2nd PUC Biology Previous Year Question Paper June 2019

Students can Download 2 nd PUC Biology Previous Year Question Paper June 2019, 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 2019

Time: 3.15 Hours
Max Marks: 70

General Instructions:

1. This question paper consists of four parts A, B, C and D. Part D consists of two parts, Section – I and Section – II.
2. All the parts are Compulsory.
3. 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.
Name the finger like projections on Trophoblast that appear during implantation.
Answer:
Chorionic villi.

Question 2.
On which bacteria Griffith conducted transformation experiment?
Answer:
Streptococcus pneumoniae.

Question 3.
Name the microbe which is used to produce citric acid.
Answer:
Aspergillus niger.

Question 4.
In which site of fallopian tube does fertilisation take place?
Answer:
Ampullary – Isthmic junction.

Question 5.
Mention the role of Alpha interferon in treatment of cancer.
Answer:
Activates the immune system of cancer patient and helps in destroying the tumor.

Question 6.
Which tissue is used as an explants to obtain virus free plants in tissue culture?
Answer:
Meristem

Question 7.
Name the stain used to visualize DNA fragments in gel electrophoresis.
Answer:
Ethidium Bromide

Question 8.
What is natality?
Answer:
Number of birth rate during a given period in the population.

Question 9.
Which programme was introduced by the Government of India in 1980s to protect forest with the participation of local community?
Answer:
Joint Forest Management.

Question 10.
Define BOD.
Answer:
BOD refers to the amount of oxygen required to oxidize total organic matter by bacteria, present in one liter of water.

part – B

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

Question 11.
Differentiate between seasonal breeders and continuous breeders.
Answer:
Seasonal Breeders

• It occurs in non – primates.
• They reproduce in a particular season.

Continuous Breeders

• It occurs in primates
• They reproduce throughout the year.

Question 12.
Mention the reasons for population explosion.
Answer:

• A rapid decline in death rate (MMR and IMR).
• Increase in number of people in reproducible age.

Question 13.
Write the Karyotype and mention any two symptoms of Klinefelter’s syndrome.
Answer:

• 47, XXY
• Such an individul has overall masculine development, however, the feminine development (development of breast, i,e., Gynecomastia) is also expressed.
• Such individuals are sterile.

Question 14.
Give any two examples for sacred grooves in India.
Answer:

• Khasi and Jaintia Hills in Meghalaya.
• Aravali Hills of Rajasthan.
• Western Ghats of Karnataka.
• Chanda and Bastar areas of Madhya Pradesh.

Question 15.
Name two species, which became extinct due to over exploitation.
Answer:

• Steller’s sea cow
• Passenger pigeon

Question 16.
Distinguish between benign and malignant tumor.
Answer:
Benign Tumor

• Normally remain confined to their original location.
• Do not spread to other location.
• Cause little damage.

Malignant Tumor

• These cells grow very rapidly.
• Invade and damage surrounding tissues.
• These cells actively divide and grow they also starve the normal cells.

Question 17.
Mention any two methods of introducing alien DNA into the host.
Answer:

• Recombinant DNA and the bacterial cells are incubated in ice, followed by placing them briefly at 42°C (heat shock) and then putting them back in ice.
• By micro injection the recombinant DNA directly injected into the nucleus of the animal cell.
• Plant cells are bombarded with high velocity micro – particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.

Question 18.
Write any four tools used in recombinant DNA technology.
Answer:

• Restriction enzymes
• Polymerase enzymes
• Ligases
• Vectors
• Host Organism

part – C

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

Question 19.
List the measures to prevent sexually transmitted diseases.
Answer:

• Avoid sex with unknown partners / multiple partners.
• Always use condoms during coitus.
• In case of doubt, contact immediately the qualified medical practitioner for early detection and cure.

Question 20.
Draw and label a typical biogas plant.
Answer:

Question 21.
Explain the mechanism of XO – type of sex determination in insects.
Answer:
In this type, the females are homogametic and have ‘XX’ chromosomes and produce only one type of egg carrying X chromosomes, while the males are heterogametic and have only one X chromosome swithout the partner. Hence they produce two types of sperms where 50% of the sperms carry X chromosome with autosomes (A + X) and other 50% of the sperms carry only autosomes but no allosomes (A + O).

Question 22.
a)Write the function of filiform apparatus.
Answer:
Filiform apparatus play an important role in guiding the pollen tubes to penetrate into the synergid.

b) Write any four characteristics of flowers pollinated by wind.
Answer:

• Wind pollination requires that the pollen grains are light in weight.
• They should by non sticky and powdery so that they can be transported easily by the wind currents.
• They often possess well exposed stamens so that the pollens are easily dispersed into wind currents.
• The flower must have feathery stigma to easily trap air borne pollen grains.

Question 23.
Mention the main three events In sexual reproduction.
Answer:

• Pre – fertilisation Events
• Fertilisation Events
• Post – fertilisation Events

Question 24.
a) What are pioneer species in ecological succession?
Answer:
The species that invaes bare area are called pioneer species.

b) Distinguish between- hydrarch and xerarch succession?
Answer:
Hydrarch succession:
Takes place in water areas, and the successional series progress from hydric to the mesic conditions.

