Download (Association of American Medical Colleges) (AAMC) organizes MCAT Medical College Admission For Medical Entrance Exam Biological Paper V Model Paper with Answers
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
Explanation:
The gametophyte of a Pteridophyte such as fern is called as prothallus. It is a small, greenish heart-
shaped structure that produces male and female gametes. Thallus is the plant body of algae and
other lower organisms that is composed of filaments. The filamentous body of fungi is called as
hyphae. Conidia are the asexually produced fungal spores. Haustoria are the specialized absorbing
structures of parasitic plants.
Question: 13
Casuarina flowers exhibit
A. Porogamy
B. Chalazogamy
C. Apogamy
D. Mesogamy
E. Acrogamy
Correct Answer: B. Chalazogamy
Explanation:
Chalazogamy is a type of fertilization in which the pollen tube penetrates into the embryo sac through
the chalaza instead of entering through the micropyle (porogamy). Chalazogamy can be seen in
flowers of casuarina.
Question: 14
Which of the following mechanisms uses ATP molecule during transport across cell
membrane?
A. Diffusion
B. Passive transport
C. Osmosis
D. Active transport
E. All the above
Correct Answer: D. Active transport
Explanation:
Pumping of molecules or ions through a membrane against their concentration gradient is called
active transport. This requires a transmembrane protein called transporter and energy in the form of
ATP. In diffusion, passive transport and osmosis the movement of molecules occurs down its
concentration gradient. Osmosis and diffusion are types of passive transport.
Question: 15
Phenylketonuria is caused by a mutation in the gene coding for
A. Pyruvate carboxylase
B. Phenylalanine hydroxylase
C. Homogentisate dioxygenase
D. Glutaryl dehydrogenase
E. None of these
Correct Answer: B. Phenylalanine hydroxylase
Explanation:
Absence of phenylalanine hydroxylase enzyme causes phenylketonuria. Phenylalanine hydroxylase
(PAH) is a hepatic enzyme needed for phenylalanine metabolism. In the absence of PAH,
phenylalanine accumulates and is converted to phenyl pyruvate (also called as phenyl ketone).
Absence of homogentisate dioxygenase causes alkaptonuria.
This post was last modified on 19 October 2021