Madhyamik life science Question Paper 2018 Solve

WB Madhyamik life science Solve

Madhyamik Pariksha 2018 Solve- life science

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SUBJECT: life science Year: 2018

Group A

Write the answer in a complete sentence by choosing the correct answer for each question with the respective serial number.

1.1 The tentacles on the leaves of an insectivorous plant, called sundew bend to trap the insect as soon as they come in contact with the insect body. This is-

(a) Seismonasty

(b) Thermonasty

(c) Photonasty

(d) Chemonasty

Ans. As soon as the leaf follicles the leaf of the sundew plant come in contact with the body of the insect, and it catches the insect by turning. he is- (d) Chemonasty

1.2 In the case of women, the Follicle Stimulating Hormone stimulates the Graafian Follicle of the Ovary to secrete the hormone, which is-

(a) TSH

(c) Oestrogen

(b) ADH

(d) ACTH

Ans. The follicle-stimulating hormone in females, which stimulates the Graafian follicles of the ovary to secrete which hormone is (c) (Oestrogen)

1.3 Which one of the following is the correct reflex arc?

(a) (Receptor)→ (Effector) → (Efferent nerve)→ (Nerve Centre) → (Afferent nerve).

(b) (Nerve Centre)→ (Receptor) → (Afferent nerve) → (Effector)→ (Efferent nerve)

(c) (Efferent nerve) → (Receptor)→ (Afferent nerve) → (Nerve Centre) (Effector)

(d) (Receptor)→ (Afferent nerve)→ (Nerve Centre) → (Efferent nerve) → (Effector)

Ans. (d) (Receptor) → (Afferent nerve)→ (Nerve Centre) → (Efferent nerve)→ (Effector)

1.4 In which stage of mitosis cell division, the nuclear membrane and nucleolus are seen to disappear-

(a) Anaphase

(b) Prophase

(c) Metaphase

(d) Telophase

Ans. In the prophase stage of mitosis cell division, the nucleus (nuclear membrane) and nucleolus disappear.

1.5 Which of the following is not a structural component of DNA-

(a) Deoxyribose sugar

(b) Uracil base

(c) Thymine base

(d) Phosphoric Acid

Ans. Of these, the uracil base is not a structural component of DNA.

1.6 Which one of the following statements is correct regarding sexual reproduction

(a) Haploid gamete formation is essential in sexual reproduction

(b) Sexual reproduction depends only on mitosis

(c) In sexual reproduction, offspring could be produced from a single parental organism

(d) The offsprings produced in sexual reproduction are genetically identical to the rental organism.

Ans. About sexual reproduction, the following statements are correct – (a) Formation of the haploid zygote is necessary for sexual reproduction.

1.7 F, Which one of the following is the genotypic ratio at F2 generation of Mendel’s monohybrid cross-

(a) 1:2:1

(b)3:1

(c) 9:3:3:1

(d) 2:1:2

Ans. F2 A crossbreed of Mendel in the generation has (a) a 1:21 genotype ratio.

1.8 Which one of the following is not controlled by the autosomal gene of human-

(a) Roller tongue

(b) Haemophilia

(c) Thalassaemia

(d) Attached earlobe

Ans. (b) Hemophilia is not controlled by the human somatic chromosome.

1.9 What would be the phenotypic ratio in the F2 generation of a monohybrid cross in case of incomplete dominance-

(a) 3:1

(b) 2:1:1

(c) 9:3:3:1

(d) 1: 2:1

Ans. The phenotype ratio in the F1 generation of a crossbred hybrid of incomplete dominance will be (d) 1: 2:1

1.10 Which one of the following is the intraspecific struggle for the same food

(a) struggle between Vulture and Hyena

(b) struggle between Eagle and Kite

(c) struggle among the members of Rohu fish in the pond

(d) struggle between Egret and Kingfisher

Ans. Intraspecific conflict for common food is (c) Conflict between Rohu fishes in a pond

1.11 Which of the following changes did not occur during the course of the evolution of horse-

(a) Lengthening of limbs

(b) Increase in the length and thickness of all digits in limbs

(c) Increase in the length and only the third digit in limbs

(d) Increase in size of the whole body

Ans. (b) The increase in length and width of all the toes did not occur during the evolution of the pod.

