Medical College Admission Test (MCAT) which is accepted by medical schools in US, Australia, Canada and Carribean Islands for making admission decision.The test assesses candidates critical analysis and reasoning skills, biological and biochemical foundations of living systems, psychological, social and biological foundations of behaviour and chemical and physical foundations of biological systems.
In this collection there will be many samples to practice this test
It will be so important to Medical students who wants to prepare for this test
Sample paper 1
Question: 1
Which photosynthetic pigment reflects yellow red light?
A. Chlorophyll A
B. Chlorophyll B
C. Carotenoid
D. Xanthophylls
E.
Phytochrome
Correct Answer: E. Phytochrome
Explanation:
Carotenoids are the photosynthetic plant pigments which reflect yellow red light. They contribute to
photosynthesis by transmitting the light energy which is absorbed from chlorophyll. They are also
known as orange photosynthetic pigment.
Question: 2
Which of the following is an example for denitrifying bacteria?
A. Nitrosomonas sp
B. Nitrobacter sp
C. Rhizobium sp
D. Pseodomonas sp
E. All of the above
Correct Answer: D. Pseodomonas sp
Explanation:
Denitrifiication is a process of reduction of nitrate to molecular nitrogen by microbial action.
Pseodomonas sp is an example of denitrifying bacteria. Nitrosomonas sp and Nitrobacter sp are
examples of nitrifying bacteria. Rhizobium sp is an example for nitrogen fixing bacteria.
Question: 3
Which of the following glands secrete the FSH hormone?
A. Islets of Langerhans
B. Anterior pituitary gland
C. Posterior pituitary gland
D. Parathyroid gland
E. Testis
Correct Answer: B. Anterior pituitary gland
Explanation:
The anterior pituitary gland secretes follicle stimulating hormone (FSH). In male, FSH stimulates
spermatogenesis and in females it stimulates the growth of ovarian follicles. Anterior pituitary gland
also secretes luteinising hormone, prolactin, thyroid stimulating hormone, adrenocorticotrophic
hormone and growth hormone.
Question: 4
Which among the following processes results in dark coloured amorphous substance during
decomposition in soil?
A. Mineralization
B. Fragmentation
C. Leaching
D. Humification
E. None of the above
Correct Answer: D. Humification
Explanation:
Decomposition in soil results in humification and mineralization. Humification refers to the
accumulation of dark coloured amorphous substance called humus which serves as a reservoir of
nutrients. It resists microbial action and so decomposition takes place very slowly. Further
degradation of humus by microbes leads to mineralization.
Question: 5
By which of the following processes, does the exchange of DNA occur due to pairing of two
chromosomes?
A. Mutation
B. Crossing over
C. Mitosis
D. Transduction
E. Transformation
Correct Answer: B. Crossing over
Explanation:
Crossing over which occurs during meiosis, is a process of exchange of genetic material from one
chromosome to other when they pair with each other. Mitosis is somatic cell division, which takes
place through phases. Mutation occurs by change in the nuclotide sequence. Transduction is the
process of transfer of DNA from one bacterium to other by bacteriophages. Transformation refers to
the alteration of DNA that results due to transfer of foreign DNA.
Question: 6
Archaeopteryx belongs to the
A. Jurassic era
B. Deuonian era
C. Cretaceous era
D. Triassic era
E. None of these
Correct Answer: A. Jurassic era
Explanation:
Archaeopteryx lived in the Jurassic era. Archaeopteryx shared some similarity with mesozoic
dinosaurs. These include sharp teeth, long bony tail, three fingers with claws etc.
Question: 7
Spleen is an organ of which of the following systems?
A. Digestive system
B. Endocrine system
C. Excretory system
D. Lymphatic system
E. Respiratory system
Correct Answer: D. Lymphatic system
Explanation:
Lymphatic system helps in balancing the body’s fluid level and it is closely associated with immune
system to act against infection. Its components are thymus, bone marrow, spleen, lymph nodes and
lymph. The B-lymphocytes that participate in defense mechanism get accumulated and get matured
in spleen, a lymphatic organ.
