AP Biology Unit 1: Foundations

Overview

• Unit 1 serves as the foundation for understanding biology.
• Covers chemistry and properties of water, hydrogen bonding, elements of life, and four biomolecule families.
• Biomolecule families: carbohydrates, lipids, proteins, nucleic acids (DNA and RNA).

Water and Hydrogen Bonding

• Polar Molecule: Water is polar due to unequal sharing of electrons between oxygen and hydrogen.
  • Partial negative (oxygen) and partial positive (hydrogen) regions.
• Hydrogen Bonds: Weak intermolecular bonds between molecules.
  • Weaker than covalent or ionic bonds.
  • Essential for structure of DNA, RNA, proteins.
• Properties of Water:
  • Cohesion: Attraction between water molecules.
  • Adhesion: Water molecules sticking to other surfaces, e.g., plant walls.
  • Surface Tension: Water molecules create a "net" that objects can rest on.
• pH and Solutions:
  • Acidic Solutions: More hydrogen ions, pH < 7.
  • Basic Solutions: More hydroxide ions, pH > 7.
  • Underlying concept for AP Bio exams.

Elements of Life

• CHNOPS: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.
  • Carbon: Central element in biomolecules.
  • Hydrogen: Energy exchange, ion gradients, ATP synthesis.
  • Phosphorus: Part of ATP, DNA.

Monomers, Polymers, and Functional Groups

• Monomers: Building blocks of carbohydrates, proteins, nucleic acids.
• Polymers: Built from monomers via dehydration synthesis (water removal) and broken down by hydrolysis (adding water).
• Functional Groups: Determine properties of molecules (e.g., energy exchange, polarity).

Carbohydrates

• Types: Monosaccharides (simple sugars), Disaccharides, Polysaccharides (e.g., starch, glycogen, cellulose).
• Functions: Energy storage, structural roles.

Lipids

• Characteristics:
  • Nonpolar, hydrophobic.
  • Not composed of repeating monomers.
• Functions:
  • Energy storage, waterproofing, membrane structure, signaling.
• Phospholipid Structure: Hydrophilic head, hydrophobic tail form cell membranes.

Proteins

• Monomer: Amino acids.
• Structure Levels:
  • Primary: Amino acid sequence.
  • Secondary: Alpha helices and beta-pleated sheets.
  • Tertiary: R group interactions (e.g., hydrogen bonds, ionic bonds).
  • Quaternary: Multiple polypeptides.
• Example: Hemoglobin, sickle cell disease.

Nucleic Acids: DNA and RNA

• DNA: Heredity molecule, double helix, base pairing rules (A-T, C-G).
• RNA: Variety of forms, information transfer, catalytic roles.
• ATP: Energy molecule, nucleotide monomer.

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Study Tips

• Review functional groups and biomolecule structures.
• Understand water properties and hydrogen bonding.
• Memorize key elements and their roles in biological molecules.
• Practice distinguishing levels of protein structure and function.

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For further study, quizzes, and tutorials, visit LearnBiology.com for comprehensive AP Bio exam preparation.