1.12 According to the opinion of the scientists the prebiotic environment of the earth that led to the origin of life was like-

(a) Hot dilute soup in the seawater

(b) Cold dilute soup in the seawater

(c) Cold dilute soup in the river water

(d) Hot dilute soup in the groundwater

Ans. According to scientists, before the origin of living beings on the earth, there was an atmosphere like- (a) hot thin soup, in sea seawater.13 Which one of the following mistakes takes part in nitrification-

(a) Nitrosomonas

(c) Pseudomonas

(b) Azotobacter

(d) Thiobacillus

Ans. Nitrosomonas organism takes part in nitrification.

1.14 An example of Ex-situ conservation is —

(a) Sunderban Tiger Reserve

(b) Corbett National Park

(c) Nilgiri Biosphere Reserve

(d) Cryopreservation

Ans. (d) Cryo protection is outer space protection.

1.15 Which of the following effect is the result of water pollution —

(a) Global warming

(b) Eutrophication

(c) Deafness

(d) Bronchitis

Ans. (b) Eutrophication is the result of water pollution.

Group ‘B’

Answer any 21 questions out of 26 questions given below as instructed.

Fill in the blanks with proper words in the following sentences (any five):

2.1 Due to a deficiency of Iodine, the synthesis of _____hormone is hampered.)

Ans. Thyroxine.

2.2 During embryonic development and growth in vertebrates _____cell division takes place.

Ans. mitosis

2.3 The different _______ of Pea Plant may show the same Phenotype.)

Ans. genotype

2.4 Homologous organs evolve due to ________ evolution.

Ans. divergent

2.5 The name of one exotic species, that affects the local biodiversity, is ______.)

Ans. water hyacinth

2.6 The fine droplets of smoke, ashes, dust pollen grains, etc., suspended in air collectively called _______, which cause various lung diseases.

Ans. suspended particulate matter

Decide whether the following statements are true or false (any five)

2.7 Hypothalamus helps to maintain body balance in humans.

False

2.8 In DNA, Adenine is linked with Guanine by hydrogen bonds.

False

2.9 In his monohybrid cross experiment, Mendel obtained 75% pure tall Pea Plants in the first filial

generation.

False

2.10 In Lamarck’s opinion, organisms can acquire any particular inheritable physical trait according to their need.

True

2.11 Acid rain is caused by SO, and NO, gases formed due to air pollution.

True

2.12 Auxin helps the seed to germinate by breaking off dormancy.

False

Match the words in Column- A with those which are most appropriate in Column B and re-write the correct pair mentioning the serial no. of both columns (any five) 🙂

Column-A	Column -B
2.13 CSF	(a) Large colloidal aggregates
2.14 Crossing over	(b) Active participation of local peoples in the restoration of forests
2.15 Hemophilia	(c) Meiosis
2.16 Coacervate	(d) Movement of daughter chromosomes toward the pole
2.17 JFM	(e) Disorder caused by a recessive gene located at the human X-chromosome
2.18 Grafting	(f) Supplies nutrients to brain cells
	(g) Stock and Scion

Ans. 2.13-(f), 2.14-(c), 2.15-(e), 2.16-(a), 2.17-(b), 2.18-(g)

Answer in a single word or a single sentence (any six):

2.19 Choose the odd one and write it 🙂 (Dwarfism), (Goiter), (Thalassemia), (Diabetes Mellitus)

Ans. thalassemia

2.20 Mention one function of the lens of the human eyeball.

Ans. The lens focuses the rays of light on the retina.

2.21 A pair of related terms is given below. Based on the relationship in the first pair write the suitable word in the gap of the second pair.

(Mitosis: Radicle::: Spore Mother cell.)

