NEET Biology Heredity and Variation MCQs Set C

Question: The genes Controlling the seven characters of a pea plant studied by Mendel are now known to be located on how many different chromosomes?

• a) Four
• b) Five
• c) Six
• d) Seven

Answer: Four

Question: Which one of the following traits of garden pea studied by Mendel was a recessive feature?

• a) Green Seed colour
• b) Round Seed shape
• c) Axial flower position
• d) Green pod colour

Answer: Green Seed colour

Question: Down's Syndrome is caused by an extra copy of chromosome number 21. What percent age of off spring produced by an affected mother and a normal father?

• a) 50%
• b) 25%
• c) 75%
• d) 100%

Answer: 50%

Question: Lack of independent assortment of two genes A and B in fruitfly the Drosophilia is due to

• a) Linkage
• b) Crossing over
• c) Recombination
• d) Repulsion

Answer: Linkage

Question: A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic gene h. What proportion of his sperms will be abh?

• a) 1/8
• b) 1/32
• c) 1/16
• d) 1/4

Answer: 1/8

Question: 

In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t).

If a plant with RRTt genotype is crossed with a plant that is rrtt.

• a) 50% will be tall with red fruit
• b) 25% will be tall with red fruit
• c) 75% will be tall with red fruit
• d) All the offspring will be tall with red fruit

Answer: 50% will be tall with red fruit

Question: A normal woman, whose father was colour blind is married with normal man. The sons would be

• a) 50% colour blind
• b) all colourblind
• c) 75% Colour blind
• d) all normal

Answer: 50% colour blind

Question: The recessive genes located on X - chromosome of humans are always

• a) expressed in males
• b) Lethal
• c) Sub - Lethal
• d) expressed in females

Answer: expressed in males

Question: Inorder to find out the different types of gametes produced by a pea plant having the genotype AaBb it should be crossed to a plant with the genotype

• a) aabb
• b) aaBB
• c) AaBb
• d) AABB

Answer: aabb

Question: A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy

• a) May be colourblind or may be of normal vision
• b) Must be colourblind
• c) Must have normal colour vision
• d) Will be partially colourblind since he is heterozygous for the colourblind mutant allele.

Answer: May be colourblind or may be of normal vision

More Questions...................................

Question: Which of the following is not a hereditary disease?

• a) Cretinism
• b) Haemophilia
• c) Thalassaemia
• d) Cystic Fibrosis

Answer: Cretinism

Question: Haemophilia is more commonly seen in human males than in human females because

• a) this disease is due to an X - linked recessive mutation
• b) this disease is due to an X- linked dominant mutation
• c) this disease is due to a Y- linked recessive mutation
• d) a greater proportion of girls die in infancy

Answer: this disease is due to an X - linked recessive mutation

Question: A woman with 47 chromosomes due to 3 copies of chromosome 21 is characterized by

• a) Down's Syndrome
• b) Triploidy
• c) Super Femaleness
• d) Turner's Syndrome

Answer: Down's Syndrome

Question:

A man and a woman, who do not show any apparent signs of a certain inherited disease, have Seven Children (2 daughters and 5 sons). Three of the Sons suffer from the given disease but none of the daughters affected. Which of the following mode of inheritance do you suggest for this disease?

• a) Sex - linked recessive
• b) Sex - linked dominant
• c) Sex - limited recessive
• d) Autosomal dominant

Answer:  Sex - linked recessive

Question: Which one of the following is an example of polygenic inheritance ?

• a) Skin colour in humans
• b) Flower colour in Miralibilis jalapa
• c) Production of male honey bee
• d) Pod shape in garden pea

Answer: Skin colour in humans

Question: Phenotype of an organism is the result of

• a) genotype and environmental interactions
• b) mutations and linkages
• c) Cytoplasmic effects and nutrition
• d) environmental changes and sexual dimorphism

Answer: genotype and environmental interactions

Question: How many different gametes will be produced by a plant having the genotype AABbCC?

• a) Two
• b) Three
• c) Four
• d) Nine

Answer: Two

Question:   

In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkledSeeds (rr), Yellow cotyledon (YY) was dominant over green cotyledon (yy).

What are the expected Phenotypes in the F2 generation of the cross RRYY x rryy? 

