07_08- Organic Compounds

Organic Compounds Overview

  • Organic Compounds: Compounds that primarily contain carbon atoms.

Key Components of Organic Molecules

Building Blocks

  • Monomers and Polymers:

    • Building blocks of larger substances.

    • Polymers: Long chains of connected monomers.

Major Types of Organic Molecules

  • Carbohydrates

  • Lipids

  • Proteins

  • Nucleic Acids

Atomic Structure

Valence Electrons

  • Valence: The number of unpaired electrons in an atom that determine how it bonds with other atoms.

    • Determined by the number of valence electrons and their arrangement in shells.

Properties of Carbon

  • Essential building block of organic life.

  • Significant Properties:

    • Small atomic size allows for versatility in bonding.

    • Valence of 4, allowing for up to four bonds.

    • Electronegative neutrality allows formation of both single and double bonds.

    • Can form chains and rings.

Chemistry Shorthand

  • Assumptions in shorthand chemical representations:

    • Unlabeled corners in structures generally represent carbon atoms.

    • Each carbon atom is filled with hydrogens unless specified otherwise.

Functional Groups

  • Functional Groups: Specific clusters of atoms that attach to hydrocarbon chains and influence chemical behavior.

    • Hydroxyl Group (OH): Polar, similar to water.

    • Carboxyl Group: Acidic, can donate protons (H+).

    • Amino Group: Basic, can accept protons.

    • Sulfhydryl Group: Similar properties to hydroxyl groups.

    • Phosphate Group: Plays a vital role in cellular energy (ATP).

Carbohydrates

Characteristics

  • Carbohydrates serve as fuel and structural materials.

  • Types of Carbohydrates:

    • Monomer: Monosaccharides (single sugar unit).

    • Dimer: Disaccharides (two sugar units joined).

    • Composed of multiples of CH2O.

    • Energy is derived from electrons in hydrogen.

    • Many form ring structures.

Glycosidic Linkage

  • A connection formed between monosaccharides which creates larger carbohydrate structures.

Types of Polysaccharides

  • Starch: Unbranched or slightly branched; a storage form of glucose.

  • Glycogen: Highly branched; allows for quick glucose release.

  • Cellulose: Structural polysaccharide found in plant cell walls; indigestible by humans.

Lipids

General Properties

  • Lipids: Group of hydrophobic (nonpolar) molecules, not true polymers.

    • Categories: Fats (triglycerides), Phospholipids, Steroids.

Triglycerides

  • Composed of three fatty acid tails and glycerol, which forms the head.

    • Structure influences fat function; types: saturated and unsaturated fats.

Phospholipids

  • Composed of two fatty acids, glycerol, and a phosphate group; create the cell membrane structure due to differing polar and nonpolar properties.

Steroids

  • Characterized by four fused carbon rings (e.g., cholesterol).

    • Important for membrane structure and as precursors for hormones.

Proteins

Structure of Proteins

  • Proteins: Made from one or more polypeptide chains.

    • Monomer: Amino acids (20 unique types).

    • Peptide bonds create these chains via dehydration synthesis.

    • Proteins make up more than 50% of the dry mass in cells.

Types of Protein Structure

  1. Primary Structure: Linear order of amino acids.

  2. Secondary Structure: Localized folding due to hydrogen bonding (e.g., alpha helices and beta sheets).

  3. Tertiary Structure: Overall three-dimensional shape due to interactions between side chains.

  4. Quaternary Structure: Assembly of multiple polypeptides.

Denaturation

  • Changes in pH, salt concentration, or temperature can lead to protein denaturation, making it biologically inactive.

Nucleic Acids

Function

  • Nucleic Acids: Store, transmit, and express hereditary information.

    • Monomer: Nucleotides (composed of base, sugar, and phosphate).

    • Polymers: Nucleic acids, like DNA and RNA.

    • DNA is double-stranded; RNA is typically single-stranded.

Structure of Nucleotides

  • Sugar-phosphate backbone with different ends (5’ to 3’).

  • Base pairing in DNA: Adenine (A) with Thymine (T) and Cytosine (C) with Guanine (G).