Question: 8
A region with high level of endemic species that is under threat from humans is called
A. Botanical garden
B. Wild life Sanctuaries
C. Zoos
D. Biodiversity hotspot
E. None of these
Correct Answer: D. Biodiversity hotspot
Explanation:
Hotspots are the regions with significant reservoir of biodiversity and high level of endemic species
that is under threat from humans. Botanical garden is a place where plants are cultivated for
education, scientific and ornamental purposes. Wildlife sanctuaries are areas in natural conditions
which are reserved for the conservation of animals within which human activity is inhibited. Zoo refers
to an institution in which living animals are kept and usually exhibited to the public.
Question: 9
G protein receptors have
A. 5 transmembrane ß helices
B. 7 transmembrane a helices
C. 5 transmembrane a helices
D. 6 transmembrane a helices
E. 7 transmembrane ß helices
Correct Answer: B. 7 transmembrane a helices
Explanation:
G protein receptors have 7 transmembrane a helices that traverse the plasma membrane and are
connected by loops of varying length. The carboxy-terminus is located inside the cell and the amino
terminus of the receptor is located outside the cell.
Question: 10
Which of the following metals is responsible for Itai-itai disease?
A. Arsenic
B. Cadmium
C. Lead
D. Mercury
E. Uranium
Correct Answer: B. Cadmium
Explanation:
Itai-itai is a disease caused by cadmium poisoning. The symptoms of the disease include weak and
brittle bones. The disease is initially characterized by spinal and leg bone pain. It also includes
complications like kidney failure.
Question: 11
Which of the following produces angiotensinogen?
A. Liver
B. Pancreas
C. Kidney
D. Thyroid gland
E. Pituitary gland
Correct Answer: A. Liver
Explanation:
Angiotensinogen is a serum globulin produced by liver. Angiotensinogen is the precursor of
angiotensin, an oligopeptide involved in regulating blood pressure. Angiotensin increases blood
pressure by enhancing vasoconstriction. Angiotensinogen belongs to the serpin family
Question: 12
Deposition of sediments or sediment accumulation is known as
A. Profundation
B. Aggradation
C. Biocoenosis
D. Trophic succession
E. None of these
Correct Answer: B. Aggradation
Explanation:
Aggradation is the accumulation of sediments resulting in an elevation of land. Aggradation occurs
when the deposition of sediments exceeds the amount of material the system can transport.
Biocoenosis describes the interacting organisms in a habitat.
Question: 13
What is the inactivated X chromosome in females called?
A. Barr body
B. Heterochromatin
C. Euchromatin
D. Nucleosome
E. None of the above
Correct Answer: A. Barr body
Explanation:
The inactivated X chromosome in females is called Barr body. Barr body was first discovered by Dr.
Murray L. Barr. Inactivation of an X chromosome occurs due to dosage compensation.
Question: 14
Lowest area of water body is called
A. Littoral zone
B. Aphotic zone
C. Photic zone
D. Benthic zone
E. None of the above
Correct Answer: D. Benthic zone
Explanation:
Lowest area of water body such as ocean or lake is called as benthic zone. Organisms living in this
zone are called as Benthos. Littoral zone is the region of lake, sea or ocean. Aphotic zone is the zone
of water body which lacks sunlight. Photic zone is the upper part of water body to which enough
sunlight penetrates and permits photosynthesis.
Question: 15
The type of petrification in which the organic matter of the dead body is replaced by double
carbonates of calcium and magnesium is called
A. Silicification
B. Pyritization
C. Carbonization
D. Dolomitization
E. None of these
Correct Answer: D. Dolomitization
Explanation:
In the process of fossil formation, the replacement of dead organic matter by the dissolved minerals is
called petrification. It is of different types according to the mineral deposited. Silicification is the
replacement of original dead matter by silica; Pyritization is the replacement by iron pyrites. When
carbon compounds are deposited, it is called carbonization. In dolomitization, magnesium carbonate
replaces the calcium carbonate that was already deposited in dead matter.
