MCQ Questions Chapter 5 Principles of Inheritance and Variation Class 12 Biology

Please refer to MCQ Questions Chapter 5 Principles of Inheritance and Variation Class 12 Biology with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 12 Biology issued for the current academic year. We have provided MCQ Questions for Class 12 Biology for all chapters on our website. Students should learn the objective based questions for Chapter 5 Principles of Inheritance and Variation in Class 12 Biology provided below to get more marks in exams.

Chapter 5 Principles of Inheritance and Variation MCQ Questions

Please refer to the following Chapter 5 Principles of Inheritance and Variation MCQ Questions Class 12 Biology with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 5 Principles of Inheritance and Variation Class 12 Biology

Question- According to Mendel ”factors” which are stably passed down unchanged from parent to offspring is through
(a) Gametes
(b) Somatic cells
(c) Emasculation
(d) Asexual reproduction

Question- Which will be the dominant phenotype of F2 generation of a monohybrid cross (TT × tt)?
(a) Tall
(b) TT
(c) Tt and TT
(d) None of these

Question- Cross between genes controlIing a single character of same generation is known as
(a) Test cross
(b) Dihybrid cross
(c) Monohybrid cross
(d) Back cross

Question- R.C. Punnett was of which nationality
(a) German
(b) American
(c) British
(d) Russian

Question- In a monohybrid cross (TT × tt) recessive parent character is expressed in
(a) F₁ generation
(b) F₂ generation
(c) Both F₁ and F₂ generation
(d) Sometimes in F₁ sometime in F₂

Question- To determine the genotype of tall plant of F2 generation Mendel performed
(a) Back cross
(b) Reciprocal cross
(c) Test cross
(d) Dihybrid cross

Question- Test cross of F₂ generation tall plants produced 50% tall and 50% dwarf plants. The tall plants thus produced will be :
(a) Homozygous
(b) Heterozygous
(c) 50% homozygous 50% heterozygous
(d) 75% homozygous 25% heterozygous

Question- In a test cross between dominant F₂ and recessive parent showed all flowers of dominant phenotype of F₂ generation is
(a) Heterozygous
(b) Homozygous
(c) Showing incomplete dominance
(d) None of these

Question- Appearance of the parental recessive character also in F₂ generation after a monohybrid cross (TT × tt) is explained by
(a) Law of dominance
(b) Law of incomplete dominance
(c) Codominance
(d) None of these

Question- Snap dragon is the common name of
(a) Antirrhinum
(b) Drosophila melanogaster
(c) Piper betel
(d) Piper betel

Question- Phenotype ratio of a monohybrid cross in case of incomplete dominance in F2 generation will be
(a) 1 : 3
(b) 3 : 1
(c) 2 : 2
(d) 1 : 2 : 1

Question- Human blood group AB is example of
(a) Law of dominance
(b) Law of incomplete dominance
(c) Law of independent assortment
(d) None of these

Question- The blood group is controlled by
(a) Gene A
(b) Gene B
(c) Gene 0
(d) Gene I

Question- Which molecules are presented on RBC which are important for blood group determination in human?
(a) Protein
(b) Sugar
(c) Lipid
(d) All of these

Question- If offspring have IA and 1B both the alleles for blood group the blood group will be
(a) A
(b) B
(c) 0
(d) AB

Question- Klinefelter’s syndrome results from the fusion of
(a) an X egg and a YY sperm.
(b) an XY egg and an X sperm
(c) an XX egg and a Y sperm.
(d) an XX egg and a YY sperm.

Question- How many pairs of autosomes are found in human?
(a) 46
(b) 23
(c) 1
(d) 22

Question- Linkage was discovered by
(a) Mendel in Pisum sativum
(b) Beadle in Neurosppra crassa
(c) Bateson in Lathyrus odoratus
(d) Morgan in pea

Question- Which one of the following is sex-linked disease?
(a) Haemophilia
(b) Down’s syndrome
(c) Albintem
(d) Turner’s syndrome

Question-Trisomy has a chromosome complement of
(a) 2n-1
(b) 2n + 2
(c) 2n + 3
(d) 2n + 1

Question- Individuals with patches of other sex is called
(a) Gynandromorph
(b) Androgynanas
(c) Andromouphs
(d) gynomorph

Question- Mutations used in agriculture are commonly
(a) spontaneous
(b) lethal
(c) induced 
(d) recessive and lethal

Question- Harmful mutations does not get eliminated from gene pool because
(a) they have survival valve
(b) they are recessive and carried by heterozygous individuals
(c) they are formed repeatedly
(d) they show genetic drift

Question- Which one of the following would represent allotetraploid7
(a) AAABB
(b) AAAA
(c) AA8B
(d) BBBB

