Category: Life Sciences Objective Questions

Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Mendel’s Principles”.

1. Who is known as the Father of Genetics?
A. Erich Tschemark
B. Carl Correns
C. Gregor Johann Mendel
D. Hugo de Vries
Answer: C
Clarification: Gregor Johann Mendel was an Austrian monk, who is known as the Father of Genetics. He published the principle of inheritance in 1856 which are popularly known as Mendel’s law. The rest of the three biologist rediscovered Mendel’s work in 1900.

2. Mendel discovered factors which remain its identity in a hybrid, these factors are _______
A. Genes
B. Alleles
C. DNA
D. Chromosomes
Answer: A
Clarification: Mendel discovered that individual traits retain their physical identity during hybrid formation when inherited as discrete factors. These factors are known as genes, which is also a unit of heredity.

3. Which of the following specimen was chosen by Mendel for his experiment?
A. Drosophila
B. Fly
C. Rat
D. Pisum sativum
Answer: D
Clarification: Pisum sativum is commonly known as a garden pea. Mendel chose this species due to its various advantages.

4. Mark the INCORRECT statement about Pisum sativum?
A. Long life cycle
B. Easy hybridization
C. Bisexual flower
D. Well-defined discrete characters
Answer: A
Clarification: Long life cycle is incorrect as pea has a relatively short life cycle and easy to cultivate. It also undergoes self fertilization process.

5. What is an allele?
A. Characteristics of an organism
B. Alternate forms of genes
C. Homologous chromosomes
D. Pair of centrioles
Answer: B
Clarification: Alleles are the alternate forms of genes present at the corresponding position on homologous chromosomes and maintain the same characteristics.

6. Reverse genetics is the evaluation of phenotype by studying the genotype.
A. True
B. False
Answer: A
Clarification: There are basically two types of genetics, one is forward genetics where the genotype is detected from the phenotype and the second one is reverse genetics where genotype inferred the phenotype of an organism.

7. Which of the following is NOT Mendel’s law of inheritance?
A. Law of dominance
B. Law of segregation
C. Law of hetrozygous
D. Law of independent assortment
Answer: C
Clarification: Law of hetrozygous is not the law of inheritance proposed by Mendel. Mendel had given three laws of inheritance which included law of dominance, law of segregation of gametes, and the law of independent assortment.

8. Out of the following, which law is also known as the law of purity of gametes?
A. Law of co-dominance
B. Law of independent assortment
C. Law of segregation
D. Law of dominance
Answer: C
Clarification: Law of segregation is also known as law of purity of gametes as gametes are always remained pure by separating the genes or factors at the time of gamete formation.

9. Name the cross by which law of independent assortment inferred.
A. Dihybrid cross
B. Monohybrid cross
C. Test cross
D. Back cross
Answer: A
Clarification: Dihybrid cross is the cross which involves the analysis of two independent traits. This law shows that during gametogenesis, assortment of one pair of genes is independent to the other pair.

10. Which of the following is an example of incomplete dominance?
A. AB blood group
B. Mirabilis jalapa
C. Shape of crown in poultry
D. Mouse coat colour
Answer: B
Clarification: The semidominant allele produces its biochemical products in lesser quantity in comparison to a dominant allele. Thus the heterozygote is of intermediate intensity. Example: cross of red and white flower gives pink flower.

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Life Sciences Questions and Answers for Entrance exams focuses on “Fibrous and Globular Proteins”.

1. What is the fundamental unit of collagen?
A. Tropocollagen
B. Hydroxyproline
C. Hydroxylysine
D. Glycine
Answer: A
Clarification: A typical collagen is long, stiff, inelastic and triple-stranded helical structure and is made up of tropocollagen. Tropocollagen consists of 3-coiled α chains. While hydroxylysine, hydroxyproline, and glycine are the amino acid sequence of tropocollagen.

2. Name the vitamins which cause scurvy.
A. Vitamin B
B. Vitamin B3
C. Vitamin C
D. Vitamin K
Answer: C
Clarification: Scurvy is a disease that affects the structure of collagen. It occurs due to impaired synthesis of collagen which results due to deficiencies of prolyl and lysyl hydroxylases.