Sample paper 2
Question: 1
An animal with two successive sets of teeth is called
A. Diphyodont
B. Monophyodont
C. Heterodont
D. Polyphodont
E. None of the above
Correct Answer: A. Diphyodont
Explanation:
Diphyodonts have two sets of teeth namely deciduous teeth and permanent teeth. The deciduous
teeth are replaced by permanent teeth. Monophyodonts are the organisms having one set of teeth
which are not replaced at later stages of life. Heterodonts are the organisms which possess different
types of teeth. Polyphodonts are the organisms whose teeth are continuously replaced.
Question: 2
Area where the movement of water is from the surface to the ground water system is called
A. Catchment area
B. Springs
C. Aquifer
D. Artesian well
E. None of these
Correct Answer: A. Catchment area
Explanation:
Catchment area is the area where the net water movement is from the surface to the ground water
system. Springs are the area where ground water reaches the surface and runs off. Aquifer is the
rocky body through which ground water flows. Artesian well is a well drilled into an aquifier that has
sufficient hydrostatic pressure to force water up into it.
Question: 3
The word ‘Savanna’ refers to
A. Temperate grasslands
B. Tropical forests
C. Deserts
D. Artic region
E. Tropical grasslands
Correct Answer: E. Tropical grasslands
Explanation:
Tropical grasslands are called as Savanna. It is located near the equator. It is scattered with shrubs
and isolated trees. Savanna
covers approximately 20% of earth’s land area.
Question: 4
The structure of a protein with linear sequence of amino acids is called
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
E. None of the above
Correct Answer: A. Primary structure
Explanation:
Proteins which have a linear sequence of amino acids in a polypeptide chain are primary structured
proteins that are held together by peptide or covalent bonds. Secondary structure is the folding of
primary sequence of amino acids into specific structures which are bound together by hydrogen
bonds. Three-dimensional structure of a protein molecule is the tertiary structure and the three-
dimensional structure and arrangement of more than one protein subunit is the quaternary structure.
Question: 5
The type of sex determination found in Crepidula fornicata is
A. Temperature dependent
B. Location dependent
C. Chromosome dependent
D. Water dependent
E. Soil dependent
Correct Answer: B. Location dependent
Explanation:
There are certain species of animals whose sex is determined by environmental factors rather than
the chromosomes. One such species is Crepidula fornicata in which location plays main role in
determining their sex. Temperature dependent sex determination is seen in reptiles such as
crocodiles and turtles.
Question: 6
Which of the following blood components carries dissolved nutrients?
A. Red blood cells
B. White blood cells
C. Platelets
D. Plasma
E. None of the above
Correct Answer: D. Plasma
Explanation:
Plasma is a straw-yellow colored fluid which constitutes 55% of blood. Plasma circulates dissolved
nutrients such as glucose, amino acids, fatty acids etc. and it removes the waste products of
metabolism. It is an aqueous solution consisting 90-93% of water.
Question: 7
Which of the following fixes nitrogen?
A. Azotobacter
B. Anabaena
C. Nostoc
D. Calothrix
E. All of the above
Correct Answer: E. All of the above
Explanation:
Azotobacter, anabaena, nostoc and calothrix are free living nitrogen fixing bacteria. Azotobacter can
be found in the soil. Anabaena, nostoc and calothrixlives in water as well as on moist rocks.
Question: 8
The substance that inactivates an enzyme by denaturing it is called
A. Feedback inhibitor
B. Competitive inhibitor
C. Allosteric inhibitor
D. Irreversible inhibitor
E. None of these
Correct Answer: D. Irreversible inhibitor
Explanation:
Irreversible inhibitors modify or denature the enzyme irreversibly. The other inhibitors will not denature
the enzyme. DIFP can irreversibly inhibit serine proteases.
Question: 9
Glucocorticoid is produced by
A. Adrenal medulla
B. Adrenal cortex
C. Pancreas
D. Pineal gland
E. Pituitary gland
Correct Answer: B. Adrenal cortex
Explanation:
Glucocorticoids are produced by the adrenal cortex. Glucocorticoids are a class of steroid hormones
that bind to the glucocorticoid receptor. They stimulate gluconeogenesis and increase the blood
glucose level.
Question: 10
In which part of the human body are Nissl’s granules present?