Question- The Klinefelter’s syndrome has chromosomal constituent
(a) 2A + XX
(b) 2A + XXY
(c) 2A + Y
(d) 2A-XY

Question- In which stage crossing over takes place?
(a) Leptotene
(b) Cytokinesis
(c) Pachytene
(d) Diakinesis

Question- Linkage reduces the frequency of
(a) hybrids
(b) all parental types
(c) homozygous recessive parents
(d) heterozygous recessive parents

Question- Two genes situated very close on the chromosome show –
(a) no crossing over 
(b) high crossing over
(c) hardly any crossing over 
(d) only double crossing over

Question- If Mendel had studied the 7 traits using a plant with 12 chromosomes instead of 14, in what way his interpretation would have been different?
(a) He would have discovered crossing over
(b) He would have discovered blending or incomplete dominance
(c) He could not have proposed that genes are earned on chromosomes
(d) He would not have discovered the law of independent assortment

Question- In mice, Y is the dominant allele for yellow fur and y is the recessive allele for grey fur. Since Y is lethal when homozygous, the result of cross Yy x Yy will be
(a) 3 yellow : 1 grey.
(b) 2 yellow : 1 grey.
(c) 1 yellow : 1 grey.
(d) 1 yellow : 2 grey.

Question- The no. of linkage groups in demosophila, Pisum, coin and nice are-
(a) 4, 7, 10, 19 respectively
(b) 4, 7, 10, 21, respectively
(c) 4, 7, 10, 21 respectively
(d) 10, 12, 17, 20 respectively

Question- In Drosophila, long wing (L) is dominant to dumpy wing (I) and grey body (G) is dominant to ebony body (g). The two genes involved are not on the same chromosome.A true-breeding long-winged, ebony-bodied fly is crossed with a true-breeding dumpy-winged, grey-bodied fly.The genotype of the F1 generation will be
(a) LIGg
(b) LLGg
(c) LLGG
(d) LIGG

Question- A comparison of the karyotypes of a normal human male and a male sufferer of Down’s syndrome shows the latter to possess
(a) one extra chromosome
(b) two Y chromosomes
(c) one extra pair of chromosomes
(d) twice the normal number of chromosomes

Question- Which of the following statements is NOT correct?
(a) Mutations provide variation upon which natural selection can act.
(b) The vast majority of mutations produce alleles which are dominant.
(c) Mutations arise spontaneously, infrequently and at random.
(d) Mutation rate can be increased by artificial means

Question- In a certain plant, yellow fruit colour (Y) is dominant to green (y) and round shape (R) is dominant to oval (r). The two genes involved are located on different chromosomes.
Which of the above will result when plant YyRr is backcrossed (testcrossed) with the double recessive parent?
(a) 9:3:3:1 ratio of phenotypes only
(b) 9:3:3:1 ratio of genotypes only
(c) 1:1:1:1 ratio of phenotypes only
(d) 1:1:1:1 ratio of phenotypes and genotypes

Question- Sickle cell anemia Las not been eliminated from the African population because-
(a) It is controlled by recessive gore
(b) It is not a foetal disease
(c) It provides immunity against malaria
(d) It is controlled by dominant gene

Question- In a certain plant, yellow fruit colour (Y) is dominant to green (y) and round shape (R) is dominant to oval (r). The two genes involved are located on different chromosomes.Which of the above will result when plant YyRr is self-pollinated?
(a) 9:3:3:1 ratio of phenotypes only
(b) 9:3:3:1 ratio of genotypes only
(c) 1:1:1:1 ratio of phenotypes only
(d) 1:1:1:1 ratio of phenotypes and genotypes

Question- This question refer to eye colour in the fruit fly. In this sex-linked trait, the allele for red eye is dominant to that for white eye.If a heterozygous red-eyed female is crossed with a white-eyed male, what percentage of the female offspring will be white-eyed?
(a) 0%
(b) 25%
(c) 50%
(d) 100%

Question- Polyploid wheat does NOT normally show an increase in
(a) size
(b) vigour
(c) resistance to disease
(d) length of life cycle.

Question- Crossing over occurs between-I
(a) Sister chromatics
(b) Non-sister chromatics
(c) Non-homologues
(d) All the above

Question- If the sequence of genes are chromosome is changed from ABCDEFG to ABCDFEG then it in
(a) Addition
(b) Deletion
(c) Substitution
(d) Inversion

Question-In mice, black coat colour (allele B) is dominant to brown coat colour (allele b). The offspring of a cross between a black mouse (BB) and a brown mouse were allowed to interbreed. What percentage of the progeny would have black coats?
(a) 25%
(b) 50%
(c) 75%
(d) 100%

Question- A human female will definitely be a haemophiliac if
(a) both of her parents are also haemophiliacs.
(b) her mother is a carrier and her father is a haemophiliac.
(c) her mother carries the allele for haemophilia on both X chromosomes.
(d) her father is a haemophiliac and her mother is normal.

