intro
Question 1:
What is the increase in temperature that doubles the rate of reaction?
Topic: Enzyme Kinetics and Temperature Effects
Correct Answer: B) 10°C
- In enzymatic reactions, a temperature increase generally boosts the reaction rate.
- From the given options, an increase of 10°C is known to double the rate of such reactions.
- Therefore, the correct answer is B, "10°C".
Question 2:
How does the reaction speed correlate with the activation energy?
Topic: Activation Energy and Reaction Rate
Correct Answer: A) Faster for lower activation energy
- Activation energy is the minimum energy required for a chemical reaction to take place.
- The lower the activation energy, the more rapidly the reaction occurs.
- Hence, the correct answer is A, "Faster for lower activation energy".
Question 3:
Which enzyme is most effective in an alkaline environment?
Topic: Enzymes and pH Levels
Correct Answer: A) Trypsin
- Enzymes have optimal pH ranges where they exhibit maximum activity.
- Trypsin works best in an alkaline environment (pH 7.8 – 8.7), while Pepsin requires an acidic environment (pH 1.5 – 1.6).
- Therefore, the correct answer is A, "Trypsin".
Question 4:
What term best describes when a molecule alters an enzyme's shape by binding to a site other than its active site, rendering the enzyme ineffective?
Topic: Enzyme Inhibition
Correct Answer: C) Non-competitive Inhibition
- Enzyme inhibition refers to a decrease in the enzyme’s activity due to a molecule binding to it.
- In the case of non-competitive inhibition, the molecule binds to the enzyme at a site other than the active site, changing the enzyme's shape and making it unable to function.
- So, the correct answer is C, "Non-competitive Inhibition".
Question 5:
Considering their composition, what category do enzymes fall into?
Topic: Enzyme Composition
Correct Answer: D) Both B and C
- Enzymes are complex proteins that function as biological catalysts, facilitating biochemical processes in the body.
- They are primarily globular proteins, which differ from fibrous proteins due to their spherical shape.
- Therefore, the correct answer is D, "Both B and C".
Question 6:
What does the enzyme contained in sweat primarily target for digestion?
Topic: Enzymatic Activity of Sweat
Correct Answer: B) Wall of bacteria
- Sweat contains the enzyme Lysozyme, which plays an important role in our body's defense mechanisms.
- Lysozyme specifically targets and digests the walls of bacteria, thus leading to the destruction of the bacteria.
- Hence, the correct answer is B, "Wall of bacteria".
Question 7:
Which one of the following enzymes operates best in an acidic environment?
Topic: Enzyme Activity and pH
Correct Answer: D) Pepsin
- The activity and efficiency of an enzyme can be significantly influenced by changes in pH.
- Pepsin, a digestive enzyme, operates optimally at an acidic pH (1.5-1.6), unlike Lipase that works at pH 8.0, Trypsin at 7.8-8.7, and Urease at 7.0.
- Therefore, the correct answer is D, "Pepsin".
Question 8:
At what temperature can the enzymes of thermophilic bacteria function effectively?
Topic: Thermophilic Bacteria and Enzyme Activity
Correct Answer: D) 90°C
- Thermophilic bacteria are a type of extremophile, organisms that thrive in extreme environments, including high temperatures.
- The enzymes produced by these bacteria are designed to function optimally at these high temperatures, in this case, 90°C.
- Therefore, the correct answer is D, "90°C".
Question 9:
What best describes the induced fit hypothesis regarding enzyme functionality?
Topic: Enzyme Activity and Induced Fit Hypothesis
Correct Answer: C) Changes in enzyme shape due to substrate presence
- The induced fit hypothesis is a model for enzyme-substrate interaction.
- It suggests that enzyme shape dynamically changes to accommodate the binding of the substrate.
- Hence, the correct answer is C, "Changes in enzyme shape due to substrate presence".
Question 10:
Which enzyme is regarded as the most abundant in the world?
Topic: Abundance of Enzymes
Correct Answer: B) RUBISCO
- There are countless enzymes, each with unique functionalities, but in terms of sheer quantity, one reigns supreme.
- RUBISCO, an enzyme involved in the first major step of carbon fixation, is considered the most abundant enzyme on Earth.
- Consequently, the correct answer is B, "RUBISCO".
Question 11:
Enzymatic reactions are regulated by which type of substances?
