Introduction
In the IB Biology syllabus, the topic of "Molecules to Metabolism" underpins the fundamental principles of molecular biology, focusing on the biochemical processes that sustain life. This study note will delve into the concepts of molecules, metabolism, and the intricate pathways that constitute metabolic processes. The content is structured to break down complex ideas into digestible sections, ensuring a comprehensive understanding of the subject.
Metabolism
Metabolism encompasses all the chemical reactions that occur within cells and organisms. These reactions are essential for maintaining life and can be broadly classified into two categories: anabolic and catabolic reactions.
Key Concepts
- Metabolites: Molecules involved in metabolic reactions.
- Metabolic Pathways: Series of interlinked metabolic reactions, each catalyzed by a specific enzyme.
- Enzymes: Biological catalysts that speed up metabolic reactions without being consumed in the process.
Types of Metabolic Reactions
Metabolic reactions can be classified into two main types:
- Anabolic Reactions
- Catabolic Reactions
Anabolism
Anabolic reactions involve the synthesis of complex molecules from simpler ones. These reactions are essential for growth, repair, and storage of energy.
Examples of Anabolic Reactions
- Photosynthesis: Conversion of carbon dioxide and water into glucose and oxygen. $$6CO_2 + 6H_2O + light \ energy \rightarrow C_6H_{12}O_6 + 6O_2$$
- Protein Synthesis: Formation of proteins from amino acids. $$\text{Amino Acids} \rightarrow \text{Protein}$$
- Fat Storage: Conversion of excess glucose into fatty acids and glycerol, which are then stored as triglycerides in fat cells.
Characteristics of Anabolic Reactions
- Condensation Reactions: Anabolic reactions often involve the removal of water molecules.
- Endergonic: These reactions require an input of energy, usually in the form of ATP.
- Energy Storage: The end products of anabolic reactions are energy-rich molecules.
Remember that anabolic reactions are building processes that require energy input.
