Biological Molecules and Chemical Bonds

This comprehensive page covers fundamental concepts of biological molecules and their structural components in AP Biology Unit 1. The content explores various molecular structures and their interactions, with particular emphasis on water molecules and major biomolecules.

Definition: Covalent bonds are chemical bonds where atoms share electrons, with oxygen having a higher electronegativity leading to unequal electron sharing.

Highlight: Water's polar nature results from oxygen's higher electronegativity, creating an unequal sharing of electrons between oxygen and hydrogen atoms.

Vocabulary:

• Cohesion: Attraction between water molecules
• Adhesion: Attraction between water and other substances
• Hydrolysis: Breaking down of polymers using water
• Dehydration: Removal of water to form covalent bonds

Example: The four levels of protein structure demonstrate increasing complexity:

1. Primary Structure: Linear polypeptide chain
2. Secondary Structure: Alpha-helix or beta-sheet formations
3. Tertiary Structure: R-group interactions
4. Quaternary Structure: Multiple protein subunit assembly

Quote: "Living systems need a constant input of energy, mainly stored in chemical bonds."

The page also details the structure of nucleotides, essential components of DNA and RNA, featuring:

• Phosphate group
• Nitrogen base
• Carbon sugar (Ribose in RNA, Deoxyribose in DNA)

Types of proteins and their structures are extensively covered, emphasizing the importance of R-groups in determining amino acid properties (Hydrophobic, Hydrophilic, Ionic).