Download (Association of American Medical Colleges) (AAMC) organizes MCAT Medical College Admission For Medical Entrance Exam Biological Paper II Model Paper with Answers
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 cel 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.
This post was last modified on 19 October 2021