A. Osteoblasts
B. Neuron
C. Chondroblasts
D. Goblet cell
E. All of the above
Correct Answer: B. Neuron
Explanation:
Nissl’s granules are present in the cell body of neuron. These are the site of protein synthesis in
neurons and are made of rough endoplasmic reticulum and ribosome. It was named after Franz Nissl.
Question: 11
Rhizobium is a bacterium that lives in the root nodules of leguminous plants. This is an
example for ________
A. Mutualism
B. Commensalism
C. Parasitism
D. Predatism
E. None of the above
Correct Answer: A. Mutualism
Explanation:
Mutualism is an association between organisms in which both organisms are benefited. Rhizobium
lives in the root of legumes and forms nodule. Rhizobium helps to fix atmospheric nitrogen in
leguminous plants. Commensalism is a type of association in which one organism benefits and the
other is unaffected. Parasitism is a type of association in which one organism is benefited (parasite)
and the other (host) is adversely affected. Predatism is a state of preying on other organisms.
Question: 12
Malleus, incus and stapes are collectively called
A. Ear Ossicle
B. Cranial bone
C. Sternum bone
D. Facial bone
E. None of the above
Correct Answer: A. Ear Ossicle
Explanation:
Malleus, incus and stapes together form the ear ossicle. They are present in the middle ear space
and are the smallest bone in human body. Sound-induced vibrations of the tympanic membrane (ear
drum) are transmitted through malleus, incus and stapes respectively to the inner ear where it is
interpreted as sound.
Question: 13
Which of the following comes under the domain eukarya?
A. Plantae
B. Animalia
C. Protista
D. Fungi
E. All of the above
Correct Answer: E. All of the above
Explanation:
Early biologists classified organisms into three major domains namely bacteria, archae and eukarya.
Eukarya is a domain which consists of protists (unicellular or multicellular, colonial, diverse
reproductive cycles) fungi (multicellular or unicellular, chemoheterotrophic, decomposers, unique
reproductive cycles) plantae (photosynthetic autotrophs, multicellular, with cell wall) and animalia
(chemoheterotrophs, without cell wall).
Question: 14
Which of the following is secreted by the pancreas?
A. Elastase
B. Carboxypeptidase
C. Amylase
D. Ribonuclease
E. All of the above
Correct Answer: E. All of the above
Explanation:
Elastase, carboxypeptidase, ribonuclease and amylase are secreted by the pancreas. Elastase
breaks down elastin. Carboxypeptidase cleaves peptide bond at the carboxyl terminal. Ribonuclease
cleaves RNA molecules.
Question: 15
Nematocyst is a characteristic feature of
A. Echinoderms
B. Arthropods
C. Molluscs
D. Cnidarians
E. Porifera
Correct Answer: D. Cnidarians
Explanation:
Nematocysts are sub-cellular organelle found in cnidocytes. They carry toxic substances.
Nematocysts are powerful weapons and a single nematocyst is sufficient to paralyse smaller
organisms. The box jellyfish has one of the most toxic nematocysts.
Sample paper 3
Question: 1
The semi fluid mass of partly digested food is called chyme. Formation of chyme takes place
in
A. Mouth
B. Small intestine
C. Large intestine
D. Liver
E. Stomach
Correct Answer: E. Stomach
Explanation:
The semifluid mass of partly digested food in stomach before entering duodenum is called as chyme.
The food mixes thoroughly with the acidic gastric juice of the stomach by the churning movements of
its muscular wall and results in the formation of chyme.
Question: 2
Which of the following kinds of signalling occurs when the cells communicate with each other
through direct contact?
A. Endocrine signalling
B. Paracrine signalling
C. Juxtacrine signalling
D. Intracrine signalling
E. None of the above
Correct Answer: C. Juxtacrine signalling
Explanation:
Juxtacrine signalling is an example of intercellular communication where cells communicate through
direct contact. Endocrine signalling occurs between cells that are present over large distance.
Paracrine signalling occurs between cells that are present over short distance. In intracrine signalling
the signals are produced inside the target cell.