Topic: Regulation of Enzymatic Reactions
Correct Answer: D) Both A and C
- The rate and direction of enzymatic reactions can be controlled by certain substances.
- Inhibitors deter or slow down enzymatic reactions, whereas activators accelerate them.
- Therefore, the correct answer is D, "Both A and C".
Question 12:
Who proposed that the substrate perfectly fits into a specific shape on each enzyme?
Topic: Enzyme-Substrate Interaction
Correct Answer: C) Emil Fischer
- The concept that each substrate perfectly fits a specific shape on an enzyme is a fundamental principle in biochemistry.
- This theory, also known as the lock and key model, was proposed by Emil Fischer.
- Hence, the correct answer is C, "Emil Fischer".
Question 13:
What suffix is typically added to the substrate name, or a phrase describing the activity of an enzyme, to name the enzyme?
Topic: Enzyme Nomenclature
Correct Answer: B) ase
- Enzyme names often derive from their substrate names or from a description of their activity, with a distinctive suffix.
- The common suffix for enzyme names is "ase".
- Therefore, the correct answer is B, "ase".
Question 14:
Identify the disease that is caused by a deficiency of enzymes:
Topic: Enzyme Deficiency Diseases
Correct Answer: D) All of the above
- Certain diseases are directly attributed to the deficiency or malfunction of specific enzymes in the body.
- Tay-Sachs, Phenylketonuria, and Glycogenosis type-II are all examples of such diseases, each resulting from the deficiency of a different enzyme.
- Consequently, the correct answer is D, "All of the above".
Question 15:
Which type of enzymatic inhibitor are insecticides an example of?
Topic: Enzyme Inhibitors
Correct Answer: B) Non-competitive inhibitor
- Some substances can inhibit the action of enzymes, classed as either competitive or non-competitive inhibitors based on their mechanism of action.
- Insecticides serve as non-competitive inhibitors, binding to allosteric sites rather than the active site to alter enzyme function.
- Hence, the correct answer is B, "Non-competitive inhibitor".
Question 16:
How does an increase in product concentration affect enzymatic activity?
Topic: Enzyme Activity and Product Concentration
Correct Answer: C) No effect
- The activity of enzymes is influenced by various factors, but the concentration of the product is not typically one of them.
- The rate of enzymatic reactions is largely independent of the amount of product formed.
- Therefore, the correct answer is C, "No effect".
Question 17:
Which hypothesis proposes the idea of the active site as a flexible structure, adjusting during the reaction process?
Topic: Enzyme Hypotheses
Correct Answer: B) Induced-fit
- There are several hypotheses about how enzymes interact with their substrates and facilitate chemical reactions.
- The induced-fit hypothesis suggests that the enzyme's active site is flexible and can modify or change during the reaction process.
- Therefore, the correct answer is B, "Induced-fit".
Question 18:
If an enzyme exhibits 50% activity at a temperature of 25°C, at what temperature will its activity peak (100%)?
Topic: Enzyme Activity and Temperature
Correct Answer: C) 35°C
- The activity of enzymes is influenced by various factors, including temperature.
- An increase in temperature by 10°C typically doubles the rate of the enzymatic reaction, implying that 100% activity should occur at 35°C.
- Hence, the correct answer is C, "35°C."
Question 19:
Which of the following statements is true about enzymes?
Topic: Basic Properties of Enzymes
Correct Answer: C) Requires only a small amount to function
- Enzymes are biocatalysts with several important characteristics.
- One key feature is that they function efficiently even in small quantities, meaning that only a minor amount is required for catalysis.
- Therefore, the correct answer is C, "Requires only a small amount to function".
Question 20:
Which of the following represents a coenzyme?
Topic: Coenzymes in Biochemical Reactions
Correct Answer: D) All of the above
- Coenzymes are organic molecules required by certain enzymes to carry out catalysis. They often act as intermediate carriers of electrons, atoms, or groups in the overall reaction.
- NAD+, FAD+, and NADP are all examples of coenzymes that play crucial roles in various biochemical reactions.
- Therefore, the correct answer is D, "All of the above".
Question 21:
What is the result of the combination of an apoenzyme and a coenzyme?
Topic: Enzyme Forms and Compositions
Correct Answer: C) Holoenzyme
- Enzymes often exist in two forms - an inactive form known as the apoenzyme, and an active form referred to as the holoenzyme.
