Category: Class 11 Biology Objective Questions

250+ TOP MCQs on Biological Classification – Fungi and Answers

Biology Exam Questions and Answers for Class 11 on “Biological Classification – Fungi – 3”.

1. Which of the following is used in brewing of beer?
a) Penicillium
b) Yeast
c) Club fungi
d) Mushroom
Answer: b
Clarification: Yeast is used in brewing of beer. Yeast helps in the fermentation of Beer and wine. Fermentation is the process in which yeast turns wheat into alcohol and CO2.

2. Which among the following is used in preparation of anti-biotic?
a) Yeast
b) Penicillium
c) Mushroom
d) Rhizopus
Answer: b
Clarification: Pencillium is used in preparation of anti-biotic called Penicillin. Penicillin was first discovered by Alexander Flemming during Second World War and was a profounding discovery that saved the lives of many soldiers during WW-II.

3. Penicillin was first discovered from _______
a) Penicillium roqueforti
b) Penicillium chrysogenum
c) Penicillium notatum
d) Penicillium camemberti
Answer: c
Clarification: Penicillin was first discovered from Penicillium notatum. Penicillium notatum is fungus belonging to the division of Ascomycetes and family of Penicillium. Today, Penicillium chrysogenum plays a vital role in the preparation of Penicillin.

4. Who discovered Penicillin and when?
a) Alexander Graham Bell in 1918
b) Alexander Flemming in 1928
c) Alexander Flemming in 1938
d) Alexander Flemming in 1948
Answer: b
Clarification: Penicillin was the first anti-biotic to be discovered by Alexander Flemming on September 28 1928. This discovery is a milestone in the history of science and changed the lives of many soldiers.

5. Yeast grows in ______
a) damp and dark conditions
b) dry and cold conditions
c) sunlight
d) hot deserts
Answer: a
Clarification: Yeast grows in damp and dark conditions. It doesn’t need sunlight to grow. Refrigerators provide cold and dry conditions that prevent growth of yeast. Yeast preferably grows well in warm conditions than that of cold conditions.

6. Which among the following is incorrect about the following figure?

a) The figure shows budding of yeast
b) In budding nuclei is split equally in both cells
c) Yeast can reproduce only through budding
d) It takes around two hours to complete a cycle of budding
Answer: c
Clarification: The figure shows budding of yeast. Yeast can reproduce both by budding and sexual spores. It takes around two hours to complete a cycle of budding. In budding nucleus split equally in both the cells.

7. Which among the following fungus are used in the manufacture of proteins?
a) Asperigillus niger
b) Saccharomyces cerevisiae
c) Trichoderma
d) Aspergillus flavus
Answer: b
Clarification: Fungi add great economic value to drug and pharmaceutical industry. They are used in preparation of beer, baking of bread and manufacture of proteins. Saccharomyces cerevisiae is used in manufacture of proteins.

8. Which among the following statements are incorrect?
a) Fungi are used in the manufacture of proteins, beer and bread
b) Fungi are the natural scavengers on the Earth
c) Penicillium camemberti is used in the manufacturing of penicillin
d) Fungi grow in damp and dark regions
Answer: c
Clarification: P.Notatum and P.chrysogenum are used in the manufacture of Penicillin. Fungi are used in the manufacture of proteins, beer and bread. Fungi are the natural scavengers on the Earth. Fungi grow in damp and dark areas.

9. Which is the main source of energy for yeast?
a) Sunlight
b) Nitrogen
c) Organic compounds
d) Nitrates
Answer: c
Clarification: Organic compounds are the main source of energy for yeast. They acquire energy from glucose, sucrose and sometimes even from disaccharides like maltose and galactose.

