cell biology lecture 3 pt 2

Types of Chemical Reactions

• Exchange Reaction: Example with Sodium Chloride and Hydrochloric Acid.

  • Sodium hydroxide + Hydrochloric acid → Sodium chloride + Water.

• Synthesis Reaction: Formation of a Triglyceride from ATP and Fatty Acids.

  • ATP + Fatty Acids → Triglyceride + Water (water is lost).

Molecules in the Human Body

• Understanding organic vs. inorganic molecules:

  • Inorganic molecules: Smaller, lack carbon, simple structure.

    • Examples: Water, salts, acids, bases.

  • Organic molecules: Larger, contain carbon, more complex.

    • Examples: Carbohydrates, proteins, nucleic acids.

Importance of Water

• Water: Most abundant molecule in the body (60-70% of body weight).

  • High heat capacity: Requires a lot of energy to change temperatures; important for maintaining body temperature (homeostasis).

  • Ability to dissolve substances: Dissolves salts (Na+ and Cl− ions), critical for muscle contraction, nerve signal transmission, and blood clotting.

  • Water participation in chemical reactions:

    • Hydrolysis: Breakdown of larger molecules using water.

    • Dehydration Synthesis: Formation of larger molecules while releasing water.

  • Importance in aging: Hydration for joint lubrication and cushioning.

Inorganic Compounds

• Salts: Formed from reaction of an acid with a base.

  • Break apart into ions (charged atoms/electrolytes).

• Acids and Bases:

  • Acids: Release hydrogen ions (H+) in water; strength depends on H+ concentration.

  • Bases: Release hydroxide ions (OH−) in water.

  • pH Scale: Ranges from 0 to 14; 7 is neutral (e.g., water); blood around 7.4; stomach acid around 1-2; definitions of hyperglycemia and hypoglycemia.

  • Importance of maintaining pH levels across different body systems; buffers help manage pH.

Organic Compounds

• Carbohydrates: Composed of carbon, hydrogen, and oxygen (C, H, O); ratio is typically 2:1 for H:O.

  • Groups of carbohydrates:

    • Monosaccharides: Single sugar units (e.g., glucose, fructose).

    • Disaccharides: Two monosaccharides (e.g., sucrose from glucose + fructose).

    • Polysaccharides: Long chains of monosaccharides (e.g., glycogen, starch).

  • Energy Storage:

    • Glucose stored as glycogen in liver/muscles and utilized during energy-intensive activities (e.g., exercise).

Molecular Structure and Function

• Structure vs. Function: The shape of molecules influences their roles and functionalities in the body (anatomy and physiology principles).

• Structural comparison: Different structures can lead to different biochemical functions, even with the same molecular formula (e.g., glucose vs. fructose vs. galactose, all C6H12O6).

Digestive Processes

• Breakdown of carbohydrates during digestion:

  • Hydrolysis of starches yields glucose.

  • Re-synthesis of glucose into glycogen for storage (energy reserves).

Summary

• The course will cover the role of various molecules (organic and inorganic) in human physiology and biochemistry, linked to digestion, homeostasis, and energy production.