MHT CET Biology

30 Pages·2016·1.02 MB·English

Useful for all Medical Entrance Examinations held across India.

Triumph Biology

STD. XII Sci.

  Sixth Edition: January 2016

Salient Features

• Exhaustive subtopic wise coverage of MCQs.
  • Memory Maps provided for each chapter.
• Hints included for relevant questions.

• Various competitive exam questions updated till the latest year.

• Includes solved MCQs from AIPMT, MHT CET 2015.

• Evaluation test provided at the end of each chapter.
  • Two Model Question Papers with answers at the end of the book.

Solutions/hints to Evaluation Test available in downloadable PDF format at

www.targetpublications.org/tp10093

Printed at: Repro India Ltd., Mumbai
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P.O. No. 13042

10093_10280_JUP
Preface

“Std. XII: Sci. Triumph Biology” is a complete and thorough guide to prepare students for a competitive
level examination. The book will not only assist students with MCQs of Std. XII, but will also help them to prepare
for AIIMS, AIPMT, CET and various other competitive examinations.
Memory Maps in the form of charts are provided at the beginning of every chapter. Topic – wise
classification of the MCQ’s has been done to help the students understand each concept thoroughly.
MCQs in each chapter are divided into three sections:
Classical Thinking : consists of straight forward questions including knowledge based questions.

Critical Thinking : consists of questions that require some understanding of the concept.

Competitive Thinking : consists of questions from various competitive examinations like AIIMS, AIPMT, CET,
WB JEEM, CPMT, etc.
Hints have been provided to the MCQs which are broken down to the simplest form possible.
An Evaluation Test has been provided at the end of each chapter to assess the level of preparation of the
student at a competitive level.
Two Model Question Papers with answers have been provided at the end of the book for practice.
The journey to create a complete book is strewn with triumphs, failures and near misses. If you think we’ve
nearly missed something or want to applaud us for our triumphs, we’d love to hear from you.
Please write to us on : [email protected]

Best of luck to all the aspirants!

Yours faithfully
Authors

Sr. Page Sr. Page
Topic Name Topic Name
No. No. No. No.
Genetic Basis of
1 1 11 Chromosomal Basis of 246
Inheritance
Inheritance
Gene: It’s Nature,
2 28 12 Genetic engineering and 272
Expression and Regulation
Genomics
Biotechnology: Process
3 62 13 Human health and 283
and Application
Diseases
Enhancement in Food
4 80 14 Animal Husbandry 307
Production
15 Circulation 319
Microbes in Human
5 95
Excretion and
Welfare 16 345
Osmoregulation
6 Photosynthesis 109
17 Control and Co‐ordination 371
7 Respiration 135
8 Reproduction in Plants 163 18 Human Reproduction 420
Organisms and Organisms and
9 193 19 464
Environment  I Environment  II
Origin and Evolution of 20 Model Question Paper  I 487
10 216
Life 21 Model Question Paper  II 494
0 1 
Genetic Basis of Inheritance 
Chapter 01 : Genetic Basis of Inheritance

Syllabus
Gregor Johann Mendel (1822 – 1884)

1.0 Introduction
1.1 Mendelian inheritance
1.2 Deviations from Mendelian ratios

Gregor Mendel was the first to give the hypothesis of
existence of a factor (Mendelian factor; gene) which
shows continuity and variation. He conducted
several hybridization experiments on Garden pea
plant (Pisum sativum). His work of experiments and
their results were published in the Natural History
Society of Bruno in 1866.

1
Std. XII : Triumph Biology 

Memory Map

MENDELISM  INHERITANCE 
 Mendel selected garden pea  Heredity  Transmission of
(Pisum sativum) for hybridization characters from parents to
experiments. offsprings.
 He selected seven pairs of  Variations  Visible differences
contrasting characters and between parents and offsprings.
formulated the three laws of  Genetics  Study of heredity and
inheritance. variations.
Multiple Alleles

of In Men  Salolemlees geanneds hapvreo dmucoere tdhiafnfe rtwenot
h d
eritan el’s la Polygenes  pegh.e n5o tydpifefse.r ent alleles for wing
c w type in Drosophila.
e s  Two or more gene pairs have
3 different alleles in ABO blood
Law of Dominance cumulative effect and determine
groups in humans.
the characters.
 Character which expresses itself  eg. Wheat kernel colour
phenotypically in F generation is
1 (2 polygenes)  1 : 4 : 6 : 4 : 1
Dominant. Co-dominance
Human skin colour (3 polygenes)
 Other character which fails to  1 : 6 : 15 : 20 : 15 : 6 : 1  Both alleles of a gene pair express
express is Recessive. themselves equally in F hybrid.
1
 eg. Coat colour in cattle.