10. Assume that after every budding cycle, the parent organism becomes barren. And the daughter organism produced further gives rise to a new organism. After a period of 78 hours, how many fertile and barren organisms would be left if the initial number of organisms N0 = 2 (Assume that every budding cycle takes 2 hours)?
a) 1 and 239-1 respectively
b) 1 and 39 respectively
c) 2 and 78 respectively
d) 2 and 240-1 respectively
Answer: c
Clarification: After one budding cycle, number of fertile and barren yeasts are 1 and 1 respectively. After two budding cycles, number of fertile and barren yeasts are 1 and 2 respectively. After n budding cycles, number of fertile and barren yeasts would be 1 and n respectively.
Therefore, after 78 hours number of budding cycles = 78/2 = 39
Since, N0 = 2, after 78 hours number of fertile and barren yeasts are 2 and 78 respectively.

11. Which among the following are incorrect?
a) Mushrooms are edible and grow in rainy season
b) Slime molds are immobile
c) Yeast are sometimes found multi-cellular by formation of hyphae
d) Yeast doesn’t need sunlight to grow
Answer: b
Clarification: Slime molds are motile and this is the major difference between molds and slime molds. Mushrooms are edible and are grown in rainy season. Yeasts are sometimes found multi-cellular by formation of hyphae. Yeast doesn’t need sunlight to grow.

12. Yeast grows exponentially through budding. If one budding cycle takes 90 minutes, what will be the population of yeast after 144 hours if the initial population N0 = 5?
a) 480
b) 5 × 296
c) 96×25
d) 144×25
Answer: b
Clarification: After 144 hours, number of budding cycles = 144 × 60/90 = 96 cycles.
Population after ‘n’ budding cycles = N0×2n.
Population after 96 cycles = 5 × 296.

13. Mushroom consists of stem, cap and spores at the bottom of the cap.
a) True
b) False
Answer: a
Clarification: Mushroom consists of stem, cap and spores at the bottom of the cap. Spores are the main mode of reproduction in mushrooms. The following figure describes the parts in a mushroom.

14. The branch involved in study of Fungi is called Mycology.
a) True
b) False
Answer: b
Clarification: The branch involved in the study of Fungi is called Mycology. Mycologists are those who study fungi in detail. Fungal infections are scientifically termed as Mycosis or Mycoses (plural).

15. Which among the following are not mycoses?
a) Candidiasis
b) Scabies
c) Tinea versicolor
d) Cryptococcosis
Answer: b
Clarification: Mycosis is the scientific terminology for fungal infection. Scabies is not a fungal infection. It is caused due to an arthropod called mite. Candidiasis, Tinea versicolor and cryptococcosis are different mycoses.

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250+ TOP MCQs on Classification of Animal Kingdom into Different Phylum-2 and Answers

Zoology MCQs on “Classification of Animal Kingdom into Different Phylum-2”.

1. Which among the following is incorrect about chordates?
a) They must have notochord at every point of their life
b) They have a post anal tail
c) They have hollow dorsal nerve cord
d) They have a ventral heart

Answer: a
Clarification: In chordates, notochord at some point of their life and may vanish after certain period of time. They have a post anal tail. They have a dorsal nerve cord. They have a ventral heart.

2. Which among the following is incorrect about chordata?
a) They have paired muscles
b) Post anal tail must be present in chordates
c) Their notochord vanishes after certain period of time
d) Pharyngeal gill slits are present

Answer: b
Clarification: Chordates have paired muscles. Post anal tail is present at the embryo but might vanish after certain period of time. Their notochord also vanishes after certain period of time. Pharyngeal gill slits are present.

3. Which among the following is odd?
a) Urochordata
b) Cephalochordata
c) Vertebrata
d) Agnatha

Answer: d
Clarification: Urochordata, Cephalochordata and Vertebrata are sub-phyla of Chordata. These sub-phyla are classified based on the period of presence of notochord in Chordates. Whereas unlike other three options, Agnatha is a super class in Chordates.

