Life Science Solution–2019

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Group – A

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

1.1 Select which of the following statement is correct related to tropic movement –
(a) It is controlled by the intensity of the stimulus
(b) Overall change of place takes place by a plant or part of the plant
(c) This movement is observed in the algae called Vol-vox.
(d) It is an induced movement of curvature controlled by the direction of stimulus (Ans)

1.2 Read the following sentences and identify the sentence which is not correct –
(a) FSH, LH and Prolactin are different types of GTH
(b) Adrenaline decreases cardiac output (Ans)
(c) Insulin facilitates the absorption of glucose into the cell through cell membrane
(d) Progesterone helps in the formation of placenta in female body

1.3 Determine the number of Cranial nerves in human body –
(a) 10 Pairs
(b) 31 Pairs (Ans)
(c) 12 pairs
(d) 21 pairs

1.4 Identify the correct feature of Amitosis cell division –
(a) Occurs in germ mother cell of sexually reproducing organism
(b) It is called indirect cell division
(c) Chromosome and Spindle fibre are formed (Ans)
(d) Chromosome and Spindle fibre are not formed (Ans)

1.5 Determine which of the following statement is correct regarding the significance of meiosis
(a) It results in overall growth and development of body
(b) It results in the growth of reproductive organs and embryo of the organism
(c) It produces haploid gamete containing hereditary variations (Ans)
(d) It regenerates the organ in the body of some animals if it is lost

1.6 Select the correct pair and write it –
(a) Multiple fission – Hydra
(b) Fragmentation – Spirogyra (Ans)
(c) Regeneration – Fern
(d) Budding – Planaria

1.7 Identify which of the following is a dominant trait –
(a) Length of the stem – Dwarf
(b) Shape of the seed – Wrinkled
(c) Colour of the cotyledon – Yellow (Ans)
(d) Colour of the flower – White

1.8 Assess how many types of gametes are produced from the Pea plant having the genotype RRYY –
(a) One type (Ans)
(b) Four types
(c) Two types
(d) Three types

1.9 Select which of the following two genotypes are responsible for the expression of the phenotype wrinkled yellow in Pea plant –
(a) RRYY and rryy
(b) RRYy and RrYy
(c) RRyy and Rryy
(d) rrYY and rrYy (Ans)

1.10 Identify which of the following indicates inter-specific struggle –
(a) Struggle among the members of guppy fish for feeding on mosquito larvae
(b) I Struggle between snakes and owls for capturing rats for eating (Ans)
(c) Struggle within a group of deer for feeding on grass at the same location
(d) Struggle between tigers in a jungle for preying on deer

1.11 Determine the term related to the theory of Lamarck –
(a) Struggle for existence
(b) Origin of variation
(c) Inheritance of acquired characters (Ans)
(d) Natural selection

1.12 Identify the animal the communicates information with other members of its own group through specific dancing pattern regarding the sources of food –
(a) Chimpanzee
(b) Cockroach
(c) Peacock
(d) Honeybee (Ans)

1.13 Decide which of the following if remains for a long time in the environment, the probability of its biomagnification increases –
(a) Newspaper
(b) Faecal matters of animals
(c) Rotten leaves
(d) Chlorinated insecticide (Ans)

1.14 Gorumara, Corbett, Kulik, Nandadevi – choose the correct sequence from the following which is correct for the above forests in sequence –
(a) Biosphere Reserve, Sanctuary, National Park, National Park
(b) National Park, National Park, Biosphere Reserve, Sanctuary
(c) National Park, National Park, Sanctuary, Biosphere Reserve (Ans)
(d) Sanctuary, Biosphere Reserve, National Park, Sanctuary

1.15 If the number of pollen grains, fungal spores, and dust particles increases suddenly in the air, decide which of the following problems may increase –
(a) Tuberculosis
(b) Asthma (Ans)
(c) Malaria
(d) Dengue

Group – B

2. Answer 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 By the influence of  Adrenaline hormone the hairs on the skin get erected at emergency situation.
2.2 Chromosome is the condensed coiled structure of D.N.A molecule.
2.3 The sexual reproduction that occurs among two genotypically different organisms belonging to the same species, is called Hybridization..
2.4 Coacervates was the aggregate of some large colloidal molecules during the early phase of origin of life.
2.5 Reserpine is derived from the root of Sarpagandha plant which is used as medicine for lowering high blood pressure.
2.6 The ex situ conservation by keeping sample seeds in liquid nitrogen at a temperature of -196°C is called Rauwolfia serpentia.