3. Arrange the following sequence of collagen synthesis in the correct order.
1) The entrance of polypeptide into the rough endoplasmic reticulum
2) Packaged in to transport vesicle
3) Hydroxylation of lysyl and prolyl residues
4) Formation of tropocollagen
5) Covalent cross-linking of tropocollagen
6) Collection of fibrils
A. 2, 3, 4, 1, 6, 5
B. 4, 3, 2, 1, 5, 6
C. 1, 2, 3, 4, 6, 5
D. 1, 3, 4, 2, 5, 6
Answer: D
Clarification: Biosynthesis of collagen starts with the entry of polypeptides which further involves the formation tropocollagen by hydroxylation of prolyl and lysyl residues. Once tropocollagen is formed, it is packed in to transport vesicle and undergo exocytosis. Fibrils are formed by the lateral covalent cross-linking of tropocollagens.

4. Name the protein which is responsible for extensibility and elasticity of connective tissues.
A. Collagen
B. Elastin
C. Actin
D. Keratin
Answer: B
Clarification: Elastin is the second major protein present in the extracellular matrix, due to its high hydrophobic nature it constitutes extensibility and elasticity to the connective tissues. It is also considered as the main component of elastic fibers found in a ligament.

5. Which of these type of curve shows the oxygen binding capacity of hemoglobin?
A. Hyperbolic curve
B. Sigmoidal curve
C. Exponential curve
D. Linear curve
Answer: B
Clarification: A single molecule of hemoglobin binds up to four molecules of oxygen (Hb+4O₂ = Hb(O₂)₄). The sigmoidal curve shows the cooperativity in binding of oxygen and hemoglobin. This curve is a plot between the fractional saturation of hemoglobin versus the partial pressure of oxygen.

6. Oxygen affinity for hemoglobin is affected by Ph and this phenomenon is known as Bohr’s effect.
A. True
B. False
Answer: A
Clarification: PH has a strong effect on the oxygen affinity of hemoglobin. Lowering of Ph reduces the oxygen affinity of hemoglobin which shifts the sigmoidal curve to the right which and it shows that more partial pressure of oxygen is required for hemoglobin to bind the given amount of oxygen.

7. What is the function of myoglobin?
A. Oxygen storage
B. Oxygen carrier
C. Antioxidant
D. Oxidant
Answer: A
Clarification: Myoglobin bind with one oxygen molecule and functions as an oxygen storage protein. Dissociation of myoglobin from oxygen is given by
MbO₂ = Mb + O₂.

8. What is the name of protein which is found in nail, hair, and horns?
A. Myoglobin
B. Hemoglobin
C. Keratin
D. Collagen
Answer: C
Clarification: Keratin is the fibrous protein present in the eukaryotes. They have been further classified into α-keratin and β-keratin, in which α-keratin is tough and insoluble and constitute almost the entire dry weight of hair, wool, nail, claws, horn, hooves etc.

9. In which iron(Fe) state myoglobin binds to the oxygen?
A. Fe²⁺
B. Fe³⁺
C. Fe
D. Fe⁴⁺
Answer: A
Clarification: Myoglobin only in the Fe²⁺ state can bind with oxygen as the iron atom has six co-ordination bonds, 4 in the flat and two in a perpendicular state to the porphyrin ring. The oxygen binding site is present on the other side of six coordination position.

10. What is the shape of the oxygen dissociation curve of myoglobin?
A. Linear
B. Hyperbola
C. Sigmoid
D. Parabola
Answer: B
Clarification: Oxygen affinity in myoglobin is more than hemoglobin, as myoglobin binds oxygen more tightly than hemoglobin due to this hemoglobin shows sigmoidal curve while myoglobin shows hyperbolic.

11. Which of these are the possible cause of sickle cell anemia with respect to hemoglobin:
A. Defect in β-chain of hemoglobin
B. Defect in α-chain of hemoglobin
C. One copy of an abnormal β-globin gene
D. Two copies of an abnormal β-globin gene
Answer: D
Clarification: If a person has one copy of abnormal β-globin gene it will show sickle cell trait but not sickle cell anemia while an individual with sickle cell anemia has both the copies of an abnormal β-globin gene.

