2nd PUC Biology Previous Year Question Paper June 2018

Students can Download 2nd PUC Biology Previous Year Question Paper June 2018, Karnataka 2nd PUC Biology Model Question Papers with Answers helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.

Karnataka 2nd PUC Biology Previous Year Question Paper June 2018

Time: 3 hrs 15 min
Max. Marks: 70

General Instructions

  • This question paper consists of four parts A, B, C and D. Part – D consists of two sections. Section – I and Section – II.
  • All the parts are compulsory.
  • Draw diagrams wherever necessary. Unlabelled diagrams or illustrations do not attract any marks.

Part – A

Answer the following questions in one word or one sentence each. (10 × 1 = 10)

Question 1.
Define Menarche?
Answer:
The first menstruation begins at puberty.

Question 2.
Name the disease caused by Haemophilus influenzae.
Answer:
Pneumonia.

Question 3.
Mention the importance of selectable markers in plasmids.
Answer:
It helps in identifying and eliminating non-transformants or selectively permitting the growth of the transformants.

2nd PUC Biology Previous Year Question Paper June 2018

Question 4.
Which is the fish caught in South Africa in 1938, which was thought to be extinct?
Answer:
Coelacanth

Question 5.
Name the hormone released by the ovary in the later phase of pregnancy.
Answer:
Relaxin

Question 6.
Why meristems are preferred in tissue culture?
Answer:
The meristem is free of virus i.e., in tissue culture if the plant is infected with a virus, by removing meristem one can grow virus-free plants.

Question 7.
Mention the type of antibody present in the colostrum.
Answer:
IgA.

2nd PUC Biology Previous Year Question Paper June 2018

Question 8.
Why mammals of colder climate generally have shorter ears and limbs?
Answer:
To minimise heat loss from the body.

Question 9.
Name the unit used to measure ozone layer thickness.
Answer:
Dobson units (DU)

Question 10.
Mention the commercial importance of Monascus Purpureus.
Answer:
Blood – cholesterol-lowering agent.

Part – B

Answer any five of the following questions in 3 to 5 sentences each: Wherever applicable: (5 × 2 = 10)

Question 11.
Distinguish between the menstrual cycle and the oestrus cycle.
Answer:
Non-primates like cows, sheep etc., show certain cyclic changes during reproduction called oestrus cycle while ¡n primates like apes and humans, the cycle is referred to as a menstrual cycle.

Question 12.
What is the test cross? Write its significance.
Answer:
It is a kind of back cross where F1 plant is crossed with its recessive parent.
It helps in finding F1 plant is homozygous or heterozygous.

2nd PUC Biology Previous Year Question Paper June 2018

Question 13.
What are analogous organs? Give an example.
Answer:
These are organs which Are different in structure and origin but perform similar functions.
Eg. Eyes of octopus and mammals.

Question 14.
Mention the objectives of biofortification. .
Answer:
Objectives of improving

  • Protein content and quality
  • Oil content and quality

Question 15.
Draw a neat labelled diagram of the structure of an antibody.
Answer:
2nd PUC Biology Previous Year Question Paper June 2018 Q15

Question 16.
What are palindromic nucleotide sequences? Write the restriction site for Eco-RI enzyme.
Answer:
The palindrome in DNA is a sequence of base pairs that read the same on the two strands in 51 → 31 direction and in 31 → 51 direction.
Restriction site for ECORI is
51 – GAATTC – 31
31 – CTTAAG – 51

2nd PUC Biology Previous Year Question Paper June 2018

Question 17.
Name any two species which have become extinct due to overexploitation.
Answer:

  • Steller’s Sea cow
  • Passenger pigeon

Question 18.
What are the sacred groves? Name any two sacred groves of India.
Answer:
Sacred grooves are large tracts of forests where trees and wildlife within are conserved due to cultural and religious beliefs.
Eg.: Khasi and Jainta hills in Meghalaya

Part – C

Answer any five of the following questions in about 40 to 80 words each wherever applicable: (5 × 3 = 15)

Question 19.
Define asexual reproduction. Mention asexual reproductive structures in penicillium and sponge.
Answer:
The production of offsprings by a single parent without formation and fission of gametes.
Penicillium – conidia
Sponge – Gemmule

Question 20.
Draw a neat labelled diagram of a typical Anatropous ovule of angiosperms.
Answer:
2nd PUC Biology Previous Year Question Paper June 2018 Q20

Question 21.
Write a note on colour blindness.
Answer:

  • It is a sex-linked recessive disorder due to defect in either red or green cone of the eye resulting in failure to discriminate between red and green colour.
  • This defect is due to mutation in certain genes present in the X-chromosome.
  • It occurs in about 8% of males and only about 0.4% of females.