Ans. miosis

2.22 In the case of the guinea pig whether the phenotype of the two genotypes bbRR and bbRr is same?

Ans. Yes, both the bbRR and bbRr genotypes have the same phenotype in the area of the guinea pig.

2.23 Write the phenotypic ratio obtained in the F2 generation of Mendel’s Dihybrid cross experiment.

Ans. The phenotype ratio found in Mendel’s Deccan experiment is 9:3:3:1.

2.24 Mention one adaptation of the Sundari plant for salt tolerance.

Ans. Some special saline glands are found in the leaves of beautiful plants, which help in excreting more salts dissolved in water in the soil.

2.25 Among the following four terms one includes the other three. Find out that term and write it: Overall knowledge regarding local biological resources, PER, Traditional belief regarding local biological resources Sustainable use of local biological resource

Ans. PBR

2.26 Name one. endangered animal conserved at Singalila National Park.

Ans. red panda

Group C

Answer any 12 questions in 2-3 sentences out of the 17 questions given below 🙂

3.1 Reflex actions occur when the following incidents happen in the everyday life of humans. Write the importance of these two reflex actions.
- When food particles enter the trachea
Ans. When food particles enter the tract, coughing is a reflex action to expel food.
- When foreign particles enter the nasal cavity
Ans. When foreign particles enter the nose, the reflex action of sneezing occurs so that those particles come out of the nose.

3.2 For correction of which defects in the vision of the eye, spectacles of convex and concave lenses are used?

Ans. Convex or convex lenses are used to correct hypermetropia. Concave or concave lenses are used to correct myopia.

3.3 List the names of the hormones related to the following functions:
- Regulation of sugar level in blood
Ans. insulin.
- Stimulation for the secretion of hormones from the Thyroid gland
Ans. Thyroid-stimulating hormone.
- Causing the growth of the Corpus Luteum and stimulating the secretion of Pages terone hormone in the female body
Ans. Luteinizing hormone.
- Increasing blood pressure due to anxiety
Ans. Adriene

3.4 A resting animal attempts to move. Mention four probable reasons behind it.

Ans. The animal which was at rest was trying to move because (i) to get food. (ii) For his security and attack on enemies. (iii) to change his place of residence. (iv) For reproduction.

3.5 Distinguish between an autosome and sex chromosome of humans based on the following features: • Nature • Number)

Ans. difference between a somatic chromosome and a silex chromosome

Symptoms

Somatic chromosome

Sex chromosome

Nature

Determines somatic symptoms.

Responsible for sex determination.

number

22 pairs / 44

a pair / 2

3.6 What are the processes of asexual reproduction in Spirogyra and Planaria?

Ans. Spirogyra – Fragmentation Planaria – Regeneration.

3.7 Mention two changes related to vision and bones in late adulthood or the senescence phase of human development.

Ans. Final culmination in human development or growth in adulthood – changes in bones – joint pain, difficulty in walking, decreased bone density, osteoporosis, osteoarthritis, etc.

Visual changes, blurred vision, presbyopia, cataract, glaucoma, etc.

3.9 One day students read an article in the newspaper on Thalassemia and were very scared to know the fate of a thalassemic patient. Write what kind of measures they can take to eradicate this disease from the population.

Ans. ways to prevent thalassemia

(i) To encourage pre-marriage genetic counseling and carrier screening and blood tests.

(ii) Even after marriage, genetic counseling should be taken and a DNA test should be done at 8 to 11 weeks of pregnancy.

3.10 What are all probable gametes to be produced from the hybrid plant YyRr produced at Fj. generation in a dihybrid cross-experiment?

Ans. In the hybridized plant YyRr to the F1 generation, the possible gametes available in dihybrid hybridization are YR, yr, yR, yr.

3.11 What are the two adaptive significances of air-sacs of pigeons

Ans. Importance in the adaptation of pigeon sacs (1) to store excess oxygen. (ii) To make the body lighter by reducing the specific gravity.

3.12 Write the names of one each vestigial organ present in the vertebral column and alimentary canal in the human body.

Ans. The coccyx present in the human cord is the coccyx and the residual organ present in the food pipe is the vermiform appendix.