To practice all areas of Life Sciences for Entrance exams, .

Life Sciences Multiple Choice Questions on “Carbohydrate Metabolism”.

1. Name the pathway for glucose synthesis by non-carbohydrate precursors?
A. Glycogenesis
B. Glycolysis
C. Gluconeogenesis
D. Glycogenolysis
Answer: C
Clarification: Synthesis of glucose from non-carbohydrate sources is carried out by gluconeogenesis. It is the universal pathway, found in all plants, animals, and microorganisms.

2. What is the site for gluconeogenesis?
A. Liver
B. Blood
C. Muscles
D. Brain
Answer: A
Clarification: Gluconeogenesis in animals takes place in the liver as well as some extent in the kidney cortex. The kidney is capable of making glucose during the condition of starvation and can make up to 50% of glucose.

3. Which of the following is not the precursor of gluconeogenesis?
A. Glycolytic products
B. Citric acid cycle intermediates
C. Glucogenic amino acid
D. Lysine or leucine
Answer: D
Clarification: Only leucine or lysine is the substrate which is not used for gluconeogenesis as these amino acids produce only acetyl-CoA upon degradation. Animals cannot carry out gluconeogenesis by two acetyl carbon of acetyl-CoA.

4. Name the enzyme which is responsible for the conversion of pyruvate to phosphoenolpyruvate (PEP)?
A. Pyruvate carboxylase
B. Pyruvate carboxykinase
C. Glucose 6-phosphatase
D. Phosphofructokinase
Answer: B
Clarification: The conversion of pyruvate to PEP takes place in two stages, the first reaction is catalyzed by pyruvate carboxylase which converts pyruvate to oxaloacetate and in second reaction oxaloacetate is converted by pyruvate carboxykinase to PEP.

5. Gluconeogenesis is also carried out in muscle and brain.
A. True
B. False
Answer: B
Clarification: Gluconeogenesis cannot be carried out in muscle and brain as they do not have glucose 6-phosphatase enzyme which is required to convert glucose 6-phosphate to glucose. Glucose 6-phosphatase can only be established in the endoplasmic reticulum of kidney and liver cells.

6. Which of the following are major sites for glycogen storage?
A. Adipose tissue
B. Bones
C. Muscle and liver
D. Kidney and liver
Answer: C
Clarification: Glycogen is stored in muscle and liver only. The amount of glycogen is high in the liver but a larger amount of glycogen stored in the greater bunch of skeletal muscles. The liver uses its glycogen for the synthesis of glucose for all of the body while muscles use its glycogen for its own energy.

7. Which of the following is the precursor of glycogen?
A. Glycerol 3-phosphate
B. Malate
C. UDP-glucose
D. Leucine and lysine
Answer: C
Clarification: Glucose 1-phosphate and uridine triphosphate work together to activate UDP-glucose which acts as a precursor of glycogen.

8. The priming function in glycogen synthesis is carried out by_________
A. Lysine
B. Arginine
C. Glycogenin
D. Glutamate
Answer: C
Clarification: Glycogen synthesis is carried out with the help of a primer by its priming action. Glycogenin is a primer which adds glucosyl residue in the polypeptide chain that already has more than four residues.

9. Name the enzyme which is used for branching of glycogen?
A. Branching enzyme
B. Hexokinase
C. Phosphoglucomutase
D. Glycogen synthase
Answer: A
Clarification: Branching enzyme is also known as amylo-1, 4 —–> 1, 6 transglycosylase which adds a branch at four residues away from the existing branch. Enzymes in hexokinase, phosphoglucomutase, and glycogen synthase are used in glycogen synthesis but not in branching.

10. Which of the following hormone maintain blood glucose level by activation of gluconeogenesis?
A. Nor-epinephrine
B. Glucagon
C. Insulin
D. Epinephrine
Answer: B
Clarification: Glucagon acts opposite to insulin, and is secreted by the α-cells of the pancreatic islets. It maintains blood glucose level by the activation of glycogenolysis and gluconeogenesis.

