RBSE 12th Biology Model Paper Set 1 with Answers in English 

Students must start practicing the questions from RBSE 12th Biology Model Papers Set 1 with Answers in English provided here.

RBSE Class 12 Biology Model Paper Set 1 with Answers in English

Time : 2.45 Hours
Maximum Marks : 56

General Instruction to the Examinee:

1. Candidate must write first his/her Roll No. on the question paper compulsorily.
2. All the questions are compulsory.
3. Write the answer to each question in the given answer book only.
4. For questions having more than one part the answers to those parts are to be written together in continuity.
5. If there is any error/difference/contradiction in Hindi & English version of the question paper, the question of the Hindi version should be treated valid.

Section – A

(1 Mark)

Question 1.
Select the correct option of the following questions and write in notebook. (1 × 9 = 9)
(i) Zoospores are the reproductive units to carry asexual reproduction in [1]
(a) Chlamydomonas
(b) Spirogyra
(c) Yeast
(d) Rhizopus
Answer:
(d) Rhizopus

(ii) Filliform apparatus is a characteristic feature of: [1]
(a) nucellar embryo
(b) generative cell
(c) aleurone cell
(d) synergids
Answer:
(d) synergids

(iii) Which is connected with multiple phenotypes? [1]
(a) Mutations
(b) Epistatis
(c) Pleiotropy
(d) Polygenic inheritance
Answer:
(c) Pleiotropy

(iv) Scientists who proved that DNA is a genetic material are: [1]
(a) Hershey and Chase
(b) Watson and Crick
(c) Sutton and Boveri
(d) Griffith and McCarty
Answer:
(a) Hershey and Chase

(v) LSD is obtained from: [1]
(a) fungus
(b) lichen
(c) algae
(d) bacterium
Answer:
(a) fungus

(vi) Antibodies belong to: [1]
(a) Lipid
(b) Protein
(c) Enzyme
(d) Amino acid
Answer:
(b) Protein

(vii) Bombay duck is a: [1]
(a) hen
(b) fish
(c) honeybee
(d) cow
Answer:
(b) fish

(viii) The component only present in Ti plasmid: [1]
(a) Gus gene
(b) Opine gene
(c) a and b both
(d) RB factor
Answer:
(b) Opine gene

(ix) Green revolution relates to: [1]
(a) fertilizer
(b) GM Crops
(c) advanced machines
(d) All of these
Answer:
(d) All of these

Question 2.
Fill in the blanks. (1 × 4 = 4)
(i) The callus and ………………. cultures can be used to achieve cell biomass. [1]
(ii) Diversity within community is called ………………. [1]
(iii) ………………. occurs in RNA, in place of thymine of DNA. [1]
(iv) Ecosystem has two main components, biotic and ………………. [1]
Answer:
(i) suspension
(ii) alpha diversity
(iii) Uracil
(iv) abiotic.

Question 3.
Give the answers of the following questions in one word or one line. (1 × 8 = 8)
(i) Define the term genetics. [1]
Answer:
The branch of biology which deals with the study of heredity and variation is called genetics.

(ii) Who is the father of genetics? [1]
Answer:
Gregor Johann Mendel is called the father of genetics

(iii) Write the full form of ELISA and NACO [1]
Answer:
ELISA : Enzyme Linked ImmunoSorbent Assay.
NACO : National AIDS Control Organisation.

(iv) How do roughage and concentrate differ from each other? [1]
Answer:
Roughage contains fibres but less nutrients e.g., fodder, while concentrate is rich in nutrients, e.g., cereal grains.

(v) Define recombinant DNA. [1]
Answer:
After the insertion of foreign gene, the newly formed DNA having new genes on it is called recombinant DNA.

(vi) Define gene therapy. [1]
Answer:
Therapy of defective genes, which are replaced by healthy genes.

(vii) Give an alternate term for ecological pyramids.
Answer:
Eltonian pyramids.

(viii) What do you mean by heterogeneity?
Answer:
Immense diversity.

Section – B

(1.5 Mark)

Question 4.
What is contraceptive? Is the use of contraceptive justified? Give reasons. [1.5]
Answer:
Contraceptive : Device that prevent conception or pregnancy without interfering with the reproductive health of the individual is called contraceptive. Yes, the use of contraceptive is completely justified. The reasons that favour are :

• Contraceptives help couples to plan their family.
• These aid in population control.

