5. Sedge meadow stage
6. Woodland stage
7. Climax forest stage.

Answer 12.
Microinjection: Recombinant DNA is directly injected into the nucleus of animals cell. ,
Biolistics: Cells are bombarded with high velocity microparticles of gold or tungsten coated with DNA.

Answer 13.
a. Adenosine deaminase (ADA) enzyme is crucial for the immune system function. Absense or decrease of this enzyme cause disorder. It is due to the deletion of the gene for adenosine deaminase enzyme.’ This is called ADA deficiency,
b. Gene therapy, Bine marrow transplantation

Answer 14.
CFC released from refrigerant to the atmosphere, is split in to chlorofluro components and combined with ozone in the ozone layer and induce its decomposition. So ozone readily become O₂ molecule. This decreases the concentration of ozone in ozone layer which cause holes in the ozone layer. Through the holes, UV rays and other harmful rays can be easily fall up on earth which cause other diseases like cancer.

Answer 15.

1. The GM props have enhanced nutritional quality and yield.
2. Transgenic crops grow well in saline soil and show salt tolerance.
3. They increase productivity of crops generally by showing resistance against plant pathogens and to some herbicides.
4. Transgenic pig organs like heart, kidney, pancreas can be transplanted into humans.

Answer 16.
Species Species Name of interaction

Answer 17.
a. Single Cell Proteins.
b. Spirullina.
c.

1. It can be grown easily on materials like waste water, straw, sewage etc.
2. It can be serve on food rich in protein, minerals,fats, carbohydrate and vitamins.
3. It reduce environmental pollution.

Answer 18.
a. Palindrome sequences
b. DNA Ligases
c. Micro-injection : Recombinant DNA is directly injected into the nucleus of animal cells.
Biolistics or gene gun: Cells are bom barded with high velocity micro par tides of gold or tungsten coated with DNA

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