Study Notes on Enzyme Activity, Metabolism, and Cellular Respiration

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Discussion of enzyme behavior including competitive and uncompetitive inhibition.

Metaphor of Traffic Lights:
- Enzymatic reactions are regulated similar to traffic signals, which have red, yellow, and green lights governing the flow of traffic (cargo).
- Regulatory signals dictate when enzymes should be active or inactive.

Definition: A method to regulate enzyme action.
Characteristics of Allosteric Enzymes:
- Composed of multiple subunits (polypeptides).
- Example: An allosteric enzyme made up of four polypeptides.
- Each polypeptide contains an active site.
Forms of Allosteric Enzymes:
- Active Form: Stabilized by an activator (green light analogy).
- Inactive Form: Stabilized by inhibitors like polar dred.
Activator and Inhibitor Interaction:
- Activators bind to the allosteric site, not the active site, promoting an active conformation.
- Inhibitors bind to the allosteric site, leading to deformation of the active sites and preventing substrate binding.

Definition: A process in metabolic pathways where the final product, in excess, inhibits the action of the initial enzyme.
Metabolic Pathway Example:
- Enzyme 1 converts initial substrate X to product A.
- Enzyme 2 converts product A to product B.
- Enzyme 3 converts product B to the final product.
- If the final product is abundant, it inhibits Enzyme 1 by binding to its allosteric site, stopping the production of substrates.
- This mode conserves energy by halting unnecessary production of the product.

Definition of Metabolism: Overall sum of chemical reactions occurring in cells, performed by enzymes.
Two Types of Metabolic Reactions:
1. Anabolism:
- Definition: Building up reactions that create larger molecules from smaller ones.
- Example: Combining monosaccharides to form polysaccharides.
- ATP is required for anabolic processes.
1. Catabolism:
- Definition: Breaking down reactions that convert larger molecules into smaller ones.
- Example: Decomposing fats into glycerol and fatty acids, releasing ATP.

Heat Generation: Both metabolic types generate heat during reactions.
Usage of ATP:
- Anabolism requires ATP for building up processes.
- Catabolism releases ATP when breaking down substances.

Anabolism: Formation of polysaccharides from monosaccharides, creation of proteins from amino acids.
Catabolism: Breakdown of fats into smaller units like glycerol and fatty acids.

Focus on:
- Aerobic Cellular Respiration (catabolic process)
- Photosynthesis (anabolic process)
Both processes occur via series of reactions known as metabolic pathways.

Pathways begin with an initial molecule and subsequently convert it through intermediate products to the final product (e.g., A → B → C → D).
Each step is catalyzed by specific enzymes, leading to the final desired molecules.

Group discussions may involve prior chapter content, participation dispersion, and collaborative learning.

Introduction to Chapter 7 with a focus on the necessity of nutrients (acids, vitamins, and minerals) for cellular functions and energy production.

Digestion Steps:
- Carbohydrates break down into glucose and maltose.
- Proteins are digested into amino acids.
- Fats are broken down into fatty acids and glycerol.
- Further digestion leads to absorption of nutrients for cellular management.

Cellular Respiration: Process of converting glucose into carbon dioxide and water while producing ATP. Equation for cellular respiration:
ext{C}6 ext{H}{12} ext{O}6 + 6 ext{O}2
ightarrow 6 ext{CO}2 + 6 ext{H}2 ext{O} + ext{ATP}
Involves digestive breakdown to facilitate energy use:
- Glucose is transported via facilitated diffusion due to its larger size.
- Oxygen required is absorbed from the air, transported to cells where it assists in metabolic reactions.
Oxidation and Reduction:
- Concept clarification where glucose loses hydrogen and is oxidized to carbon dioxide; oxygen gains hydrogen and is reduced to water.
Redox Reaction: Involves electron transfer between molecules, influencing energy equilibrium in cellular processes.

NAD and FAD: Key electron carriers in cellular respiration.
- NAD+ (Nicotinamide adenine dinucleotide)
- Accepts electrons, transforms into NADH.
- FAD (Flavin adenine dinucleotide)
- Similar functions with variations in hydrogen acceptance.
- Reactions involve protons released back into the surroundings.

Types of Phosphorylation:
1. Substrate-Level Phosphorylation:
- Direct addition of phosphate to ADP to form ATP, occurs in all cells, both eukaryotic and prokaryotic.
1. Oxidative Phosphorylation:
- Occurs in mitochondria and involves electron transport systems to generate ATP from energy released by electrons from glucose.
1. Photophosphorylation:
- Process in photosynthetic organisms, converting light energy into ATP.
Differences determined by energy sources (organic vs. inorganic phosphates) and localization of reactions across cellular structures.

Mitochondria: Integral for ATP production through cellular respiration, features extensive inner membrane folding for maximizing ATP synthesis.

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