BIOCHEMISTRY MID 2

Which ones are correct?

1. Enzymes for humans generally stability temperature up to 35-45 °C.

2. Most enzymes exhibit optimal activity at pH value between 5-9.5.

3. The Km, also known as the Michaelis constant, does not vary from enzyme to enzyme, but it

does change when environmental conditions such as pH and temperature change.

A) 1-2

B) 1-3

C) 1

D) 1-2-3

E) 2-3

Which ones are correct?

Enzymes class Examples

A) Ligases RNA polymerase

B) Lysases Lysozyme

C) Transferases Fumarase

D) Isomerases Hexokinase

E) Hydrolases RNA polymerase

Which ones are correct?

A) Enzymes reduction activation energy.

B) Enzymes increases activation energy.

C) Enzyme acts on substrate in such a way that they lower the activation energy by changing

the route of the reaction.

D) Rate constant is independent from enzymes.

E) Enzymes are synthesized by mitochondria which are attached to the rough endoplasmic

reticulum.

1.What criteria are used in the classification of enzymes?

a) Molecular weight

b) Similarity between two substrates

c) Reaction rate

d) Color change

e) Electric charge

2.What term is used to describe the mechanism of enzyme action?

a) Catalysis

b) Denaturation

c) Inhibition

d) Reversibility

e) Hydrolysis

3.Molecules that enhance the catalytic activity of an enzyme are referred to by which term?

a) Cofactor

b) Substrate

c) Inhibitor

d) Coenzyme

e) Activator

4.Which type of inhibition is reversible and irreversible among the inhibition types?

a) Reversible

b) Irreversible
c) Non-competitive

d) Allosteric

e) Covalent

5.Enzymes catalyze which types of chemical reactions?

a) Only acidic reactions

b) Only basic reactions

c) Only redox reactions

d) Various types of reactions

e) Only hydrolysis reactions

1. Fill in the given below blank

Enzymes are biological catalysts that …. the rate of biochemical reaction.

a) speed up b) slow down c) doesn’t change d) run

ans: a

2. Which of them are true for Co-factors?

I. Co-factors are two types.

II. Co-factor is the non-protein molecule which carries out chemical reactions that can

not be performed by standard 20 amino acids.

III. Organic co-factors and inorganic co-factors are the types of co-factors.

a) Only II b) I,II and III c) Only III d) I and II

Ans : b

3. Fill the below blank

An enzyme with its co-factor removed is designated as …

a) Co-factor b) amino acid c) apoenzyme d) Glycogen

Ans:c

4. Lock and Key model are used for indicating which of the option?
a) Substrate-enzyme b) co-factor – apoenzyme c) amino acid – fatty acid

Ans:a

5. Which option is correct for the given definition?

The least amount of energy needed for a chemical reaction to take place.

a) Activation energy b) enzyme c) protein d) catalyst

Ans:a

1.Which one false in factors affecting rate of enzyme

catalyzed reactions?

A. Raising the temperature increases the rate of

enzyme catalyzed reaction by increasing kinetik

energy of reacting moleküler.

B.Enzymes work maximum over a particular

temperature known as optimum temperature.

C. Enzymes for humans generally exhibit stability

temperature up to 35-45 C.

D. Most enzymes exhibit optimal activity at pH value

between 1 and 3.

Answer:D

2.Which is not one of the methods used in the kinetics of

enzyme activity?

A.Its could measure appearance of colored product

made from an uncolored substrate.

B.Its could measure appearance of a UV absorbent

product made from a non- UV- absorbent substrate.

C.Its could measure apperance of a IR spectroscopy.

D.Its could measure apperance of radioactive product

made from radioactive substrate.

Answer:C

3.Which one false for Michaelis Constant(Km) ?

A.Km iş constant for any given enzyme/substrate pair.

B.Small Km means tight binding; large Km means

weak binding.

C.Units are in terms of pressure.

D.Km is are measure of ES binding; relative measure

of the affinity of a substrate for an enzyme.

Answer:C

4.Which one false in enzyme class?

A. Oxidoreductases

B.Transferases

C.Hydrolases

D.Lysosims

Answer:D

5.Which one false name of the enzymes?

A.Protease

B.Amylase

C.Lipase

D.Maltose

Answer:D

1. Enzymes are ............. that speed up the rate of the biochemical reaction.

What should come in the blank?

a) Chemical reaxion

b) Physical reaxion
c) Rate constant

d) Biochemical catalyst

Answer: D

2. I. The reactant in biochemical reaction is termed as “substrate”

II. When the substrate binds to an enzyme it forms an “enzyme-substrate complex”

III. Information for the synthesis of enzyme is carried by “DNA”

Which of the above are true?

a) All of them

b) 1 and 2

c) 1 and 3

d) Only 1

Answer: A

3. Which of the following statements about enzymes is true?

A) Enzymes are consumed and used up in chemical reactions.

B) Enzymes make the reaction happen faster

C) Enzymes are only involved in breaking down molecules and not in building them up.

D) Enzymes are exclusively found in plant cells and not in animal cells.

Answer: B

4. What is the primary function of enzymes in biological systems?

A) Providing structural support to cells.

B) Storing genetic information in the form of DNA.

C) Facilitating and speeding up chemical reactions.

D) Transporting nutrients across cell membranes.

Answer:C

5. What is the optimal temperature range for most enzymes to function effectively in biological
systems?

A) 0-10°C

B) 25-30°C
C) 37-42°C

D) 60-70°C

Answer: C

1)What is true regarding the catalytic activity of enzymes?

a) Enzymes cannot change the reaction rate.

b) Enzymes consume substrates.

c) Enzymes initiate or accelerate reactions.

d) Enzymes increase pH levels.

e) Enzymes disturb the equilibrium state of reactions.

