2023
LIFE SCIENCE
(For Regular and External candidates)
Time: Three Hours and Fifteen Minutes
(Frist fifteen minutes for reading the question paper only)
Full Marks: 90 for regular candidates
Full Marks: 100 for external candidates
Special credit will be given for brief and to the point answers.
Marks will be deducted for spelling mistakes and tidiness and bad had handwriting
Instructions: Regular candidates will answer questions from groups ABC and D . External candidates will answer questions from group E
Group A
( All questions are compulsory)
1. Choose the correct answer for each question and write it with its respective serial numa ber.
1.1) Which of the following is not structural feature of Axon?
a) Node of Ranvier
b) Myelin sheath
c) Nissle granules
d) Schwann Cell
1.2) Which of the following is function of the hormone ADH?
a) Increases blood pressure by constricting arterioles
b) Helps in the production of sperm and ovum in adult life
c) Convert glucose into glycogen and storethe in the hepthe atic and muscle cells
d) Causes development of nervous system and maintains its normal funcion
1.3) Cornea, Choroid, Lens, Aqueous humourthe , Irismediumsreous mour- How many of these are refractory medium of the eye Ball ?
a) 3
b) 4
c) 5
d) 6
1.4) Which of the following is correct regarding the chemical composition of nucleotide?
a) 5 C sugar + phosphoric acid = Neucleotide
b) Nitrogen base + phosphoric acid = Neucleotide
c) 5 C sugar + nitrogenous base = Neucleotide
d) 5 C sugar + nitrogen base + phosphoric acid = Neucleotide
1.5) Which of the following pair is correct in respect of the process of cross pollination?
Mode of Pollination. Name of plant
a) Anemophilous Mango
b) Hydrophilous Paddy
c) Entomophilous. Hydrilla.
d) Ornitophilous. Palash/Butea
1.6) Which of the following stages is not included under the sporophytic generation in the alternation of generation of the fern?
a) Prothallus
b) Sorus
c) sprongium
d) Spore mother cell
1.7 What is the ratio of the number of genotype BbRr and BBRR produced in the F2 generation of dihybrid cross in guinea pig ?
a) 2:1
b) 4:1
c) 1:2
d) 1:1
1.8 Which two of the following genotypes represent the genotype of a pea plant with yellow coloured and wrinkled seeds?
a) YYrr, Yyrr
b) YYRr, YyRR
c) yyRR, yyRr
d) YYRR, yyrr
1.9 Which would be the genotypic and phenotypic ratio in the F2 generation of a hybrid cross in case of incomplete dominance?
a) 2 :1 : 1
b) 1: 1: 1
c) 1: 2: 1
d) 1: 2: 2
1.10 Which of the following is not a tenet of Darwinism?
a) Inheritance of acquired character
b) Struggle for existence
c) Variation
d) Natural selection
1.11) identify the features of homologous organs -
a) Different by structure but identical by origin and function
b) Different by origin and function but identical by structure
c) Different by origin but identical by structure and function
d) Identical by origin and structure but different by function
1.12) Which reactant are used in the experiment of Miller and Uray regarding chemical origin of life ?
a) Oxygen, Methane , Nitrogen dioxide
b) Water, Methane, Ammonia , Hydrogen
c) Methane, Hydrogen sulphide, Carbon monoxide
d) Nitrous oxide, Methane, Carbon dioxide
1.13) Identify the correct sequence of nitrogen cycle --
a) Fixation of Nitrogen - Denitrification - Ammonification - Nitrification
b) Ammonification - Nitrification- Nitrogen fixation- Denitrification
c) Nitrogen fixation- Ammonification fixation- Nitrification -Denitrification
d) Nitrification- Nitrogen fixation- Denitrification - Ammonification
1.14) Decide which of the following pair of cause of depletion and victimised species is correct regarding the depletion of biodiversity
a) Introduction of exotic species- one horned rhinoceros
b) Pollution - Royal Bengal tiger
c) Global warming and climate changes - Polar bear
d) Hunting and poaching- Vulture
1.15) Which of the following phenomena occurs when chlorinated insecticides enter a food chain?
a) Biomeganification
b) Eutrophication
c) Global warming
d) Deafness
Group B
2. Answer 21 questions out of the 26 questions given below, as instructed. ( 1 ×21=21)
Fill in the blanks with proper words in the following sentences (any five) (1 × 5= 5)
2.1) Nastic movement is influenced and controlled by the _________________ of an external stimulus.
