PSC Biology Questions

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PSC Biology Questions. We covered all the PSC Biology Questions in this post for free so that you can practice well for the exam.

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PSC Biology Questions for Students

Which of the following is a function of sphincter muscles?

(a) Control peristalsis.

(b) Grind large food particles.

(c) Secrete digestive juices into the GI tract.

(d) Control the passage of food through the GI tract.

Option d – Control the passage of food through the GI tract

Which one among the following statements is not correct?

(a) Pulses are rich in proteins.

(b) Milk is a rich source of Vitamin A.

(c) Cereals are a very poor source of carbohydrates.

(d) Vegetables are a rich source of minerals.

Option c – Cereals are a very poor source of carbohydrates

In the human digestive system, the process of digestion starts in

(a) Esophagus

(b) Buccal cavity

(c) Duodenum

(d) Stomach

Option b – Buccal cavity

The action of pepsin is to

(a) Curdle milk.

(b) Break down proteins to peptones.

(c) Break down polypeptides into amino acids.

(d) Break down polysaccharides into disaccharides.

Option b – Break down proteins to peptones

The main factor of evolution is

(a) Mutation

(b) Achieved quality

(c) Vaginal birth

(d) Natural selection

Option d – Natural selection

Which of the following situations would most likely result in the highest rate of natural selection?

(a) Reproduction by asexual method

(b) Low mutation in a stable environment

(c) Little competition

(d) Reproduction by sexual method

Option d – Reproduction by sexual method

Genetic drift operates in

(a) large isolated populations

(b) small isolated populations

(c) fast reproductive populations

(d) slow reproductive populations

Option b – small isolated populations

The biological species concept of organisms is based on

(a) morphological traits

(b) evolutionary traits

(c) reproductive isolation

(d) geographical isolation

Option c – reproductive isolation

Living organisms are kept separate from closely related species inhabiting the same geographical region by a reproductive isolating mechanism called

(a) phylogenetic species concept

(b) morphological species concept

(c) genetic species concept

(d) biological species concept

Option d – biological species concept

The biological concept of species is mainly based on

(a) reproductive isolation

(b) morphological features only

(c) method of reproduction only

(d) morphology and method of reproduction

Option d – morphology and method of reproduction

Among the following, which one is not an ape?

(a) Gibbon

(b) Urangutan

(c) Gorilla

(d) Langur

Option d – Langur

The difference between Homo sapiens and Homo erectus was

(a) Homo sapiens originated in Africa, while Homo erectus originated in Asia.

(b) Homo erectus were much smaller in size than Homo sapiens.

(c) Homo erectus stayed in Africa, while Homo sapiens did not.

(d) The size of the brain of Homo erectus was smaller than that of Homo sapiens.

Option d – The size of the brain of Homo erectus was smaller than that of Homo sapiens

Homo erectus evolved about 1.7 million years ago. They used fire and tools and also used animal hides as clothing. The fossil of Homo erectus was named as

(a) Neanderthal man

(b) Cro-magnon man

(c) Java ape man

(d) Proconsul

Option c – Java ape man

Anthropoids evolved into

(a) apes, proconsul, and monkeys

(b) apes, Cro-magnon men, and old-world monkeys

(c) Proconsul, New World Monkeys, and Peking man

(d) new world monkeys, proconsul, and Homo habilis

Option a – apes, proconsul, and monkeys

Mammoth is the ancestor of

(a) dog

(b) horse

(c) camel

(d) elephant

Option d – elephant

The latest ancestor of modern humans is

(a) Java man

(b) Cro-Magnon man

(c) Neanderthal man

(d) Peking man

Option b – Cro-Magnon man

Double-helical structure of DNA was given by

(a) Jacob and Monod

(b) Watson and Crick

(c) H G Khorana

(d) None of the above

Option b – Watson and Crick

Mendel selected pea plants for his experiment because

(a) they are cheaper

(b) they are easily available

(c) they are of great economic importance

(d) they have contrasting traits

Option d – they have contrasting traits

Who is the father of modern genetics?

(a) Gregor Johann Mendel

(b) Hugo De Vries

(c) Charles Darwin

(d) Thomas Hunt Morgan

Option a – Gregor Johann Mendel

Mendel worked on

(a) edible pea

(b) wild pea

(c) garden pea

(d) pigeon pea

Option c – garden pea

Gregor Johann Mendel is famous for

(a) Cell Theory

(b) Mutation Principle

(c) Law of Heredity

(d) Heredity of acquired characters

Option c – Law of Heredity

The unit of heredity in our body is called

(a) Chromosome

(b) DNA

(c) Gene

(d) Nucleus

Option c – Gene

Which of the following is responsible for controlling the hereditary characteristics of living cells?