Answer: c) Enzymes initiate or accelerate reactions.

2)What is the optimum temperature for an enzyme?

a) Only 37°C

b) It is constant for every enzyme.

c) The temperature that maximally increases enzyme activity.

d) Only 0°C

e) Only 100°C

Answer: c) The temperature that maximally increases enzyme activity.

3)Which model best describes the enzyme-substrate complex?

a) Needle-pole b) Lock-key c) Snake-ladder d) Broken-wave e) Sailboat-ship

Answer: b) Lock-key

4)Among the following factors, which one does not affect enzyme activity?

a) pH level b) Temperature c) Cofactors d) Radiation e) Reactant concentration

Answer: d) Radiation

5)Which enzyme breaks down carbohydrates into glucose?

a) Amylase b) Lipase c) Protease d) RNA polymerase e) Helicase

Answer: a) Amylase

1. Which one false in factors affecting rate of enzyme catalyzed reactions?

A. Raising the temperature increases the rate of enzyme catalyzed reaction by

increasing kinetik energy of reacting moleküler.

B.Enzymes work maximum over a particular temperature known as optimum

temperature.

C. Enzymes for humans generally exhibit stability temperature up to 35-45 C.

D. Most enzymes exhibit optimal activity at pH value between 1 and 3.

Answer:D

2. Which is not one of the methods used in the kinetics of enzyme activity?

A.Its could measure appearance of colored product made from an uncolored

substrate.

B.Its could measure appearance of a UV absorbent product made from a non- UV-

absorbent substrate.

C.Its could measure apperance of a IR spectroscopy.

D.Its could measure apperance of radioactive product made from radioactive

substrate.

Answer:C

3. Which one false for Michaelis Constant(Km) ?

A.Km iş constant for any given enzyme/substrate pair.

B.Small Km means tight binding; large Km means weak binding.

C.Units are in terms of pressure.

D.Km is are measure of ES binding; relative measure of the affinity of a substrate

for an enzyme.

Answer:C

4. Which one false in enzyme class?

A. Oxidoreductases
B.Transferases

C.Hydrolases

D.Lysosims

Answer:D

5. Which one false name of the enzymes?

A.Protease

B.Amylase

C.Lipase

D.Maltose

Answer:D

1. Which one false in factors affecting rate of enzyme catalyzed reactions?

A. Raising the temperature increases the rate of enzyme catalyzed reaction by
increasing kinetik energy of reacting moleküler.
B.Enzymes work maximum over a particular temperature known as optimum
temperature. C. Enzymes for humans generally exhibit stability temperature up to
35-45 C.
D. Most enzymes exhibit optimal activity at pH value between 1 and 3.
Answer:D

2. Which is not one of the methods used in the kinetics of enzyme activity?
A.Its could measure appearance of colored product made from an uncolored substrate.
B.Its could measure appearance of a UV absorbent product made from a non- UV-
absorbent substrate. C.Its could measure apperance of a IR spectroscopy. D.Its could
measure apperance of radioactive product made from radioactive substrate.
Answer:C

3. Which one false for Michaelis Constant(Km) ? A.Km iş constant for any given
enzyme/substrate pair.
B.Small Km means tight binding; large Km means weak binding.
C.Units are in terms of pressure.
D.Km is are measure of ES binding; relative measure of the affinity of a substrate for an
enzyme. Answer:C

4. Which one false in enzyme class?

A. Oxidoreductases
B.Transferases
C.Hydrolases
D.Lysosims
Answer:D

5. Which one false name of the enzymes?

 A.Protease
B.Amylase
C.Lipase
D.Maltose
Answer:D

1) The op�mum opera�ng temperature of an enzyme has been determined and the enzyme works

most effec�vely at this temperature. However, which of the following situa�ons could reduce the

ac�vity of the enzyme?

A) The temperature is above the op�mum value

B) The temperature is below the op�mum value

C) pH is below the op�mum value

D) Increase in substrate concentra�on

E) Increased coenzyme presence

2) Enzymes o�en work specifically on a par�cular substrate. Which of the following op�ons most

affects the substrate specificity of an enzyme?

A) Size of the enzyme

B) Ac�va�on energy of the enzyme

C) Cofactors of the enzyme

D) Shape of the ac�ve site of the enzyme

E) Inhibitors of the enzyme

3) Which of the following op�ons is a common strategy used to increase the rate of an enzyma�c

reac�on?

A) Denature the enzyme

B) Reducing substrate concentra�on

C) Removing enzyme cofactors

D) Reducing enzyme concentra�on

E) Ensuring op�mum pH

4) The ac�vity of enzymes can be affected by various factors. Which of the following situa�ons can

nega�vely affect the ac�vity of an enzyme?

A) High substrate concentra�on

B) Op�mum pH
C) Op�mum temperature

D) Presence of inhibitor molecules

E) Presence of enzyme cofactors

5) In reac�ons catalysed by enzymes, binding of substrates to the ac�ve site is an important step.

Which of the following op�ons most affects the interac�on of the substrate with the enzyme?