Question: 3
Chains of sarcomeres in muscles are organized into
A. Sarcolemma
B. Sarcoplasm
C. Myoblasts
D. Myofibrils
E. Fascia
Correct Answer: D. Myofibrils
Explanation:
Sarcolemma is the muscle cell membrane and the sarcoplasm is the cytoplasm of muscle cell. The
connective tissue outside the epimysium (sheath of connective tissue that surrounds each muscle)
that separates two muscles is called the fascia. The parallelly arranged filaments in the sarcoplasm,
which are arranged by the chains of sarcomeres are called myofibrils. The embryonic cell that gives
rise to muscle cell is called myoblast.
Question: 4
Which of the given organelles is not present in animal cells?
A. Nucleus
B. Golgi apparatus
C. Lysosome
D. Leucoplast
E. Mitochondria
Correct Answer: D. Leucoplast
Explanation:
Among the given organelles, leucoplasts are present only in plant cells but not in animal cells. They
are the sites responsible for storage of proteins, starch and lipid molecules.
Question: 5
The adipose tissue plays role in
A. Pigment storage
B. Fat storage
C. Stretching
D. Binding organs
E. None of the above
Correct Answer: B. Fat storage
Explanation:
Adipose is a type of connective tissue whose cells get expanded with fat droplets and hence the
nucleus and cytoplasm of this cell are pushed towards edges to form ring like structure. Adipose
tissue provides insulation, stores fat and gives protection. Pigmented connective tissue that is present
in eyes and skin is meant to store pigments. Elastic connective tissue helps in stretching. Dense
connective tissues bind the organs together.
Question: 6
The shortest phase of cardiac cycle is
A. Atrial systole
B. Ventricular systole
C. Atrial diastole
D. Ventricular diastole
E. Equal duration for A and B
Correct Answer: A. Atrial systole
Explanation:
Atrial systole is the shortest phase of cardiac cycle. Atrial systole gets completed in 0.1 seconds.
Duration of atrial diastole is 0.7 seconds. Duration of ventricular systole and diastole is 0.3 seconds
and 0.5 seconds respectively.
Question: 7
Implantation is the process where
A. The blastocyst becomes embedded in the endometrium.
B. The sperm nuclei fuse with the egg nuclei
C. Loss of the lining of endometrium takes place
D. The gastrula becomes embedded in the endometrium
E. None of the above
Correct Answer: A. The blastocyst becomes embedded in the endometrium.
Explanation:
The process of embedding of blastocyst to the endometrium is known as implantation. The fetus
receives oxygen and nutrients from mother due to this adhesion. The blastula differentiates into three
layers namely endoderm, mesoderm and ectoderm to form gastrula.
Question: 8
Acceptor stem is present in
A. tRNA
B. rRNA
C. siRNA
D. mRNA
E. hnRNA
Correct Answer: A. tRNA
Explanation:
tRNA consists of variable loop, TΨC loop, anticodon loop, D-loop and acceptor stem. The anticodon
loop is needed for binding to the mRNA. Acceptor stem is needed for attaching the amino acid.
Question: 9
In the process of animal development, gastrulation is represented as
A. Gamete to zygote
B. Zygote to blastula
C. Blastula to gastrula
D. Gastrula to neurula
E. None of the above
Correct Answer: D. Gastrula to neurula
Explanation:
Gastrulation is the stage in development of an embryo, in which three distinct germ layers (ectoderm,
endoderm and mesoderm) are formed. It takes place next to cleavage, in which blastula formation
occurs from zygote. After gastrulation is neurulation which is the typical organogenesis.
Question: 10
A measure of the disorder or randomness in a closed system is called
A. Entropy
B. Enthalpy
C. Potential energy
D. Kinetic energy
E. None of the above
Correct Answer: A. Entropy
Explanation:
Entropy is the measure of the disorder or randomness which is derived from the second law of
thermodynamics. Enthalpy is the sum of the internal energy of the system plus the product of its
volume multiplied by the pressure. Potential energy is the ability of a system to do work due to its
position or internal structure. Kinetic energy of an object is the energy it possesses due to its motion.