(a) Enzyme

(b) Hormone

(c) RNA

(d) DNA

Option d – DNA

Linkage was first suggested by

(a) Sutton and Boveri

(b) Morgan

(c) de Vries

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(d) Pasteur

Option b – Morgan

Linked genes are present on

(a) the same chromosome

(b) different chromosomes

(c) heterologous chromosomes

(d) paired chromosomes

Option a – the same chromosome

Mendel’s principles of inheritance are based on

(a) vegetative reproduction

(b) asexual reproduction

(c) sexual reproduction

(d) All of the above

Option c – sexual reproduction

Jumping genes, transposons, or movable genetic elements were discovered by Barbara McClintock in

(a) maize

(b) wheat

(c) barley

(d) rice

Option a – maize

Who is responsible for the sex determination of a child?

(a) Father

(b) Mother

(c) Both (a) and (b)

(d) None of the above

Option a – Father

Chromosomes can be counted best in

(a) Metaphase

(b) Early prophase

(c) Mid prophase

(d) Late prophase

Option a – Metaphase

An increase in age decreases

(a) crossing over

(b) linkage

(c) polyploidy

(d) mutations

Option a – crossing over

Genes present on Y-chromosomes are called

(a) holandric genes

(b) basic genes

(c) pleiotropic genes

(d) polygenic genes

Option a – holandric genes

Sex determination by environmental factors is commonly observed in

(a) Drosophila melanogaster

(b) Mirabilis jalapa

(c) Melandrium album

(d) Bonellia Viridis

Option d – Bonellia Viridis

By which combination of chromosomes will a child be male?

(a) X from male and X from female

(b) X from male and Y from female

(c) Y from male and X from female

(d) Y from male and Y from female

Option c – Y from male and X from female

The strength of the linkage between two genes is

(a) proportionate to the distance between them

(b) inversely proportionate to the distance between them

(c) dependent on the chromosomes

(d) dependent on the size of chromosomes

Option b – inversely proportionate to the distance between them

Linkage and crossing over are

(a) the same phenomena

(b) different phenomena

(c) opposite phenomena

(d) identical phenomena

Option c – opposite phenomena

Genes are made up of

(a) nucleic acids

(b) proteins

(c) carbohydrates

(d) lipids

Option a – nucleic acids

The cancer-causing gene is

(a) protooncogene

(b) oncogene

(c) transposon

(d) mutable gene

Option b – oncogene

Who among the following was awarded the Nobel Prize for the artificial synthesis of nucleic acids?

(a) Ochoa, Kornberg, and HG Khorana

(b) Jacob and Monod

(c) Gierer and Schwann

(d) Hershey and Aunt Julia

Option a – Ochoa, Kornberg, and HG Khorana

Change in the basic sequence of a gene is known as

(a) mutation

(b) transversion

(c) conjugation

(d) reproduction

Option a – mutation

Which phenomenon leads to the variation in DNA?

(a) DNA Mutation

(b) Linkage

(c) Both (a) and (b)

(d) Mitosis

Option a – DNA Mutation

Chromosomal aberrations are commonly found in

(a) cancer cells

(b) normal cells

(c) healthy cells

(d) autosomal cells

Option a – cancer cells

Point mutation arises due to a change in

(a) a single base of DNA

(b) a single base pair of DNA

(c) a segment of DNA

(d) a double base pair of DNA

Option a – a single base of DNA

A classical example of point mutation is

(a) sickle-cell anemia

(b) thalassemia

(c) cancer

(d) All of the above

Option a – sickle-cell anemia

Frameshift mutation arises due to

(a) deletion of a base pair of DNA

(b) insertion of a base pair of DNA

(c) Both (a) and (b)

(d) change in a single base pair of DNA

Option c – Both (a) and (b)

Mutagens are

(a) chemical agents that cause changes in DNA

(b) physical agents that cause mutations

(c) cancer-producing agents

(d) Both (a) and (b)

Option d – Both (a) and (b)

Genes located on mitochondrial DNA

(a) generally show maternal inheritance

(b) are always inherited from the male parent

(c) show biparental inheritance

(d) are not inherited like nuclear genes

Option a – generally show maternal inheritance

The number of chromosomes in a normal human body cell is

(a) 43

(b) 44

(c) 45

(d) 46

Option d – 46

Sexual reproduction causes genetic variation because of

(a) blending of genes

(b) chromosomal changes

(c) shuffling of genes

(d) All of the above

Option d – All of the above

Mutation is a phenomenon that results in the alteration of

(a) sequence

(b) carbohydrates

(c) proteins

(d) fat

Option a – sequence

Mutation may result in

(a) a change in genotype

(b) a change in phenotype

(c) a change in metabolism

(d) All of the above

Option d – All of the above

For a colorblind person, the red color appears as

(a) yellow

(b) blue

(c) green

(d) violet

Option c – green

Barr body is absent in somatic cells of

(a) Klinefelter syndrome individual.

