Macromolecules, Photosynthesis, and Cellular Respiration: ANP Study Notes

Macromolecules

Monomers and Polymers

Macromolecules are large organic molecules essential for life, built from smaller units called monomers. When monomers join together, they form polymers through a process called polymerization.

• Monomer: A single, basic molecular unit.

• Polymer: A chain of many monomers bonded together.

• Polymerization: The chemical process of linking monomers to form polymers.

Example: Glucose is a monomer; starch is a polymer made of many glucose units.

Dehydration Synthesis and Hydrolysis

Polymers are assembled and disassembled by two key reactions:

• Dehydration Synthesis: Monomers are joined to form polymers, releasing water as a byproduct.

• Hydrolysis: Polymers are broken down into monomers by the addition of water.

Example: During digestion, enzymes hydrolyze starch into glucose monomers.

Types of Macromolecules

There are four main types of biological macromolecules, each with distinct structures and functions:

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

Carbohydrates

Carbohydrates are composed of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio. They serve as the main short-term energy source for cells.

• Monomer: Monosaccharide (simple sugar, e.g., glucose)

• Polymer: Polysaccharide (e.g., starch, cellulose)

• Function: Provide energy for cellular processes

Lipids

Lipids are hydrophobic molecules composed mainly of carbon, hydrogen, and oxygen. They are not soluble in water and serve as long-term energy storage, insulation, and protection for organs.

• Monomer: Glycerol and fatty acids

• Function: Energy storage, membrane structure, insulation

Proteins

Proteins are composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. They are made of amino acid monomers and perform a wide variety of functions, including catalyzing reactions (enzymes), transport, support, and movement.

• Monomer: Amino acid

• Function: Enzymes, structural support, transport, movement

Nucleic Acids

Nucleic acids store and transmit genetic information. They are composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus. The two main types are DNA and RNA.

• Monomer: Nucleotide

• Function: Store and communicate genetic information

Photosynthesis

Overview and Purpose

Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. This process is essential for life on Earth as it provides oxygen and organic compounds for other organisms.

• Equation: $6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + \text{light energy} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2$

• Organelle: Chloroplast

• Stages: Light-dependent reactions and light-independent reactions (Calvin Cycle)

Stages of Photosynthesis

• Light-Dependent Reactions: Occur in the thylakoid membranes; require sunlight and water; produce ATP, NADPH, and oxygen as a byproduct.

• Light-Independent Reactions (Calvin Cycle): Occur in the stroma; use ATP, NADPH, and carbon dioxide to produce glucose; do not require sunlight directly.

Cellular Respiration

Overview and Purpose

Cellular respiration is the process by which cells convert glucose and oxygen into ATP (usable energy), carbon dioxide, and water. It occurs in all eukaryotic cells and is essential for energy production.

• Equation: $\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2 \rightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + \text{ATP}$

• Location: Cytoplasm (glycolysis) and mitochondria (Krebs cycle and electron transport chain)

Stages of Cellular Respiration

1. Glycolysis: Occurs in the cytoplasm; does not require oxygen (anaerobic); breaks glucose into 2 pyruvic acid molecules and produces 2 ATP.

2. Krebs Cycle: Occurs in the mitochondria; requires oxygen (aerobic); produces CO2, H2O, and 2 ATP.

3. Electron Transport Chain: Occurs in the mitochondria; requires oxygen; produces the majority of ATP and water.

Fermentation (Anaerobic Respiration)

When oxygen is not available, cells can produce energy through fermentation, which is much less efficient than aerobic respiration.

• Lactic Acid Fermentation: Occurs in muscle cells and some bacteria; produces lactic acid and ATP.

• Alcohol Fermentation: Occurs in yeast and some bacteria; produces alcohol, carbon dioxide, and ATP.

Comparison: Aerobic vs. Anaerobic Respiration

Feature	Aerobic Respiration	Anaerobic Fermentation
Oxygen Required?	Yes	No
ATP Yield	High (up to 38 ATP)	Low (2 ATP)
End Products	CO2, H2O, ATP	Lactic acid or alcohol, ATP

Example: Human muscle cells use lactic acid fermentation during intense exercise when oxygen is scarce.

*Additional info: The above content integrates foundational biochemistry and cell biology concepts essential for understanding human anatomy and physiology at the college level.*