Metabolism Overview Quiz

Study Notes

Metabolism Overview

Definition: Metabolism is the sum of all chemical reactions in an organism that maintain life. It involves converting food to energy, building cellular structures, and eliminating waste products.
Types:
- Catabolism: Breakdown of molecules to release energy.
- Anabolism: Synthesis of molecules for growth and repair, using energy.

Energy Currency

ATP (Adenosine Triphosphate):
- Primary energy carrier in cells.
- Produced during catabolic reactions and consumed during anabolic reactions.

Metabolic Pathways

Enzyme Regulation: Enzymes facilitate metabolic reactions and are regulated by:
- Allosteric sites
- Feedback inhibition
Pathway Types:
- Linear: Sequential series of reactions.
- Cyclic: Reactions that regenerate the starting molecule (e.g., Krebs cycle).

Cellular Respiration

Types:
- Aerobic Respiration:
  - Occurs in the presence of oxygen.
  - Produces more ATP (up to 36-38 ATP molecules per glucose).
  - Stages include Glycolysis, Krebs Cycle, and Electron Transport Chain.
- Anaerobic Respiration:
  - Occurs without oxygen.
  - Produces less ATP (2 ATP molecules per glucose).
  - Includes processes like fermentation (e.g., lactic acid and alcoholic fermentation).

Photosynthesis

Process: Conversion of light energy into chemical energy in plants.
Stages:
- Light-dependent Reactions: Occur in thylakoid membranes; chlorophyll captures light to produce ATP and NADPH.
- Calvin Cycle: Occurs in the stroma; uses ATP and NADPH to convert CO2 into glucose.

Factors Affecting Metabolism

Enzymatic Activity: Temperature, pH, and substrate concentration can influence enzyme activity.
Hormonal Regulation: Hormones (e.g., insulin, glucagon) play a key role in regulating metabolic pathways.
Nutritional Status: Availability of substrates (carbohydrates, fats, proteins) affects metabolic rates.

Metabolic Disorders

Examples:
- Diabetes: Impaired glucose metabolism.
- Phenylketonuria (PKU): Inability to metabolize phenylalanine due to enzyme deficiency.

Importance of Metabolism

Maintains homeostasis.
Provides energy for physiological processes.
Enables growth, repair, and reproduction of cells.

Metabolism Definition

The sum of all chemical reactions that sustain life in an organism
Includes processes like converting food into energy, building cells, and removing waste

Metabolism Types

Catabolism: Breaking down molecules to release energy
Anabolism: Building molecules for growth and repair using energy

Energy Currency

ATP (Adenosine Triphosphate): The primary energy carrier in cells
Produced during catabolic reactions and used during anabolic reactions

Metabolic Pathways

Enzyme Regulation: Enzymes control the speed and type of metabolic reactions
- Allosteric sites: Molecules bind to an enzyme at a location other than the active site, affecting its function
- Feedback inhibition: The product of a pathway inhibits an enzyme earlier in the pathway, preventing overproduction

Pathway Types

Linear: Reactions occur in a specific linear sequence
Cyclic: Reactions regenerate the starting molecule, creating a cycle (e.g., the Krebs Cycle)

Cellular Respiration

The process of breaking down glucose to release energy
Aerobic Respiration: Requires oxygen and produces more ATP (up to 36-38 ATP per glucose)
- Glycolysis: Breaks down glucose into pyruvate
- Krebs Cycle: Oxidizes pyruvate to produce ATP and electron carriers
- Electron Transport Chain: Uses electron carriers to generate the majority of ATP
Anaerobic Respiration: Occurs without oxygen and produces less ATP (2 ATP per glucose)
- Includes fermentation processes like lactic acid fermentation and alcoholic fermentation

Photosynthesis

The process that plants use to convert light energy into chemical energy
Light-dependent Reactions: Occur in the thylakoid membranes within chloroplasts
- Chlorophyll captures light energy to produce ATP and NADPH
Calvin Cycle: Occurs in the stroma
- Uses ATP and NADPH to convert CO2 into glucose

Factors Affecting Metabolism

Enzymatic Activity: Factors like temperature, pH, and substrate concentration can influence enzyme function
Hormonal Regulation: Hormones like insulin and glucagon regulate the use and storage of energy
Nutritional Status: The availability of substrates (carbohydrates, fats, proteins) affects metabolic rates

Metabolic Disorders

Occur when there are problems with metabolism
Diabetes: Impaired glucose metabolism
Phenylketonuria (PKU): Inability to metabolize phenylalanine due to a missing enzyme

Importance of Metabolism

Maintains homeostasis (stable internal environment)
Provides energy for cell processes
Enables cell growth, repair, and reproduction

Description

Test your knowledge on the basics of metabolism, including its definitions, types like catabolism and anabolism, as well as the role of ATP as the energy currency of cells. Understand various metabolic pathways and the differences between aerobic and anaerobic respiration.