Enzyme Function and Active Site

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Questions and Answers

What does Dalton's Law of Partial Pressure state about the total pressure in a mixture of gases?

It is equal to the volume of the gases combined.

It is determined by the highest partial pressure among the gases.

It is equal to the sum of the partial pressures of the individual gases. (correct)

It is the product of the densities of the gases.

How is the partial pressure of a gas calculated?

By converting the gas concentration into a percentage and dividing by the total pressure.

By multiplying the fractional concentration of the gas by atmospheric pressure. (correct)

By taking the square root of its molar mass and multiplying by atmospheric pressure.

By summing the volumes of all gases present in the mixture.

What is the partial pressure of O2 when delivered at sea level in a 30% O2 mixture?

228 mm-Hg (correct)

160 mm-Hg

760 mm-Hg

300 mm-Hg

If the atmospheric pressure is 550 mm-Hg, what is the partial pressure of O2 in that environment?

116 mm-Hg Signup and view all the answers

What is the partial pressure for N2 in the atmosphere at sea level?

600 mm-Hg Signup and view all the answers

What is the primary purpose of carbohydrates in the body?

To release energy Signup and view all the answers

Which type of carbohydrate contains a ketone functional group?

Ketose Signup and view all the answers

What defines a monosaccharide?

It is a single sugar molecule with a specific number of carbon atoms Signup and view all the answers

In Fisher projections, how are horizontal and vertical lines represented?

Horizontal lines represent atoms towards the viewer and vertical lines away Signup and view all the answers

What is the ratio of oxygen to hydrogen in carbohydrates?

2 to 1 Signup and view all the answers

Which classification of carbohydrates includes those made of many sugar units?

Polysaccharides Signup and view all the answers

What do Lewis dot structures illustrate?

The type of bonds formed between atoms using valence electrons Signup and view all the answers

Which of these describes a characteristic feature of simple carbohydrates?

They can contain both aldehydes and ketones Signup and view all the answers

What is the role of amino acid side chains in enzyme function?

They create the specific shape needed for substrate binding. Signup and view all the answers

Which enzyme system is known as the 'mixed-function oxidase system'?

Cytochrome P450 Signup and view all the answers

What effect does an inducer have on an enzyme-catalyzed reaction?

It speeds up the reaction. Signup and view all the answers

What is the primary metabolic action of Pseudocholinesterase?

To metabolize succinylcholine. Signup and view all the answers

How does grapefruit juice affect drug metabolism?

It serves as an inhibitor of enzyme activity. Signup and view all the answers

Which type of receptor is primarily responsible for transmitting signals via GTP?

G-protein coupled receptors Signup and view all the answers

What occurs when the M2 receptor is inhibited in the SA node?

Heart rate decreases. Signup and view all the answers

What is a significant characteristic of the fluidity of the cell membrane?

It allows proteins to move around, facilitating cell function. Signup and view all the answers

Which enzyme is involved in converting a prodrug to its active metabolite?

Alkaline Phosphatase Signup and view all the answers

What happens to metabolism in a patient who is both acidic and hypothermic?

Metabolism slows down considerably. Signup and view all the answers

What happens to temperature when pressure is decreased in a gas system?

Temperature decreases. Signup and view all the answers

What is the primary reason for the drop in pressure observed when the nitrous oxide cylinder is at 1/4 full?

The liquid N2O is evaporating, causing heat loss. Signup and view all the answers

Which method is used to accurately measure the amount of N2O remaining in a cylinder?

Weighing the cylinder. Signup and view all the answers

What is the molecular weight of nitrous oxide (N2O)?

44 g/mol Signup and view all the answers

How long will a full nitrous oxide cylinder last if 2 liters are administered per minute?

280 minutes Signup and view all the answers

Why can PSI gauges on N2O cylinders not be relied upon as they are for O2 cylinders?

N2O exists as both liquid and gas. Signup and view all the answers

What is the weight of the N2O in a full cylinder given that its full weight is 5.6 kg and the tare weight is 4.5 kg?

1.1 kg Signup and view all the answers

According to the Joule-Thompson effect, what occurs when a compressed gas is allowed to escape freely into space?

The gas experiences an adiabatic cooling effect. Signup and view all the answers

What happens to the pressure in a N2O cylinder as it empties?

Pressure decreases even when N2O liquid is present. Signup and view all the answers

How is the Joule-Thompson effect related to pressure in a constant-volume cylinder?

Decreased temperature leads to decreased pressure. Signup and view all the answers

According to Avogadro's hypothesis, how many liters does one mole of a gas occupy at STP?

22.4 L Signup and view all the answers

What is Avogadro's number?

6.022 x 10^23 molecules Signup and view all the answers

What condition defines the critical temperature of a gas?

