biology MCQs - 12th class Chapter 08 Mcqs

1

The basic unit of biological information is called?

A

Allele

B

Gene

C

Chromosome

D

Locus

2

What is the position of a gene on the chromosome called?

A

Locus

B

Allele

C

Telomere

D

Centromere

3

Partners of a gene pair are called?

A

Homologues

B

Genotypes

C

Alleles

D

Phenotypes

4

What is the term for the form of appearance of a trait?

A

Genotype

B

Phenotype

C

Allele

D

Gene Pool

5

All the genes found in a breeding population at a given time are collectively called the?

A

Gene Pool

B

Genome

C

Genotype

D

Phenome

6

Who is credited with laying the foundation of classical genetics?

A

Charles Darwin

B

Gregor Johann Mendel

C

T.H. Morgan

D

Carl Correns

7

Which plant did Mendel use for his breeding experiments?

A

4 O'clock

B

Rose

C

Garden pea (Pisum sativum)

D

Fruit fly

8

How many sharply distinct traits of the pea plant did Mendel focus on?

A

5

B

7

C

9

D

14

9

In Mendel's monohybrid cross, what was the phenotypic ratio in the F2 generation?

A

1:1

B

2:1

C

3:1

D

9:3:3:1

10

A cross used to test the genotype of an individual showing a dominant phenotype is called a?

A

Monohybrid cross

B

Dihybrid cross

C

Test cross

D

Back cross

11

In a dihybrid cross, what is the phenotypic ratio found in the F2 generation?

A

3:1

B

1:2:1

C

9:3:3:1

D

1:1:1:1

12

The law of independent assortment applies to genes located on?

A

The same chromosome

B

Linked linkage groups

C

Non-homologous chromosomes

D

The X chromosome only

13

When the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes, it is called?

A

Complete dominance

B

Codominance

C

Incomplete dominance

D

Over dominance

14

In which plant did Carl Correns observe incomplete dominance?

A

Garden pea

B

4 O'clock

C

Drosophila

D

Rose

15

When both alleles express independently in a heterozygote and form their respective products, it is called?

A

Incomplete dominance

B

Codominance

C

Over dominance

D

Pleiotropy

16

The human MN blood group system is an example of?

A

Complete dominance

B

Incomplete dominance

C

Codominance

D

Multiple alleles

17

A gene that has more than two altered alternative forms is said to have?

A

Multiple alleles

B

Polygenes

C

Linked genes

D

Pleiotropic genes

18

The ABO blood group system is encoded by a single polymorphic gene 'I' on which chromosome?

A

Chromosome 7

B

Chromosome 9

C

Chromosome 11

D

Chromosome 19

19

In the ABO blood group system, which allele is recessive to both IA and IB?

A

i

B

IA

C

IB

D

I

20

Individuals with which blood group are called universal donors?

A

B

C

AB

D

O

21

Individuals with which blood group are called universal recipients?

A

B

C

AB

D

O

22

The Rh factor was first discovered in which animal by Landsteiner?

A

Grasshopper

B

Fruit fly

C

Rhesus monkey

D

Pea plant

23

A phenomenon where an effect caused by one gene pair interferes with or hides the effect of another gene pair is called?

A

Dominance

B

Pleiotropy

C

Epistasis

D

Linkage

24

The Bombay phenotype is an example of?

A

Codominance

B

Incomplete dominance

C

Epistasis

D

Pleiotropy

25

When a single gene affects two or more traits, the phenomenon is called?

A

Polygenic inheritance

B

Pleiotropy

C

Epistasis

D

Linkage

26

Traits like height, weight, and skin color in humans are examples of?

A

Discontinuous variations

B

Mendelian traits

C

Continuously varying traits

D

Sex-linked traits

27

Continuously varying traits are also known as?

A

Pleiotropic traits

B

Polygenic traits

C

Linked traits

D

Dominant traits

28

How many gene pairs contribute to the wheat grain color studied by Nilsson-Ehle?

A

One

B

Two

C

Three

D

Four

29

All the genes located on the same chromosome are said to be?

A

Alleles

B

Polygenes

C

Linked

D

Mutated

30

The phenomenon of staying together of all the genes of a chromosome is called?

A

Assortment

B

Segregation

C

Linkage

D

Crossing over

31

An exchange of segments between non-sister chromatids of homologous chromosomes during meiosis is called?

A

Linkage

B

Segregation

C

Independent assortment

D

Crossing over

32

Recombination frequency is directly proportional to the?

A

Number of genes

B

Distance between linked gene loci

C

Number of chromosomes

D

Size of the chromosome

33

In Drosophila melanogaster, how many pairs of chromosomes are there?

A

3

B

4

C

8

D

23

34

The chromosomes that are not sex-chromosomes are called?

A

Homologues

B

Autosomes

C

Heterosomes

D

Gametes

35

What is the male-determining gene located on the Y-chromosome in humans?

A

SRY

B

TDF

C

HGH

D

MODY

36

In grasshoppers, what is the sex chromosome combination for a male?

A

XY

B

XX

C

XO

D

ZZ

37

In birds and moths, which sex is heterogametic?

A

Male

B

Female

C

Both

D

Neither

38

In humans, an individual with Klinefelter's syndrome has which set of sex chromosomes?

A

XO

B

XY

C

XXY

D

XXX

39

A trait whose gene is present on the X chromosome is called?

A

Y-linked trait

B

Autosomal trait

C

X-linked trait

D

Sex-influenced trait

40

An X-linked trait passes in a crisscross fashion from?

A

Father to son

B

Mother to daughter

C

Maternal grandfather to grandson

D

Paternal grandmother to granddaughter

41

Haemophilia is a rare X-linked ______ trait.

A

dominant

B

recessive

C

codominant

D

incomplete dominant

42

Red-green color blindness is caused by mutations in genes for?

A

Rod cells

B

Blue opsins

C

Red and green opsins

D

Melanin

43

Hypophosphatemic rickets is an example of an X-linked ______ trait.

A

recessive

B

dominant

C

codominant

D

Y-linked

44

A trait that is limited to only one sex due to anatomical differences is called?

A

Sex-influenced trait

B

Sex-limited trait

C

X-linked trait

D

Y-linked trait

45

Pattern baldness in humans is an example of a?

A

Sex-limited trait

B

Sex-influenced trait

C

X-linked dominant trait

D

X-linked recessive trait

46

Type I diabetes mellitus (IDDM) is what kind of disorder?

A

Viral infection

B

Bacterial infection

C

Autoimmune disorder

D

Hormonal imbalance

47

The insulin gene is located on which human chromosome?

A

Chromosome 7

B

Chromosome 9

C

Chromosome 11

D

Chromosome 19

48

Maturity Onset Diabetes of the Young (MODY) can be inherited as an autosomal ______ trait.

A

recessive

B

dominant

C

polygenic

D

X-linked

49

The ability to roll the tongue into a U shape is due to a single ______ gene.

A

recessive

B

dominant

C

polygenic

D

linked