Decide whether the following statements are true or false (any five):
2.7 Dilute urine is profusely eliminated by a person affected with Diabetes Insipidus. True
2.8 The Carpel of flowering plants collect pollen grains with the help of hairy and sticky style. False
2.9 A pair of sex-determining sex chromosomes are present in the ovum of humans. False
2.10 According to Darwin organisms reproduce at geometric ratio. False
2.11 One-horned rhinoceros is conserved at Manas National Park of West Bengal. False
2.12 Acetylcholine and adrenaline are neurotransmitters. True

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 the columns (any five):

2.13) PresbyopiaNear vision is defective
2.14) Cell differentiation of Phase
of growth
Formation of tissue organ and system
2.15) Genotype of Guineapig having
black and coarse
2.16) Hot dilute soupHaldane
2.17) Destruction of forest and erosion
of ecosystem
Change of climate and global warming
2.18) CentrosomeFormation of spindle fibre during animal cell division

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

2.19 Chose the odd one and write it– Glossopharyngeal, Oculomotor, Trigeminal, Oxytocin.

2.20 What is the function of the fluid present in the intermediate chamber between lens and retina of the eyeball?
Ans: The function of the fluid present in the intermediate chamber between the lens and the retina of eyeball is to maintain the shape of the eyeball.

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 second pair.
Grafting: Mango: Vegetative propagation : China Rose

2.22 What is the cause of expression of haemophilia disease only at homozygous condition?
Ans: The cause of expression of haemophilia disease only at homozygous condition is that the haemophilia disease is a X linked recessive disease.

2.23 Write the genotypic ratio obtained at 2nd filial generation in the monohybrid experiment done by Mendel?
Ans: 1:2:1 is the genotypic ratio obtained at 2nd filial generation in the monohybrid experiment done by Mendel.

2.24 Which type of evolution is indicated by homologous organs?
Ans: Divergent Evolution is indicated by homologous organs.

2.25 Among the following four terms one includes the other three. Find it out and write it: Pesticides used in Agriculture, Typhoid, Water Pollution, liquid wastes from factories?
Ans: Water pollution is the term that includes the two.

2.26 In which type of in situ conservation practice, the diversity, culture, and lifestyle of humans are preserved along with microorganisms, wild animals, and wild plants?
Ans: National park is the type of in situ conservation practice, the diversity, culture, and lifestyle of humans are preserved along with microorganisms, wild animals, and wild plants.

Group – C

3. Answer any 12 questions in 2-3 sentences out of 17 questions given below:

3.1 Illustrate with the help of a word diagram the nervous pathway of the way you will open the door by hearing the doorbell.
Ans: Stimuli(sound of the doorbell)

Receptor(the spiral organ of corti)

Sensory neurone (Optic nerve)

Nerve Center (Brain)

Motor neurone (Cranial nerve)

Effector (The hand will move up by muscles contraction)

Response (open the door)

3.2 State the locations of Meninges and CSF.

MeningesIt is located outside of the whole brain and spinal cord i.e.,the brain and spinal cord covered by 3 layered (dura matter, arachnoid matter and pia matter) membranes called meninges.
CSFIt is located in the ventricles of brain, neural canal of spinal cord and sub arachnoid space. It is clear colourless modified tissue fluid. It is about 150 ml in adult man.

3.3 What influences gibberellin hormone exert on the seeds and intenode of plants? Explain.
Ans: Gibberellins break dormancy in seeds and it produces elongation of stem by increasing the length of internodes.