4. Which among the following is not correct about Urochordata?
a) They are a classification under Protochordates
b) They have post anal tail only till their larval stage
c) Most of these are marine and almost extinct
d) They don’t contain gill clefts

Answer: d
Clarification: Urochordata is classified under Protochordates. They have post anal tail only till their larval stage. Most of these are marine and almost extinct. They contain pharyngeal gill slits in the form of gill clefts.

5. Branchiostoma is an example of Cephalochordata.
a) True
b) False

Answer: a
Clarification: Ascidia, Salpa, Doliolum etc. are examples of Urochordata. Branchiostoma which resembles like finless fish is actually an example of Cephalochordata. The Cephalochordates and Urochordates are grouped under Protochordates.

6. Which among the following is incorrect about Vertebrata?
a) All chordates are vertebrates
b) In vertebrates, notochord is replaced by vertebral column in adults
c) They might not have post-anal tail after a certain period of time
d) Notochord is present during embryonic period

Answer: a
Clarification: All vertebrates are chordates but the vice-versa is not true. Notochord is present during embryonic period. It is replaced by vertebral column in adults. They might also not have post-anal tail after a certain period of time.

7. Agnatha is an example of ________
a) Sub-phylum
b) Phylum
c) Super-class
d) Class

Answer: c
Clarification: Super-class is a taxonomic category that is just above the class and below sub-phylum. Animal kingdom is divided into 10 phyla and one among them is Chordates. Chordates are further classified into two sub-phylum, namely, protochordates and vertebrata. Vertebrata are further classified into super classes, namely, agnatha and gnathostomata.

8. Which among the following is incorrect about Agnatha?
a) These are also called as jawless fishes
b) Scales and fins are present
c) They adopt parasitic mode of nutrition
d) They have a circular mouth that acts as sucker

Answer: b
Clarification: Agnatha are also called as jawless fishes. Scales and fins are absent. They adopt parasitic mode of nutrition. Their circular mouth acts as sucker. They are aquatic and most of them are extinct. The only class that exists in this super-class is cyclostomata.

9. Which among the following is incorrect about Cyclostomata?
a) Their vertebral column is made of cartilage
b) Lamprey and hagfish are examples of this class
c) Their digestive system is complete with stomach, food pipe and intestines
d) Their circulatory system is closed with a 2 chambered heart

Answer: c
Clarification: Vertebral column is made of cartilage in Cyclostomata. They don’t have a stomach. Their circulatory system is closed with a 2 chambered heart. Lamprey and hagfish are examples of this class.

10. Which among the following is incorrect about Gnathostomata?
a) These are vertebrates with jaws
b) This super class is classified into Pisces and tetrapods based on their type of blood
c) Pisces use fins for their movement
d) Tetrapods use limbs for their movement

Answer: b
Clarification: Gnathostomata are vertebrates with jaws. This super class is classified into psices and tetrapods based on the organs they use for their movement. Pisces use fins for their movement. Tetrapods use limbs for their movement.

250+ TOP MCQs on Anatomy of Monocotyledonous Plants and Answers

Biology Multiple Choice Questions on “Anatomy of Monocotyledonous Plants”.

1. Vascular cylinder comprises of the pericycle, xylem, phloem and pith.
a) True
b) False
Answer: a
Clarification: Vascular cylinder comprises of the pericycle, xylem, phloem and pith. Cortex includes the portion exterior to the endodermis and comprising of parenchyma cells, hypodermis and epidermis.

2. Which among the following is correct about the anatomy of monocot root?
a) The outermost layer in the root is called epidermis
b) The endodermis has casparian strip that avoids water leakage from the vascular bundles and invasion of foreign particles
c) Channels that connects the parenchyma cells are called plasmodermata
d) A cambium is present in between the xylem and phloem
Answer: d
Clarification: The outermost layer in the root is called epidermis. The endodermis has casparian strip that avoids water leakage from the vascular bundles and invasion of foreign particles. Channels that connect the parenchyma cells are called plasmodermata. Cambium is absent in between the xylem and phloem.

