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Life Science Solution –2017

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Group A

1.Multiple choice question.

1.1 Some flowers open after sunrise and close after sunset. This is –
(a) Photonasty (Ans)
(b) Seismonasty
(c) Chemonasty
(d) Thermonasty

1.2 A person affected with Diabetes Mellitus is unable to secrete which of the following hormone in adequate quantity-
(a) Adrenaline
(b)Insulin (Ans)
(c) Thyroxine

1.3 The part of human brain associated with controlling body temperature is
(a) Thalamus
(b) Cerebellum
(c) Hypothalamus (Ans)
(d) Medulla

1.4 You have observed the separation of two sister chromatids at one stage of mitotic cell division the stage is
(a) Prophase
(b) Telophase
(c) Anaphase (Ans)
(d) Metaphase

1.5 Which of the following pair is correct
(a) Budding-Yeast (Ans)
(b) Fragmentation
(c) Sphere-formation-amoeba
(d) Regeneration-Dryopteris

1.6 Which phase of human development is associated with the maturity of reproductive organ and reproductive gland –
(a) Childhood
(b) Adolescence (Ans)
(c) Late Adulthood
(d) Infancy

1.7 Which of the following traits in pea plant is recessive –
(a) Wrinkled seed (Ans)
(b) Yellow coloured seed
(c) Purple coloured flower
(d) Axial flower

1.8 How many types of gametes are formed pea plant having genotype YyRr?
(a) 1
(b) 4 (Ans)
(c) 2
(d) 3

1.9 The probability of hemophilic girl children born to a hodophilia carrier mother and normal father is –
(a) 75%
(b) 50%
(d) 0% (Ans)

1.10 The gas which was absent in the environment during the origin of life is –
(a) Hydrogen
(b) Oxygen (Ans)
(c) Methane
(d) Ammonia

1.11 The feature of analogues organ is –
(a) Different in origin and function are also different (Ans)
(b) Different in origin but function are same
(c) Indicates divergent evolution
(d) Identical in origin and structure

1.12 Which of the following absorbs the gas of swim bladder in bony fishes –
(a) Red gland
(b) Anterior chamber
(c) Gastric gland
(d) Retia mirabilis (Ans)

1.13 Which of the following phase of nitrogen cycle Pseudomonas is associated with-
(a) Nitrogen fixation
(b) Nitrification
(c) Denitrification (Ans)
(d) Ammonification

1.14 One endangered species of the Eastern Himalayas biodiversity hotspot is –
(a) Lion tailed macaque
(b) Orangutan
(c) Red panda (Ans)
(d) Nilgiri thar

1.15 The diseases associated with air pollution are –
(a) Diarrhoea, Typhoid, Hepahepatitis,
(b) Hepahepatitis, Bronchitis, Deafness
(c) Bronchitis, Asthma, Lung cancer (Ans)
(d) Lung cancer, Polio, Malaria

Group B

2. Answer the following question (alternatives are to be noted).
Fill in the blanks:
2.1 The process of necessary adjustment of the focal length of the lens in human eyes is called Power of accommodation.
2.2 Adenine is a Purines type of nitrogenous base.
2.3 Hemophilia is a disease created by the sex-linked genes.
2.4 The earliest ancestor in the evolution of horses is Eohippus.
2.5 An inflammable greenhouse gas produced from the paddy field is Nitrous oxide.
2.6 Sundarban National parks is a biosphere reserve located in West Bengal.

Decide whether the following statements are true or false (any five)
2.7 Gibberellin hormone prevents immature shedding of the leaf of plants. False
2.8 Ovum is only produced as a result of mitosis. False
2.9 Self – pollination can be exercised in flowers of pea plant according to the need. True
2.10 The fundamental tenet of the evolutionary theory of Darwin is the process of natural selection. True
2.11 Degradable pollutant is responsible for biomagnification. False
2.12 Flagella is the locomotory organ of Paramecium. False

Match the right column with the left column: (Any five)

2.13) Blind SpotThe point of connection of retina and optic nerve
2.14)CytokinesisFormation of cell plates
2.15)44A+XYChromosomal attachments of human male
2.16)Wings of bat and birdsHomologous organs
2.17)ArsenicPollution of ground water
2.18)Transfer to stigmaPollen grain

Answer in a single word or in a single sentence (any six) :
2.19 Choose the odd one and write it: TSH, ACTH, GTH, CSF

2.20 Write one function of the myelin sheath.
Ans: Myelin sheath protects the nerve from other electrical impulses.

2.21 A pair of related terms is given below. On the basis of the relationship in the first pair write the suitable word in the gap of the second pair.
Prophase: Disappearance of nuclear membrane and nucleolus:: Telophase : Reappearance of nuclear membrane and nucleolus.

2.22 Give an example of a variation inherited in man along with the generation.
Ans: Colour of eye is an example of a variation inherited in man along with the generation.

2.23 Which type of chromosome in humans carries the gene responsible for the disease thalassemia?
Ans: Autosomes are the chromosome in humans carries the gene responsible for the disease thalassemia.

2.24 Mention one morphological adaption of the cactus to prevent transpiration.
Ans: Leaves are wanting and reduced in number.