- The transition from an apoenzyme to a holoenzyme requires the binding of a coenzyme or a cofactor, which helps to mediate the enzyme's catalytic activity.
- Therefore, the correct answer is C, "Holoenzyme".
Question 22:
What is the potential outcome if the activation energy of a reaction increases?
Topic: Activation Energy and Reaction Rate
Correct Answer: A) Rate of reaction decreases
- The activation energy is the minimum amount of energy needed for a chemical reaction to occur. It has a direct impact on the rate of the reaction.
- If the activation energy increases, the rate of the reaction decreases because fewer molecules have the required energy to overcome the activation energy barrier.
- Hence, the correct answer is A, "Rate of reaction decreases".
Question 23:
Which of the following enzymes are not found in the stomach?
Topic: Digestive Enzymes in Different Organs
Correct Answer: D) None of the above
- Digestive enzymes are specialized proteins that help break down food into absorbable nutrients.
- The stomach primarily contains protein-digesting enzymes (like pepsin) and lipid-digesting enzymes (like gastric lipase).
- Therefore, the correct answer is D, "None of the above".
Question 24:
What are the non-protein organic molecules that are attached to enzymes near the active site?
Topic: Role of Co-Enzymes in Enzymatic Reactions
Correct Answer: B) Co-enzymes
- Co-enzymes are organic molecules that work in tandem with enzymes to facilitate the conversion of substrates into products.
- They are often found attached to the enzyme close to the active site and participate in the transfer of functional groups or electrons during the reaction.
- Hence, the correct answer is B, "Co-enzymes".
Question 25:
Which of the following can act as a non-competitive inhibitor?
Topic: Inhibitors in Enzymatic Reactions
Correct Answer: D) Both A and C
- Non-competitive inhibitors bind to an enzyme at a location other than the active site, altering the enzyme's shape and making it less effective.
- Cyanide and certain insecticides can function as non-competitive inhibitors, while sulphonamides typically act as competitive inhibitors.
- Thus, the correct answer is D, "Both A and C".
Question 26:
What designation is shared by cyanide, heavy metal ions, and some insecticides in relation to enzymes?
Topic: Types of Enzyme Inhibitors
Correct Answer: C) Non-competitive inhibitors
- Enzyme inhibitors are molecules that interfere with the functioning of enzymes. They can be categorized into competitive and non-competitive inhibitors.
- Competitive inhibitors compete with the substrate for the active site of the enzyme, while non-competitive inhibitors bind to a different site, causing a change in the enzyme's shape and reducing effectiveness.
- Cyanide, heavy metal ions, and some insecticides are examples of non-competitive inhibitors.
- Thus, the correct answer is C, "Non-competitive inhibitors".
MCQs 27:
In feedback inhibition, which part of the enzyme's structure is implicated?
Topic: Enzyme Regulation Mechanisms
Correct Answer: D) Allosteric site
- Feedback inhibition is an essential regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme involved in its production.
- In this process, the end product binds to the allosteric site of the enzyme, causing a conformational change that inhibits the enzyme's function.
- Therefore, the correct answer is D, "Allosteric site".
MCQs 28:
What would likely happen if a molecule with a shape very similar to an enzyme's substrate attaches to its active site?
Topic: Enzyme Inhibition Mechanisms
Correct Answer: B) Inhibit the enzyme's function
- Molecules that have a similar shape to an enzyme's substrate can bind to its active site, blocking the actual substrate from attaching.
- This process, known as competitive inhibition, prevents the enzyme from performing its function.
- Thus, the correct answer is B, "Inhibit the enzyme's function".
MCQs 29:
Which of the following is the only enzyme secreted in an active form?
Topic: Enzyme Secretion Mechanisms
Correct Answer: C) Amylopsin
- Many enzymes are secreted in their inactive form, known as zymogens, to prevent autodigestion. They are then activated in the location where they are needed.
- Pepsinogen and carboxypeptidase, for example, are secreted in their inactive forms. However, Amylopsin is an exception as it's secreted in its active form.
- Hence, the correct answer is C, "Amylopsin".
MCQs 30:
What is the term for the type of inhibition where the inhibitor is typically a reaction product formed during the metabolic pathway?
Topic: Enzyme Inhibition Mechanisms
Correct Answer: A) Feedback inhibition
- Feedback inhibition is a regulatory mechanism in which a reaction product acts as an inhibitor of an enzyme earlier in the pathway.