3.13 Write in chronological sequence the names of four main fossil ancestors during the course of the evolution of the horse.

Ans. Eohippus, Mesohippus, Merychippus, and Pliohippus are the names of the four main fossil ancestors in the evolution of the horse.

3.14 “Nitrogen cycle is affected due to human activities”. -state two phenomena to justify it.

Ans. Influence of nitrogen cycle by human activities:

(i) The use of excessive amounts of nitrogenous fertilizers by humans in agricultural work affects the nitrogen cycle.

(ii) The use of fossil fuels in vehicles and factories unbalances the amount of nitrogen in the atmosphere.

3.15 What would be the environmental consequences as a result of recurrent destruction of wetlands and depletion of the number of agricultural lands?

Ans. Impact on the environment of the destruction of wetlands

(i) Lack of drinking water.

(ii) Loss of biodiversity. Effects on the environment of the destruction of agricultural land – Destruction of agricultural land will reduce food production, which will result in increased conflict between organisms and people will become victims of hunger.

3.16 What are the harmful impacts sound pollution can exert on the ears and heart in the human body?

Ans. Due to noise pollution, the hearing capacity of the ears decreases. A man can also be completely deaf. Noise pollution increases the heart rate. The blood pressure rises which increases the chances of having a heart attack.

3.17 If the water level in the sea increases enormously due to global warming, what problems the humans and biodiversity of Sundarban may face?

Ans. Biodiversity problems of man and Sundarbans due to additional increase in seawater due to geothermal heat: – Due to the increase in seawater, the coastal shore is getting submerged. Such a situation occurs due to the melting of the ice sheet. In this situation, there will be a shortage of habitat in the coastal areas, due to which the natural balance there will be disturbed. This will lead to a shortage of drinking water, the spread of diseases, and the degradation of cultivable land. There will be a decrease in the number of tigers, fish, tortoises, etc.

Group D

Answer any six questions in seven or eight sentences, taking at least one from each segment:

Segment: D.1

Draw a diagram of a reflex arc and label the following parts.

(a) Receptor (b) Sensory nerve (c) Nerve center (d) Motor nerve

Draw the morphology of an ideal eukaryotic chromosome and label the following parts :

(a) Chromatid (b) Centromere (c) Nucleolar Organizer (d) Telomere

4.2 What types of chemical components are synthesized in different stages of Interphase in a cell cycle? What might happen if normal control at different points of a cell cycle is lost?

Depict the alternation of generation in a fern with the help of. Flowchart…. “In case of Prophase and Telophase changes of opposite nature happens” – Write two such changes.

4.3 Color of seed and shape of seed of a pea plant-taking these e two characters Mendel performed a dihybrid cross. Write the genotypes of seeds plants having yellow and round seeds produced in the F2 generation of this experiment. State the law of Independent Assortment of Mendel.

State the opposite traits for each of the characters of flowers of pea plants chosen by Mendel for his experiment. “For developing the scientific ideas on heredity, the experiments performed armed by Mendel on pea plants are epoch-making.”-Mention three reasons behind his success in performing these experiments.

4.4 How the special feature of RBC in camels is related to their ability to withstand the extreme loss of water? Give examples of the ways Chimpanzees solve their problems intelligently for procuring food and preventing disease.

Explain the process of Natural Selection as proposed by Darwin with the help of a suitable example. What are the roles of the swim bladder in the aquatic adaptation of fish?

4.5 “A lot of indiscriminate activities of humans pollute the environment” -Support the statement by giving three examples in favor of it. Give examples of a national park and a biosphere reserve situated in West Bengal.

Show the steps of the Nitrogen Cycle with the help of a flow of seawater.

4.6 What environmental factors may seawater in humans? If the water level in the sea increases enormously due to global warming, what problems the humans and the biodiversity of Sundar ban may face?

Mention the in-situ measures adopted for the conservation of lions in Gir National Park of India. What environmental problems may arise in a locality due to the ever-increasing human population?