Question: 11
In amphibian, vitellogenin is synthesized by
A. Oocyte
B. Uterus
C. Liver
D. Spleen
E. Intestine
Correct Answer: C. Liver
Explanation:
Vitellogenin is a precursor protein that is expressed in the females of all oviparous species including
amphibians, fishes, reptiles and birds. Vitellogenin is a glycolipoprotein secreted by the liver.
Vitellogenin can be expressed by the male (in a few species) in the presence of estrogenic endocrine
disruptive chemicals. Vitellogenin precursors provide the major egg yolk proteins which serves as
nutrients.
Question: 12
The state of a neuron which inhibits the generation of action potential is said to be
A. Depolarized
B. Repolarized
C. Hyperpolarized
D. Resting potential
E. A, B and D
Correct Answer: C. Hyperpolarized.
Explanation:
Resting potential is the state of a neuron which is not under any stimulus. The normal resting potential
of human nerves is -70 mV. When a neuron
receives stimulus, the cell’s interior will be depolarized
with influx of Na+ ions which will result in action potential. Immediately after the generation of action
potential the cell is hyperpolarized; that makes the cell more negative and keeps the neuron in a
refractory period so that the next action potential cannot generate. Next is the repolarization i.e.
neuron will come to its original resting state.
Question: 13
The term ‘staminate’ refers to
A. Unisexual male flower bearing stamens
B. Unisexual female flower bearing pistils
C. Bisexual flower bearing stamens and pistils
D. Unisexual male flower bearing pistils
E. Unisexual female flower bearing stamens
Correct Answer: A. Unisexual male flower bearing stamens
Explanation:
Staminate refers to the male flowers that bear only stamens but lack pistils. Pistillate refers to the
female flowers that bear only pistils but lack stamen.
Question: 14
Which protein is targeted by cholera toxin?
A. G proteins
B. Actin
C. Permease
D. Vinculin
E. Vitonectin
Correct Answer: G proteins
Explanation:
Cholera toxin inhibits the GTPase activity of the G protein. So the protein always remains in the
activated state. This results in the constant activation of adenylate cyclase enzyme. cAMP level rises
due to the activation of adenylate cyclase. This eventually leads to secretion of water, sodium ions etc
to the intestinal lumen.
Question: 15
The process of delivery of foetus is called
A. Implantation
B. Lactation
C. Parturition
D. Fertilization
E. None of the above
Correct Answer: C. Parturition
Explanation:
The process in which the foetus is delivered is called as parturition. Oxytocin is released during
parturition which is responsible for the contraction of uterus.
Sample paper 5
Question: 1
A plant that lives in calcium- rich soil is called
A. Calcifuge
B. Calciplant
C. Limnophyte
D. Agarophyte
E. Calcicole
Correct Answer: E. Calcicole
Explanation:
Calcicole is a plant that grows well in calcareous soil (lime-rich soil). Calciphile and calciphyte are the
other terms by which such a plant is referred. Some plants cannot tolerate more calcium so they are
not capable of living in lime-rich soil. Such plants are called calcifuges. Limnophytes are the plants
that grow in marshy conditions and in shallow water. Agarophyte is a sea weed from which agar is
produced.
Question: 2
Highly repeated eukaryotic non-coding DNA sequences that are clustered in heterochromatin
are
A. Mitochondrial DNA
B. Spacer DNA
C. Satellite DNA
D. Single copy DNA
E. Complementary DNA
Correct Answer: C. Satellite DNA
Explanation:
Satellite DNA is a highly repeated eukaryotic non-coding DNA sequence that is clustered in
heterochromatin region of chromosome. Mitochondrial DNA is located in organelles called
mitochondria. Spacer DNA is the sequence of nucleotides that occurs between genes. Single copy
DNA are the nucleotide sequences present once in haploid genome. DNA transcribed from a specific
mRNA through the action of the enzyme reverse transcriptase is called complementary DNA.
Question: 3
Inner mitochondrial membrane has high amounts of
A. Cholesterol
B. Cardiolipin
C. Ergosterol
D. Stigmasterol
E. Galactolipids
Correct Answer: B. Cardiolipin
Explanation:
Cardiolipin is a glycerophospholipid. It is seen at high concentration in the inner membrane of
mitochondria. Its concentration is very low in plasma membrane. Ergosterols are found widely in the
plasma membrane of fungi. Stigmasterol is found in plant cell membrane.