3.4 Write the names of the different refractive medium of eyeball in proper sequence.
Ans: The different refractive medium of eyeball are:
Air (outside of eye) → water ( aqueous humour) glass(biconvex lens) jelly like transparent (Vitreous humour)

3.5 During the meiosis cell division, reduction in the number of chromosomes and exchange of segments between chromatids take place Analyse what are the significance of these two phenomena.
Ans: During Meiosis cell division, the significance of the following two phenomena are:
1.Reduction in the number of chromosomes: The chromatids of each chromosome get separated. Therefore, in meiosis final product get half the number of chromosome of the mother cell. This Led to the formation of gametes.
2. Exchange of segment between chromatid: Exchange in the segment between two chromatids give birth to the new variations in the offspring.

3.6 Distinguish between asexual and sexual reproduction on the basis of following features:
• Number of Parents
• Nature of offspring

3.7 Identify the stages of Karyokinesis of mitotic cell division depending on the following features:
• Alignment of chromosomes along the equator of the cell and their arrangement in a definite pattern
• Disintegration of spindle fibres
• Disappearance of nuclear membrane and nucleolus
• Movement of daughter chromosomes to the opposite poles of cell
Ans: Alignment of chromosomes  along the equator of the cell and their arrangement in a definite pattern – Metaphase
Disintegration of spindle fibres – Anaphase
Disappearance of nuclear membrane and nucleolus – Prophase
Movement of daughter chromosomes to the opposite poles of cell – Anaphase

3.8 To establish the law of segregation in case of Pea plants, you are asked to select characters. Write two such characters having opposite traits.
Ans: Pure tall and pure dwarf or purple flower and white flower.

3.9 A daughter is born to a woman carrier for the colour-blind disease who married a colour-blind man. What would be the probability of expression of colour blindness in that girl child? Analyse your answer.
Ans: So, there is a 50% probability of expression of colour blindness in that girl child–

3.10 Write the name of two genetic diseases which are expressed in human populations.
Ans: Colour-blindness and Haemophilia are the two genetic diseases expressed in human population.

3.11 Tigers are extinct but there are many deer in the jungle. A few tigers are brought from another sanctuary and released in such a jungle. Imagine and write the names of different kinds of struggle for existence those tigers have to be involved in.
Ans: Interspecific and Intraspecific struggle.

3.12 Describe any two adaptations in Sundari plant for tolerance of salt.
Ans: The following are the two adaptations in Sundari plant for tolerance of salt:
1.Plants develop pencil like pneumatophores which can absorb O2 from air.
2.Salt glands on the surface of the leaves secrete salt.

3.13 Explain how do the chimpanzees hunt termites for food.
Ans: Chimpanzees is quite clever and can prepare a tool with a small branch of a tree. After defoliating the tip of the twig, it is crushed to prepare it like a brush. Then the brush is inserted into the termite mound. This stick like brush is then pulled out when quite a good number of termites may be collected for eating.

3.14 List the harmful effects of the following pollutants
(i) Greenhouse gas
(ii) SPM
(iii) Chemical fertilizers used in agriculture
(iv) Non-biodegradable chemical insecticide
Ans: (i) Greenhouse gas: The depletion of the ozone layer results in the entry of the harmful UV rays to the earth’s surface that might lead to skin cancer and can also change the climate drastically. The major cause of this phenomenon is the accumulation of natural greenhouse gases.
(ii) SPM: Exposure to such particles can affect both your lungs and your heart. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:  decreased lung function. increased respiratory symptoms.
(iii) Chemical fertilizers used in agriculture:Overuse of chemical fertilizers has hardened the soil, decreased fertility, strengthened pesticides, polluted air and water, and released greenhouse gases, thereby bringing hazards to human health and environment.
(iv) Non-Biodegradable chemical insecticide: Excessive use of non-biodegradable wastes like chemical pesticides (D.D.T) and fertilizers make the soil acidic or alkaline thereby affecting the soil fertility.

3.15 Give one example of exotic species causing damage to local biodiversities in each terrestrial and aquatic ecosystem.

3.16 Write the in-situ conservation measures taken for one endangered reptile species and name one site of such conservation in West Bengal.

3.17 “Poaching is one of the fundamental causes of endangeredness of animal diversity in India” Assess four causes for which animals are poached in India.

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