2.2 ) __________________ cell division maintains the number of chromosomes constant in a species
2.3) The wrinkled shape of seed is a _________________________trait.
2.4) Because of its ________________ shape, the RBC of camel can withstand a considerable loss of water.
2.5 A disease related to air pollution is _______________________.
2.6 Nilgiri and ________________________are both Biosphere Reserves.
Decide whether the following statements are True or False (any five) : (1× 5=5)
2.7 ) Auxin hormone inhibits the growth of apical bud and increases the growth of axillary bud.
2.8 ) Cell division becomes uncontrolled if the function of checkpoints becomes hampered.
2.9) Only one type of gamete is produced from a pea plant having genotype YyRR.
2.10) Both intraspecific and interspecific struggles might be observed among the different types of tigers in a forest.
2.11) Nitrous oxide is a greenhouse gas.
2.12) Triceps is a flexor muscle.
Match the following words of column A with the most appropriate words in column B and rewrite the correct pair mentioning the serial number of both columns ( Any five) (1×5=5)
Column A Column B
2.13) Meninges. a) Decrease in the number of digit in the legs
2.14) Sexual reproduction. b) Submergence of island
2.15) Roller tongue. c) Centrosome
2.16) Evolution of horse. d) Telomere
2.17) Environmental
problem of Sundarban e) Protects brain & spinal cord from mechanical injury
2.18) Attach chromosome
with spindle fibre f) Controlled by autosome
g) Occurs through production of gametes and their union
Answer in a single word or in a single sentence any six. (1×6=6)
2.19) Choose the oddword and right it:
Testosterone, Insulin, Progesterone, oestrogen
2.20) What is the relation between lens and accommodation of eyes?
2.21) On the basis of the relationship in first related pair of world write a suitable word in the gap of this second pair :
Mitosis : Equational division :: _____________; : Reduction division
2.22 ) In spite of being pure in respect to one trait what else could an organism be in respect of another trait ?
2.21) Write one feature of the gene responsible for colour blindness.
2.24) Which theory can be reached at from the comparative study of the embryos of different vertebrate animals ?
2.25) Among the following four terms, one includes the other three. Find it out and write it:
Shrinking of agricultural land, shortage of fresh water, problems of ever increasing population, deforestation
226 ) Write one feature of biodiversity hotspot.
Group - C
3. Answer any 12 questions each in 2-3 sentences out of 17 questions given below. (2 ×12=24)
3.1) The two reflex actions, namely sneezing and coughing help in avoiding danger - justify the statement.
3.2) How does the Gibberellin hormone cause the seeds to germinate and the plants to grow in height ?
3.3) Write one influence each of Thyroxine hormone on the heart and the RBC.
3.4 ) Explain the following two terms
¶ Ganglia ¶ Synapse
3.5) Write two features of Amitotic cell division.
3.6) Mention any two phenomena during G1 phase of Interphase.
3.7 ) Explain the process of segmentation with the help of a proper example of plants.
3.8 ) What is the importance of genetic counselling in arranging a marriage ?
3.9) Write two reasons behind selection of pea plant by Mendel for his experiments on heredity.
3.10) Judge with reason the probability of what percentage of the children born to a colour blind father and a completely normal mother would be colour blind.
3:11) An inherent trait of organisms is the prodigality of reproduction, as a result the number of organisms increase in a geometric proportion --- justify the validity of the statement with two proper examples.
3.12) How do worker bees communicate the information to the other worker bees of the have when they spot any source of food?
3.13) What do you mean by natural selection?
3.14) One of the problems associated with ever increasing population is destruction of wetland -- Mention any two consequences of this.
3:15) Invasion of exotic species causes reduction in biodiversity -- establish the validity of this statement with two examples with reference to India.
