Maharashtra Board Class 12 Biology Sample Paper Set 1 with Solutions

Maharashtra State Board Class 12th Biology Sample Paper Set 1 with Solutions Answers Pdf Download.

Maharashtra Board Class 12 Biology Model Paper Set 1 with Solutions

Section – A

Question 1.
Select and write the correct answers to the following questions:

(i) Budding in Hydra is a form of ………..
(a) Apoptosis
(b) Sexual reproduction
(c) Asexual reproduction
(d) None of these
Answer:
(c) Asexual reproduction

(ii) The enzyme required for transcription is ………
(a) DNA polymerase
(b) RNA polymerase
(c) RNase
(d) Restriction enzyme
Answer:
(b) RNA polymerase

(iii) The muscular structure that separates the thoracic and abdominal cavity is ……..
(a) Pleura
(b) Trachea
(c) Larynx
(d) Diaphragm
Answer:
(d) Diaphragm

(iv) Secondary consumers are ………
(a) Carnivores
(b) Herbivores
(c) Decomposers
(d) Producers
Answer:
(a) Carnivores

(v) “Continuity of germplasm” theory was given by ………
(a) De Vries
(b) Weismann
(c) Darwin
(d) Lamarck
Answer:
(b) Weismann

(vi) Apospory is direct formation of ………..
(a) Gametophytefrom sporophyte
(b) Gametophytefrom gametophyte
(c) Sporophyte from gametophyte
(d) Sporophyte from sporophyte
Answer:
(a) Gametophytefrom sporophyte

(vii) The principle pathway of water translocation in angiosperms is ………
(a) Sieve cells
(b) Sieve tube elements
(c) Xylem
(d) Phloem
Answer:
(c) Xylem

(viii) The DNA polymerase enzyme used in PCR is obtained from
(a) E. coli
(b) Salmonella typhi
(c) Bacillus haemophilus
(d) Thermus aquaticus
Answer:
(d) Thermus aquaticus

(ix) The earliest geological time period among the following is ………
(a) Cambrian
(b) Permian
(c) Jurassic
(d) Quaternary
Answer:
(a) Cambrian

(x) Select the correct sequence of stages of spermatogenesis in a human male ………..
(a) Spermatogonium → Spermatids → Spermatocytes → Spermatozoa
(b) Spermatogonium → Spermatocytes → Spermatids → Spermatozoa
(c) Spermatids → Spermatogonium → Spermatocytes → Spermatozoa
(d) Spermatocytes → Spermatogonium → Spermatids → Spermatozoa
Answer:
(b) Spermatogonium → Spermatocytes → Spermatids → Spermatozoa

Question 2.
Answer the following questions:

(i) Define the term Health.
Answer:
Health is defined as the state of complete physical, mental and social well being and not merely the absence of disease or infirmity.

(ii) What is symplast pathway?
Answer:
Symplast pathway is the pathway for the transport of water from one living cell to other living cell through plasmodesmata.

(iii) Give statement of law of dominance.
Answer:
“When two homozygous individuals with one or more sets of contrasting characters are crossed, the characters that appear in F₁ generation are dominant and those which do not appear are recessive.

(iv) Expand following acronyms:
(a) BAC
(b) GMO
Answer:
(a) BAC – Bacterial Artificial Chromosome
(b) GMO – Genetically Modified Organisms

(v) Which hormone is responsible for fruit ripening?
Answer:
Ethylene is responsible for fruit ripening.

(vi) Name the hormone secreted by pineal gland.
Answer:
Melatonin (Sleep hormone) is secreted by Pineal gland.

(vii) Which instrument is used to measure the blood pressure ?
Answer:
Sphygmomanometer (B.P. apparatus) is used to measure the blood pressure.

(viii) What is ornithophily ?
Answer:
Pollination by birds is called ornithophily.

Section – B

Question 3.
Sketch and label.- Graafian follicle.
Answer:

Question 4.
Match the following:

Column A	Column B
(i) Dropithecus	(a) Java and Peking
(ii) Ramapithecus	(b) Toung in South Africa
(iii) Australopithecus	(c) Lake Victoria of Africa
(iv) Homo erectus	(d) Shivalik hills in India

Answer:
(i) → (c),
(ii) → (d),
(iii) → (b),
(iv) → (a)

Question 5.
Give the factors which affect the blood pressure.
Answer:

1. Cardiac output
2. Blood volume
3. Age
4. Emotions
5. Sleep
6. Exercise
7. Anxiety

Question 6.
What is Chiropterophily? Why the transfer of pollen grains is important?
Answer:
The transport of pollen grains by bats is called Chiropterophily. The transfer of pollen grains is important for the reproduction in plants as the male gamete participates in the process.