A) Size of the substrate

B) Electric charge of the substrate

C) Shape of the substrate

D) Concentra�on of the substrate

E) Reac�on rate of the substrate

What chemical compounds are enzymes?

a) Protein b) Carbohydrate c) Lipid d) Nucleic acid e) Vitamin

Correct Answer: a) Protein

To which class do enzymes belong?

a) Lipases b) Amines c) Catalysts d) Carbohydrates e) Cofactors

Correct Answer: c) Catalysts

By what mechanism do enzymes work?

a) Cellular diffusion b) Reservoir effect c) Ionization d) Key-lock model e) Activation energy

Correct Answer: d) Key-lock model

What is the process that reduces the activity of enzymes called?

a) Cofactoring b) Substrate binding c) Inhibition d) Catalytic conversion e) Coenzyme effect

Correct Answer: c) Inhibition

Which of the following factors increases enzyme activity?

a) Reaction rate b) Substrate concentration c) Reactive cofactors d) Catalytic site e) Inhibition factors

Correct Answer: b) Substrate concentration

1. Which of the following statement is wrong?

a) They are highly specific in their action that is each enzyme can catalyze one kind of substrate

b) Enzymes are sensitive to change in ph temprature and substrate concentration

c) Their presence does effect the nature and properties of end product
d) Small amount of enzymes can accelerate chemical reactions

Answer : C

2. What is the difference in transitional state and substrate called?

a) Activational Barrier

b) Pancreas

c) Enzyme-Substrate complex

d) Holoprotein

Answer : A

3. Which of the statements about Induced fit model are correct?

I- There is any progress regarded with the latest studies of induced fit model

II- The exposure of an enzyme to substrate does not cause a change in enzyme

III- The active site change its shape to allow enzyme and substrate to bind

a) Only I

b) I, II

c) Only III

d) I, III

Answer : D

4. Which kinds of products can not be measured?

a) Appearance of UV absorbent product made from a non- UV- absorbent substrate

b) Appearance of colored product made from an uncolored substrate

c) Appearance of radioactive product made from radioactive substrate

d) Appearance of IR absorbent product made from a non-IR- absorbent substrate

Answer: D

5. What is the catalytic perfection?

a) When every substrate that hits the enzyme causes a reaction to take place

b) Upper limit is diffusion controlled maximum rate at which two freely diffusion molecules can

collide with each other in aqueous solution

c) When Km has the same units as substrate concentration

d) When the ES complex is produced and broken down at the same rate

Answer: A

1-) What is wrong about enzymes?

A-) Enzimes are biological catalysts that speed up the rate of the biochemical reaction.
B-) Most enzymes are the three dimensional globular proteins (tertiary and quaternary structure).
C-)Most enzymes are proteins but some are lipids
D-)Some special RNA species also act as enzymes and are called Ribozymes e.g. hammerhead
ribozyme.
Answer is C

2-)Which one or ones are correct about structure of enzymes?

1. The active site of an enzyme is the region that bind substrates, co-factors and prosthetic
groups and contains residue that helps to hold the substrate.
2. Active site has a specific shape due to tertiary structure of protein
3. A change in the shape of protein affects the shape of active site and function of the enzyme
A-) 1 B-)1,3 C-) 2,3 D-)3 E-) 1,2,3
Answer is E

3-) Which one is wrong about classification of enzymes?

A-) A systematic classification of enzymes has been developed by International Enzyme
Comission
B-) There are six major classes.
C-) This classification is based on the type of reactions catalyzed by enzymes.
D-) We can classify enzymes according to their surface area.
Answer is D
4-)Which is not take place in enzyme class?
A-)Oxidoreductases
B-)Transferases
C-)Monosaccharide
D-)Hydrolases
Answer is C
1. Enzymes are _________________ that speed up the rate of the biochemical reaction.
a) Globular proteins
b) Ribozymes
c) Active site
d) Biological catalysts
e) Apoenzyme
2. Enzymes are synthesized by _____________ which are attached to the rough
____________.
a) Lysosome-ribosome
b) Ribosome-endoplasmic reticulum
c) Chlorapast centrosome
d) Ribosome-centrosome
e) Lysosome-golgi

3. ______________ is defined as the number of substrate molecules transformed per minute

by one enzyme molecules.
a) Turnover number
b) Nusselt number
c) Biot number
d) Reynold number
e) Peclet number

4. I. Tempereature
II. Hydrogen ion concentration(pH)
III. Substrate concentration
Which factors affect the rate of reactions catalyzed by enzymes?
a) I-II
b) I-III
c) I-II-III
d) Only I
e) Only II

5. An enzyme with it’s co-factor removed is designatedas _____________.

a) Holoenzyme
b) Holoprotein
c) Poloenzyme
d) Apoenzyme
e) Poloprotein
1. What is a characteristic feature of intracellular enzymes?
A) Synthesized and used outside the cell
B) Secreted from the cell for external use
C) Synthesized and retained within the cell
D) Produced in the nucleus and used in the cytoplasm
Answer: C

2. Which of the following statements accurately describes the role of enzymes in chemical
reactions?
A) Enzymes increase the total energy of the system during a reaction.
B) Enzymes lower the activation barrier, accelerating reaction rates significantly.
C) Enzymes disturb the equilibrium state by altering the total energy of the system.
D) Enzymes slow down uncatalyzed reactions by forming transitional states with high
activation
energy.
Answer: B

3. What is the term for the reactant in a biochemical reaction, and what occurs when it binds
to an
enzyme?
A) Catalyst
B) Product
C) Substrate
D) Intermediate
Answer: C

4. Which statements accurately describe the Lock and Key Model proposed by Emil Fischer
in 1894?
A) The lock and key hypothesis suggests that the active site of enzymes is flexible in shape.
B) According to the model, there is a change in the active site before and after a chemical
reaction.

C) The Lock and Key Model assumes that the active site of enzymes is rigid in its shape.
D) Emil Fischer proposed the model in 1994, emphasizing dynamic changes in enzyme active
sites.
Answer: C

5. Which model proposes that exposure of an enzyme to a substrate induces a change in the
enzyme,
leading to a modification in the shape of the active site to facilitate binding?
A) Lock and Key Model
B) Fischer's Hypothesis
C) Induced Fit Model
D) Activation-Induced Conformation
Answer: C

1. The part of the enzyme where the substrate binds is called the:
A) Large subunit
B) Catalyst
C) Inhibitor
D) Active site
Answer: D) Active site

2. What are enzymes are made of?

A) DNA
B) Fatty acids
C) Proteins
D) Sugars
Answer: C) Proteins

3.
Which statement best describes the enzyme represented in the graphs?
A) This enzyme works best at a temperature of 50°C and a pH of 12.
B) This enzyme works best at a temperature above 50°C and a pH above 12.
C) Temperature and pH have no effect on the action of this enzyme.
D) This enzyme works best at a temperature of 35°C and a pH of 8.
Answer: D) This enzyme works best at a temperature of 35°C and a pH of 8.

