Plus Two Botany Previous Year Question Paper Say 2018

Kerala Plus Two Botany Previous Year Question Paper Say 2018 with Answers

Time: 1 Hour
Cool off time : 10 Minutes
Maximum : 30 Score

General Instructions to candidates:

• There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hrs.
• You 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 3) : Answer all the questions. Each question carries 1 score. (3 × 1 = 3)

Question 1.
Identify the freshwater fish from the following:
a) Sardine
b) Mackerel
c) Rohu
d) Hilsa
Answer:
c) Rohu

Question 2.
In Gel electrophoresis the separated DNA fragments can be visualized after staining. Name the stain used for it.
Answer:
Ethidium bromide

Question 3.
In a forest ecosystem different plant species are occupied in different vertical levels. Name such vertical arrangement.
Answer:
Stratification

(Questions 4 to 14. Answer any 9 questions. Each question carries 2 scores. (9 × 2 = 18)

Question 4.
Primate and non-primate female mammals exhibit cyclic changes in the activities of ovaries and accessory ducts as well as hormones during the reproductive phase. Name the cyclic changes in these groups.
Answer:
Primates – menstrual cycle
Nonprimate – oestrous cycle

Question 5.
Bamboo species and Strobilanthus Kunthiana exhibit usual flowering phenomena. Explain their flowering characteristics.
Answer:
Bamboo – flower only after 50- 100 years
Strobilanthus kunthiana – flower once in 12 years

Question 6.
A population has certain attributes that an individual organism does not. What are they?
Answer:

• Natality
• Mortality
• Sex ratio
• Population density

Question 7.
Multiple copies of gene of interest can be synthesised in vitro. Name the technique and its requirements.
Answer:
Polymerase chain reaction
2 set of Primers and DNA Polymerase enzyme

Question 8.
Catalytic converters are used in automobiles to control air pollution. Briefly comment on its role.
Answer:
Unburnt hydrocarbons are converted into carbon dioxide and water.
Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas respectively.

Question 9.
Your friend wishes to start a poultry farm. What are the important suggestions given to him for successful management of the farm?
Answer:

1. Selection of disease free breeds
2. Proper and safe farm conditions,
3. Proper feed and water and hygiene and health care are components of poultry farm management.

Question 10.
Pollination by water is seen in Zostera and Vallisneria. Enumerate its adaptations.
Answer:

• In Vallisneria, the female flower reach the surface of water by the long stalk and the male flowers or pollen grains are released on to the surface of water. Stigma collects the pollen grains and reached the water inside.
• In zostera female flowers are found inside the water and pollen grains are released in the water.
• In some species pollen grains are prevented from wetting by mucilaginous covering.

Question 11.
Parasites evolved special adaptations to live on host. What are they?
Answer:

• Loss of unnecessary sense organs
• Presence of suckers to cling on to the host
• Loss of digestive system and
• High reproductive capacity.

Question 12.
Domestic sewage and industrial effluents contain large amount of nutrients. What are the probable effects of these nutrients on water bodies?
Answer:

1. It causes excessive growth of planktonic (free- floating) algae, called an algal bloom which gives colour to the water bodies.
2. Algal blooms cause lose of the water quality and fish mortality.

Question 13.
Match the Column A with Column B :

Answer:

Question 14.
Humification leads to accumulation of a dark coloured amorphous substance. Identify the substance and its peculiarities.
Answer:
The substance is humus.
It is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. It serves as the reservoir of nutrients.

(Questions 15 to 18): Answer any 3 questions. Each question carries 3 scores. (3 × 3 = 9)

Question 15.
Bt cotton is a transgenic pest resistant plant.
a) How this was achieved?
b) How do this plant survive on pest attack?
Answer:
a) Cry genes are isolated from Bacillus thuringiensis and inserted into cotton by gene manipulation technique.

b) Bt toxin protein exists as inactive protoxins. It is converted into an active form in the presence of the alkaline pH of insect gut.

The activated toxin binds to the surface of midgut epithelial cells and creates pores that causes cell swelling and lysis and results in the death of insect.

Question 16.
Depending on the source of pollen, pollination can be divided into three types. What are they? Explain each.
Answer:
i) Autogamy:
It is the transfer of pollen grains from the anther to the stigma of the same flower.
ii) Geitonogamy:
Transfer of pollen grains from the anther to the stigma of another flower of the same plant.
iii) Xenogamy:
Transfer of pollen grains from anther to the stigma of a different plant.

Question 17.
Hydrach succession takes place in wetter areas and the successional series progress from ‘hydric’ to ‘mesic’ condition. List out the stages in correct sequence.
Answer:

• Phytoplankton stage.
• Submerged plant stage.
• Submerged free-floating plant stage
• Reed swamp stage
• Marsh – meadow stage.
• Scrub stage.
• Forest stage.

Question 18.
Restriction endonuclease enzymes are used to cut the DNA at specific sequence.
a) Write the name of first isolated one.
b) Write the convention for naming these enzymes.
Answer:
a) Hind II

b) First capital letter – genus name
Second two letters – species name
Next letter – the strain of bacterium from which the restriction enzyme is isolated
Last roman letter – order of isolation of enzyme.

Plus Two Botany Previous Year Question Papers and Answers