Question 22.
Define adaptive radiation.
Answer:
The evolution of closely related species in a given geographical area starting from a point.
Eg.: Darwin’s finches Australian marsupials

2nd PUC Biology Previous Year Question Paper June 2018

Question 23.
What are the ecological pyramids? Draw an ideal pyramid of energy and mention its units.
Answer:
Pyramid of Energy: It is a graphic representation of available energy at successive trophic levels in a food chain. The energy level is expressed as kilocalorie. It is the typical upright pyramid. It illustrates decreasing energy level at successive trophic levels from producers at the base to the consumers. The energy level is maximum in producers and less in consumers. e.g.: Pond food chain.
2nd PUC Biology Previous Year Question Paper June 2018 Q23

Question 24.
What is a biopsy test? Mention any two techniques of cancer detection and diagnosis.
Answer:
A thin piece of the suspected tissue is stained and examined under a microscope.

  • Radiography
  • C.T Scan

Question 25.
Write the important use of the following in rDNA technology.

  1. P.C.R.
  2. Ethidium bromide
  3. Bioreactor (1 + 1 + 1)

Answer:

  1. It is used to synthesise multiple copies of the gene of interest.
  2. It is used to stain separated DNA fragments.
  3. It is used to produce a large number of products where large volumes of culture can be processed.

2nd PUC Biology Previous Year Question Paper June 2018

Question 26.
Describe the process of primary succession on bare rocks.
Answer:

  • In primary succession on rocks, lichens are the pioneer species. Lichens secrete acids to dissolve rock helping the weathering and soil formation.
  • These later pave the way to some very small plants like bryophytes, which are able to take hold in the small amount of soil.
  • They are with time succeeded by bigger plants and after several more stages, ultimately a stable climax forest community is formed.
  • The climax community remains stable as long as the environment remains unchanged.

Part – D

Section – I

Answer any four of the following questions in about 200 to 250 words each, wherever applicable: (4 × 5 = 20)

Question 27.
(a) What are false fruits? Give an example. (2)
Answer:
The fruits develop from the ovary and thalamus.
Eg.: Apple, cashew

(b) Write the characteristic features of insect-pollinated flowers. (3)
Answer:

  • The flowers are large, conspicuous, coloured and showy.
  • The flowers have a fragrance and sweet nectar.
  • Pollen grains are rough and surrounded by a sticky substance called pollen kit.

Question 28.
Draw a neat labelled diagrammatic view of the human male reproductive system.
Answer:
2nd PUC Biology Previous Year Question Paper June 2018 Q28

Question 29.
(a) Explain the following assisted reproductive technologies:
(i) IVF-ET
(ii) ZIFT
(iii) ICSI (1 + 1 + 1)
Answer:
(a) (i) IVE-ET: The fertilisation outside the body of the mother in a simulated condition. The transfer, of the embryo to the fallopian tube or uterus of a surrogate mother.
(ii) ZIFT: Zygotes with 8 blastomeres are transferred into the fallopian tube.
(iii) ICSI: Sperm is directly injected into the ovum in the laboratory.

2nd PUC Biology Previous Year Question Paper June 2018

(b) Name any two hormone-producing XUD’s. (2)
Answer:
Progestasert LNG – 20.

Question 30.
Explain the law of independent assortment with reference to seed shape and seed colour in garden tea plant.
Answer:
Refer Dihybridcross & Law of independent Assortment, Page No. 96 & 97.

Question 31.
Describe the various steps of plant breeding programs.
Answer:
Plant breeding is the manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant.
(i) Collection of variability:
Collection and preservation of all the different wild varieties, species and closely related plants of the cultivated species is a pre-requisite for effective exploitation of natural genes available in the populations. This collection constitutes thé germplasm.

(ii) Evaluation and selection of parents:
The germplasm so collected is evaluated to identify’ plants with desirable characters.
The selected plants are multiplied and used in the process of hybridisation.
Pure lines are created (by repeated self-pollination) wherever possible and desirable.

(iii) Cross hybridisation of the selected parents:
It involves crossing of two plants which differ in one or more desirable characters to produce a hybrid having the characters of both the parents.
This is a very time-consuming and tedious process.
Also, it is not necessary that the hybrids will combine the desirable characters.