Question: 4
Haemocoel is a characteristic feature of phylum _____________
A. Porifera
B. Cnidaria
C. Mammalia
D. Arthropoda
E. Platyhelminthes
Correct Answer: D. Arthropoda
Explanation:
Haemocoel is a cavity in the organs of arthropods and molluscs through which blood circulates. It
develops from part of blood system.
Question: 5
Maturation of sperm takes place in which part of male reproductive system?
A. Prostate gland
B. Seminal vesicles
C. Vas deferens
D. Epididymis
E. Scrotal sac
Correct Answer: D. Epididymis
Explanation:
Epididymis is a coiled tube attached to the backside of testis. It is present within the scrotum. Sperms
take longer time to pass through this tube. The maturation of spermatozoa takes place here and later
moves to vas deferens.
Question: 6
The type of mutation that codes for a stop codon is called
A. Misscense mutation
B. Nonsense mutation
C. Silent mutation
D. Both A and C
E. All of the above
Correct Answer: B. Nonsense mutation
Explanation:
In nonsense mutation, a mutation in the DNA sequence stops the translation and results in an
incomplete and non functional protein. It codes for a stop codon. A mutation which causes insertion of
different amino acid in the polypeptide chain which results in an altered protein is called as misscense
mutation. Silent mutation is a type of mutation where the mutation in DNA will not result in amino acid
change.
Question: 7
Which of the following is called as pacemaker?
A. SAN (sino-atrial node)
B. AVN (atrio-ventricular node)
C. Right Ventricle
D. Aorta
E. Pulmonary vein
Correct Answer: A. SAN (sino-atrial node)
Explanation:
Sino-atrial node is a patch of tissue present in the right upper corner of the right atrium which is
responsible for initiating and maintaining the rhythmic contractile activity of the heart. Each wave of
excitation begins at this region and acts as stimulus for next wave of excitation and hence SAN is
called pacemaker.
Question: 8
Disulphide bond can be formed between
A. Two threonine molecules
B. Two serine molecules
C. Two cysteine molecules
D. A Tyrosine and Glycine molecule
E. An aspartic acid and glutamic acid molecule
Correct Answer: C. Two cysteine molecules
Explanation:
Disulphide bond is a covalent bond formed by the oxidation of two SH groups that are attached to
cysteine molecules. It can be inter or intra molecular bridges. Cysteine is the only amino acid that
have sulfhydryl group.
Question: 9
The malarial parasite plasmodium is
A. An amoeboid protozoan
B. A flagellated protozoan
C. A ciliated protozoan
D. A sporozoan
E. Both B and D
Correct Answer: D. A sporozoan
Explanation:
Plasmodium is a protozoan which is a causative organism of malaria. It has no locomotory organ and
it belongs to the class sporozoa. Sporozoans are also called as apicomplexa since they share an
apical complex of microtubules at one end. They have an infectious spore
–like stage in their life
cycle.
Question: 10
Cuticles of annelids are made of
A. Chitin
B. Collagen fibres
C. Calcium carbonate
D. Pectins
E. None of these
Correct Answer: B. Collagen fibres
Explanation:
Cuticles of annelids are made of collagen fibres. Collagen is secreted by the epidermis. Chitin is
present in the exoskeleton of arthropods. Pectin is a structural polysaccharide present in primary wall
of plants.
Question: 11
The method used to predict genotypic and phenotypic ratios of progeny from a genetic cross
is called
A. Punnett square
B. Chi square
C. Friedman test
D. Paired t test
E. None of the above
Correct Answer: A. Punnett square
Explanation:
Punnett square, multiplication rule and addition rule are the methods used for determining the
outcome of a genetic cross. The rest of the given methods are statistical methods.
Question: 12
The gametophyte of fern is called
A. Prothallus
B. Thallus
C. Hyphae
D. Conidia
E. Haustoria
Correct Answer: A. Prothallus