4. Which of the enzymes are correct according to their substrate?

I. Lactose --> Lactase
II. Starch --> Starchase
III. Protein --> Protease
A) Only I B) Only III C) I and II D) I and III E) I,II and III
Answer : D) I and III

5.
The graph shows the relative rates of action of four enzymes, A, B, C, and D. A solution with
a pH
of 7 contains enzyme C and its substrate. If a base is gradually added to this solution, the rate
of
action of enzyme C would most likely
A) Increase, then decrease
B) Decrease, then increase
C) Decrease constantly
D) Remain constant
Answer : A) Increase, then decrease

1. What is the formula for the rate of the forward reaction in an enzyme-catalyzed reaction?
a. 1/k_k + 1/k_
b. 1/k_k - 1/k_
c. k_k + k_
d. k_k - k_
2. What is the formula for the rate of the reverse reaction in an enzyme-catalyzed reaction?
a. 1/k_k + 1/k_
b. 1/k_k - 1/k_
c. k_k + k_
d. k_k - k_

3. What is the assumption made when analyzing enzyme-catalyzed reactions at steady state?
a. The enzyme-substrate complex (ES) is at its maximum value.
b. The rate of formation of the enzyme-substrate complex (ES) is equal to the rate of its
breakdown.
c. The rate of formation of the products (P) is equal to the rate of breakdown of the enzyme-
substrate complex (ES).
d. The rate of formation of the enzyme-substrate complex (ES) is proportional to the rate of
its breakdown.

4. What is the Michaelis-Menten equation used for?

a. To determine the rate of enzyme-catalyzed reactions.
b. To find the dissociation constant of the enzyme-substrate complex (ES).
c. To calculate the maximum velocity (V_max) of an enzyme-catalyzed reaction.
d. To determine the substrate concentration where the initial velocity (v_0) is equal to one-
half of the maximum velocity (V_max).
5. What is catalytic perfection in the context of enzyme-catalyzed reactions?
a. A situation where every substrate that hits the enzyme causes a reaction to take place.
b. A condition where the rate of the forward reaction is equal to the rate of the reverse
reaction.
c. A state where the enzyme-substrate complex (ES) is at its maximum value.
d. A phenomenon where the rate of formation of the products (P) is equal to the rate of
breakdown of the enzyme-substrate complex (ES).
1.Which of the following statements about enzymes or their function is true?
A)Enzymes do not alter the overall change in free energy for a reaction
B)Enzymes are proteins whose three-dimensional form is key to their function
C)Enzymes speed up reactions by lowering activation energy
D)All of the above
2.Beta pleated sheets are examples of protein's
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
3.Which one is the heaviest particulate component of the cell?
A) Nucleus
B) Mitochondria
C) Cytoplasm
D) Golgi Apparatus
4. The digestive enzymes of cellular compounds are confined to
A) Lysosomes
B) Ribosomes
C) Peroxisomes
D) Polysomes
5.Which of the following is true of enzymes?
I. They increase the rate of reaction by stabilizing the transition state
II. They raise activation energy to shift the equilibrium to favor the products
III. They lower activation energy by altering the products of a reaction
A) I
B) II, III
C) I, III
D) III
1)An enzyme with its co-factor removed is designated as…..

A)holoenzyme

B)apoenzyme

C)ribozyme

D)residue
Answer:B

2)Which one is incorrect about active site?

A)Active site of an enzyme is the region that binds substrates,co-factors and prosthetic groups.

B)It contains residue that helps hold the substrate.

C)It has specific shape due to tertiary structure.

D)It is divided into 2 groups as binding site and globular site.

Answer:D

3)Which one is true about enzymes?

A)Their presence does not affect the end product.

B)Enzyme speed up the reaction by increasing activation energy.

C)Small amount of enzymes can not accelerate the reaction.

D)They synthesized by DNA.

Answer:A

4)………….defined as the number of substrate molecules transformed per minute by one enzyme

molecule.

A)Reynolds Number

B)Nusselt Number

C)Turnover Number

D)Prandtl Number

Answer:C

5)Which substrate-enzyme pairing is wrong?

A)lipid-lipase

B)starch-starase

C)protein-protease

D)maltose-maltase Answer:B

1)........ are non-protein molecule which carries out chemical reactions that cannot be performed by

standard 20 amino acids.

A)Co-factors B)Substrates C)Prosthetic groups D)Residues

Answer:A

2)I.Intracellular enzymes synthesized and retained in cell for the use of cell itself.

II.Extracellular enzymes synthesized in cell but secreted from cell to work externally

III.Intracellular enzymes are found in cytoplasm,nucleus,chloroplast etc.

Which of the above is true about Intracellular and Extracellular enzymes?

A)I and II

B)II and III

C)I,II and III

D)Only II

Answer:C

3)Which one is wrong about enzymes?

A)Each enzyme can catalyze one kind of substrate

B)Enzymes are sensitive to change in pH, temperature and substrate concentration.

C)Most enzymes are three dimensional globular proteins.

D)Their presence affect the properties of end product.

Answer:D

4) Which factor is not one of the factors that affecting rate of enzymed catalyzed reactions?

A)Temperature B)Enzyme volume C)Substrate concentration D)pH

Answer:B

5)Substrate fits into a perfectly shaped space in the enzyme.It implies very rigid inflexible active site.

