Organic Molecules and Macromolecules

Definition and Composition

Organic molecules are fundamental to living organisms, primarily composed of carbon and hydrogen, often with oxygen, nitrogen, phosphorus, and sulfur (CHON or CHONPS).

• Organic Molecules: Molecules containing carbon and hydrogen in living things.

• Elements involved: Carbon, Hydrogen, Oxygen, Nitrogen, sometimes Phosphorus and Sulfur.

Monomers of Biological Macromolecules

• Proteins: Amino acids

• Fats (Lipids): Glycerol and fatty acids

• Carbohydrates: Monosaccharides (simple sugars, e.g., glucose)

• Nucleic acids: Nucleotides (Additional info: not explicitly listed in the notes)

Protein Structure

Proteins have four levels of structure, each contributing to their function:

• Primary: Sequence of amino acids in a polypeptide chain; determines the protein's unique characteristics.

• Secondary: Local folding into structures like alpha-helices and beta-sheets, stabilized by hydrogen bonds between nearby amino acids.

• Tertiary: Three-dimensional folding due to interactions among R-groups (side chains), including covalent and noncovalent bonds.

• Quaternary: Association of multiple polypeptide subunits; e.g., hemoglobin is made from four globular protein subunits.

Protein Denaturation

• Definition: Loss of protein shape due to heat, pH, or chemicals, resulting in loss of function.

Major Chemical Bonds in Biology

• Ionic bonds: Transfer of electrons (e.g., NaCl, sodium chloride)

• Covalent bonds: Sharing of electrons (e.g., H2O, CO2)

• Hydrogen bonds: Weak bonds between molecules, important in water and DNA structure

Cell Growth and Death: Hypertrophy, Hyperplasia, Necrosis, Apoptosis

• Hypertrophy: Cells get bigger

• Hyperplasia: More cells form

• Necrosis: Cell death from damage

• Apoptosis: Programmed cell death (clean cell death)

Cell Transport and Membrane Structure

Modes of Cell Transport

• Passive transport: No energy required; includes diffusion, osmosis, and facilitated diffusion

• Active transport: Requires energy (ATP); includes pumps, endocytosis, and exocytosis

Saturated vs. Unsaturated Fats

• Saturated fats: No double bonds, solid at room temperature (e.g., butter)

• Unsaturated fats: Double bonds, liquid at room temperature (e.g., olive oil)

• Trans fats: Artificial, hydrogenated oils, considered unhealthy

Cell Membrane Structure

• Phospholipid bilayer: Main structural component

• Membrane proteins: Act as channels, pumps, and receptors

Na+/K+ Pump Function

• Moves 3 Na+ out, 2 K+ in, using ATP

• Keeps cell electrically balanced and ready for nerve/muscle function

Enzymes and Their Properties

• Properties: Speed up reactions, reusable, specific to one reaction

• Examples: Amylase (starch → sugar), Lipase (fats → fatty acids)

• Function: Controls what enters/exits, communication

Cell Organelles and Their Functions

• Mitochondria: Energy (ATP) production

• Ribosomes: Protein synthesis

• Synthesis sites:

  • Proteins – ribosomes

  • Lipids – smooth endoplasmic reticulum (ER)

  • Nucleic acids – nucleus

Genetics and Protein Synthesis

• DNA → mRNA: Transcription (in nucleus)

• mRNA → Protein: Translation (at ribosome)

Tissue Types

• Epithelial

• Connective

• Muscle

• Nervous

Cell Junctions

• Tight junctions: Seal cells together

• Desmosomes: Anchor cells for strength

• Gap junctions: Allow molecules/ions to pass directly

Metabolism and Energy Production

Aerobic vs. Anaerobic Respiration

• Aerobic: Uses oxygen, produces ~36 ATP per glucose

• Anaerobic: No oxygen, produces ~2 ATP (lactic acid formed)

Glycolysis and Citric Acid Cycle

• Glycolysis: Occurs in cytoplasm; input is glucose, output is pyruvate, ATP, and NADH

• Citric Acid Cycle (Krebs): Occurs in mitochondria; input is pyruvate, output is CO2, NADH, FADH2, and ATP

Key Equations:

• Glycolysis: $\text{Glucose} + 2\,\text{NAD}^+ + 2\,\text{ADP} + 2\,\text{P}_i \rightarrow 2\,\text{Pyruvate} + 2\,\text{NADH} + 2\,\text{ATP} + 2\,\text{H}_2\text{O}$

• Citric Acid Cycle: $\text{Acetyl-CoA} + 3\,\text{NAD}^+ + \text{FAD} + \text{ADP} + \text{P}_i \rightarrow 2\,\text{CO}_2 + 3\,\text{NADH} + \text{FADH}_2 + \text{ATP} + \text{CoA}$

Diabetes and Hormonal Regulation

Types of Diabetes

• Type 1: Immune system destroys insulin-producing cells; requires insulin injections

• Type 2: Body cells resist insulin, often linked to obesity/lifestyle

Insulin and Glucagon

• Insulin: Lowers blood sugar by moving glucose into cells

• Glucagon: Raises blood sugar by signaling the liver to release stored glucose

Beta Cell Function

• Beta cells in the pancreas sense high blood glucose and release insulin

Isotopes

• Definition: Atoms of the same element with different numbers of neutrons (e.g., Carbon-12 vs. Carbon-14)

Summary Table: Cell Junctions

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard Anatomy & Physiology curriculum.