3. The layer just below the epidermis in a monocot stem is _________
a) Hypodermis
b) Vascular bundles
c) Endodermis
d) Parenchyma
Answer: a
Clarification: The layer just below the epidermis in a monocot stem is called Hypodermis. Hypodermis provides additional mechanical strength to the epidermis and avoids water leakage from the stem.

4. Which among the following is not correct about monocot stem?
a) In a monocot stem, the vascular bundles are scattered
b) More than one conjoint vascular bundle is present
c) Cambium is absent
d) Cortex is present
Answer: d
Clarification: In a monocot stem, the vascular bundles are scattered. More than one conjoint vascular bundle is present. Cambium is absent i.e. secondary growth of vascular bundles are not possible. Cortex is absent.

5. In a monocot stem, endodermis and cambium is absent.
a) True
b) False
Answer: a
Clarification: In a monocot stem, endodermis and cambium is absent. They don’t require an endodermis since their vascular bundles are scattered. Absence of cambium leads to the lack of secondary growth.

6. Which among the following is incorrect about anatomy in a monocot leaf?
a) Stomata is present both on abaxial and adaxial epidermis
b) Mesophyll is well differentiated into Palisade and spongy parenchyma cells
c) Vascular bundles are seen in veins and mid-rib and are surrounded by thick walled bundle sheath
d) Most of the cells are parenchyma cells
Answer: b
Clarification: Stomata is present both on abaxial and adaxial epidermis. Mesophyll is undifferentiated. Vascular bundles are seen in veins and mid-rib and are surrounded by thick walled bundle sheath. Most of the cells are parenchyma cells.

7. Which among the following statements is incorrect about monocotyledonous tissue system?
a) Buliform cells that help in the curling of leaves are absent in monocot leaf
b) Epidermis covers the entire plant and protects the plant from external damage
c) Vascular bundles in monocot stem are neither radial nor conjoint
d) In a monocot stem pericycle is absent
Answer: a
Clarification: Buliform cells that help in the curling of leaves are present in monocot leaf. Epidermis covers the entire plant and protects the plant from external damage. Vascular bundles in monocot stem are neither radial nor conjoint. In a monocot stem pericycle is absent.

8. Pith in monocot stem is made of ___________
a) Parenchyma cells
b) Collenchyma cells
c) Sclerenchyma cells
d) Tracheid cells
Answer: c
Clarification: Pith in monocot stem is made of rigid sclerenchymatous cells. Also, the hypodermis and large number of vascular bundles that are scattered are surrounded by sclerenchymatous cells.

9. Hypodermis of a monocot stem is made of _________
a) Sclerenchymatous cells
b) Parenchymatic cells
c) Collenchymatic cells
d) Chlorenchymatic cells
Answer: a
Clarification: Hypodermis along with the pith of a monocot stem is made of sclerenchymatous cells. Also, several numbers of scattered vascular bundles are surrounded by sclerenchymatous cells.

10. Which among the following is incorrect about vascular bundles in monocot stem?
a) They are more than one vascular bundle present
b) The vascular bundles are of open type
c) They are scattered
d) They are surrounded by sclerenchymatous bundle sheaths
Answer: b
Clarification: There are more than one vascular bundles present in a monocot stem. The vascular bundles are of closed type. They are scattered. They are surrounded by sclerenchymatous bundle sheaths.

250+ TOP MCQs on Animals Structural Organisations – Frogs-1 and Answers

Biology Multiple Choice Questions on “Animals Structural Organisations – Frogs-1”.

1. Which of these statements is true about frog?
a) It lives both on land and in sea water
b) They cannot survive in freshwater
c) Rana tigrina is a rare species
d) They belong to class Amphibia
Answer: d
Clarification: Frog belongs to class Amphibia. It lives on land and in fresh water. The species Rana tigrina is the most common in India. Frogs are chordates and are poikilotherms. This means they do not have a constant body temperature.