3.16) Write the names of one endangered plant and one endangered animal species of the Eastern Himalayas biodiversity hotspot.
3.17) Write one role of Joint Forest Management (JFM) and People's Biodiversity
Register (PBR) each for the conservation of biodiversity.
Group 'D'
(Long answer type questions)
Write all the 6 questions or their alternatives given below. Sightless candidates have to answer question no. 4.1(A) instead of question no. 4.1. The marks allotted for each questions is 5 (the division of marks is either 3+2, 2-3 or 5)
5×6=30
4.1) Draw a scientific diagram of the vertical section of a human eyeball and label the following parts:. ( 3+2=5)
(a) Choroid
(b) Lens
(e) Cornea
(d) Vitreous humor
OR
Draw a scientific diagram of the anaphase stage of mitotic cell division in an animal cell and label the following parts-. (3+2=5)
(a) Centromere
(b) Daughter chromosome
(c) Polar region
(d) Spindle fibre
(FOR SIGHTLESS CANDIDATES ONLY)
4.1 (A) Write one function of each of the following five pusts of the human eyeball. (1×5=5)
(a) Cornea
(b) Lens
(c) Choroid
(d) Vitreous humor
(e) Retina
Or
Mention there changes occurring during the Anaphase stage of Mitosis in animal cell.
Write the names of any two structural parts of eukaryotic Chromosome.
4.2) Explain the following three significances of cell division - (3+2=5)
¶ Growth
¶ Repair
¶ Reproduction
Tabulate the site of occurrences of meiotic cell division in living world.
OR
Explain the process of micropropagation. Distinguish between axual and sexual reproduction on the basis of the following three features -
Number of Parental organisms .
Cell Division
Origin of variation. (2+3=5)
4.3) With the help of a checkerboard show the phenotypic ratio of offspring produced in F2 generation as a result of a cross between a pure black coloured and rough haired gainea-pig and a pure white and smooth haired guinea-pig. (3+2=5)
"Father plays the main role in the determination of sex of the offspring - justify the statement with the help of a checkerboard. ( 3+2= 5)
OR
Write three reasons behind Mendel's success.
Establish relationship between phenotype and genotype with the help of proper example. (3+2=5)
4.4 ) Explain the theory of Darwin with regards to lengthening of neck of giraffe.
What do you mean by "Hot Dilute Soup?
(3+2=5)
OR
Construct the sequence of major events of organic evolution with the help of a schematic diagram.
Give two examples of problem solving ability of chimpanzee. (3+2=5)
4.5) Write one symptom each of two diseases which might be caused if suspended particulate matter enters into the respiratory tract through inspiration.
Construct the sequence of events when agricultural runoff is drained into water bodies. ( 2+3=5)
OR
Poaching is one of the main reasons behind depletion of biodiversity - Prepare a list of any three sach endangered wild animals resulting from it.
Show the various methods of conservation of biodiversity with the help of a chart.
(3+2=5)
4.6) Three environmental problems of the Sunderbans are -
¶ Imbalance in the numbers of prey and predators
¶ Destruction of mangrove plants due to urbanisation.
¶ Rising sea level.
Analyse the probable effects of the three problems.
Mention the location and the name of one endangered species of a biodiversity hotspot distributed in and outside the geographical area of India. (3+2=5)
OR
Describe the nitrogen cycle with the help of a word diagram.
Analyse any two problems which may arise if nitrogen cycle is disturbed. (3+2=5)
Group 'E'
(FOR EXTERNAL CANDIDATES ONLY)
Answer any four questions: (1×4=4)
5.1 Write one feature of epithelial tissue.
5.2 What is the function of ribosome ?
5.3 Write one function of parenchyma tissue.
5.4 Write one advantage of self-pollination.
5.5 Give an example of a proteolytic enzyme.
Answer any three questions:. ( 2×3=6)
6.1 Write two differences between axon and dendron.
6.2 Write the names of two nitrogenous excretory products of plants.
6.3 Write one function each of mitochondria and centrosome.
6.4 Write the name of two sanctuaries of West Bengal.
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