11. Name the hormone which is secreted in an emergency or in stress condition?
A. Epinephrine
B. Glucagon
C. Insulin
D. Melanin
Answer: A
Clarification: Epinephrine is also known as emergency hormone and it is secreted in the condition of stress and emergencies like injury, pain, fear, accident, and grief. It increases the level of sugar in the blood by stimulating glycogenolysis.

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Life Sciences Multiple Choice Questions on “Cell Division”.

1. Name the type of cell division in which daughter cells receive an exact copy of chromosomes from parent cell?
A. Mitosis
B. Cleavage
C. Interphase
D. Meiosis
Answer: A
Clarification: Basically eukaryotes have two types of cell division, mitosis, and meiosis. Meiosis is reductional division while mitosis is equational division and the number of chromosomes in parent and daughter cells remain same.

2. Who coined the term mitosis?
A. Robert Hook
B. Walther Flemming
C. Farmer and Moore
D. F. Twort
Answer: B
Clarification: Walther Flemming in 1882 introduced the term mitosis. It is the process where one round of DNA replication is trailed by a single round of chromosomal segregation. It generates two genetically identical cells.

3. Which of the following is a microtubule organizing center?
A. Centrosome
B. Kinetochore
C. G2 phase
D. Centrioles
Answer: A
Clarification: Microtubule organizing center (MTOC. is centrosome, present outside the nuclear membrane. It regulates the cycle of cell division as well as microtubule formation.

4. Among the following, which one is not the substage of mitosis?
A. Prophase
B. Metaphase
C. Anaphase
D. Nucleation
Answer: D
Clarification: Mitosis starts with the nuclear division called karyokinesis followed by cytokinesis. This phase is further divided into four substages: prophase, metaphase, anaphase, and telophase.

5. Name the protein which holds two sister chromatids?
A. Securin
B. Separase
C. Cohesin
D. APC
Answer: C
Clarification: SMC (Structural Maintenance of Chromosome) protein cohesin hold together the sister chromatids at centromere while separase is ubiquitous cysteine protease which degrades cohesin during anaphase.

6. Which of the following microtubule pulls the chromosomes towards pole?
A. Astral
B. Polar
C. Kinetochore
D. Centrioles
Answer: C
Clarification: Kinetochore microtubule is a mitotic spindle which attaches to chromosome at the specific site called kinetochores. It pulls the two sister chromatids at the opposite pole during anaphase.

7. Plant cells have centrosomes and astral microtubule at their spindle poles.
A. True
B. False
Answer: B
Clarification: Plant cells do not have centrosomes and astral microtubule at their poles. In plant cells, mitotic spindle formed from MTOC originate from nuclear envelop itself.

8. Spindle fiber attached to the chromosome by a process known as_________
A. Congression
B. Binding
C. Alignment
D. Search and capture
Answer: D
Clarification: Search and capture is a process by which plus end of microtubule search the kinetochore site at the chromosome and attach to it. These microtubules radiate from the MTOC of the poles.

9. What is congression?
A. Attachment of microtubule to chromosomes
B. Attachment of two sister chromatids
C. The endpoint of the spindle pole
D. The midpoint of two spindle poles
Answer: D
Clarification: The arrangement of chromosomes at the center of the poles or at the metaphase plate, which is a midpoint and this midpoint is called congression.

10. In which of the following phase, sister chromatids move towards opposite poles?
A. Telophase
B. Anaphase
C. Prophase
D. Metaphase
Answer: B
Clarification: The sister chromatids are attached to the kinetochore tubule at the metaphase state and start moving towards the opposite poles at anaphase stage. At anaphase, the sister chromatids split apart and move to opposite poles of the spindle.

11. Which of these proteins is responsible for depolymerization of microtubule?
A. Kin I kinesin
B. CENP-E
C. Dynein
D. Actin
Answer: A
Clarification: CENP-E, Kin I kinesin, and dynein are the motor proteins which contain kinetochores. Out of them only Kin I kinesis is responsible for depolymerization of microtubule from its plus end while dynein generates poleward forces toward its minus end.