2. Frogs are _______
a) homeothermic
b) warm-blooded
c) poikilothermic
d) heterothermic
Answer: c
Clarification: Frogs are poikilothermic animals. This means that they have a fluctuating body temperature which varies with the environmental conditions, or they lack constant body temperature.

3. Which of these methods are utilized by frogs for protection?
a) Speed
b) Spikes
c) Mimicry
d) Playing dead
Answer: c
Clarification: Frogs have the ability to change their color to defend themselves from predators. This phenomenon is known as camouflage and the protective coloration using which it hides in its surroundings is knows as mimicry.

4. Which of these statements is false about frogs?
a) They do not aestivate
b) They change color
c) They live in burrows
d) They hibernate
Answer: a
Clarification: Frogs have the ability to change color to protect themselves from predators. This camouflaging technique is called mimicry. They live in burrows to shelter themselves from extreme weather and they show both aestivation and hibernation.

5. Which of these describes the skin of frog?
a) Thick, leathery
b) Smooth, slippery
c) Hard, dry
d) Thin, membranous
Answer: b
Clarification: The skin of a frog is smooth and slippery due to the presence of mucus. The skin has a moist characteristic which is maintained. A frog does not drink water but has the ability to absorb water through its skin.

6. Which of these are the divisions of the body of a frog?
a) Head, trunk, abdomen
b) Head, thorax, abdomen
c) Head, trunk
d) Head, thorax, trunk
Answer: c
Clarification: The body of the frog is divided into a head and a trunk. Neck and tail are absent. Frogs are green with dark irregular spots on the dorsal side. On the ventral side, they are pale yellow in color.

7. Which of these structures protects the eyes of the frog in water?
a) Nictitating membrane
b) Tympanum
c) Bidder’s canal
d) Cloaca
Answer: a
Clarification: The nictitating membrane protects the eyes of the frog in water. The tympanum is the ear of the frog. Cloaca are excretory organs. Bidder’s canal is a part of the male reproductive system of frogs.

8. Which of these structures in frog receive sound signals?
a) Webbed feet
b) Skin
c) Nictitating membrane
d) Tympanum
Answer: d
Clarification: The tympanum is the ear of frog. It receives sound signals from the environment. The tympanum is a membranous structure. The received environmental sound signals is then transmitted to the nervous system.

9. How many digits does the forelimb and hindlimb of frog have respectively?
a) 3, 4
b) 5, 4
c) 4, 5
d) 4, 3
Answer: c
Clarification: Each forelimb of frog has four digits while each hindlimb of frog has five digits. The hindlimbs are larger and more muscular than the forelimbs. The limbs are used for leaping, swimming and burrowing.

10. Frogs show sexual dimorphism. True or false?
a) True
b) False
Answer: a
Clarification: Frogs show sexual dimorphism. This means that apart from differences in reproductive organs of the two sexes, the appearance or phenotypic characteristics differs with sex within the same animal species.

11. Which of this is not a distinguishing feature of a male frog?
a) Narrow abdomen
b) Copulatory pad
c) Vocal sacs
d) Moist, slippery skin
Answer: d
Clarification: All frogs have characteristic moist, slippery skin. This is due to the secretion of mucus on the surface of the skin. Male frogs can be differentiated from female frogs by distinguishing features such as narrow abdomen, copulatory pad and vocal sacs.

12. Where are the copulatory pads in male frog present?
a) Second digit of the hindlimbs
b) First digit of the hindlimbs
c) First digit of the forelimbs
d) Second digit of the forelimbs
Answer: c
Clarification: The copulatory pads of the male frog are present on the first digit of the forelimbs. Frogs show sexual dimorphism and the presence of copulatory pads in male frogs is a distinguishing feature of the two sexes.

13. Frogs are ______
a) herbivores
b) omnivores
c) carnivores
d) scavengers
Answer: c
Clarification: Frogs are carnivores. This means that their diets consist of food material which are solely animal in origin. Frogs normally feed on insects such ad flies, mosquitoes, dragonflies and worms.