Which enzyme-substrate interaction model is this?

A)Induced Fit Model

B)Michaelis -Menten Model

C)Lock and Key Model

D)Lineweaver-Burk Model

Answer:C

1. Which of the following correctly classifies enzymes based on their functions?

A) Oxidoreductases, lysases, hydrolases

B) Antibodies, hormones, nucleases

C) Lipids, carbohydrates, proteins

D) Cytoplasmic, nuclear, mitochondrial

Answer: A) Oxidoreductases, lysases, hydrolases

I.Substrate concentration

II.Hydrogen ion concetration

III.Hydroxil ion concentration

2. Which ones affect the rate of catalyzed reactions of enzymes?

A)Only I C) Only III

B)I and II D)I and III

Answer: B)I and II

3. Which of the following is NOT a classification of enzymes?

A) Oxidoreductases B) Transferases C) Ligases D) Passive transporters

Answer: D) Passive transporters

4. Which of the following statements about active sites of enzymes is TRUE?

A) Active sites are rigid structures that do not change shape

B) Active sites bind to substrates, but do not participate in the catalytic reaction

C) Active sites can only bind one type of substrate and catalyze one specific reaction

D) Active sites are located on the outer surface of the enzyme molecule

Answer: C) Active sites can only bind one type of substrate and catalyze one specific reaction

5. Which organelle is responsible for enzyme synthesis in prokaryotic cells?

A) Nucleus B) Ribosomes C) Golgi apparatus D) Vacuoles

Answer: B) Ribosomes

1.Which one not a factor affecting rate of enzyme

catalyzed reactions?

A. Temperature

B.Pressure

C.Hydrogen ion concentration

D.Substrate concentration

Answer:B

2.Which one false in structure of enzymes?

A.The active site of an enzyme is the region that binds

substrates, co-factors anda prosthetic groups anda

contains residue that helps to hold the substrate.

B.Active sites generally occupy less than 5% of the

total surface area of enzyme.

C.Active site has a same shape due to tertiary

structure of protein.

D.A change in the shape of protein affects the shape

of active site anda function of the enzymes.

Answer:C

3.Which one false for intracellular and extracellular

enzymes?

A. Intracellular enzymes are synthesized anda

retained in the cell for the use of cell itself.

B.Intracellular enzymes are found in the cytoplasm,

nucleus, mitochondria and chloroplast.

C.Oxydoreductase catalyses chemical oxidation.

D.Extracellular enzymes are synthesized in the cell

but sekreter from the cell to work externally.

Answer:C

4.Whice one false enzymes of characteristics?

A.Enzymes speed up the reaction by lowering the

activation energy of the reaction.

B.Their presence does not effect the nature anda

properties of end product.

C.They are lowly specific in their action that is each

enzyme can catalyze one kind of substrate.

D.Small amount of enzymes can accelerate chemical

reactions.

Answer:C

5.Which iş not the name of enzyme?

A.Lactase

B.Maltase

C.Cellulase

D.Lipid

Answer:D
1. Which of the option is wrong for the figure is given above?

A) As [S] is first increased, the initial rate or velocity (Vo) increases with increasing
substrate concentration
B) As [S] increases, V increases less and less
C) Finally, V doesn't increase anymore and velocity reaches its maximum (V_{tuax}).
D) Velocity won't change no matter how much substrate is present. At this point, the
enzyme is saturated with substrate, S.
E) As S increases, V decreases less and less.

2. V max Vo = Vmax [S]/ KM +[S] This above equation is belong to who?

A) The Michaelis - Menten equation
B) Nerst equation
C) Newton method equation
D) Dimitry Mendeleyev equation
E) Linevear and Burk equation

3. Enzymes work maximum over a particular temperature known as....... temperature.

Which one should fill the blank?
A) maximum
B)optimum
C)large
D) small
E) minimum

4) Active site can be further divided into two groups. What is the name one of these
two groups?
A) co-factor
B) inactive site
C) Binding site
D) uncatalytic site
E) regular site

5) CO-FACTORS
Co-factor is the non protein molecule which carries out chemical reactions that can
not be performed by standard 20 amino acids.
• Co-factors are of two types, what are these two types?

A) catalytic , uncatalytic
B) Organic and Inorganic cofactors
C) regular and irregular
D) maximum and minimum
E) active and inactive

1. I. Temperature
II.Hydrogen ion concentration(pH)
III.Substrate concentration
Which of the above FACTORS AFFECTING RATE OF ENZYME CATALYZED
REACTIONS?
A) only I
B) I and II
C)I and III
D)only II
E) I ,II and III

2 . Which of the below information is not true about effect of temperature?

A)Raising the temperature increases the rate of enzyme catalyzed reaction by
increasing kinetic energy of reacting molecules.
B) Enzymes work maximum over a particular temperature known as optimum temperature.
Enzymes for humans generally exhibit stability temperature up to 35-45 °C
C)The temperature coefficient is a factor Q10 by which the rate of biological
processes increases for a 10 C increase in temperature.
D)For most biological processes Q10 = 5
E) Some times heat energy can also increase kinetic energy to a point that exceed
the energy barrier

3.Most enzymes exhibit optimal activity at Ph value between ........and ..........

Which of the following answer is correct for the blanks?
A) 2 and 6
B) 1 and 4
C)5 and 9
D) 3 and 8
E) 6 and 7

4) A+B <---> C
The rate of the rxn catalyzed by enzyme E
Which of the following is not correct for define the rxn?
A) -d[A]/Dt
B)-d[B] / dt
C) d[P]/dt
D) d[C]/Dt
5) The figure of Enzyme Kinetics given above.
The ..............of an enzyme-catalyzed reaction is dependent upon the substrate
concentration [S]
Which of the following is correct for the blank ?