Question- What will be the number of linkage groups in a cell having 2n = 20?
(a) 15
(b) 40
(c) 10
(d) 4

Question- A pea plant that is heterozygous for the flower gene makes gametes. What is.the probability that one of its gametes contains the recessive white allele for flower color?
(a) 0%
(b) 25%
(c) 50%
(d) 75%

Question- Haemophilia is a condition in which blood fails to clot or clots only very slowly. Studies of this human sex-linked trait show that
(a) every X chromosome carries the dominanfallele.
(b) a Y chromosome never carries the dominant allele.
(c) both X and Y chromosomes can bear the recessive allele.
(d) neither X nor Y chromosomes can bear the recessive allele.

Question-In a certain species of sweet pea plant, flowers are either purple or white. Colour is determined by two unlinked,genes. The alleles of the first gene are X and x; those of the second gene are Y and y.In order to bear purple flowers, a plant must possess at least one X and one Y allele. Those genotypes which fail to do so, result in the formation of white flowers.
If two purple-flowered plants of genotype XxYy are crossed then the expected phenotypic ratio of offspring would be
(a) 12 purple 4 white
(b) 9 purple 7 white
(c) 10 purple 6 white
(d) 8 purple 8 white

Question- Given are the statements regarding linkages of genes:
(i) The strength of the linkage is determined by the distance between the 2 genes in question.
(ii) The strength of the linkage is directly proportional to the distance between the two genes.
(iii) The two genes are said to be linked when they fail to show independent assortment. Out of these statements:
(a) all are correct
(b) (i) and (ii) are correct
(c) (i) and (iii) are correct
(d) (ii) and (iii) are correct

Question- In humans, the gene for red blood corpuscle shape (alleles elliptical E and normal ) is linked to gene for Rhesus blood (alleles Rhesus positive R and Rhesus negative ) A person with alleles E and R on one chromosome and e and r on its homologous partner will defined produce gametes with the genotypes
(a) EeandRr.
(b) Eeander
(c) ERandRr.
(d) ERander.

Question- A and B genes are linked. What shall be genotype of progeny in a cross between AB/ab and ab/ab?
(a) AAbbandaabb
(b) AaBbandaabb
(c) AABBandaabb
(d) None of these

Question- Which of the following is not a dominant trait?
A. Colourblindness B. Rhfactor C. Albinism D. Haemophilia
(a) A, C,D
(b) A,B,C, D
(c) B, C, D
(d) A, B,C

Question- Two organisms that are true-breeding for a certain genetic characteristic are mated and their offspring analyzed.Which of the following statements about this situation is true?
(a) Both parents are homozygotes.
(b) The offspring are either all homozygotes or all heterozygotes.
(c) The offspring represent the F1 generation, the gametes produced by the offspring will carry only one allele for this gene.
(d) All of the above

Question- Cri-du-chot syndrome in humans in caused by
(a) Fetilisation of an XX egg by a normal Y-sperm
(b) Loss of Lalf of the short arm of chromosome 5
(c) Loss of half of the long arm of chromos are 5
(d) Trisomy of the 21st chromosome

Question- In snapdragon plants, broad leaf is compie4 ”’ dominant to narrow leaf whereas red flower colour is incompletely dominant to ivory. (The genes for leaf width and flower colour are not linked.) If a plant which is heterozygous for both genes is crossed with a true-breeding broad-leaved red-flowered plant,then the expected proportion of broad-leaved plants with pink flowers amongst the offspring would be
(a) 1 in 4.
(b) 2 in 4.
(c) 3 in 4.
(d) 4 in 4.

Question- Which of the following is suitable for experiments on linkage?
(a) MBBxaabb
(b) AaBbxAa’Bb
(c) aaBBxaaBB
(d) AAbb xAaBB

Question- Which of the following genes have similar genotypic e’ffecfwrien present separately but produce different trait after interacting together and give a ratio of 9 : 7 in F2 generation?
(a) Complementary genes
(b) Jumping genes
(c) Duplicate genes
(d) House-keeping genes

Question- Which of the following statements about mutations is false?
(a) Mutations are the source of new alleles for genes.
(b) Organisms are able to create mutations to meet their specific needs.
(c) Mutations are random events and can happen in any cell at any time.
(d) Most mutations tend to be harmful or have no effect on organisms.