14. Which of these characteristics of frog is the reason for its short alimentary canal?
a) Carnivorous
b) Sexual dimorphism
c) Amphibian
d) Chordate
Answer: a
Clarification: Frogs are carnivorous. This means that their diet consists of food which is purely of animal origin. For this reason, the length of its intestine is reduced. Thus, frogs have a short alimentary canal.

15. Identify ‘3’ in the pathway of food ingested by frog.

a) Larynx
b) Pharynx
c) Gizzard
d) Crop
Answer: b
Clarification: Structure 3 is pharynx. In the digestive system of frog, the pharynx lies after the buccal cavity and before the esophagus. The structures larynx, gizzard and crop are not a part of the digestive system of frog.

250+ TOP MCQs on Biomolecules – Chemical Analysis and Answers

Biology Multiple Choice Questions on “Biomolecules – Chemical Analysis – 1”.

1. What chemical is used to grind tissues for chemical analysis?
a) Formaldehyde
b) Methanol
c) Hydrofluoric acid
d) Trichloroacetic acid
Answer: d
Clarification: To analyze tissues for chemical analysis, the tissue material needs to be grinded and homogenized using pestle and mortar. This grinding is done using trichloroacetic acid. The rest are generally toxic.

2. What is the nature of the filtrate after grinding tissue?
a) Basic
b) Acid-insoluble
c) Acid-soluble
d) Acidic
Answer: c
Clarification: The tissue is grinded using mortar and pestle in order to homogenize it, using trichloroacetic acid. It is then strained through cheesecloth and the filtrate obtained is acid-soluble in nature.

3. What is the acid-insoluble fraction of grinded tissue known as?
a) Extract
b) Filtrate
c) Retentate
d) Supernatant
Answer: c
Clarification: The homogenized and grinded tissue material, when passed through layers of cheesecloth, divides into an acid-soluble fraction and an acid-insoluble fraction. The acid-insoluble fraction is the retentate.

4. How can we get a theoretical idea about the molecular formula of a compound?
a) Analytical techniques
b) Chemical treatment
c) Biological treatment
d) Combustion
Answer: a
Clarification: Techniques defined under analytical chemistry and stoichiometric calculations allow us to approximately determine the molecular formula of a compound. It is the easiest and most accurate method out of all the options.

5. Which of these cannot be determined by analytical techniques?
a) Probable structure
b) Chemical properties
c) Conformation
d) Molecular formula
Answer: b
Clarification: Analytical techniques are used to determine the probable structure and approximate molecular formula of compounds. Various conformations of a structure can also be determined but chemical properties cannot be determined.

6. What percentage of the Earth’s crust is Sulphur?
a) 0.14
b) 46.6
c) 0.03
d) 2.8
Answer: c
Clarification: Sulphur occupies 0.03% of the Earth’s crust by weight. Hydrogen occupies 0.14% of the Earth’ crust by weight, oxygen occupies 46.6% by weight and sodium occupies 2.8% of the Earth’s crust by weight.

7. Which of these elements is negligible in the human body?
a) Silicon
b) Magnesium
c) Sodium
d) Sulphur
Answer: a
Clarification: Sodium is an important electrolyte in our body. Magnesium is a cofactor for many enzymes. Sulphur is a component of some amino acids. The amount of silicon in our body is negligible.

8. Which of these components have the least percentage by weight in the Earth’s crust?
a) Oxygen
b) Sodium
c) Magnesium
d) Nitrogen
Answer: d
Clarification: Oxygen has the highest percentage by weight in the Earth’s crust, that is, 46.6%. Sodium and magnesium are also present in some amounts. However, the percentage by weight of nitrogen is very little.

9. What is done to obtain the inorganic substances from tissue?
a) Acidification
b) Evaporation
c) Complete combustion
d) Dilution
Answer: c
Clarification: In order to obtain inorganic substances from tissue, the tissue is first allowed to sit so that the water evaporates. The carbon compounds are eliminated. The remaining ash contains inorganic compounds.