A) density
B ) rate
C) concentration
D) Velocity
E) viscosity

1)..... is the non protein molecule which carries out chemical reactions that can not be

performed by standard 20 amino acids.

Which of the following is the term defined above?

A)Apoenzyme

B)Substrate

C)Co-factor

D)Catalyst

E)Holoenzyme

2)Information for the synthesis of enzyme is carried by .......

A)Ribosome

B)DNA

C)Endoplasmic Reticulum

D)RNA

E)Mitochondria

3)I.Enzymes are highly specific in their action that is each enzyme can catalyze one kind of

substrate.

II.Enzymes speed up the reaction by increasing the activation energy of the reaction.

III.Small amount of enzymes can accelerate chemical reactions.

Which of the above information about enzymes is correct?

A)I,II

B)Only I

C)I,III

D)I,II,III

E)II,III

4) Which of the following is not an enzyme?

A)Maltase

B)Pepsin

C)Lipase

D)Cellulose

E)Trypsin

5)I.pH

II.Pressure

III.Temperature

IV.Substrate concentration

Which of the above are factors that affect the rate of enzyme-catalyzed reactions?

A)I,III

B)II,III,IV

C)I,IV

D)I,II,III,IV

E)I,III,IV

1- ……… are biological catalysts that speed up the rate of the biochemical reaction. Which of

the following should fill in the blank?

A. Carbohydrates

B. Lipids

C. Enzymes

D. Amino acids

2- Which of the following is incorrect?

A. Enzymes speed up the reaction by lowering the activation energy of the reaction.

B. Enzymes are highly specific in their action, that is each enzyme can catalyze one kind

of substrate.

C. Enzymes are sensitive to change in pH, temperature and substrate concentration.

D. The presence of enzymes does effect the nature and properties of the end product.

3- What is Enzyme Inhibition?

A. Enzyme activation

B. Decrease in enzyme activity

C. Binding of substrates

D. Acceleration of cell division

4- Which one is not one of the factors affecting the rate of enzyme catalyzed reactions?

A. pH

B. Temperature

C. Pressure

D. Substrate concentration

5-

I. Enzymes are synthesized by ribosomes which are attached to the rough endoplasmic

reticulum.

II. Information for the synthesis of enzymes is carried by DNA.

III. Amino acids are bonded together to form specific enzymes according to the DNA&#39;s

codes.

Which one or which ones are correct?

A. Only I

B. I – III

C. II – III

D. All of them.

What is the structure of the active parts of enzymes?

a) Monomer structure

b) chain structure

c) linear structure

d) tertiary structure

Answer: D

When a substrate binds to an enzyme it forms an ……………… .

a) enzyme synthesis

b) ribosomes

c) DNA

d) Enzyme-substrate complex

Answer: D

How is the glucose molecule obtained from maltose?

a) With galactose

b) With lipase
c) With cellulase

d) With maltase

Answer: D

What is the working model of enzymes?

a) With Oktar hypothesis

b) According to physics rules

c) Randomly

d) Lock and Key Model

Answer: D

Which does not affect enzyme kinetics?

a) Temperature

b) Hydrogen ion concentration

c) Substrate concentration

d) number of ribosomes

Answer: D

1. What is the Michaelis-Menten constant (Km) in enzyme kinetics?

a) The maximum reaction rate (Vmax).

b) The substrate concentration at half of Vmax.

c) The rate constant for the breakdown of the ES complex.

d) The rate constant for the formation of the product.

Answer: b

2. In enzyme kinetics, what does Vmax represent?

a) The maximum enzyme concentration in the reaction.

b) The maximum rate of the enzyme-catalyzed reaction.

c) The concentration of the substrate at the beginning of the reaction.

d) The rate constant for the formation of the ES complex.

Answer: b

3. What is the significance of the turnover number (kcat) of an enzyme?

a) It represents the maximum rate of the enzyme-catalyzed reaction. b) It

indicates the efficiency of the enzyme at low substrate concentrations. c) It

measures the rate of breakdown of the ES complex.

d) It quantifies the number of substrate molecules converted to product per

enzyme active site per unit time.

Answer: d

4. Which of the following best describes the Lineweaver-Burk plot? a) It is

a graphical representation of the Michaelis-Menten equation. b) It shows the

relationship between enzyme concentration and reaction rate. c) It is used to

determine the Vmax of an enzyme-catalyzed reaction. d) It represents the

inverse of the Michaelis-Menten equation.

Answer: d

5. What is the role of an enzyme cofactor in catalyzing a reaction?

a) It provides structural stability to the enzyme.

b) It increases the substrate concentration.

c) It facilitates the formation of the ES complex.

d) It assists the enzyme in catalyzing the reaction by participating in the

reaction mechanism.

Answer: d

1) Enzymes are ……………. that speed up the rate of the biochemical reaction.

Which one fits the best in the sentence above?

A) Globular proteins

B) Ribozymes

C) Hammerhead ribozymes

D) Chemical catalysts

E) Biological catalysts

Answer: E

2) Which ones are included in active site:

I)Binding site

II)Catalytic site

III)Protein site

A) I, II

B) I, III

C) I, II, III

D) II, III

E) II
Answer: A

3) Which one is wrong about co-factors and enzymes?

A) Co-factors can carry out reactions that cannot be done by standard 20 amino acids.

B) Co-factors are protein molecules.

C) There are two types of co-factors: organic and inorganic.

D) Pyridoxal phosphate is an organic co-factor.

E) Enzyme with removed co-factor is called apoenzyme.

Answer: B

4) Which of the following information is wrong?

A) Substrates are the reactants in biochemical reactions.

B) Enzymes are synthesized by ribosomes.

C) Enzymes lower the activation energy and speed up the reaction.

D) Each enzyme can catalyze one kind of substrate.

E) Extracellular enzymes work inside the cell they synthesized.