Question 7.
Define the terms:
(i) Biopatent
(ii) Biopiracy
Answer:
(i) Biopatent It is the patent awarded by Government for the invention in the biology. It is awarded for strains of microorganisms, GMOs, biotechnological processes, products and product applications.

(ii) Biopiracy: It is the unlawful commercial exploitation of various natural products without providing benefits to the host country.

Question 8.
Define: Camouflage.
Answer:
Camouflage is adaptation in which organisms are cryptically coloured as per surrounding to avoid being detected easily by other organisms.

Question 9.
Write a note on parasitism.
Answer:

1. It is an association between two organisms where one organism (parasite) gets benefited at the cost of other (host).
2. The parasite obtains food from the host.
3. Majority of parasites harm the host They may reduce the survival growth and reproduction of the host and may cause death. Example: Plant parasite Cuscuta, Animal parasite, Mosquito.

Question 10.
Distinguish between Inspiration and Expiration.
Answer:

Inspiration	Expiration
Draw air into the lungs	Expulsion of air from the lungs.
An active process.	A passive process.
The diaphragm moves downwards,         becomes flat.	The diaphragm moves upward and becomes dome shaped.
The intercostal muscles contract.	The intercostal muscles relax.
The volume of thoracic cavity increases.	The volume of thoracic cavity decreases.

Question 11.
Write drawbacks of Darwin’s theory.
Answer:

1. Darwin considered small fluctuating variations as basic factors of evolution which are non-inheritable and have no role in evolution.
2. The theory does not explain the effect of use and disuse and the presence of vestigial organs.
3. Darwin could not explain whether the instincts are acquired and modified through natural selection.
4. He could not differentiate between somatic and germinal variations and considered all variation are heritable.

Question 12.
Write a note on incomplete dominance.
Answer:

1. In the incomplete dominance both the genes (dominant and recessive) express themselves partially.
2. The dominant gene can not supress the expression of the recessive gene completely.
3. In F₁ hybrid there is an intermediate expression. For example:
   The flower colour of Mirabilis jalapa.
   If a red flowered plant (RR) crossed with white coloured plant (rr), F₁ hybrids have pink flowers (Rr).

Question 13.
Draw flow chart of Central Dogma.
Answer:

1. The central dogma was proposed by Crick in 1958.
2. It is unidirectional flow of information from DNA to mRNA and mRNA to protein.

Question 14.
Sketch and label – structure of stomatal apparatus.
Answer:

Section – C

Attempt any Eight of the following questions:

Question 15.
A plant with red flowers was crossed with another plant with yellow flowers. If F₁ showed all flowers orange in colour, explain the inheritance.
Answer:
This phenomenon is called Incomplete dominance. In Incomplete dominance where the two alleles (genes) of an allelomorphic pair express themselves partially producing intermediate hybrid in F₁ generation. In this case, a new phenotype in between the two original phenotype appears.

Question 16.
Enlist role and deficiency symptoms of
(i) Potassium
(ii) Zinc
(iii) Calcium
Answer:
(i) Potassium (K⁺)
Role: To determine ionic baLance in cells involved in protein synthesis, involved information of cell membrane, opening and closing of stoma. Deficiency: Yellow edges of leaves, premature death.

(ii) Zinc (Zn²⁺)
Role: Activation of various enzymes especially carboxylases needed for auxin synthesis.
Deficiency: Malformed leaves.

(iii) Calcium (Ca²⁺)
Role: Involved in selective permeability of cell membranes, activates certain enzymes required for development of stem and root apex and as calcium pectate in the middle lamella of the cell wall.
Deficiency: Stunted growth.

Question 17.
What do you mean by “Central Dogma” of Molecular biology?
Answer:
(i) The central dogma of molecular biology explains the flow of genetic information, from DNA to RNA to make a functional product, a protein.

(ii) It is flow of genetic information from DNA to mRNA by the process of transcription and mRNA to proteins by the process of translation.

(iii) It suggests that DNA contains the information needed to make all of our proteins and RNA is a messenger that carries this information to the ribosomes.