10. All biomolecules are carbon compounds. True or false?
a) True
b) False
Answer: a
Clarification: A biomolecule is a compound produced by a living organism. It is divided into four broad groups, namely carbohydrates, proteins, nucleic acids and lipids. All of these substances contain carbon.

11. Which of these are not present in every amino acid?
a) Amino group
b) Acidic group
c) α-carbon
d) Sulphur
Answer: d
Clarification: Amino acids are the building blocks of proteins. The have a chiral carbon or α-carbon. It contains one amino group and one acidic group. Only a few amino acids such as cysteine and methionine contain Sulphur.

12. An amino acid is a substituted ______
a) carboxylic acid
b) alcohol
c) methane
d) aldehyde
Answer: c
Clarification: An amino acid has an α-carbon, surrounded by one amino group, one acidic group and two other groups. Methane is similar in structure, with four hydrogens surrounding the central carbon.

13. How many amino acids are present in the body?
a) 10
b) 15
c) 21
d) 20
Answer: c
Clarification: The body contains 21 amino acids and various combinations of sequences of these amino acids form peptides, polypeptides and proteins. They are classified into essential and non-essential amino acids.

14. Which of these amino acids do not possess a chiral carbon?
a) Glycine
b) Alanine
c) Valine
d) Leucine
Answer: a
Clarification: Glycine is the only amino acid that does not possess a chiral carbon. This is because, along with one amino group and one acidic group attached to the α-carbon, it possesses two hydrogen atoms.

15. What is the simplest amino acid?
a) Valine
b) Glycine
c) Methionine
d) Alanine
Answer: b
Clarification: Glycine is the simplest amino acid. This is because its R group, which is attached to the α-carbon is a hydrogen atom. Hence, the α-carbon is symmetrical and does not possess a chiral carbon.

250+ TOP MCQs on Biomolecules – Enzymes and Biocatalysts-2 and Answers

Biology Online Quiz for Medical Entrance Exams on “Biomolecules – Enzymes and Biocatalysts-2”.

1. The energy of the transition state of an enzymatic reaction is _____
a) higher than the energy of the product but lesser than that of the substrate
b) lower than the energy of the product
c) equal to the energy of the substrate
d) higher than the energies of both the substrate and the product
Answer: d
Clarification: The transition state occurs during an enzymatic reaction when the substrate binds to the enzyme molecule in order to be converted into a product. The energy of this state is higher than that of the substrate and the product.

2. Which of these statements is false regarding transition states in enzymatic reactions?
a) They are more unstable than products
b) They have high energy
c) They have a lower energy than both substrate and product
d) An enzyme-substrate complex is formed during this period
Answer: c
Clarification: The transition state occurs during an enzymatic reaction when the substrate binds to the enzyme molecule in order to be converted into a product, via the production of a high energy enzyme-substrate complex.

3. Which of these conditions signify an exothermic reaction?
a) The energy of the product is lesser than that of the enzyme-substrate complex
b) The energy of the product is higher than that of the substrate
c) The energy of the product is lesser than that of the substrate
d) The energy of the product is equal to that of the substrate
Answer: c
Clarification: In an enzymatic reaction, a substrate is converted into a product via the formation of a higher energy enzyme-substrate complex. If the energy of the product is lesser than that of the substrate, it signifies an exothermic reaction.

4. Which of these is the second step of an enzymatic reaction?
a) Binding of the substrate to the enzyme
b) Change in the conformation of the enzyme
c) Production of an enzyme-substrate complex
d) Release of product from the enzyme
Answer: a
Clarification: In an enzymatic reaction, a substrate first binds to the active site of an enzyme. This induces a conformational change in the enzyme to form an enzyme-substrate complex. This is converted into a product which is then released.