Question 5.
Define medical termination of pregnancy. Our government has intentionally imposed strict conditions for MTP in our country. Justify giving a reason. [1.5]
Answer:
Medical Termination of Pregnancy (MTP): Intentional or voluntary termination of pregnancy before the foetus becomes viable is called medical termination of pregnancy. MTP or induced abortion is the termination of pregnancy due to certain medical issues. Government of India legalised MTP in 1971 with strict conditions to check its misuse, i.e., to check indiscriminate and illegal female foeticides.

Question 6.
(a) Explain how to overcome inbreeding depression in cattle. [1.5]
(b) List three advantages of inbreeding in cattle.
Answer:
(a) In order to overcome the cattle from inbreeding depression, selected animals of the breeding population should be mated with unrelated superior animals of the same breed. This helps in restoring the fertility and yield in the cattle.

(b) (i) Pure line can be obtained.
(ii) Harmful recessive genes are exposed that are eliminated by selection.
(iii) It can concentrate on the genes of a superior ancestor.

Question 7.
Write three important points to remember in poultry farming. [1.5]
Answer:
Important point to remember in poultry farming:

• To develop improved poultry breeds to produce good egg layers and good broilers for meat especially by cross breeding programme.
• Good poultry care through maintenance of proper temperature and lightning and hygienic conditions in housing, poultry feeds etc.
• Prevention and control of their diseases and pests.

Question 8.
Draw the diagram of pBR322. or draw the diagram of cloning vector. [1.5]
Answer:

Question 9.
What is the role of selectable market in a cloning vector ? Name the selectable market in pBR322.
Answer:
Selectable markers allow the positive selection of transformants over non transformants. Antibiotic resistance genes are often used as selectable marker. Examples are ampicillin, p-galactosidase.

Ampicillin and tetracycline resistance genes are present as selectable marker in pBR322.

Question 10.
Explain in brief “Biotechnology applications in medicine”. [1.5]
Answer:
Biotechnology has proved to be a boon in the field of medicine which has worked at a very high level to fight disease like corona virus and pandemic. The applications of genetic engineering has made to produce many hormones such as insulin, steroid hormones, sex hormones, relaxin hormones etc. These genetic engineering hormones and growth factors are highly purified, effective and have very few side effects.

Question 11.
What were the conventional methods to produce insulin. Who designed artificial insulin and how? [1.5]
Answer:
Initially, insulin given to a diabetic patient was extracted from the pancreas by killing animals such as cow and pig. This insulin, taken from animals was injected into the human body, was less beneficial and cause allergies, they had to suffer many kind of problems.

In 1983, American company Elililly designed two DNA sequence, similar to A and B chain of insulin. E. coli bacteria used to produce A and B chains in culture medium separately through disulphide linkage, both the chains are exactly like mature insulin.

Question 12.
What is ecosystem? Give one example of each terrestrial ecosystem and aquatic ecosystem. Write three components of ecosystem. [1.5]
Answer:
An ecosystem is a functional unit of nature where living organisms interact among themselves and with environment.
Terrestrial ecosystem — Grassland ecosystem
Aquatic ecosystem — Pond ecosystem.

Components of Ecosystem :

1. Producers
2. Consumers
3. Decomposers

Question 13.
Write three differences between production and decomposition. [1.5]
Answer:

	Production	Decomposition
1.	Rate of producing food (organic matter) by producers is known as production.	Disintegration of complex organic matter from the bodies of dead animals and plants with the help of decomposers into organic raw material namely water, carbon dioxide, other such nutrients is decomposition.
2.	For primary production, sunlight is required.	Decomposition does not require sunlight.
3.	Dependent on the photosynthetic capacity of producers.	Takes places with the help of decomposers.

Question 14.
How do ecologists estimate the total number of species present in the world? [1.5]
Answer:
Living entities exhibit a vast diversity on Earth. Researchers estimate it to be close to seven million. Ecologists can estimate the total number of species on Earth through a statistical comparison between species richness of a well-studied group of insects of tropical and temperate regions. Later these ratios are extrapolated with groups of other plants and animals to estimate the net species richness found on Earth.

Question 15.
What is fragment habitat? Give one example.
Answer:
When large sized habitats are broken into smaller parts due to human activities they are called fragmented habitat and it leads to population decline. Example, a small forest near an urban settlement.

Section – C

(3 Marks)

Question 16.
Offspring formed due to sexual reproduction have better chance of survival. Why? Is this statement always true? [3]
Or
What is clone? Why is the offspring formed by asexual reproduction referred to as clone? [3]
Answer:
Offsprings formed due to sexual reproduction have better chances of survival because they accumulate genetic variations, many of which may be helpful for better adaptation to the environment.

Sexual reproduction occurs in adverse conditions in lower organisms, so sexual spores survive in adverse condition.