Answer: E

5) Which one is wrong about the kinetics in biochemistry?

A) Enzymes work best at optimum temperature. For humans, it is 35-45°C.

B) Most enzymes exhibit at pH 5-9.

C) Velocity (reaction rate) is not related with substrate concentration [S].

D) The graph of velocity against substrate concentration is called saturation plot or

Michaelis-Menten plot.

E) Increase in temperature also increases rate.

Answer: C

1. The active site of an enzyme is the region that binds substrates, cofactors, and prosthetic

groups and contains residue that helps to hold the substrate. Active site can be divided into

two groups. Which option represents these two groups?

A. Binding site- Catalytic Site

B. Organic-Inorganic

C. Negative side – Positive side

D. Ribosoms – DNA

2. ………………….. enzymes are synthesized and retained in the cell for the use of cell itself. Which
word comes to the blank?

A. Intracellular

B. Into

C. Through

D. Inside

3. The systematic classification of enzymes has been developed by the International Enzyme

Commission. There are six major classes. Which is not one of these classes?

A. Oxidoreductases

B. Transferases

C. Hydrolases

D. Lysosom

4. Enzymes work maximum over a particular temperature known as ……………………. Enzymes for

humans generally exhibit stability temperatures up to 35-45 C.

A. Optimum temperature

B. Great temperature

C. Activation energy

D. Low temperature

5. Which one is not one of the factors affecting rate of enzyme catalyzed reaction.

A. Temperature

B. Hydrogen ion concentration

C. Substrate concentration

D. Exchange ion concentration

1) Which of the following is the definition of activation energy?

a)The least amount of energy needed for a chemical reaction to take place.

b) Energy an object has because of its motion.

c) Form of potential energy. It is an energy associated with gravity or gravitational force.

d) Type of kinetic energy that travels in waves.

e) Movement of electrons (the tiny particles that makeup atoms, along with protons and

neutrons).

2) Which equation describes the kinetic behaviour of many enzimes?

a) Arrhenius equation ‘’ k= Ae*RT-Ea’’

b) Michaelis-Menten equation

c) Van't Hoff equation ln(k2/k1)= (-ΔrH0/R)*(1/T2-1/T1)

d) Avogadro’s Law (V ∝ n)

e) Dalton’s Law of Partial Pressures ‘’ Ptotal = PA + PB + ⋯’’

3) Which one is false about Effect of pH?

a) Rate of almost all enzymes catalyzed reactions depends on pH.

b) Most enzymes exhibit optimal activity at pH value between 5 and 9.

c) High or low pH value than optimum value will cause ionization of enzyme which

result in denaturation of enzyme.

d) pH does not effect rate of reaction.

4) Which is the following is false about structure of enzymes?

a) The active site of an enzyme is the region that binds substrates, co-factors and

prosthetic groups.

b) Activate sites generally occupy less than 10% of the total surface area of enzyme.

c) Activate site has a spesific shape due to tertiary structure of protein.

d) A change in the shape of protein affects the shape of active site and function of the

enzyme.

5) Which enzyme-product pairing is incorrect?

a)Lactase Glucose+galactose

b)Cellulase Glucose

c)Lipase Glycerol+fatty acid

d)Protease Peptides+galactose

e)Amylase Maltose

1-) What level of structure of the protein causes the active site to have a particular

shape?

A-) Primary

B-) Secondary

C-) Quaternary
D-) Tertiary

E-) Globular

(Answer: D)

2-) What carries information about enzyme synthesis?

A-) RNA B-) Cytoplasm C-) DNA D-) mRNA E-) Golgi Apparatus

(Answer : C)

3-) Under conditions of pH 7, 25°C and a Hexokinase concentration of 3.0 mol/L, the KM

for Hexokinase for the substrate glucose was determined to be 4.0 x 10-4 M. When the

glucose concentration was set to 180 μΜ, the initial rate of the reaction was found to be

65.0 μmol/(mL•s). What is Vmax for Hexokinase under these conditions?

A-) 65 B-) 66 C-) 67 D-) 68 E-) 64

(Answer: A)

4-) Which option is incorrect regarding thermodynamic changes in enzymes?

A-) Enzymes provide an alternate pathway for conversion of substrate into products.

B-) The reaction rate is increased many folds in the presence of enzymes.

C-) The total energy of the system remains the same and equilibrium state is disturbed.

D-) Enzymes accelerate reaction rates by forming transitional state having low activational

energy.

E-) Rate of uncatalyzed reactions is much slow

(Answer: C)

5-) Which is not a class of enzyme?

A-) Transferases

B-) Oxidoreductases

C-) Hypolases

D-) Ligases

E-) Isomerases

(Answer:C)

1What is the main role of enzymes in biological processes?

a) Energy storage

b) Structural support
c) Speeding up chemical reactions

d) Transport of gases

e) Genetic information storage

Correct answer: c) Speeding up chemical reactions

2Which statement is true about enzymes?

a) They decrease the rate of chemical reactions

b) They are consumed in the reactions they catalyze

c) They are specific in their action and target only one substrate

d) They are inorganic molecules

e) They have no effect on reaction rates

Correct answer: c) They are specific in their action and target only one substrate

3What is the function of enzymes in biological systems?

a) Store genetic information

b) Act as structural components of cells

c) Speed up chemical reactions

d) Transport oxygen in the blood

e) Provide energy for cellular activities

Correct answer: c) Speed up chemical reactions

4Which term best describes the specific region of an enzyme where the substrate binds?

a) Nucleus

b) Active site

c) Ribosome

d) Mitochondria

e) Cytoplasm

Correct answer: b) Active site

5What can affect the activity of enzymes?

a) Temperature and pH

b) Sunlight exposure

c) Cellular size

d) Electron configuration

e) Atmospheric pressure
Correct answer: a) Temperature and pH

1)What is the primary function of enzymes in biological systems?

