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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
(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
(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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