2.25 Among the following four terms one includes the other three, Find out that term and write it:
Embryo, meristematic tissue, Seed, Cryopreservation.

2.26 Write the name of the cause of the latest concern regarding the environment of Sundarbans.
Ans: Sundarbans mangroves spread across the ganges delta was the cause the latest concern regarding the environment of sundarban.

Group C

3. Answer any 12 questions in 2-3 sentences out of 17 questions given below:
3.1 Write two differences between tropic movement and nastic movement.

Tropic movementNastic movement
It is movement of locomotion.It is movement of curvature.
It is influenced by direction of external stimulus either toward or away.It is influenced by intensity of external stimulus.

3.2 Write two roles of GTH in the secretion of hormones from the reproductive
glands in the human body.
Ans: These are the two roles of GTH:
 i) It stimulates leyding cells in male to secrete Testosterone and corpus luteum in female to secrete Progesterone.
ii) It stimulate the development of mammary gland during pregnancy.

3.3 Categorize the following actions as natural or inherited reflex actions.
The willingness of infants for breast-feeding ,Cycling,
Sneezing, Catching ball by wicket-keeper with swiftness
Ans: The willingness of infants for breastfeeding – Natural
Cycling – Inherited
Sneezing – Natural
Catching ball by wicket keeper with swiftness -Inherited

3.4 Write the parts of the central nervous system and peripheral nervous system.
Ans: Central nervous system(CNS) consists of the brain and the spinal cord, while the Peripheral Nervous System(PNS) is made up of all the nerves travelling from the CNS to all the organs in your body.

3.5 Write two important of the cell cycle.
Ans: These are the two importance of cell cycle:
i) It helps in the survival and Growth of organisms by renewing damaged cells.
ii) Maintenance of Chromosome number.

3.6 Distinguish between DNA and RNA based on the following features:
Pyrimidine base 5-C sugar

3.7 Which agents perform the function of pollination in the following plants? Paddy Hydrilla Shimul Mango.

i) PaddyAir
ii) HydrillaWater
iii) ShimulBird
iv) MangoInsect

3.8 State with an example of how the dominant trait is expressed in the experiment of hybridization.
Ans: Mendel in his first hybrid experiment took pea plants with tall and short characteristics and produced progeny from them. He observed the percentage of short plants and tall plants and found that all plants were tall. Parents that are pure for contrasting characters are crossed, only one form of the trait will appear and the dominant trait appears in the next generation. This best explains the Law of Dominance.

3.9 What would be the ratio of phenotype and genotype of F2 generation in a monohybrid experiment in case of incomplete dominance?
Ans: 1:2:1 is the ratio of the phenotype and the genotype of the F2 generation in a monohybrid experiment in case of incomplete dominance.

3.10 Show with the help of a cross, how color blindness is inherited.

3.11 Write the name of reactants used and one origin compound formed in the experiment of Miller and Urey in connection with the chemical origin of life.
Ans: In the experiment, Miller and Urey Kept methane, ammonia and hydrogen in a ratio 2:2:1 within water vapour.
One organic compound formed is Glycine – A

3.12 Write four important features modified in the evolution of the horse.
Ans: The four features of a horse that have undergone evolutions from the primitive to the modern horse is as follows:
i)Smaller body, head and neck
ii)Forelimbs with four and hindlimbs with three nailed digits
iii)No serrations upon the molar teeth
iv)lengthening of limbs and feet

3.13 How Sundari plant excretes the excess salt of its body?
Ans: Sundari plant excrete the excess salt through the specialised glands knows as Salt glands that are seen on the surface of the leaves.

3.14 Write the names of two micro-organisms participating in the process of biological nitrogen fixation.
Ans: Rhizobium and Azotobacter are the two micro- organisms participating in the process of biological nitrogen fixation.

3.15 Mention two damages as a result of acid rain.
Ans: The two main damages of acid rain are as follows:
i)Acid rain causes damage to the buildings, historic monuments ad statues.
ii)Acid rains washes away the nutrients of soil which are necessary for agriculture.

3.16 Give four examples of damages to biodiversity as a result of global warming.
Ans: Major damages of the biodiversity caused by global warming are given below:
i)Global warming has led to an incredible increase in earth’s temperature, resulting in an increase in the melting of glaciers, which have led to an increase in the sea level. This could have devastating effects on coastal regions.
ii)Global warming has affected the coral reefs that can lead to a loss of plant and animal lives. Increase in global temperatures has made the fragility of coral reefs even worse.
iii)Global warming has led to a change in climatic conditions. There are droughts at some places and floods at some. This climatic imbalance is the result of global warming.
iv)A global shift in the climate leads to the loss of habitats of several plants and animals. In this case, the animals need to migrate from their natural habitat and many of them even become extinct. This is yet another major impact of global warming on biodiversity.

3.17 Write the major topics regarding biodiversity documented in the People’s Biodiversity Register (PBR).
Ans: PBR or the People’s Biodiversity Register has a crucial role to play in promoting conservation, sustainable utilisation and documentation or chronicling of details regarding biological diversity. It also aims to put an end to the illegal and irregular harvesting of the biological resources.

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