L2 Pleiotropy A cross between Red coat (RR)
aw nd colour cattle with White coat

 A single gene controls two (WW) produces Roan colour
Law of Segregation (or more) different characters. (RW) in F generation. Roans
1
 eg. In Sickle cell anaemia, the gene have mixture of Red and White.
T he alleles of every unit character
for sickle cell anaemia in  Ratio  1 : 2 : 1
remain together in F hybrid, but
1 homozygous condition (Hbs Hbs) is
s egregate during gamete formation.
lethal, but produces sickle cell trait
in heterozygous condition (HbA Incomplete Dominance
Hbs)
Law3rd  Ratio  2 : 1  Bpaortthia llgye. nes express themselves
 F1 shows intermediate expression.
Law of Independent  eg. In Mirabilis jalapa, cross
Assortment between Red flowered (RR) plant
Intergenic (Non-allelic)
and White flowered plant (rr)
 “When two homozygous parents
Occurs between alleles of different produces Pink flowered (Rr)
differing from each other in two or
more pairs of contrasting characters genes on same or different plants.
are crossed, then the inheritance of chromosomes.  Ratio  1 : 2 : 1

one pair of characters is
Gene interaction
independent of the other pair of

characters”.
POST‐MENDELISM
 eg. Cross between Yellow Round
(YYRR) seeded plant and Green
 Mendel’s laws do not hold true in
Wrinkled (yyrr) plant produces
all cases.
Yellow Wrinkled (YYrr) and Green
 Different inheritance patterns and
Round (yyRR) + Parental
gene interactions were discovered Intragenic (Inter-allelic)
phenotypes by scientists by performing Gene
experiments on different plants and interaction Occurs between alleles of the
same gene.
animals.

2
Chapter 01 : Genetic Basis of Inheritance

10. Offsprings are
Classical Thinking
(A) exactly identical to either of their

parents.

1.0 Introduction (B) not exactly identical to either of their
parents.
1. The phenomenon of ‘like begets like’ is due to
(C) show intermediate characters inherited
(A) genetics (B) heredity
from both the parents.
(C) germplasm (D) variation
(D) both (B) and (C)

2. Transmission of characters from one
11. The term “factor” for gene was coined by
generation to the next or from parents to
offsprings is called (A) William Bateson
(A) heredity (B) variation (B) Johann Mendel
(C) recombination (D) mutation (C) Johannsen

(D) F. Griffith
3. Variation is

(A) differences between parents and
12. Gregor Mendel was born in
offsprings.
(A) U.K (B) Austria
(B) differences between individuals of same
(C) Russia (D) Czechoslovakia
species.
(C) differences among the offsprings of the 13. Mendel was a
same parents. (A) physiologist (B) mathematician
(D) all of the above.
(C) cytologist (D) taxonomist

4. The term “genetics” was coined by
14. The first scientific study leading to the
(A) Morgan
formulation of laws of inheritance was carried
(B) William Bateson
out by
(C) Johannsen
(A) Darwin (B) Hugo De Vries
(D) Karl Correns
(C) Lemarck (D) Mendel
5. The greek word which means ‘to grow into’ is
15. Under which title was Mendel’s work
(A) genetics (B) genesis
published in Natural History Society of
(C) inheritance (D) factor
Brunn?
6. The first scientific explanation regarding (A) Mendel’s Laws of Inheritance
inheritance was given by (B) Experiments in Plant Hybridization
(A) William Bateson (C) Experiment on Heredity and Variation
(B) Gregor Johann Mendel (D) Origin of Species
(C) Griffith
(D) Johannsen 16. Mendel’s laws were first published in the year

