Micro Lecture: Quiz on Enzymes and ATP

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Questions and Answers

Explain what ATP and nucleic acids have in common.

ATP and DNA both have a phosphate group and pentose sugar. ATP is made of adenine and three phosphates, while RNA has ribose sugar and DNA has deoxyribose sugar.

What is the function of lactase and what does lactose intolerance mean?

Lactase is the enzyme responsible for breaking down lactose, a sugar found in milk. Lactose intolerance is a condition where the body doesn't produce enough lactase, leading to GI distress.

Name three categories of enzymes and provide an example of each one.

Oxidoreductase (e.g., Cytochrome oxidase), Hydrolase (e.g., Lipase), Isomerase (e.g., Glucose-phosphate isomerase).

How do the lock and key hypothesis and the induced fit hypothesis differ?

The lock-and-key theory states the active site is a perfect fit for the substrate, while the induced fit model suggests both the enzyme's active site and the substrate change shape slightly during binding. Signup and view all the answers

Explain the temperature and pH optima for enzymes found in halophiles.

Optimal growth temperature is around 80°C, with some species surviving up to 120°C. pH can be near or below zero with examples like Sulfolobus having a pH optimum of 2. Signup and view all the answers

Explain the temperature and pH optimum for an enzyme found in thermophilic bacteria.

Optimum temperature is above 80°C, with a record of 121°C. For pH, it is around 7 and can be found in environments such as hydrothermal vents. Signup and view all the answers

Explain how the term 'activation energy' applies to enzyme activity.

Activation energy is the energy required to start a reaction, and enzymes lower the activation energy needed for reactions. Signup and view all the answers

Provide a chemical reaction and identify substrate, product, enzyme, pH optima, temperature optimum.

Substrate: Lactose; Product: Glucose + Galactose; Enzyme: Lactase; pH optima: 7; Temp optimum: 37°C. Signup and view all the answers

Explain what enzymatic inhibitors and negative feedback have in common.

Both involve mechanisms that regulate enzyme activity. Enzymatic inhibitors prevent substrate binding, while negative feedback reduces process stimulus. Signup and view all the answers

How might substrate concentration affect enzyme activity?

An increase in substrate concentration initially increases enzymatic activity until saturation is reached. Signup and view all the answers

Describe the differences between proteins and enzymes.

Enzymes are biochemical catalysts that speed up reactions, while proteins serve various structural and regulatory roles in the body. Signup and view all the answers

What is the purpose of NAD, FAD and REDOX reactions?

NAD and FAD are coenzymes involved in energy metabolism by accepting and donating electrons during redox reactions. Signup and view all the answers

Describe reaction coupling, endergonic and exergonic.

Exergonic reactions release energy and can power endergonic reactions, which require energy input, often coupling these two processes. Signup and view all the answers

Describe the reactions by which ATP releases energy and include the structure.

ATP (Adenosine Triphosphate) releases energy via hydrolysis, breaking down into ADP, inorganic phosphate, and energy. Signup and view all the answers

Provide three examples each of kinetic and potential energy.

Kinetic Energy: A shooting arrow, a ball rolling down a hill, a person diving from a cliff. Potential Energy: An archer aiming an arrow, a ball sitting on a hill, a diver on a cliff. Signup and view all the answers

What are coenzymes?

Organic cofactors Signup and view all the answers

What is allosteric inhibition?

Allosteric inhibition is a form of noncompetitive inhibition where the inhibitor changes the enzyme’s shape, rendering it inactive. Signup and view all the answers

What is a competitive inhibitor?

A competitive inhibitor fills an enzyme's active site but does not undergo a chemical reaction. Signup and view all the answers

What is an irreversible competitive inhibitor?

An irreversible competitive inhibitor prevents any further reaction with the substrate. Signup and view all the answers

What is a reversible competitive inhibitor?

A reversible competitive inhibitor slows the reaction and may be removed by high substrate concentrations. Signup and view all the answers

What are sulfonamide drugs?

Sulfonamide drugs are competitive inhibitors that structurally resemble PABA and interfere with folate synthesis in bacteria. Signup and view all the answers

What is feedback inhibition?

Feedback inhibition is a metabolic control method where the end product acts as an inhibitor of an upstream enzyme in a pathway. Signup and view all the answers

What are ribozymes?

Ribozymes are RNA molecules that function as enzymes. Signup and view all the answers

What are coupled reactions?

Coupled reactions involve using the energy released by an exergonic reaction to drive an endergonic reaction. Signup and view all the answers

Study Notes

ATP and Nucleic Acids

Adenosine triphosphate (ATP) remains a single nucleotide.
ATP and DNA contain a phosphate group and pentose sugar.
ATP consists of adenine, three phosphate groups, and ribose; whereas RNA has ribose and DNA has deoxyribose.
All living organisms power cellular functions using ATP.
Nucleic acids are polymers of nucleotides that have a nitrogenous base, a pentose sugar, and a phosphate group.

