Maharashtra HSC Class 12 Biology July 2024 question paper

Maximum marks 70 · Time 3 hours

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Section A

1 mark each

Q.1 (i)1 mark $In monocot embryo the protective sheath of plumule is called _____.$
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Q.1 (ii)1 mark $The synonymous term for centromere is _______.$
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Q.1 (iii)1 mark $Protein digesting enzyme is ______.$
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Q.1 (iv)1 mark $Spermatids get transformed into a functional spermatozoa by the process of ______ .$
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Q.1 (v)1 mark $Industrial melanism is one of the best example of _____.$
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Q.1 (vi)1 mark $Value of root pressure is +1 to +2 bars which is enough to pump water to a height of ______.$
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Q.1 (vii)1 mark $_____ cellular fragments are formed from megakaryocytes.$
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Q.1 (viii)1 mark $Degeneration of dopamine producing neurons in the CNS causes ______ .$
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Q.1 (ix)1 mark $Choose the correct name of phases A, B and C in the given figure :$
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Q.1 (x)1 mark $Rivet Popper Hypothesis explains$
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Q.2 (i)1 mark $Write the ratio of methane, ammonia and hydrogen respectively in Urey and Miller’s experiment.$
Q.2 (ii)1 mark $What are the cells of Rauber?$
Q.2 (iii)1 mark $Which gene is introduced in tobacco against pest like Zabrotes subfasciatus ?$
Q.2 (iv)1 mark $How many haploid nuclei are present in mature female gametophyte of Angiosperms?$
Q.2 (v)1 mark $Name the connection between pulmonary trunk and aortic arch representing remnant of embryonic ductus arteriosus.$
Q.2 (vi)1 mark $Which endocrine gland plays an important role in the development of immune system?$
Q.2 (vii)1 mark $Mention the type of association between sea anemone and clown fish.$
Q.2 (viii)1 mark $Name the pioneer species in the aquatic habitat during primary succession.$

Section B

2 marks each · attempt any 8

Q.32 marks $(a) Why DNA replication is called semi-conservative replication? (b) Name the scientist who experimentally proved the same.$
Q.42 marks $Distinguish between Asexual and Sexual reproduction with reference to : (a) Cell division (b) Genetic makeup$
Q.52 marks $Arrange the following stages of human evolution in the order of their increasing cranial capacity : (a) Homo - Sapiens (b) Neanderthal man (c) Australopithecus (d) Homo-erectus$
Q.62 marks $21^{\text{st}}$
Q.72 marks $What is radial and tangential translocation of food in plants?$
Q.82 marks $Explain any two causes of genetic variation.$
Q.92 marks $Identify A,B,C and D from the following table regarding respiratory system : Organism Habitat Respiratory organ A Terrestrial Tracheal tubes and spiracles Scorpions Terrestrial B Sponges C Plasma membrane Turtles Underwater D$
Q.102 marks $Give the function of Nebenkern and Zona pellucida.$
Q.112 marks $Give location of corpus callosum and arbor vitae of human brain.$

Organism	Habitat	Respiratory organ
A	Terrestrial	Tracheal tubes and spiracles
Scorpions	Terrestrial	B
Sponges	C	Plasma membrane
Turtles	Underwater	D

Q.122 marks

Match cells of immune system in column-I and their functions in column-II and rewrite it. Column-I Column-II (i) Cytotoxic T cells (a) Activation of helper T cells (ii) Plasma cells (b) Blood group antigens (iii) Antigen presenting cells (c) Secretion of perforins (iv) Red blood cells (d) Antibody production

Q.132 marks $Give any two examples of commercially exploited products of transgenic plants.$
Q.142 marks $Write causative agent, two symptoms and mode of transmission of typhoid.$

Column-I	Column-II
(i) Cytotoxic T cells	(a) Activation of helper T cells
(ii) Plasma cells	(b) Blood group antigens
(iii) Antigen presenting cells	(c) Secretion of perforins
(iv) Red blood cells	(d) Antibody production

Section C

3 marks each · attempt any 8

Q.153 marks $Suggest the specific term for the following : (a) Both male and female reproductive organs present in same organism. (b) Y- linked gene (c) Unfertilised egg develops into haploid male bee.$
Q.163 marks $Explain the role of diazotrophs in nitrification.$
Q.173 marks $Explain the following events of cardiac cycle with respect to type of valves and duration : (a) atrial systole (b) ventricular systole (c) joint diastole$
Q.183 marks $What is reflex action? Explain with one example each of the types of reflex actions based on previous experiences.$

Q.193 marks

Select and fill in the boxes (i) to (vi) from given list of options. List of options — Sickle cell anaemia, Widow’s peak, Flower colour of Mirabilis, Human blood groups, Coat colour of cattle, Klinefelter’s syndrome. Genetic trait Example (a) Incomplete dominance (i) _____(b) Pleiotropy (ii) _____(c) Codominance (iii) _____(d) Multiple allelism (iv) _____(e) Sex chromosomal disorder (v) _____(f) Autosomal disorder (vi) _____

Q.203 marks $Give the role of following mycoherbicides (a) Phytophthora (b) Alternaria (c) Fusarium$
Q.213 marks $Explain the following terms with respect to survival of an organism in a changed environment. (a) Regulate (b) Conform (c) Migrate$
Q.223 marks $Describe any three causes for loss of biodiversity.$
Q.233 marks $Give physiological effects and applications of cytokinin.$
Q.243 marks $What is mycorrhiza? Name its types and state any two benefits of mycorrhiza.$
Q.253 marks $(a) Explain the following : (i) Leaching (ii) Humification and mineralisation (b) What is humus?$
Q.263 marks $(a) What is hematocrit? (b) Mention the term with respect to - (i) Temporary increase in number of WBCs (ii) Decrease in number of RBCs$

Genetic trait	Example
(a) Incomplete dominance	(i) _____
(b) Pleiotropy	(ii) _____
(c) Codominance	(iii) _____
(d) Multiple allelism	(iv) _____
(e) Sex chromosomal disorder	(v) _____
(f) Autosomal disorder	(vi) _____

Section D

4 marks each · attempt any 3

Q.274 marks $Describe mechanism of opening and closing of stomata with reference to : (a) Starch-sugar interconversion theory (b) Proton transport theory$
Q.284 marks $(a) Define Hormone. (b) Enlist any two properties of hormones. (c) Give diagrammatic representation of mode of hormone action through membrane bound receptors.$
Q.294 marks $With respect to diagram, answer the following : (a) Which type of ovule is given in the figure? (b) Name the first cell of embryo sac. (c) Identify and write the function of ‘A’ and ‘B’.$
Q.304 marks $How transgenic pigs and cattle are commercially beneficial?$
Q.314 marks $With the help of a suitable diagram describe histology of testis.$