Chemistry of Life

Carbohydrates

  • Definition

    • Carbohydrates are biomolecules composed of Carbon (C), Hydrogen (H), and Oxygen (O).

    • The general chemical formula for carbohydrates follows the ratio of 1:2:1 for C:H:O.

    • Example of a carbohydrate: Glucose has the chemical formula C6H12O6.

Types of Carbohydrates

  1. Simple Carbohydrates

    • Description: Simple carbohydrates are sugars consisting of basic units called monosaccharides (monomers).

      • Monosaccharide: From the Greek 'mono' meaning one and 'saccharide' meaning sugar.

    • Bonding: When monosaccharides bond together, they can form sugars with multiple units:

      • Di- (two units)

      • Poly- (three or more units)

      • Examples include glucose (monosaccharide), maltose (disaccharide), and starch (polysaccharide).

  2. Complex Carbohydrates

    • Definition: These are formed when multiple monosaccharides bond together, commonly referred to as starches.

    • Sources:

      • Found abundantly in plants, particularly in foods such as grains, pasta, and bread.

    • Function:

      • Storage: They serve as long-term energy storage in plants.

      • Energy Source: All organisms break down sugars for energy.

      • Examples: Common simple sugars typically end with the suffix ‘-ose’ (e.g., glucose, fructose).

Lipids

  • Definition: Lipids encompass a variety of biomolecules, including fats, oils, and waxes.

Composition

  • Monomers: Comprised largely of Carbon (C) and Hydrogen (H), with a tiny bit of Oxygen (O).

  • Structure: Lipids consist of two primary subunits:

    • Glycerol

    • Fatty Acid Chains (2-3 chains linked to glycerol).

Functions and Uses

  1. Energy Storage:

    • Used for long-term energy storage in animals.

  2. Insulation:

    • Example: Whale blubber, which provides insulation against cold waters.

  3. Hormone Regulation:

    • Hormones that are lipid-based (e.g., steroids).

  4. Cell Membrane Structure:

    • Phospholipids are crucial for forming cell membranes due to their hydrophilic heads and hydrophobic tails.

    • Lipids are classified as nonpolar molecules, meaning they possess no charge and are neutral.

  5. Types of Lipids:

    • Steroids: Cholesterol is the most common steroid, influencing hormonal activity.

    • Waxes: Highly saturated lipids that remain solid at room temperature, often serving waterproof functions.

Proteins

  • Definition: Proteins are macromolecules vital for numerous body functions and life processes.

Sources

  • Found in dietary items such as meat, fish, dairy products, nuts, and seeds.

Functions

  • Functions of proteins include:

    • Structural support

    • Chemical signaling

    • Cell growth and repair

    • Transportation of substances

    • Catalyzing biochemical reactions.

Monomers and Structure

  • Basic Unit: Amino acids (AA) are the fundamental building blocks of proteins.

  • Total of 20 different amino acids, each of which can have unique properties based on its side chain.

  • Key Element:

    • Nitrogen (N) is a crucial component of amino acids, articulated as part of the acronym “CHON” (Carbon, Hydrogen, Oxygen, Nitrogen).

Polypeptide Formation

  • Amino acids are linked together through strong covalent bonds known as peptide bonds, forming polypeptides (the polymer form of proteins).

Types of Proteins

  1. Structural Proteins

    • Make up the primary structures of animal bodies.

    • Typical naming convention ends with “-in” (e.g., collagen).

  2. Functional Proteins (Enzymes)

    • Act as catalysts that speed up chemical reactions.

    • Most enzymatic names end in “-ase” (e.g., lactase, amylase).

Enzyme Functionality

  • Any molecule that can lower the activation energy for a reaction is called a catalyst.

  • Enzymes facilitate reactions by lowering the activation energy required.

    • Analogy: The substrate is likened to a locked door, while enzymes function as keys that open the door.

  • Denaturing: External factors (like temperature or pH) can disrupt the secondary and tertiary structures of proteins, leading to loss of function.

Factors Influencing Enzymatic Activity

  1. Temperature

    • Low temperatures lead to slow reactions; high temperatures can cause denaturation.

  2. pH Levels

    • Extreme pH can denature enzymes.

  3. Concentration Levels

    • Enzyme Concentration: Insufficient enzyme or substrate can slow reactions.

    • Inhibitors: Substances that improperly bind to enzymes and inhibit their function.

Nucleic Acids

  • Definition: Nucleic acids are macromolecules that carry genetic information.

Monomers and Polymers

  • Monomers: The basic units of nucleic acids are nucleotides.

  • Polymers: DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).

Composition

  • Elements involved in nucleic acids include:

    • Carbon (C)

    • Hydrogen (H)

    • Oxygen (O)

    • Nitrogen (N)

    • Phosphate (P)

DNA Structure

  1. Components of DNA Nucleotides:

    • Phosphate Group

    • Deoxyribose Sugar

    • Nitrogen Bases: Includes Adenine (A), Thymine (T), Guanine (G), Cytosine (C).

  2. Configuration: DNA forms a double-stranded structure known as a double helix.

RNA Structure

  1. Components of RNA Nucleotides:

    • Phosphate Group

    • Ribose Sugar

    • Nitrogen Bases: Includes Adenine (A), Uracil (U), Guanine (G), Cytosine (C).

  2. Configuration: RNA exists as a single strand.

DNA vs. RNA Comparison

  • Sugar Component:

    • DNA: Contains deoxyribose sugar.

    • RNA: Contains ribose sugar.

  • Nitrogenous Bases:

    • DNA: Uses Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

    • RNA: Uses Adenine (A), Uracil (U), Guanine (G), and Cytosine (C); Uracil replaces Thymine.

  • Strandedness:

    • DNA: Typically forms a double-stranded helix.

    • RNA: Generally exists as a single strand.

  • Primary Function:

    • DNA: Stores and transmits genetic information, serving as the blueprint for life.

    • RNA: Involved in the expression of genetic information, translating DNA into proteins (e.g., mRNA, tRNA, rRNA).