It is the temperature above which a gas cannot be liquefied, regardless of pressure. Signup and view all the answers

Which equation represents the ideal gas law?

PV = nRT Signup and view all the answers

In a clinical application, how does the pressure in a Bourdon's gauge correspond to gas content?

It indicates pressure proportional to the number of molecules in the cylinder. Signup and view all the answers

What occurs in a closed space when a cylinder of compressed gas is opened?

Both pressure and temperature rise rapidly. Signup and view all the answers

Study Notes

Enzyme Function

Active site on enzymes is the specific area where substrates bind to facilitate reactions.
Amino acid composition is crucial; side chains determine the enzyme's shape and ability to accommodate substrates.
Binding of amino acid residues alters enzyme shape, size, and chemical behavior, contributing to the formation of the enzyme-substrate complex.

Cytochrome P450

Critical enzyme system for metabolizing anesthetic drugs, referred to as the "mixed-function oxidase system."
Use of anti-seizure medications can induce the CYP450 system, potentially rendering other medications like Rocuronium ineffective.
Inducers accelerate metabolic reactions, necessitating higher doses of medications such as fentanyl and midazolam for analgesic effect.
Inhibitors, like grapefruit juice, reduce enzyme activity, enhancing the effects of opioids and benzodiazepines.

Plasma Pathways of Metabolism

Pseudocholinesterase: Metabolizes succinylcholine, allowing for rapid drug clearance compared to traditional agents like neostigmine.
Nonspecific Esterase: Rapid metabolism of remifentanil, enabling swift recovery from its effects.
Alkaline Phosphatase: Converts prodrug Frospropofol into its active form.
Hoffman Elimination: Reaction rate affected by pH and temperature; for instance, metabolic rates of cisatracurium decrease in acidic, hypothermic conditions.

Cellular Communication

Extracellular communication occurs via chemical signals (hormones, neurotransmitters), electrical signals (action potentials), and mechanical signals (pressure).
Cells receive signals through receptors that convert extracellular input into specific intracellular responses.
Most receptors are membrane-bound, although some exist intracellularly.

Types of Receptors

Extracellular Receptors: Include ion channels, G-protein coupled receptors, and enzyme-linked receptors.
Intracellular Receptors: Respond to signals from within the cell.
Cell membrane, composed of a phospholipid bilayer, enables protein mobility crucial for cellular functions.

G-Protein Coupled Receptors

These 7-transmembrane receptors transmit signals from extracellular substances to intracellular molecules, activating GTP.
Ligand binding triggers G-proteins, which can then influence channels, transport, enzymes, receptors, or structural proteins.
These receptors act to either open/close ion channels or activate/inhibit intracellular enzymes, impacting physiological functions like heart rate.

Carbohydrates

Carbohydrates are biomolecules primarily composed of carbon, hydrogen, and oxygen, exemplifying a 2:1 hydrogen-oxygen ratio similar to water.
Classified into simple carbohydrates based on functional groups (ketose, aldose) and by the number of sugar molecules (monosaccharides, disaccharides, polysaccharides).
Fischer projections provide a means to visualize carbohydrate structures in two dimensions.

Lewis Dot Structures

Illustrate bonds formed between atoms through valence electrons, aiding in understanding molecular interactions.

Dalton's Law of Partial Pressure

Total gas pressure is the combined pressure of individual gases in a mixture, assuming no chemical interaction.
At sea level, partial pressures of O2 (160 mmHg) and N2 (600 mmHg) combine for a total atmospheric pressure of 760 mmHg.
Partial pressures are calculated by multiplying the gas fraction by atmospheric pressure, assisting in anesthesia calculations.

Avogadro's Number and Hypothesis

Equal volumes of gases at the same temperature and pressure contain equal particle numbers.
One mole of gas occupies 22.4 liters at standard conditions.

Cylinders and Gas Principles

Critical Temperature: The highest temperature at which a gas can exist as a liquid; gas cannot be liquefied above this temperature.
Adiabatic Processes: Rapid pressure release from gas leads to a temperature increase due to heat conservation.
Joule-Thompson Effect: Gas expansion under low pressure results in cooling; decreased pressure causes a temperature drop.

Nitrous Oxide Cylinder (N2O)

Gauge readings do not accurately represent gas quantity as N2O exists as both liquid and vapor.
Pressure decreases significantly as the tank empties, requiring weight measurements for accurate content assessment.
Full N2O cylinder weighs approximately 5.6 kg and can provide anesthesia based on predefined weight and flow rate calculations.

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Description

This quiz explores the role of the active site in enzymes and how the amino acid composition influences the enzyme-substrate complex. Understand the significance of side chains in shaping the active site and their effect on enzyme functionality. Test your knowledge on enzyme mechanics and binding dynamics.