• a) Round Seeds with yellow cotyledons, and wrinkled seeds with yellow cotyle dons
• b) Only round seeds with green cotyledons
• c) Only wrinkled seeds with yellow cotyledons
• d) Only wrinkled seeds with green cotyledons

Answer: Round Seeds with yellow cotyledons, and wrinkled seeds with yellow cotyle dons

Question: Test cross involves

• a) Crossing between two F₁ hybrids
• b) Crossing the F₁ hybrid with a double recessive genotype
• c) Crossing between two genotypes with recessive trait
• d) Crossing between two genotypes with dominant trait

Answer:  Crossing between two F₁ hybrids

Question: Cri - du -chat Syndrome in humans is caused by the

• a) loss of half of the short arm of chromosome 5
• b) loss of half of the long arm of chromosome 5
• c) Fertilization of an XX egg by a normal Y - bearing sperm
• d) trisomy of 21st chromosome

Answer: loss of half of the short arm of chromosome 5

Question: If a colourblind woman marries a normal visioned man, their sons will be

• a) all colourblind
• b) all normal visioned
• c) one - half colourblind and one - half normal
• d) three - fourths colourblind and one - fourth normal

Answer: all colourblind

Question: In the hexaploid wheat, the haploid (n) and basic (X) numbers of chromosomes are

• a) n = 21 and X = 7
• b) n = 7 and X =21
• c) n = 21 and X =14
• d) n = 21 and X = 21

Answer:  n = 21 and X = 7

Question: In pea plants, yellow seeds are dominant to green, If a heterozygous yellow seeded plant isCorssed with a green seeded plants, what ratio of yellow and green seeded plants, would you expect in F1 generation?

• a) 50 : 50
• b) 3 : 1
• c) 1 : 3
• d) 9 : 1

Answer: 50 : 50

Question:   A human male produces sperms with the genotypes AB , Ab , aB , ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

• a) AaBb
• b) AABB
• c) AABb
• d) AaBB

Answer: AaBb

Question: Which one of the following conditions in human is correctly matched with its chromosomal abnormality / linkage ?

• a) Colour blindness - Y - linked
• b) Kline Felter's syndrome - 44 autosomes +XXY
• c) Down's syndrome - 44 autosomes +XXY
• d) Erythro blastosis foetalis - X - linked

Answer: Colour blindness - Y - linked

Question:  Study the pedigree chart given below what does it show?

• a) Inheritance of a Condition like phenyl ketonuria as an autosomal recessivetrait
• b) The pedigree chart is wrong as this is not possible
• c) Inheritance of recessive sex - linked disease like haemophilia
• d) None of this

Answer: Inheritance of a Condition like phenyl ketonuria as an autosomal recessivetrait

Question: The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because "O" in it refers to having

• a) no antigens A and B on RBCs
• b) other antigens besides A and B on RBCs
• c) One antibody only - either anti - A or anti - B on the RBCs
• d) Overdominance of this type on the genes for A and B types

Answer: no antigens A and B on RBCs

Question: Sickle cell anemia is

• a) Caused by a change in a single base pair of DNA
• b) Caused by substitution of Valine by glutamic acid in the beta globin chain of haemo globin.
• c) Characterized by elongated sickle like RBCS with a nucleus
• d) An autosomal dominant trait.

Answer: Caused by a change in a single base pair of DNA

Question: Which one of the following can not be explained on the basis of Mendel's law of dominance?

• a) Alleles do not show any blending and both the characters recover as such in F₂ generation.
• b) Factors occur in pairs
• c) Out of one pair of factors one is dominant, and the other recessive.
• d) The discrete unit controlling a particular character is called a factor

Answer:  Alleles do not show any blending and both the characters recover as such in F₂ generation.

Question: The genotype of a plant showing the dominatnt phenotype can be determined by

• a) test cross
• b) dihybrid cross
• c) pedigree analysis
• d) Back Cross

Answer: test cross

Question: Select the correct statement from the ones given below with respect to dihybrid cross

• a) Tightly linked genes on the samechromosome show very few recombinations
• b) Genes loosely linked on the same chrososome show similar recombinations
• c) Genes far apart on the same chromosome show very few recombinations
• d) Tightly linked genes on the same chromosomes show higher recombinations

Answer: Tightly linked genes on the samechromosome show very few recombinations

Question: ABO blood groups in humans are controlled by the gene I. It has three alleles - IA , IB and i . Since there are 3 different alleles six different genotypes are possible. How many phenotypesOccur?