5. Which of these is the third step of an enzymatic reaction?
a) Binding of the substrate to the enzyme
b) Change in the conformation of the enzyme
c) Production of an enzyme-substrate complex
d) Release of product from the enzyme
Answer: c
Clarification: In an enzymatic reaction, a substrate first binds to the active site of an enzyme. This induces a conformational change in the enzyme to form an enzyme-substrate complex. This is converted into a product which is then released.

6. Which of these substances is structurally similar to succinate?
a) Pyruvate
b) Acetate
c) Malonate
d) Oxaloacetate
Answer: c
Clarification: Malonate is structurally similar to succinate. Malonate acts as a competitive inhibitor for the substrate succinate. Binding of malonate instead of succinate inhibits the activity of the enzyme succinic dehydrogenase.

7. How many classes are enzymes divided into?
a) 6
b) 7
c) 5
d) 8
Answer: a
Clarification: Enzymes are divided into 6 classes based on the type of reactions they catalyze. The six classes of enzymes are as follows-oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases.

8. Nicotinamide adenine dinucleotide is a _____
a) cofactor
b) prosthetic group
c) apoenzyme
d) coenzyme
Answer: d
Clarification: Nicotinamide adenine dinucleotide (NAD) is a coenzyme. It is an organic compound that transiently associates with an apoenzyme during the process of catalysis. It contains the vitamin niacin.

9. What does the graph represent?

a) Effect of change in pH on enzyme activity
b) Effect of change in temperature on enzyme activity
c) Effect of change in concentration of substrate on enzyme activity
d) Effect of change in pressure on enzyme activity
Answer: c
Clarification: The graph given above represents the effect of change in concentration of substrate on enzyme activity. Velocity of the reaction increases with an increase in substrate concentration at first, but it ultimately reaches a maximum velocity.

10. Velocity of an enzymatic reaction keeps on increasing with an increase in substrate concentration. True or false?
a) True
b) False
Answer: b
Clarification: Velocity of an enzymatic reaction increases with an increase in substrate concentration at first, but it ultimately reaches a maximum velocity. This is due to the saturation of substrate molecules.

11. Which of these statements is true regarding competitive inhibitors?
a) It inhibits the activity of substrate
b) Malonate increases succinic dehydrogenase activity
c) They are structurally different from the substrate
d) They are used in the control of bacterial pathogens
Answer: d
Clarification: Competitive inhibitors inhibits the activity of enzymes. They are structurally similar to the substrate. Malonate is a competitive inhibitor for succinic dehydrogenase. They are used to control pathogens.

12. What type of enzyme catalyzes the conversion of d-lactic acid to l-lactic acid?
a) Oxidoreductases
b) Transferases
c) Isomerases
d) Ligases
Answer: c
Clarification: D-lactic acid and l-lactic acid are optical isomers. They can be interconverted into either form with the help of isomerases. These enzymes catalyze the interconversion of optical, positional and geometric isomers.

13. Which of these is the cofactor for carboxypeptidase?
a) Manganese
b) Magnesium
c) Zinc
d) Copper
Answer: c
Clarification: Carboxypeptidase is a proteolytic enzyme. It functions with the help of a metal ion, zinc, working as the cofactor. Zinc forms one or more coordinate bonds with the enzyme as well as with the substrate.

14. The association of which of these with apoenzymes is transient?
a) Coenzyme
b) Prosthetic group
c) Metal enzyme
d) Apoenzyme
Answer: a
Clarification: Coenzymes are organic compounds. The associations of coenzymes and apoenzymes are transient and occur during catalysis. Vitamins are important chemical components of coenzymes.

15. What is the heme portion of catalase known as?
a) Coenzyme
b) Prosthetic group
c) Metal enzyme
d) Apoenzyme
Answer: b
Clarification: Heme is a prosthetic group of the catalase enzyme. It is an organic compound which is bound tightly to the apoenzyme. The prosthetic group is present at the active site of the catalase enzyme.

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