(A) 1875 (B) 1890
7. Who is known as “Father of Genetics”?
(C) 1928 (D) 1866
(A) Theophrastus (B) Stephen Hales
(C) Mendel (D) Aristotle 17. The year 1900 A.D. is highly significant for

geneticists due to
1.1 Mendelian inheritance
(A) chromosome theory of heredity
8. Organisms produced by asexual reproduction
(B) discovery of genes
are called
(C) rediscovery of Mendelism
(A) clones
(D) principle of linkage
(B) offsprings
(C) factors 18. The Mendelian principles of inheritance were
(D) both (A) and (B) rediscovered by

(A) Sutton and Boveri
9. Organisms produced by sexual reproduction
(B) Hugo de Vries, Tschermark and Correns
are called
(A) offsprings (B) clones (C) Lederberg and Tatum
(C) characters (D) genes (D) Morgan

3
Std. XII : Triumph Biology 
19. Mendel’s work was rediscovered by three 27. Who coined the term ‘gene’ for ‘factor’?
biologists from which of the following (A) Mendel (B) Morgan
countries? (C) Johannsen (D) Punnett

(A) Holland, France and England
28. Alleles or allelomorphs occupy
(B) Holland, England and Austria
(A) same position on homologous
(C) Germany, France and England
chromosomes.
(D) Austria, Holland and Germany
(B) same position on heterozygous
20. Mendel selected pea plant because of chromosomes.
(A) its short life span. (C) different position on homologous
(B) it produced many seeds and large chromosomes.
flowers. (D) different position on heterozygous
(C) many contrasting characters. chromosomes.

(D) all of these
29. Who proposed the term ‘Allelomorph’?
21. The botanical name of garden pea is (A) Hugo De Vries (B) Morgan
(A) Pisum sativum (C) Tschermak (D) Bateson

(B) Lathyrus odoratus
30. Dominant allele means
(C) Mangifera indica
(A) an allele whose effect is masked by
(D) Solanum tuberosum
another allele.

22. Which of the following is a dominant (B) an allele that prevents the expression of
character in pea? the other allele.
(A) Wrinkled seeds (C) an allele without any effect.
(B) Inflated pod (D) an allele which cannot express in
presence of other.
(C) Terminal flower

(D) Dwarf plant 31. The external appearance of an individual for

any trait is called as
23. Which of the following character was not
(A) phenotype (B) karyotype
considered by Mendel?
(C) morphology (D) physique
(A) Seed coat colour

(B) Wrinkled or round leaves 32. Genotype is
(C) Tallness or dwarfness (A) genetic constitution of an organism.
(D) Position of flower (B) genetic constitution of somatic cells.

(C) genetic constitution of plastids.
24. An inherited character and its detectable
(D) genetic constitution of germ cells.
variant is called

(A) allele 33. Homozygous individuals
(B) trait (A) breed true to the trait.
(C) gene (B) does not breed true to the trait.
(D) both (A) and (B) (C) produce only one type of gamete.

(D) both (A) and (C)
25. Which one of the following best describes a

gene? 34. Which of the following term indicates a pair
(A) A triplet of nucleotide bases. of dissimilar alleles?
(B) A specific length of DNA responsible (A) Homozygous
for the inheritance and expression of the (B) Heterozygous
character. (C) Homologous
(C) A specific length of single stranded (D) All of these
RNA.
35. A cross between two pure individuals,
(D) Both (B) and (C)
differing in atleast one set of characters, is
26. Mendel’s “factors” are in fact called
(A) units (B) chromosomes (A) monohybrid (B) polyploid
(C) genes (D) none of these (C) mutant (D) variant

4
Chapter 01 : Genetic Basis of Inheritance
36. F generation means 44. Emasculation means
1
(A) first flowering generation (A) removal of stamens before anthesis.
(B) first fertile generation (B) removal of stigma before anthesis.
(C) first filial generation (C) removal of petals before anthesis.
(D) first seed generation (D) removal of sepals before anthesis.

37. Filial means 45. In pea flower, how many stamens are free and
(A) offsprings produced in sexual how many are fused?
reproduction. (A) 1, 9 (B) 2, 8
(B) offsprings produced in asexual (C) 5, 5 (D) 4, 6

reproduction.
46. F generation was obtained by
(C) offsprings produced in vegetative 3
(A) selfing F hybrids
reproduction. 1
(B) selfing F hybrids
(D) both (B) and (C) 2
(C) crossing F with either parent
1
38. F2 generation is produced by (D) none of these
(A) crossing F progeny with one of the
1
47. What result did Mendel obtained after
parents.
monohybrid cross between tall and dwarf pea
(B) selfing the heterozygous progeny.
plant?
(C) selfing the parents.
(A) All new plants were dwarf.
(D) a cross between recessive parents.
(B) All new plants were tall.
39. In genetics, the use of checkerboard was done (C) 50% plants were dwarf and 50% plants
by were tall.
(A) Mendel (B) Correns (D) 75% plants were tall and 25% plants
(C) Punnet (D) Darwin were dwarf.