• a) Four
• b) Two
• c) One
• d) Three

Answer: Four

Question: Which one of the following symbols and its representation used in human pedigree analysis is correct?

• a) Mating between relatives
• b) unaffected male
• c) unaffected female
• d) affected male

Answer: Mating between relatives

Question: Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the character

• a) The female parent is heterozygous
• b) The parent could not have had a normal daughter for this character
• c) The trait under study could not be colourblindness
• d) The male parent is homozygous dominant

Answer: The female parent is heterozygous

Question: Which one of the following conditions correctly describes the manner of determining the sex?

• a) XO type of sex chromosomes determine male sex in grasshopper
• b) Homozygous sex chromosomes (ZZ) determine female sex in birds
• c) Homozygous sex chromosomes (XX) produce male in Drosophila
• d) XO condition in humans as found in Turner's syndrome, determines female sex

Answer: XO type of sex chromosomes determine male sex in grasshopper

Question: Mutations can be induced with

• a) gamma radiations
• b) Ethylene
• c) IAA
• d) Infra red radiations

Answer: gamma radiations

Question: Test cross in plants or in Drosophilia involves crossing

• a) the F₁ hybrid with a double recessive genotype
• b) between two genotypes with dominant traits
• c) between two F₁ hybrids
• d) between two genotype with recessive trait

Answer:  the F₁ hybrid with a double recessive genotype

Question: Which one of the following conditions of the Zygotic cell would lead to the birth of a normal human female child?

• a) Two X Chromosomes
• b) Only One Y Chromosomes
• c) Only One X Chromosomes
• d) One X chromosome and One Y chromosome

Answer: Two X Chromosomes

Question: F₂ generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1 . It represents in case of

• a) Monohybrid cross with incomplete dominance
• b) Monohybrid cross with complete dominance
• c) Dihybrid Cross
• d) Co - Dominance

Answer: Monohybrid cross with incomplete dominance

Question:  A normal - Visioned man whose father was colourblind, marries a woman whose father was also colourblind. They have their first child as a daughter. What are the chances that this child would be colourblind?

• a) 0%
• b) 100%
• c) 25%
• d) 50%

Answer: 0%

Question: A test cross is carried out to

• a) determine the genotype of a plant at F₁
• b) Predict whether two traits are linked
• c) assess the number of alleles of a gene
• d) determine whether two species or varieties will breed successfully.

Answer: determine the genotype of a plant at F₁

Question:  Represented below is the inheritance pattern of a certain type of trait in humans. Which one of the following conditions could be an example of this pattern?

• a) Haemophilia
• b) Phenyl ketonuria
• c) Sickle Cellanaemia
• d) Thalassemia

Answer: Haemophilia

Question:  A cross between AaBB X aaBB yields a genotypic ratio of

• a) 1 AaBB : 1 aaBB
• b) I AaBB : 3aaBB
• c) 3 AaBB : 1 aaBB
• d) None of this

Answer: 1 AaBB : 1 aaBB

Question:  Which of the following is non - heritable?

• a) Point mutation
• b) Gene mutation
• c) Chromosomal mutation
• d) Somatic mutation

Answer: Point mutation

Question: Dihybrid cross proves the law of

• a) segregation
• b) Dominance
• c) Purity of gametes
• d) Independent assortment

Answer: segregation

Question: How many types and in what ratio the gametes are produced by a dihybrid heterozygous?

• a) 4 types in the ratio of 1: 1: 1 : 1
• b) 3 types in ratio of 1: 2: 1
• c) 2 types in the ratio of 3 : 1
• d) 4 types in the ratio of 9 : 3 : 3 : 1

Answer: 4 types in the ratio of 1: 1: 1 : 1

Question: In a cross between a pure tall plant with green pod and a pure short plant with yellow pod. How many short plants are produced in F2 generation out of 16?

• a) 4
• b) 9
• c) 3
• d) 1

Answer: 4

Question: In a dihybrid cross between AABB and aabb the ratio of AABB, AABb, aaBb, aabb in F₂ generation is

• a) 1: 2: 2: 1
• b) 1 : 1 : 2 : 2
• c) 1: 1: 1: 1
• d) 9 : 3 : 3: 1

Answer: 1: 2: 2: 1

Question: The allele which is unable to express its effect in the presence of another is called

• a) Recessive
• b) Complementary
• c) Supplementary
• d) Co - dominant

Answer: Recessive