12. Name the medication which hinders the shortening of the microtubule.
A. Colchicine
B. Cytochalasin
C. Taxol
D. Vinblastine
Answer: C
Clarification: All of these drugs affect the process of cell division at different stages like colchicine inhibits microtubule formation, cytochalasin inhibits cytokinesis, and taxol prevents the shortening of microtubules.

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Life Sciences Multiple Choice Questions on “Gene Interaction”.

1. The Phenomenon of two or more than two genes affecting the expression of each other is called ___________
A. Crossing over
B. Pairing
C. Gene interaction
D. Linkage
Answer: C
Clarification: Mendel described every character is influenced by the particular expression of the gene, but when the characters are controlled by the combination of more than one gene, called gene interaction.

2. Which of the following ratio shows complementary gene interaction?
A. 9:7
B. 15:1
C. 1:2:1
D. 9:3:3:1
Answer: A
Clarification: Complementary gene interaction is first discovered by William Bateson and Reginald Punette in 1906. 9:7 ratio shows the 9 offspring have both dominant genes, while 7 is having either one dominant or both recessive.

3. Which of the following does not show Mendel’s law of inheritance?
A. Masking gene interaction
B. Epistasis
C. Supplementary gene interaction
D. Codominance
Answer: D
Clarification: Codominance is the phenomenon where both the alleles of the gene pair in a heterozygote are expressed and resulting in offspring which is neither dominant nor recessive. Example: AB blood group.

4. Crossing of two white flowers gives a colored flower, this shows complementary gene interaction.
A. True
B. False
Answer: A
Clarification: Two true varieties of white flowered plant crossed and result in purple color progeny which shows that there must be some enzyme secreted by both the dominant alleles which contributed in the color of the flowers.

5. What is epistasis?
A. Type of linkage
B. Masking or modifying gene effect
C. Upper portion of a chromosome
D. Group of genes
Answer: B
Clarification: It is a non-allelic suppression which involves two pairs of alleles. It can suppress both dominant or recessive alleles.

6. Which of the following is NOT the type of epistasis?
A. Dominant
B. Recessive
C. Collabrative
D. Supplementary
Answer: C
Clarification: Epistasis can be of many types based on the ability of an allele in masking and modification of gene effects. It can be of dominant, recessive, complementary or supplementary.

7. Choose the correct ratio, which shows the masking gene interaction?
A. 12:3:1
B. 9:3:4
C. 1:2:1
D. 9:7
Answer: A
Clarification: Masking gene interaction is also recognized as dominant epistasis. Here, dominant allele of one gene can mask the effect of either allele of the second gene.

8. Name the phenomenon where two genes have the same expression of the character?
A. Pleiotropy
B. Phenocopy
C. Penetrance
D. Expressivity
Answer: A
Clarification: Pleiotropy is the condition where either a single gene has multiple functions in the body or two genes have the same expression of the single character.

9. What is psudoallele?
A. Allele with similar function
B. Allele with similar structure
C. Alleles with similar function and structure
D. Alleles with similar function and different structure
Answer: D
Clarification: When two types of allele have similar functions but different structures, it is called pseudoallele. These genes located in close proximity.

10. Name the effect which shows the change in expression of alleles of the gene due to a specific environmental condition.
A. Pleiotropy
B. Linkage
C. Phenocopy
D. Penetrance
Answer: C
Clarification: It is a type of phenotypic variation where a single trait of an organism is usually changed due to environmental effects. This is not a hereditary effect when environmental conditions removed it goes back to normal.

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Life Sciences Multiple Choice Questions on “Protein Folding”.

1. Protein folding is a process in which a polypeptide folds in to ___________
A. 2-D structure
B. Globular form
C. 3-D structure
D. Linear form
Answer: C
Clarification: Protein folding is a process in which a polypeptide is folded into a 3-dimensional conformation which is necessary for proper protein function. Failure to fold can produce inactive protein. A protein molecule folds during or after its biosynthesis.