Question 18.
Sketch and label: T.S. of spinal cord.
Answer:

Question 19.
Match the following pairs:

Column I	Column II
(i) PCR	(a) DNA transferred to nylon membrane
(ii) Electrophoresis	(b) DNA amplification
(iii) Southern blotting	(c) Restriction digestion
(iv) Autoradiography	(d) Produce fragments of different size
(v) Alkali treatment	(e) Separation of DNA fragments on gel slab
(vi) DNA treated with REN	(f) X-ray photography

Answer:
(i) → (b), (ii) → (e), (iii) → (a), (iv) → (f), (v) → (d), (vi) → (c)

Question 20.
Write physiological effect of cytokinin.
Answer:

1. It promotes cell division and cell enlargement.
2. It promotes root development, buds and shoot development.
3. Controls apical dominance.
4. It delays senescence or aging and abscission process.
5. It breaks seed dormancy and promotes germination.
6. It induces RNA synthesis and formation of interfascicular cambium.

Question 21.
Write a note on types of cancer.
Answer:
The types of cancer are:

1. Carcinoma: Cancer of epithelial tissue covering or lining of body organs, e.g., cancer, skin cancer.
2. Sarcoma: Cancer of connective tissue, e.g., bone tumors, muscle tumors.
3. Lymphoma: Cancer of lymphatic tissue, e.g., occurs in lymphatic nodes, spleen.
4. Leukemia: It is a type of blood cancer, excessive formation of WBCs or leucocytes in bone marrow.\
5. Adenocarcinoma: Cancer arises in thyroid, pituitary gland.

Question 22.
Write the microbial source of following organic acids:
(i) Citric acid
(ii) Fumaricacid
(iii) Acetic acid
Answer:
(i) Citric acid → Aspergillus niger
(ii) Fumaric acid → Rhizopus arrhizus
(iii) Acetic acid → Acetobacter aceti

Question 23.
Write advantages of SCP (Single cell protein).
Answer:

1. Microorganisms have a high rate of multiplication so a large quantity of biomass can be produced in short duration.
2. They can be easily genetically modified and they have high protein contents.
3. They can use a broad spectrum of raw materials including waste materials, help in removal of pollutants.
4. Strains with high yield and good composition can be selected or produced easily.
5. Land requirement is low and beneficial ecologically.
6. Independent on climate.

Question 24.
Write name, type and origin of following cranial nerves:
No. III, No. VI, No. X.
Answer:

Number	Name	Type	Origin
III	Occulomotor	Motor	Floor of mid brain
VI	Abducens	Motor	Pons
X	Vagus	Mixed	Side of medulla oblongata

Question 25.
Explain movement of water in the root.
Answer:

1. Water is absorbed by root hair cells through processes like imbibition, diffusion, osmosis.
2. Water passes through the epidermal cell, cortex, endodermis, casparian strip, pericycte and then to protoxylem.
3. When root hair cell absorbs water it becomes turgid, the turgour pressure increases but DPD decreases. The cortical cells adjacent to root hair cell absorb water from the turgid root hair cell The cortical cells become turgid. The flaccid root hair cell now absorbs water from soil.
4. Water from the turgid cortical cell is absorbed by the inner cortical cell and the process goes on.
5. Water moves rapidly across the cells of cortex and to the cells of endodermis and finally into the cells of pericycle.
6. Due to root pressure water from pericycle is forced into the xylem.

Question 26.
Distinguish between primary succession and secondary succession.
Answer:

Primary Succession	Secondary Succession
Primary Succession can be defined as the process of growth in an area that was previously uninhabited, barren, unoccupied and there was no initial vegetation.	Secondary Succession can be defined as the growth of the community in such area which was previously occupied, inhabited and that has primary vegetation but got disturbed or damaged due to some external or internal factors.
Rate of succession is very slow.	Rate of succession is very fast.
Primary succession takes a long time for completion, 1000 years or more.	Secondary succession takes less time for completion, 50 to 200 years.
Soil is absent.	Soil is present.
There is no humus in the beginning.	Humus is present from the very beginning.
Reproductive structures of any previous community are absent.	Reproductive structures of the previous occupants are present in the area.

Section – D

Attempt any Three of the following questions:

Question 27.
(i) Draw the neat labelled diagram of internal structure of human heart.
Answer:

(ii) What is phosphorylation?
Answer:
It involves trapping the heat energy in the form of high energy bond of ATP molecule. ATP is used to carry out vital life processes and so is called as energy currency of the cell.
ADP + iP + 7.3 Kcal → ATP

Question 28.
(i) Describe the process of double fertilisation.
Answer:
The process of double fertilisation:

(a) Double fertilisation is a complex process in Angiosperms where both the male gametes participate in the process of fertilisation. First male gamete fuses with egg or ova to produce diploid zygote while second male gamete fuses with secondary nuclei to produce triploid primary endospermic nucleus (PEN).