40. Mendel, in his experiments 48. When Mendel allowed natural selfing of F
1
(A) maintained qualitative records. hybrids during monohybrid cross between
(B) maintained quantitative records. pure tall and pure dwarf pea plant, he found
(C) conducted ample crosses and reciprocal (A) all plants were tall.
crosses. (B) all plants were dwarf.
(D) all of the above (C) dwarfness reappeared in some plants.

(D) tallness reappeared in some plants.
41. To eliminate chance factor, Mendel performed
(A) monohybrid cross 49. During monohybrid cross experiments,
(B) dihybrid cross Mendel performed reciprocal cross by
(C) reciprocal cross selecting
(D) trihybrid cross (A) tall plant as male and dwarf plant as

female.
42. Mendel always started his experiment
(B) tall plant as female and dwarf plant as
(Monohybrid and Dihybrid cross) with
male.
(A) any pea plant
(C) both male and female plant as tall.
(B) a heterozygous plant
(D) both male and female plant as dwarf.
(C) a pure line plant
(D) a fresh new plant 50. After performing reciprocal cross between tall

and dwarf plants, the ratio of tall and dwarf
43. Mendel carried out artificial cross by
plants obtained was
(A) emasculation of selected female parent
(A) 1:2 (B) 3:1
plant
(C) 1:3 (D) 2:1
(B) emasculation of selected male parent
plant 51. Mendel grouped all contrasting characteristics
(C) dusting of pollen grains from selected in _______ pairs.
male plant over selected female plant (A) 15 (B) 14
(D) both (A) and (C) (C) 7 (D) 6

5
Std. XII : Triumph Biology 
52. The conclusion drawn by Mendel based on 59. The monohybrid ratio is defined as
monohybrid cross was (A) phenotypic ratio obtained in F
2
(A) each factor exist in two contrasting or generation of monohybrid cross.
alternative forms. (B) phenotypic ratio obtained in F
1
(B) one of the forms is dominant and other generation of monohybrid cross.
is recessive. (C) genotypic ratio obtained in F generation
2
(C) inheritance of each character is of monohybrid cross.
controlled by a pair of factors. (D) genotypic ratio obtained in F generation
1
(D) all of the above of monohybrid cross.

53. From the reappearance of recessive trait in F2 60. Which of the following is phenotypic ratio of
generation, Mendel concluded that Mendel’s monohybrid cross ?
(A) factors do not mix with each other in F1 (A) 1:2:1 (B) 3:1
generation. (C) 1:1:2 (D) 1:3
(B) factors remain together in F generation.
1
61. The law of dominance is illustrated in the
(C) factor mix with each other in F
1
garden pea by
generation.
(D) both (A) and (B) (A) heterozygous tall  heterozygous tall

(B) homozygous tall  homozygous tall
54. During gamete formation,
(C) pure short  pure dwarf
(A) diploid gametes are formed.
(D) homozygous tall  pure dwarf
(B) each gamete receives only one factor.

(C) factors do not segregate. 62. Which of the following Mendel’s laws has not
(D) all offsprings show recessive characters. been proved to be true in all cases?

55. The crossing of a homozygous tall pea plant (A) Law of segregation
and homozygous dwarf pea plant would yield (B) Mendel’s second law of inheritance
plants in the ratio of (C) Law of dominance
(A) 2 tall : 2 dwarf. (D) Law of purity of gametes