It is not always necessary that the offsprings produced by sexual reproduction have better chances of survival. Under some circumstances, asexual reproduction is more advantageous for certain organisms. For instance, some organisms who do not move from one place to another and are well settled in their environment. Also, asexual reproduction is a fast and quick mode of reproduction which does not consume much time and energy as compared to sexual reproduction.

Question 17.
Which plant was selected by Mendel for his experiment? Mention the advantage of selecting that plant. List contrasting traits noted by mendel in 7 characters of that plant. [3]
Or
(a) A diploid organism is heterozygous for 4 loci, how many types of gametes can be produced?
(b) Differentiate between monohybrid and dihybrid cross. [3]
Answer:
Mendel’s experimental plant was a common garden pea (Pisum sativum).
He selected garden pea for the following reasons :

• The pea plant is small, annual and easy to grow.
• The plant is naturally self-pollinating but can be easily cross-pollinated experimentally.
• It reproduces a large number of offsprings and completes its life cycle in one season.
• A large number of true breeding varieties of pea are available.
• The plants had a number of contrasting characters, for example, red vs. white flowers, round vs. wrinkled seeds etc.

Contrasting traits noted by Mendel in seven characters of garden pea

	Characters	Dominant	Recessive
1.	Seed shape	Round	Wrinkled
2.	Seed colour	Yellow	Green
3.	Flower colour	Violet	White
4.	Pod shape	Full	Constricted
5.	Pod colour	Green	Yellow
6.	Flower position	Axial	Terminal
7.	Stem height	Tall	Dwarf

Question 18.
What are the various public health measures, which you would suggest as safeguard against infectious disease ? [3]
Or
Differentiate between B-lymphocytes and T-Lymphocytes. [3]
Answer:
Public Hygiene : It can be improved by sanitation and public health measures.

• Proper sanitation of public places such as parks, cinema halls, schools, offices and hospitals should be taken care of.
• Proper disposal of waste and excreta. Garbage containers should be properly covered and garbage is not be allowed to litter on the streets or garbage collection sites.
• Standard practices of hygiene at public catering. Eating at places such as roadside dhabas and rehris should checked for cleanliness.
• No stagnation of water around residential areas and drains should be covered to reduce chances of breeding of flies and mosquitoes.
• Periodic cleaning and disinfection of water reservoir, ponds, cesspools and tanks.
• Insecticides should be sprayed in residential areas at regular intervals to reduce the number of mosquitoes.

Section – D

(4 Marks)

Question 19.
Draw a diagrammatic scatch of L.S. of a typical flower and explain briefly with one function of each of the following: [4]
(i) Calyx
(ii) Corolla
(iii) Anther
(iv) Ovary
Or
Write short note on the following: [4]
(a) Androecium
(b) Gynoecium.
Answer:

• Calyx : This is the outermost whorl of floral appendages. The single unit is called sepal. They are generally green in colour. It protects the flower parts in bud condition.
• Corolla : This is the second whorl of floral appendages. The single unit is called petal. They have different colours. It attracts pollinators for pollination.
• Anther : It is a part of male reproductive organ Androecium. Single unit of androecium is called Stamen. Stamen have filament and Anther. Anther produces pollen grains.
• Ovary : Gynoecium or pistil is female part of flower. Pistil consists of one or many carpels. Each carpel have three parts ovary, style and stigma. It produces ovules.

Question 20.
(a) If a double stranded DNA has 20 per cent of cytosine, calculate the percent of adenine in the DNA.
(b) If the sequence of one strand of DNA is written as follows : 5′-ATGCATGCATGCATGCATGCATGCATGC-3′
Write down the sequence of complementary strand in 5′ → 3′ direction. [4]
Or
What are nucleic acids? Expand DNA and RNA. Write four differences between DNA and RNA. [4]
Answer:
(a) According to Chargaff’s rule, the DNA molecule should have an equal ratio of purine (adenine and guanine) and pyrimidine (cytosine and thymine). It means that the number of adenine molecules is equal to thymine molecules and the number of guanine molecules is equal to cytosine molecules.
%A = %T and %G = %C

If double stranded DNA has 20% of cytosine, than according to law, it would have 20% of guanine.
Thus, percentage of G + C content = 40%.

The remaining 60% represent both A + T contents. Since adenine and thymine are always present in equal numbers, the percentage of adenine molecule is 30%.

(b) Complementary sequence in 3′-5′ is : 3′-TACGTACGTACGTACGTACGTACG-5′. Then in 5′- 3′ direction complementary strand will be 5L-GCATGCATGCATGCATGCATGCAT-3′