a. Energy storage

b. Structural support

c. Catalyzing chemical reactions

d. Cell communication

2) Which of the following statements about enzymes is true?

a. Enzymes are consumed during a chemical reaction.

b. Enzymes alter the equilibrium of a reaction.

c. Enzymes increase the activation energy of a reaction.

d. Enzymes are specific for a single substrate

3) What is the term used to describe the specific region on an enzyme where a

substrate binds?

a. Active site

b. Binding site

c. Catalytic center

d. Substrate zone

4) What is the effect of temperature on enzyme activity?

a. Enzyme activity increases with temperature until it reaches an optimum, then decreases.

b. Enzyme activity decreases linearly with temperature.

c. Enzyme activity is not affected by temperature.

d. Enzyme activity increases indefinitely with temperature.

5) Which of the following is a coenzyme commonly involved in enzyme-catalyzed

reactions?

a. ATP

b. NAD+

c. DNA

d. RNA

1. Which of the following statements are correct?

I. Information for the synthesis of enzymes is carried by RNA.

II. Enzymes are synthesized by ribosomes which are attached to the smooth E.R.

III. Amino acids are bonded together to form specific enzymes according to the DNA’s

codes.
A) I, III

B) I, II, III

C) I, II

D) Only III

E) Only II

Cevap:D

2. Which of the following statements are not correct for characteristics of enzymes?

A) Enzymes speed up the reaction by lowering the activation energy of the reaction.

B) They are highly spesific in their reaction, that is each enzyme can catalyze one kind of substrate.

C) Their presence affect the nature and properties of end product.

D) Small amounts of enzymes can accelerate chemical reactions.

E) Enzymes are sensitive to the change in pH, temperature and substrate concentration.

Cevap:C

3. Which of the following factors affect the rate of enzyme catalyzed reactions?

I. Temperature

II. pH

III. Substrate concentration

A) I and II

B) All

C) III

D) I

E) II

Cevap:B

4. Which substrate-enzyme pair is not correct?

A) Lactose-lactase

B) Maltose-maltase

C) Lipid-amylase

D) Protein-protease

E) Cellulose-cellulase

Cevap:C

5. Which statement cannot is not correct for enzyme structures?

A) Active site has a spesific shape due to the tertiary structure of protein.

B) Active sites generally occupy more than 5% of the total surface area of enzyme.

C) A change in the shape of protein affects the shape of active site.

D) Active sites can be categorized into binding site and catalytic site.

E) Catalytic size performs the catalytic action of enzyme.

Cevap: B

1. Which of the following is NOT a general characteristic of enzymes?

a) They are specific catalysts

b) They are sensitive to temperature and pH.

c) They change the ΔG value of a reaction.

d) They accelerate reactions they catalyze.

e) They remain unchanged in the reaction products.

2. Which of the following best describes a cofactor?

a) An inactive form of the enzyme. b) Non-protein organic molecules.

c) Small molecules that directly interact with the enzyme.

d) Protein segments directly affecting the enzyme's catalytic activity.

e) The substrate of the enzyme.

3. Which is a reversible enzyme inhibitor?

a) Competitive inhibition. b) Non-competitive inhibition. c) Irreversible inhibition.

d) Allosteric inhibition. e) Feedback inhibition.

4. Which of the following best describes the primary structural difference between fats and

oils?

a) Fats are solid at room temperature, while oils are liquid.

b) Fats are primarily saturated, while oils are primarily unsaturated.

c) Fats contain more glycerol molecules than oils.

d) Oils are derived only from plants, while fats are derived from animals.

e) Fats are hydrophilic, whereas oils are hydrophobic.

5. Function and Composition: In terms of their physiological roles, which statement regarding

fats and oils is accurate?

a) Fats primarily serve as energy storage molecules in animals, while oils are more involved in

membrane structure.

b) Both fats and oils are exclusively used for energy storage in organisms. c) Oils are solid at

room temperature, providing structural rigidity in cell membranes.

d) Fats and oils have identical fatty acid compositions but differ in their glycerol
backbones.

e) Neither fats nor oils have any significant role in the biochemistry of living

organisms.

1) The op�mum opera�ng temperature of an enzyme has been determined and the enzyme works

most effec�vely at this temperature. However, which of the following situa�ons could reduce the

ac�vity of the enzyme?

A) The temperature is above the op�mum value

B) The temperature is below the op�mum value

C) pH is below the op�mum value

D) Increase in substrate concentra�on

E) Increased coenzyme presence

2) Enzymes o�en work specifically on a par�cular substrate. Which of the following op�ons most

affects the substrate specificity of an enzyme?

A) Size of the enzyme

B) Ac�va�on energy of the enzyme

C) Cofactors of the enzyme

D) Shape of the ac�ve site of the enzyme

E) Inhibitors of the enzyme

3) Which of the following op�ons is a common strategy used to increase the rate of an enzyma�c

reac�on?

A) Denature the enzyme

B) Reducing substrate concentra�on

C) Removing enzyme cofactors

D) Reducing enzyme concentra�on

E) Ensuring op�mum pH

4) The ac�vity of enzymes can be affected by various factors. Which of the following situa�ons can

nega�vely affect the ac�vity of an enzyme?

A) High substrate concentra�on

B) Op�mum pH

C) Op�mum temperature

D) Presence of inhibitor molecules

E) Presence of enzyme cofactors

5) In reac�ons catalysed by enzymes, binding of substrates to the ac�ve site is an important step.

Which of the following op�ons most affects the interac�on of the substrate with the enzyme?

A) Size of the substrate

B) Electric charge of the substrate

C) Shape of the substrate

D) Concentra�on of the substrate

E) Reac�on rate of the substrate