Question- Which contributed to the success of Mendel?
A. Selection of pea plant B. His knowledge of biology
C. Consideration of one character at one time D. He had knowledge of linkage
(a) A, C,D
(b) A,B, C,D
(c) A,C
(d) A,B, C

Question- Chromosomal aberration occurs due to
A. deletion B. duplication C. inversion D. translocation.
(a) A, C, D
(b) A, B, C, D
(c) B, C, D
(d) A, B, C

Question- In humans, the gene for red blood corpuscle shape (alleles elliptical E and normal e) is linked to the gene for Rhesus blood (alleles Rhesus positive R and Rhesus negative r).If crossing over occurs between these two genes, then the two additional types of gametes that could result are
(a) RE and re.
(b) EE and rr.
(c) Er and eR.
(d) ee and RR.

Question- Which of the following statements is true about Mendel?
(a) His discoveries concerning genetic inheritance were generally accepted by the scientific community when he published them during the mid 19th century.
(b) He believed that genetic traits of parents will usually blend in their children.
(c) His ideas about genetics apply equally to plants and animals.
(d) He discovered linkage

Question- What is not true of law of independent assortment?
A. Applicable to all the dominant alleles
B. Applicable to all genes on the same chromosome
C. Not applicable to genes present on the same chromosome
D. Applicable to all recessive alleles
(a) A, C,D
(b) A, B.C.D
(c) B, C, D
(d) A, B, D

Question- A mutation is a
(a) sudden temporary change in an organism’s genetic material.
(b) change in phenotype followed by a change in genotype.
(c) change in hereditary material directed by a changing environment.
(d) change in genotype which may result in a new expression of a characteristic.

Question- Consider a gene that has two alleles and shows complete dominance. When two heterozygotes for this gene breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time they breed,what are the chances that they will once again have a homozygous recessive progeny?
(a) 0%
(b) 25%
(c) 50%
(d) 75%

Question- If a colomblind woman marries a normal visional
(a) All normal visional
(b) One-half coloublined and one-half normal
(c) Three-founths colorblind and one-founths normal
(d) All colomblind

Question- Bateson used the terms coupling and repulsion for linkage and crossing over. Name the correct parental or coupling type along with its cross over or repulsion:
(a) Coupling aaBB, aabb; Repulsion AABB, aabb
(b) Coupling AABB, aabb; Repulsion AABB, AAbb
(c) Coupling AAbb, aaBB; Repulsion AaBb, aabb
(d) Coupling AABB, aabb; Repulsion AAbb, <aB8

Question. Which of the following condition is called monosomics 
(a) 2n+1
(b) 2n+2
(c) 2n-1
(d) n+1

Question. If heterozygous round seeded pea plants are self pollinated, the offsprings will be       
(a) 75% round
(b) 50% heterozygous
(c) 25% rr
(d) All of these

Question. Turner’s syndrome is         
(a) XO
(b) XXY
(c) XXX
(d) XYY

Question. Skin colour is controlled by     
(a) Pleiotropic genes
(b) Dominant genes
(c) Polygenes
(d) Recessive gene

Question. X – linked recessive gene is      
(a) Always expressed in male
(b) Always expressed in female
(c) Never expressed in males
(d) Always expressed in males and female

Question. Indicate, the inheritance of which of the following is controlled by multiple alleles   
(a) Colour blindness
(b) Sickle cell anemia
(c) Blood group
(d) Phenylketoneuria

Question. Segregation of genes occurs in       
(a) Embryo formation
(b) Anaphase II
(c) Anaphase I
(d) Metaphase II

Question. HbA and HbS alleles of normal and sickle cell haemoglobin are       
(a) Co-dominant alleles
(b) Multiple alleles
(c) Dominant-recessive alleles
(d) Cumulative alleles

Question. The plant in which Hugo de Vries introduces the concept of mutation is        
(a) Oenothera lamarkiana
(b)Pisum sativum
(c) Allium cepa
(d) Mirabilis jalapa

Question. Erythroblastosis foetalis occurs when           
(a) Mother is Rh negative and father is Rh positive
(b) Father is Rh negative and mother is Rh positive
(c) Both are Rh positive
(d) Both are Rh negative

Question. How many different genotypes are possible from a cross between the parents RR and rr     
(a) Four
(b) One
(c) Three
(d) Two

Question. In birds, females are         
(a) XX
(b) ZZ
(c) ZO
(d) ZW

Question. In Snapdragon two plants with pink flowers were hybridized. The F1 plants produced red,pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR and white by rr genes.     
(a) Rr
(b) rr
(c) rrr
(d) RR

Question. Test cross is a cross between    
(a) Hybrid x Dominant parent
(b) Hybrid x Recessive parent
(c) Hybrid x Hybrid
(d) Dominant parent x Recessive parent

Question. Which Mendelian cross can produce two genotypes and two phenotypes?     
(a) Monohybrid cross
(b) Monohybrid test cross
(c) Incomplete dominance
(d) Co-dominance

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