2. Chaperones are the molecular protein which assists in proper protein folding or prevents them from aggregating.
A. True
B. False
Answer: A
Clarification: Molecular chaperones are proteins which binds to incompletely folded protein to assist their proper folding. These proteins also assist the formation of oligomeric structures and for transport of proteins by membranes.

3. Which of them contains all the information required to fold the polypeptide chain in its 3-D structure?
A. DNA sequences
B. RNA
C. Histone protein
D. Amino acid sequences
Answer: D
Clarification: The native conformation of a protein is determined by its amino acid sequences. This hypothesis was proved by an experiment, in which denaturation followed by renaturation folds the chain in its native structure.

4. Which sentence is INCORRECT regarding molten globule state of protein?
A. Hydrophobic interaction among non-polar residues
B. The collapsed state
C. It is less compact
D. The denatured state
Answer: D
Clarification: Molten globule is a state in which interior side chains remain mobile, less compact and there is no proper packing. This state is completely different from the native and denatured state.

5. Which of the following name is given to molecular chaperones?
A. Allosteric protein
B. Heat shock protein
C. Denaturation protein
D. Ribonuclease
Answer: B
Clarification: The ability of chaperones to synthesis in large amount after a brief exposure to elevated temperature(42°C. makes them heat shock protein(Hsp). Basically, the eukaryotic cell has two major families of chaperones called Hsp60 and Hsp70.

6. Which of these heat shock proteins prevent protein misfolding and maintain polypeptide chain in the unfolded state.
A. Hsp60
B. Hsp28
C. Hsp70
D. Hsp32
Answer: C
Clarification: Hsp70 is induced by stress and these are the primary proteins which prevent polypeptide chain from misfolding and maintained it in an unfolded state. It also helps in translocation of the protein from the cytosol into ER or mitochondria.

7. Among all the heat shock proteins which one is known as chaperonins?
A. Hsp70
B. Hsp32
C. Hsp60
D. Hsp30
Answer: C
Clarification: Hsp60 family of chaperones forms a large barrel-shaped structure that acts later when protein is being fully synthesized. Chaperonins bind incorrectly folded, partly folded or unfolded protein but not in their native state.

8. Which one of the following reagent is also known a Sanger’s reagent?
A. 1-fluoro-2,4-dinitrobenzene (FDNB)
B. Phenylisothiocyanate
C. Cyanogen bromide
D. β-mercaptoethanol
Answer: A
Clarification: FDNB reacts with a free amino group of N-terminal amino acid in alkaline solution to form yellow dinitrophenol. This reaction was first used by Sanger to determine the primary structure of the polypeptide hormone.

9. Proteolytic enzyme trypsin cleaves protein at which of these specific sites?
A. Carboxyl side of Alanine, Glycine
B. Carboxyl side of Lysin or Arginine
C. Carboxyl side of aromatic amino acid
D. The amino side of aromatic amino acid
Answer: B
Clarification: The specificity of these enzymes determined by the side chain of amino acid on either side of a peptide bond. This cleavage is necessary to sequence protein which is made up of more than 50 amino acid residues.

10. Mark the correct statement which depicts the correct statement of protein assay?
A. To determine the amount of protein
B. To characterize the function of the protein
C. To determine the structure of the protein
D. To determine the sequence of the protein
Answer: A
Clarification: Protein assay is a technique to determine the amount of protein in an unknown solution. It is done by measuring the absorbance at 280nm. Aromatic side chain containing amino acids like tyrosine, tryptophan, and phenylalanine exhibit strong UV light absorbance.

11. In a living organism, strong interactions between molecules are formed by a certain type of bond. Name that?
A. Hydrogen bonding
B. Covalent bond
C. Electrostatic interactions
D. Van der Waals forces
Answer: B
Clarification: Covalent bond is considered as a strong bond between molecules whereas rest options are of the non-covalent bond which is regarded as weak interactions. In a covalent bond, electrons are shared by both the atoms which makes it stronger.

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