(iv) Selection and testing of superior recombinants:
First, the individuals with the desired combination of characters have to be selected from among th progeny of hybrids.
Such hybrids are superior to both of the parents (hybrid vigour/heterosis).
They are self-pollinated for several generations till they reach a state of homozygosity so that there will be no segregation of characters in the progeny.

(v) Testing, release and commercialisation of new cultivars:
(a) Evaluation:
The selected lines are evaluated for their yield and other agronomy traits, disease resistance, etc.
Evaluation is done by growing these plants in the research fields and recording their performance under ideal conditions of irrigation, application of fertilisers and other crop management practices.

(b) Testing:
The plants selected after evaluation are tested in the farmers’ fields for at least three growing seasons, at several locations in the country, representing different agroclimatic zones, where the crop is normally grown.
The material is evaluated in comparison to the best available local cultivar as reference material.

(c) Release:
The material thus selected is certified and released as a variety.

2nd PUC Biology Previous Year Question Paper June 2018

Question 32.
(a) Mention the chemical linkages between the components of DNA. (3)
Answer:
H-bond, Glycosidic bond &phospho diester bond.

(b) Differentiate Euchromatin from Heterochromatin. (2)
Answer:
Euchromatin: Loosely packed and transcriptionally active chromatin.
Heterochromatin: Densely packed and inactive region of chromatin.

Section – II

Answer any three of the following questions in about 200 to 250 words each wherever applicable: (3 × 5 = 15)

Question 33.
What are VNTR’s? Mention the steps to detect VNTR’s in identifying criminals in forensic investigations.
Answer:
The DNA fragments that show very high degree polymorphism.

  • Isolation of DNA
  • Digestion of DNA by restriction endonucleases.
  • Separation of DNA fragments by electrophoresis.
  • Transferring of separated DNA fragments to synthesize membranes, such as nitrocellulose or nylon.
  • Hybridisation using labelled VNTR probe.
  • Selection of hybridised DNA fragments by autoradiography.

Question 34.
(a) Draw a neat labelled diagram of the typical biogas plant. (3)
Answer:
2nd PUC Biology Previous Year Question Paper June 2018 Q34(a)

(b) Mention the beneficial role of anaerobic bacteria in secondary sewage treatment.
Answer:
Anaerobic bacteria digest the bacteria and fungi (FLOCS) in the sludge. During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases form biogas & can be used as a source of energy.

Question 35.
List the benefits, of transgenic animals.
Answer:
1. Normal physiology and development: Transgenic animals can be specifically designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development.

2. Study of disease: Many transgeñic animals are designed to increase our understanding of how genes contribute to the development of the disease. e.g.: Cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.

3. Biological products: Medicines required to treat certain human diseases are biological products. But such useful biological products can be created by the introduction of the portion of DNA (or genes) into an animal which codes for a particular transgenic product.

4. Vaccine safety: Safety of vaccines must be confirmed before they are administered. e.g.: Transgenic mice are being used to test the safety of the polio vaccine.

5. Chemical safety testing: This is known as toxicity/safety testing. The procedure is the same as that used for testing the toxicity of drugs. Transgenic animals are made to carry genes which make them more sensitive to toxic substances than non-transgenic animals. They are then exposed to the toxic substances and the effects studied.

2nd PUC Biology Previous Year Question Paper June 2018

Question 36.
(a) Write any four factors that influence population density. (2)
Answer:
Natality, Mortality, Immigration & Emigration

(b) Draw a graph showing exponential growth curve. (2)
Answer:
2nd PUC Biology Previous Year Question Paper June 2018 Q36(b)

(c) What is sexual deceit? (1)
Answer:
One petal of Ophrys resembles a female bee in size. So male bee pseudocopulation with the flower. It is brown as sexual deceit.

Question 37.
Write a short note on the following :

  1. Greenhouse gases
  2. Catalytic converter
  3. Ultra-violet B
  4. Ozone layer
  5. Electrostatic precipitator. (1 + 1 + 1 + 1 + 1)

Answer:

  1. CO2, methane, CFCs & N2O are known as greenhouse gases. They are responsible for the greenhouse effect.
  2. The catalytic converter is fitted into automobiles for reducing the emission of poisonous gases.
  3. UV-B damages DNA and mutation may occur. It causes ageing of the skin, damage to skin cells, skin cancers and snow blindness.
  4. The ozone layer acts as a shield and absorbs ultraviolet radiation from the sun.
  5. It is a device used to remove particulate matter in the exhaust from a thermal power plant.

Leave a Comment