Xerarch succession:
Takes place in dry areas arid the series progress from xeric to mesic conditions.

Question 25.
Schematically represent the phosphorous cycle.
Answer:

Question 26.
Write a note on MOET.
Answer:

• It is used to improve chances of successful production of hybrids.
• Cow is administered hormones with FSH – like activity induce follicular maturation and super ovulation.
• Production of 6 – 8 eggs instead of one egg per cycle.
• The female is either mated with an elite bull or aritificially inseminated.
• Non – surgical recovery of fertilized eggs at 8 – 32 cells stages. Each one transferred to surrogate mother.
• This technology is used to increase herd size in a short time.

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.
Describe the structure of dicot embryo with the help of a labelled diagram.
Answer:

It consists of an embryonal axis and two cotyledons.

• The portion of embryonal axis above the level of cotyledons is the Epicotyl which terminates with the plumule or stem tip.
• The cylindrical portion below the level of cotyledons is hypocotyls that terminates at its lower end is the radical or root tip. The root tip is covered by root cap.

Question 28.
a) Mention the four barriers of innate immunity with an example for each.
Answer:

• Physical barrier
  Ex: Mucus coating of epithelium
• Physiological barrier
  Ex: Acid in stomach / saliva in the mouth / tears from eyes
• Cellular barrier
  Ex: WBC / Natural killer cells / Macrophages
• Cytokinin barrier
  Ex: Interferons

b) What is allergy?
Answer:
The exaggerated response of the immune system to certain antigens present in the environment is called allergy.

Question 29.
a) What is commensalism? Explain with any two examples.
Answer:
This is the interaction in which one species benefits and the other is neither benefited nor harmed.

• Orchids growing as an epiphyte on a mango branch.
• Clown fish living among tentacles of sea anemone.
• Barnacles on back of whales.
• Cattle Egret and grazing cattle,

b) How does our body overcome altitude sickness?
Answer:

• The body compensates low oxygen availability by increasing red blood cell production.
• The body compensates decreasing binding capacity of hemoglobin with oxygen, by increasing rate of breathing.

Question 30.
Draw a neat labelled diagram of sectional view of mammary gland.
Answer:

Question 31.
List the goals of human genome project.
Answer:

• Identify all the approximately 20,000 – 25,000 genes in human DNA.
• Determine the sequence of all 3 billion chemical base pairs.
• Store this information in data bases.
• Improve tools for data analysis.
• Transfer related technologies to other sectors, such as industries.

Question 32.
(a)State Hardy – Weinberg principle. Mention any four factors which affecting Hardy Weinberg equilibrium.
Answer:
Gene frequency remains constant from generation to generation unless it is altered by the external agencies.

• Gene flow
• Genetic drift
• Mutation
• Genetic recombination
• Natural selection

b) What are analogous organs? Give an example in plants.
Answer:
The organs whose structure and origin are different but performing similar functions.
Ex: In plants sweet potato (root modification) and potato (stem modification)

Section -II

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

Question 33.
Explain one gene inheritance with reference to stem height in pea plants.
Answer:

When two F₁ hybrid offsprings are self crossed
Punnett’s square showing gametic combination and the nature of second filial (F2) generation :

Question 34.
a) Mention the criteria for a molecule that acts as the genetic material.
Answer:

• It should be able to generate its replica (replication).
• It should be chemically and structurally stable.
• It should provide the scope for slow changes (mutation) that required for evolution.

b) Write the schematic structure of transcription unit.
Answer:

Question 35.
If you are a successful beekeeper suggest the points you would like to follow.
Answer:

• Knowledge of the nature and habits of honey bees.
• Selection of suitable location for keeping the beehives.
• Catching and hiving of swarms (group of bees)
• Management of beehives during different seasons.
• Handling and collection of honey and of beeswax.

Question 36.
Briefly explain the uses of transgenic animals.
Answer:
1. Normal physiology and development : Transgenic animals are specifically designed to allow studying about.

• How the genes are regulated.
• How the gene affects normal functioning of body.
• How it affects growth and development. E.g. insulin like growth factor. The animals are made transgenic to know the biological effect and result.

2. Study of disease : Transgenic animals are designed to understand how genes contribute to the development of disease like cancers, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.

3. Biological products : Transgenic animals are used to produce biological product of human interest :

• ∞ -1 antitrypsin used to treat emphysema.
• Proteins for treatment for PKU and cystic fibrosis.
• Transgenic cow Rosie, produce human protein enriched milk (2.4 gm / lit. human a – lactalbumin).

4. Vaccine safety

• Transgenic mice are being developed and use in testing the safety of vaccines before they are used for humans.
• Polio vaccine is tested in mice.
• Chemical safety testing
• This is also known as tocicity / safety testing.
• Transgenic animals are used to know the effects of toxic chemicals.

Question 37.
Explain in case study of remedy for plastic waste.
Answer:

• Poly blend, a find powder of recycled modified plastic, was developed in the factory.
• Polyblend is mixed with bitumen that is used to lay roads.
• It increases the water repelling property of bitumen, and helped to increase road life by a factor of three.
• The raw material used for polyblend is plastic film waste.
• It is economical also.