(b) The pollen tube carrying male gametes penetrates in embryo sac of ovule through its micropylar end. The tip of the pollen tube absorbs water from synergids and ruptures to release both the male gametes.

(c) The first haploid male gamete fuses with haploid female gamete to produce a diploid zygote (syngamy) whereas in triple fusion, second haploid male gamete fuses with diploid secondary nucleus producing triploid primary endosperm nucleur (PEN) that develops into triploid endosperm.

(d) In double fertilisation two products are obtained— a diploid zygote which develops into an embryo and a triploid primary endosperm nucleus which develops into nutritive endosperm tissue.

(e) Double fertilisation is significant as it utilizes both the male gametes, avoids polyembryony.’ The endosperm provides nourishment to the developing embryo.

(ii) What is Geitonogamy?
Answer:
It is the transfer of pollen grain to a stigma of a different flower produced on the same plant. It is functionally similar to cross pollination as it involves pollinating agents but it cannot bring about genetic variations and is only of ecological significance e.g. Cucurbita maxima. It is similar to autogamy as pollen grains come from same plant.

Question 29.
Describe menstrual cycle in human female.
Answer:
Menstural cycle includes:

(i) Menstural phase
(ii) Follicular phase
(iii) Ovulatory phase
(iv) Luteal phase

(i) Menstrual phase: The cycle begins with the menstrual phase, which lasts for approximately five days. The endometrium of uterus breaks down. The blood, endometrial tissues, mucus and unfertilised egg is discharged through vagina.

(ii) Follicular phase (5^th to 13^th day): After menstruation the endometrium in the uterus begins to regenerate. Regeneration involves formation of endothelial cells, uterine glands and network of blood vessels. The endometrium becomes thick. In this phase several follicles start maturing in the ovaries. Few secondary follicles develop but only one develops into Graafian follicle.

(iii) Ovulatory phase (14^th day): It is the shortest phase and it involves release of ovum from the mature Graafian follicle into the pelvic cavity.

(iv) Luteal phase (15^th to 28^th day): After release of ovum the remaining tissues of Graafian follicle transforms into corpus luteum. Corpus luteum secretes progesterone and estrogen. If the ovulated ovum is fertilised within 25 hours then the corpus luteum will survive.

If not then after two weeks it degenerates into a white scar called corpus albicans. Under the influence of progesterone and estrogen the endometrium will become more vascularised and thickfor fertilisation and implantation. If the egg is not fertilised, the endometrium will break and menstrual flow will start.

Question 30.
Explain formation of a typical spinal nerve with the help of neat, Labelled diagram.
Answer:

(i) All spinal nerves are of the mixed type i.e., they have sensory as well as motor nerve fibres.
(ii) Each spinal nerve is formed inside the neural canal of vertebral column by two roots – the dorsal sensory root and ventral motor root.
(iii) The dorsal sensory and the ventral motor nerves together form the mixed spinal nerve.
(iv) It emerges out from both sides of the spinal cord through intervertebral foramen.
(v) As soon as it emerges out of vertebral column it divides into 3 branches.
(a) Ramus dorsalis – From skin and muscles of dorsal side
(b) Ramus ventrails – The organs and muscles of lateral side.
(c) Ramus communicans – Joins sympathetic genglia.

Question 31.
What are the different strategies for biodiversity conservation in India?
Answer:
There are two main strategies for conservation of biodiversity:
(i) In-situ conservation: The natural habitat of the organisms is protected so protection of organisms takes place automatically.
It includes:

(a) Biosphere reserves: There are 425 biosphere reserves in the world of which 14 are in India. India has three of world’s biodiversity hotspots. Hotspots are the areas with high density of endemic and endangered species.

(b) National park or wildlife sanctuaries: India has about 90 national parks and 448 wildlife sanctuaries. In Maharashtra there are 5 national parks and 11 sanctuaries.

(c) Sacred groves: These are undisturbed stretches of forests protected in the name of god. Some endangered varieties of plants and animal species survive here.

(ii) Ex- situ conservation: It is the process of protecting the endangered species of plants or animals by removing it from threatened habitat and placing ‘ them under care of humans.
It includes:

(a) Botanical garden, zoological park and arboreta are conventional methods of ex-situ conservation.
(b) Seed banks to conserve wild varieties of food grains and vegetables.
(c) Cryopreservation to the storage of materials at low temperature.

Maharashtra Board Class 12 Biology Previous Year Question Papers