Life Science Solution–2018

1.Multiple choice question.
1.1 The tentacles on leaves of an insectivorous plant, called sundew bend to trap the insect as soon as they come in contact with insect body. This is —
(a) Seismonasty 
(b) Thermonasty
(c) Photonasty
(d) Chemonasty (Ans)

1.2 In case of women, the Follicle Stimulating Hormone stimulates the Graafian Follicle of the Ovary to secrete the hormone is —
(a) TSH
(b) ADH
(c) Oestrogen (Ans)
(d) ACTH

1.3 Which one of the following is the correct reflex are?
(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)

1.4 In which stage of mitosis cell division, the nuclear membrane and nucleolus are seen to disappear
(a) Anaphase
(b) Prophase (Ans)
(c) Metaphase
(d) Telophase

1.5 Which of the following is not a structural component of DNA —
(a) Deoxyribose sugar
(b)Uracil base (Ans)
(c) Thymine base
(d)phosphoric Acid

1.6 Which one of the following statements is correct regarding sexual reproduction—
(a) Haploid gamete formation is essential in sexual reproduction (Ans)
(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 with parental organism

1.7 Which one of the following is the genotypic ratio at F2generation of Mendel’s monohybrid cross —
(a) 1 : 2 :1 (Ans)
(b) 3 : 1
(c) 9 : 3 : 3 : 1
(d) 2 : 1 : 2

1.8 Which one of the following is not controlled by the, autosomal gene of human —
(a) Roller tongue
(b) Hemophilia (Ans)
(c) Thalassemia
(d) Attached ear lobe

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)

1.10 Which one of the following is the intraspecific struggle for the same food —
(a) struggle between Vulture and Hyaena
(b) struggle between Eagle and Kite
(c) struggle among the members of Rohu fish in pond (Ans)
(d) struggle between Egret and Kingfisher

1.11 Which of the following changes did not occur during the course of 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 thickness of only the third digit in limbs
(d) Increase in size of the -whole body (Ans)

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 tie sea water (Ans)
(b) Cold dilute soup in the sea water
(c) Cold dilute soup in the river water
(d) Hot dilute soup in the ground water

1.13 Which one of the following microbes take part in nitrification?
(a) Nitrosomonas (Ans)
(b) Azotobacter
(c) Pseudomonas
(d)Thiobacillus

1.14 An’ example of Ex-situ conservation is
(a) Sundarbans Tiger Reserve
(b) Corbet National Park
(c) Nilgiri Biosphere Reserve
(d) Cryopreservation (Ans)

1.15 Which of the following effect is the result of water pollution—
(a) Global warming
(b) Eutrophication (Ans)
(c) Deafness
(d) Bronchitis

Group B

2. Answer any 21 question 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 deficiency of Iodine, the synthesis of hormone is hampered Thyroid
2.2 During embryonic development and growth in vertebrates Mitosis cell division take place.
2.3 The different of Pea Plant may show same Phenotype Genotype
2.4 Homologues organs evolve due to Divergent evolution.
2.5 The name of one exotic species, that affects the local biodiversity, is Amazon sailfin catfish.
2.6 The fine droplets of smokes, ashes, dusts, pollen grains etc., suspended in air collectively called Air pollution , which cause various lung diseases.

Decide whether the following statements are true or false (any five)
2.7 Hypothalamus helps to maintain body balance in human. True

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 SO2 and NO2 gases formed due to air pollution. True
2.12 Auxin helps the seed to germinate by breaking of dormancy. False

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

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

2.19 Choose the odd one and write, it:
Dwarfism, Goiter, Thalassemia, Diabetes, Mellitus

2.20 Mention one function of lens of human eyeball?
Ans: The Lens of the eyeball helps to focus the light onto the retina.

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.
Mitosis: Radicle ::  Meiosis: spore mother cell

2.22 In case of guineapig whether the phenotype of the two genotypes bbRR and bbRr is same?
Ans: No, in the case of the Guinea pig, the phenotype of the two genotype bbRR and bbRr is not the same. 

2.23 Write the phenotypic ratio obtained in the F2 generation of Mendel’s dihybrid cross experiment?
Ans: The phenotypic ratio obtained in the F2 generation of Mendel’s dihybrid cross experiment is 9:3:3:1.

2.24 Mention one adaptation of sundari plant for salt tolerance?
Ans: Plants develop pencil like pneumatophores which can absorb O₂ from air.

2.25 Among the following four terms one includes the other
three. Find out that term and write it:
Overall knowledge regarding local biological resource, PBR,
Traditional belief regarding local biological resource, Sustainable
use of local biological resource
Ans: PBR or the “ people’s Biodiversity Registers” is the term that includes the two.

2.26 Name one endangered animal conserved at Singalila National park?
Ans: Red panda is the one of the endangered animal conserved at Singalila National park.

Group C

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

3.1 Reflex actions occur when the following incidents- happen in everyday life of human. Write the importance of these two reflex actions.
When food particles enter into the trachea
When foreign particles enter inside the’ nasal cavity
Ans: i) When the food enters enter into the trachea, that result the person to start coughing, thus preventing the windpipe from food particles

ii) If some foreign particles enter inside the naval cavity. Sneezing occurs to remove the foreign particles that irritate the nasal mucosa

3.2 For correction of which defects in vision of eye spectacles of convex and concave lenses are used?
Ans: For myopia we use concave lens spectacles and for hyperopia we use convex lens spectacles.