(b) Triple X syndrome individual.

(c) Turner syndrome individual.

(d) Sub-human mammalian female individual.

Option c – Turner syndrome individual

Which of the following is an X-linked genetic disease?

(a) Becker’s muscular dystrophy

(b) Daltonism Color Blindness

(c) Martin-Bell syndrome

(d) All of the above

Option d – All of the above

Down’s syndrome is due to

(a) chromosome number increase in the 21st pair autosome.

(b) chromosome number decreases in the 21st pair autosome.

(c) chromosome number increases in the 18th pair autosome.

(d) chromosome number decreases in the 18th pair autosome.

Option a – chromosome number increase in the 21st pair autosome

Gynandromorph is

(a) male with female traits.

(b) female with male traits.

(c) half male and half female.

(d) None of the above

Option c – half male and half female

Which one of the following is not a genetic disorder?

(a) Color blindness

(b) Down’s syndrome

(c) Hemophilia

(d) Xerophthalmia

Option d – Xerophthalmia

Which one among the following is not correct about Down’s syndrome?

(a) It is a genetic disorder.

(b) Affected individual has early aging.

(c) Effected person has mental retardation.

(d) The affected person has a furrowed tongue.

Option b – Affected individual has early aging

The gene for color blindness is located on

(a) Y-chromosome

(b) 13th chromosome

(c) X-chromosome

(d) 21st chromosome

Option c – X-chromosome

Hemophilia is a genetic disorder that leads to

(a) a decrease in hemoglobin levels.

(b) rheumatic heart disease.

(c) decrease in WBC.

(d) prevent the clotting of blood.

Option d – prevent the clotting of blood

In the context of genetic disorders, consider the following. A woman suffers from color blindness, while her husband does not suffer from it. They have a son and a daughter. In this context, which one of the following statements is most probably correct?

(a) Both children suffer from color blindness.

(b) Daughter suffers from color blindness while son does not suffer from it.

(c) Both children do not suffer from color blindness.

(d) Son suffers from color blindness, while daughter does not suffer from it.

Option d – Son suffers from color blindness, while daughter does not suffer from it

Down’s syndrome is characterized by

(a) 21st trisomy

(b) two X and Y-chromosomes

(c) 19 trisomy

(d) only one X-chromosome

Option a – 21st trisomy

Gaucher’s disease is associated with abnormal metabolism of

(a) fat

(b) nucleic acid

(c) protein

(d) carbohydrate

Option a – fat

The absence of the Y-chromosome in human beings causes

(a) Turner’s syndrome

(b) Klinefelter’s syndrome

(c) Down’s syndrome

(d) No abnormality

Option a – Turner’s syndrome

Who synthesized DNA in vitro?

(a) Arthur Kornberg

(b) Robert Hooke

(c) Edward Jenner

(d) Joseph Lister

Option a – Arthur Kornberg

Who proposed the 3-D helical DNA model?

(a) Franklin and Wilkins

(b) Watson and Crick

(c) Yanofsky

(d) Meselson and Stani

Option b – Watson and Crick

DNA as genetic material was proved by

(a) Altman

(b) McLeod

(c) Fredrick Meischer

(d) Griffith

Option d – Griffith

In the genetic dictionary, there are 64 codons because

(a) 64 amino acids are to be coded

(b) 64 types of tRNA are present

(c) there are 44 non-sense codons and 20 sense codons

(d) the genetic code is triplet

Option d – the genetic code is triplet

The formation of RNA (mRNA) over a DNA template is called

(a) translation

(b) transcription

(c) reverse transcription

(d) initiation

Option b – transcription

Which of the following features of DNA makes it unequally suited to store and transmit genetic information from generation to generation?

(a) Complementarity of the two strands

(b) Double helix

(c) Number of base pairs per turn

(d) Sugar-phosphate backbone

Option b – Double helix

The number of DNA molecules per chromatid is

(a) one

(b) two

(c) three

(d) four

Option b – two

The nucleosome is

(a) histone proteins

(b) DNA wrapped around histones

(c) RNA wrapped around histones

(d) DNA wrapped around acidic protein

Option b – DNA wrapped around histones

In prokaryotes, multiple ribosomes (polysomes) participate in

(a) translation process

(b) transcription process

(c) linkage

(d) crossing over

Option a – translation process

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