Lactase and Lactose Intolerance

Lactase is an enzyme that breaks down lactose, a sugar found in milk.
Lactose intolerance occurs when the body lacks sufficient lactase, leading to gastrointestinal discomfort.

Categories of Enzymes

Oxidoreductase: Involves oxidation-reduction (e.g., Cytochrome oxidase, Lactate dehydrogenase).
Hydrolase: Catalyzes hydrolysis reactions (e.g., Lipase, Sucrase).
Isomerase: Rearranges molecular structures (e.g., Glucose-phosphate isomerase, Alanine racemase).

Lock and Key vs. Induced Fit Hypothesis

The lock-and-key model proposes that the enzyme's active site is a perfect fit for the substrate without changing shape.
The induced fit model suggests minor changes to both the enzyme's active site and the substrate upon binding.

Halophiles' Enzyme Characteristics

Optimal growth temperature for halophiles is around 80°C but records show growth at up to 120°C.
They thrive in environments with over 25% salt and may have pH optima below zero (e.g., Sulfolobus with a pH of 2).

Thermophilic Bacteria Enzyme Parameters

Archaea thermophiles have an optimal temperature of 80°C, with a record of 121°C.
Pyrococcus abyssi thrives at approximately 98°C and pH 7, while Sulfolobus can endure pH 2 and 70°C.

Activation Energy and Enzymes

Activation energy is the energy required to initiate a chemical reaction.
Enzymes lower the activation energy needed to accelerate reactions.

Enzymatic Reaction Parameters

Describes a typical digestion reaction:
- Substrate
- Product
- Enzyme
- pH optimum
- Temperature optimum

Enzymatic Inhibitors and Feedback

Competitive Inhibitors: Block substrate binding at the active site.
Non-competitive Inhibitors: Bind elsewhere, altering enzyme shape and function.
Feedback inhibition occurs when a metabolic pathway's end product inhibits the first enzyme in the process.

Substrate Concentration Effects

Increased substrate concentration enhances enzyme activity until enzymes become saturated, beyond which reaction rates level off.

Enzymes vs. Proteins

Enzymes act as biochemical catalysts facilitating faster reactions, while proteins have diverse functions including structure and transport.
Classification of enzymes is based on function, whereas proteins are classified by composition.

Role of NAD and FAD in Redox Reactions

NAD is crucial in energy metabolism for accepting and donating electrons, transforming NAD+ to NADH.
FAD participates similarly by converting to FADH2 through reduction.
Redox reactions are vital as they release energy through the oxidation of molecules.

Reaction Coupling

Coupling exergonic reactions (energy-releasing) with endergonic reactions (energy-requiring) allows cells to perform work efficiently.

ATP Energy Release Mechanism

ATP consists of an adenosine unit and three phosphate groups.
Hydrolysis of ATP to ADP releases energy, utilized for biological processes.

Metabolism, Catabolism, and Anabolism

Metabolism encompasses all processes converting food into energy.
Catabolism breaks down larger molecules, releasing energy (exergonic).
Anabolism builds complex molecules from simpler ones, consuming energy (endergonic).

Kinetic and Potential Energy Examples

Kinetic Energy: Movement of objects (e.g., a rolling ball, a flying arrow).
Potential Energy: Stored energy in objects (e.g., a ball on a hill, an archer preparing to shoot).

Coenzymes and Cofactors

Coenzymes are organic molecules assisting enzyme functions.
Cofactors are non-protein helpers, either tightly or loosely associated with enzymes (e.g., metals like Iron and Zinc).

Allosteric Inhibition

Occurs when an inhibitor binds to an enzyme, altering its shape and inactivating it, distinguishing it from competitive inhibition.

Types of Inhibitors

Competitive Inhibitor: Occupies the enzyme's active site without undergoing a reaction.
Irreversible Competitive Inhibitor: Permanently blocks substrate interaction.
Reversible Competitive Inhibitor: Temporarily slows reactions, removable by increasing substrate concentration.

Sulfonamide Drugs Mechanism

Competitive inhibitors similar to PABA, interfering with folate synthesis in bacteria, limiting their growth.

Feedback Inhibition

Metabolic control mechanism where the end product inhibits the pathway's first enzyme, preventing overproduction.

Ribozymes

RNA molecules that possess enzymatic functions, catalyzing biochemical reactions.

Coupled Reactions Defined

Coupled reactions utilize energy released from exergonic processes to drive endergonic reactions, maintaining cellular energy balance.

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Description

Test your knowledge about the roles of ATP and nucleic acids in biological systems through this engaging quiz. Explore how ATP functions as an energy carrier and its structural similarities with nucleic acids like DNA and RNA. Get ready to dive deep into the world of enzymes and energy!