3.3 List the names of the hormones related to following functions:
Regulation of sugar level in blood
Stimulation for the secretion of hormones from the Thyroid gland.
Causing the growth of Corpus Luteum and stimulating the
secretion of Progesterone hormone in the female body
Increasing blood pressure due to anxiety
Ans: (i) Regulation of sugar level in the blood – Insulin and Glucagon
(ii) Stimulation for the secretion of hormones from the Thyroid gland – Thyroid stimulating hormone (TSH)(iii) Causing the growth of Corpus Luteum and stimulating the secretion of progesterone hormone in the female body – Luteinising hormone
(iv) Increasing blood pressure due to anxiety – Adrenaline

3.4 A resting animal attempts to move. Mention four probable reasons behind it?
Ans: A resting animal attempts to move for these four probable reasons as given below:
i)To find food and water
ii)In search of a suitable habitat
iii)To escape from predators
iv)In search of a mate.

3.5 Distinguish between autosome and sex chromosome of human based on the following features.
Nature
Number
Ans: 

3.6 What are the processes of asexual reproduction in spirogyra and planaria?
Ans: In Spirogyra, asexual reproduction takes place by fragmentation.Fragmentation, the splitting of cells into two parts and makes new bodies is known as fragmentation. Each fragment develops into a mature clone genetically and morphologically identical to its parent.
In Planaria, asexual reproduction takes place by regeneration. Regeneration is the power of growing a new organism from the lost body part. For eg., when a lizard loses its tail, a new tail grows. This is because the specialized cells present in the organism can differentiate and grow into a new individual.

3.7 Mention two changes related to vision and bones at late adulthood or senescence phase of human development?
Ans:During the senescence phase of human development or late adulthood, about 10% of the people may see without the lenses. Some common eye defects for these people include cataract, glaucoma or presbyopia.
Meanwhile, as we age, we may have to undergo the effects of osteoporosis and osteoarthritis. Bone loses the minerals and tends to become more fragile. Also, the ligaments and the connective tissue between the bones become more flexible and less elastic.

3.8 With the help of a cross show how the sex of offsprings of humans is determined?

3.9 One day students read an article in 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:The treatment for thalassemia depends on the sort and severity of the disease involved. Your doctor will provide you with a course of treatment that may work best for your particular case.
Some of the treatments include:
• Blood transfusions
• Bone marrow transplant
• Medications and supplements
• Possible surgery to get rid of the spleen or gallbladder

3.10 What are all probable gametes to be produced from the hybrid plant YyRr produced at F1 generation in a dihybrid cross experiment?
Ans: The gametes produced will be YR, Yr, yR, and yr.

3.11 What are the two adaptive significances of air sacs of pigeon?
Ans: The two adaptive significance of air sacs for pigeons are:
i) Air sacs are air filled cavities which help the bird in flight.
ii) There are two separate sets of sacs and such network of sacs reduces the specific gravity of the body of birds making them light.

3.12 Write the names of one each vestigial organ present in vertebral column and alimentary canal in human bod?
Ans:.The Coccyx at the end of the vertebral column represents the vestigial tail of a human. Meanwhile, an appendix can be considered as one of the vestigial organs present in the alimentary canal of a human.

3.13 Write in chronological sequence the names of four main fossil ancestors during the course of evolution of the horse.
Ans: Mesohippus – Merychippus – Pliohippus – Equus

3.14 “Nitrogen cycle is affected due to human activities” state two phenomena to justify it.
Ans: Due to Human activities, Atmospheric Nitrogen inputs oxides of nitrogen (NO_x), ammonia (NH₃) and nitrous oxide (N₂O) from the aquatic and terrestrial ecosystem and NO_x from fossil fuel and biomass combustion. The following are the two phenomena:
i) Due to nitrogen enrichment, the soil acidification being acidification and changes in mycorrhizal communities have allowed stress tolerant species to out – compete sensitive species
ii) Increased soil acidification invading grasslands replace low and health.

3.15 What would be the environmental consequences as results of recurrent destruction of wetlands and depletion of quantity of agricultural lands?
Ans: Wetland destruction and depletion of agricultural lands over the years could cause significant disasters. The depletion of these wetlands could result in environmental and economic effects such as loss of biodiversity, flooding caused by climatic change, disruption of the water cycle, etc.

3.16 What are the harmful impacts sound pollution can exert on the ears and heart in human body?
Ans: Prolonged exposure to loud sound or noise pollution can harm human health. Other than an annoyance, loud noise can cause irritation and mental tension and emotional disturbance at work. Apart from these, the auditory effect includes fatigue and deafness due to continued exposure to noise pollution. It also increases the risk of heart diseases, as the noises of decibels higher than 60 can cause high blood pressure, irregular heart rate, rise in cholesterol, heart attacks, quicker pulse rates and so.

3.17 Mention the roles of biodiversity in the following two aspects in the progress of human civilization:
Production of foods
Manufacturing of medicines
Ans: (i) Biodiversity can be considered the basis or foundation for agriculture and food production, thus making way for the farming systems to evolve. Agricultural biodiversity pertains to plants’ genetic resources such as crops, wild plants that are harvested and managed, wild animals hunted for food and so on. Agricultural biodiversity provides food and raw materials for food. It also contributes to food security and nutrition.
(ii) Biomedical research mainly relies on the natural supply of plant and animal materials and microbes to understand humans’ physiology and treat diseases. Numerous medicines, such as antibiotics and painkillers, are often resourced from plants and animal sources. It is seen that recent discoveries also allow for the development of medicine and the treatment of diseases