(B) all homozygous dwarf.
63. The second law of inheritance proposed by
(C) all heterozygous tall.
Mendel deals with
(D) one homozygous tall : one homozygous
(A) dominance
dwarf : two heterozygous tall.
(B) independent assortment
56. Mendel crossed a pure white flowered pea (C) segregation
plant with pure red flowered plant. The first (D) epistasis

generation of hybrids from the cross should
64. Reappearance of recessive trait in F
show 2
generation is due to
(A) 75% red flowered and 25% white
(A) Law of independent assortment
flowered plants.
(B) Law of dominance
(B) 50% white flowered and 50% red
(C) Law of codominance
flowered plants.
(D) Law of purity of gametes
(C) all red flowered plants.
(D) all white flowered plants. 65. Which of the Mendel’s laws will always prove

to be universally true in all cases?
57. In monohybrid cross between pure tall and
(A) All three laws
pure dwarf pea plant, how many types of
(B) Only the 2nd law
genotypes are found in F generation ?
2 (C) 2nd and 3rd laws
(A) 4 (B) 3
(D) 1st and 2nd laws
(C) 8 (D) 9

58. Out of the four progenies obtained in F 66. Mendel formulated the law of dominance and
2
generation by crossing pure tall and pure law of purity of gametes on the basis of
dwarf, how many of them will receive only (A) test cross
recessive trait from both parents? (B) back cross
(A) all four (B) one (C) monohybrid cross
(C) two (D) three (D) dihybrid cross

6
Chapter 01 : Genetic Basis of Inheritance
67. A cross between two pure individuals 74. Mendel’s pattern of inheritance systematically
differing in two sets of characters is called showed the progeny in
(A) dihybrid cross (A) checker board (B) square board
(B) monohybrid cross (C) cross board (D) all of these

(C) trihybrid cross
75. The conclusions made by Mendel based on
(D) reciprocal cross
dihybrid cross was
68. The phenotype of plant with genotype YyRr (A) when a dihybrid or polyhybrid forms
must be gametes, each gamete receives only one
(A) Yellow wrinkled (B) Green round allele from each pair
(C) Yellow round (D) green wrinkled (B) the assortment of alleles of different

traits is totally independent of their
69. Dihybrid ratio is defined as
parental combination
(A) phenotypic ratio obtained in F
2
generation of dihybrid cross. (C) both (A) and (B)
(B) phenotypic ratio obtained in F (D) none of the above
1
generation of dihybrid cross.
76. When Mendel crossed pea plants with yellow
(C) genotypic ratio obtained in F generation
2 round seed and green wrinkled seed, the seeds
of dihybrid cross.
obtained in F hybrid were,
1
(D) genotypic ratio obtained in F generation
1 (A) yellow wrinkled (B) yellow round
of dihybrid cross.
(C) green wrinkled (D) green round

70. While performing dihybrid cross, Mendel
77. The phenotypic ratio of F progeny in a
(A) selected a variety of pea plant having 2
dihybrid cross is
yellow and round seed as female parent
(A) 9 : 3 : 3 : 1: 1
and another variety having green and
(B) 9 : 3 : 3 : 1
wrinkled seeds as a male parent.
(C) 9 : 1 : 3 : 3 : 1
(B) obtained pure lines by selfing
(D) 1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1
(C) performed artificial cross by emasculation

(D) all of the above
78. The genotypic ratio obtained in a Mendelian

71. Out of the four phenotypes obtained in F dihybrid cross is
2
generation of dihybrid cross between yellow (A) 1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1
round and green wrinkled seeds of pea plant, (B) 9 : 3 : 3 : 1
(A) two were parental and two were new (C) 1 : 4 : 4 : 1 : 2 : 2 : 1 : 1
combination (D) 9 : 7

(B) all were parental combination
79. New character combinations appear in F
(C) all were with recessive trait 2
generation of a dihybrid cross mainly because
(D) all were new combination
of
72. The statement – “Probability of two (A) dominance
independent events occurring simultaneously (B) recessiveness
is the product of their individual probabilities” (C) principle of unit character
is (D) independent assortment
(A) law of dominance
80. Law of independent assortment can be
(B) principle of probability
explained by
(C) law of segregation
(D) law of new combinations (A) monohybrid cross and monohybrid ratio

(B) dihybrid cross and dihybrid ratio
73. (3 : 1)  (3 : 1) = 9 : 3 : 3 : 1
(C) trihybrid cross and trihybrid ratio
This signifies
(D) all of the above
(A) trihybrid ratio
(B) two monohybrid ratio 81. _______ occurs due to crossing over taking
(C) dihybrid ratio is a product of two place during meiosis.
monohybrid ratios (A) Linkage (B) Recombination
(D) none of the above (C) Segregation (D) Mutation

7