- This mechanism helps control the production of such products, ensuring cells don't waste resources by making more than needed.
- Thus, the correct answer is A, "Feedback inhibition".
MCQs 31:
What are the standard temperature and pH for the human body's enzymes?
Topic: Enzyme Optimal Conditions
Correct Answer: A) 37°C and 4–5
- Each enzyme has an optimal temperature and pH at which it functions best. For human enzymes, this is usually around 37°C and a pH of 4-5.
- Deviating from these optimal conditions can reduce the enzyme's activity or, in extreme cases, denature the enzyme.
- Therefore, the correct answer is A, "37°C and 4–5".
MCQs 32:
At what temperature do enzymes in plants start to denature?
Topic: Enzyme Denaturation in Plants
Correct Answer: C) 60°C
- Enzymes are proteins that facilitate biochemical reactions and their structure is crucial to their function.
- High temperatures cause enzymes to denature, altering their structure and inhibiting their function.
- For plant enzymes, denaturation typically begins at around 60°C.
- Hence, the correct answer is C, "60°C".
MCQs 33:
Which vitamin is found in co-enzyme A?
Topic: Components of Co-enzymes
Correct Answer: C) Vit-B5
- Co-enzymes are non-protein compounds that assist enzymes in their function.
- Co-enzyme A, in particular, contains Vitamin B5 or pantothenic acid, which plays a significant role in the metabolism of proteins, fats, and carbohydrates.
- Therefore, the correct answer is C, "Vit-B5".
Question 34:
What is the pH level of lipase from the pancreas?
Topic: Optimal Conditions for Enzyme Function
Correct Answer: C) 8
- Lipase is an enzyme that breaks down dietary fats into smaller molecules called fatty acids and glycerol.
- The optimal pH for the function of pancreatic lipase is around pH 8.
- Thus, the correct answer is C, "8".
Question 35:
What happens to the rate of a reaction when the concentration of an enzyme increases?
Topic: Enzyme Concentration and Reaction Rate
Correct Answer: B) The rate of reaction increases
- Enzymes accelerate chemical reactions by lowering activation energy.
- When the concentration of an enzyme is increased in a reaction, there are more active sites available to catalyze the reaction, leading to an increased rate of the reaction.
- Thus, the correct answer is B, "The rate of reaction increases".
Question 36:
Which enzyme best digests egg albumin into peptides and amino acids under alkaline conditions?
Topic: Enzyme Activity in Alkaline Conditions
Correct Answer: D) Trypsin
- Different enzymes function optimally under different pH conditions.
- Trypsin is known to digest proteins, such as egg albumin, into peptides and amino acids most efficiently under alkaline conditions (pH 7.8 – 8.7).
- Hence, the correct answer is D, "Trypsin".
Question 37:
What is the term for a non-protein organic substance that activates the apo-enzyme?
Topic: Enzyme Activation
Correct Answer: A) Co-enzyme
- Apo-enzymes are the inactive protein component of enzymes.
- They require a co-enzyme, a non-protein organic substance, to become active and catalyze a reaction.
- Therefore, the correct answer is A, "Co-enzyme".
Question 38:
What does a non-competitive inhibitor prevent the formation of?
Topic: Non-Competitive Enzyme Inhibition
Correct Answer: C) ES-complex
- Non-competitive inhibitors are types of enzyme inhibitors that do not compete with the substrate for the enzyme's active site.
- Instead, they bind to an allosteric site on the enzyme, changing the shape of the enzyme and preventing the formation of the enzyme-substrate complex.
- Therefore, the correct answer is C, "ES-complex".
Question 39:
Which enzyme in animal stomachs has an optimum pH of 1?
Topic: Enzyme Function in Extreme Conditions
Correct Answer: A) Protease
- Certain enzymes can function at extreme pH levels.
- For instance, protease, an enzyme present in the stomachs of animals, operates most efficiently at an extremely acidic pH of 1.
- Hence, the correct answer is A, "Protease".
Question 40:
Which enzymes catalyze reactions where bond cleavage is facilitated by the addition of water?
Topic: Enzyme Function and Classification
Correct Answer: A) Hydrolases
- Enzymes can be classified based on the type of chemical reaction they catalyze.
- Hydrolases are a class of enzymes that catalyze reactions wherein bond cleavage is accomplished by the addition of water.
- Thus, the correct answer is A, "Hydrolases".