Molecules of Life Notes

Introduction to Biomolecules

  • Food as a source of large molecules needed for life called biomolecules, also known as macromolecules.

  • Four classes of biomolecules:

    • Carbohydrates

    • Lipids

    • Proteins

    • Nucleic Acids

  • Different types of food may have varying amounts of these biomolecules.

    • Example: Peanut butter is high in both proteins and lipids.

  • The focus of the discussion is on classes of biomolecules and their importance in cellular structure and function, rather than nutrition.

Monomer

  • Definition: A monomer is a building block, referring to the parts that make up a larger substance.

  • Each biomolecule class may have a corresponding monomer.

Carbohydrates

  • Food sources high in carbohydrates include bread, pasta, fruit, and vegetables.

  • Monomer of carbohydrates: Monosaccharide.

    • Example: Glucose, which is crucial in cellular respiration to produce ATP (adenosine triphosphate), the energy currency of cells.

  • Combining two monosaccharides results in a disaccharide.

    • Example: Two glucose molecules combine to form maltose.

  • Naming convention: Many sugars end with -ose (glucose, maltose, lactose, sucrose, fructose).

  • Multiple monosaccharides can combine to form a polysaccharide.

  • Importance of carbohydrates in organisms and cells:

    • Structural:

    • Plants have cell walls comprised of carbohydrates, specifically cellulose.

    • Fungi have cell walls made of chitin, which also forms the exoskeleton of insects.

    • Functional:

    • Glucose is vital for ATP production, making carbohydrates a rapid energy source for cells.

    • Energy can be stored in polysaccharide forms such as starch (plants) and glycogen (animals).

Lipids

  • Lipids encompass fats and oils; examples of food sources include butter and olive oil.

  • Diverse types of lipids include:

    • Triglycerides

    • Phospholipids

    • Steroids

  • General building blocks of lipids are glycerol and fatty acids.

  • Key characteristic: Lipids are generally hydrophobic and do not dissolve in water, contrasting with other biomolecules.

  • Importance of lipids in organisms and cells:

    • Cell Membranes:

    • Phospholipids form the phospholipid bilayer constituting cell membrane structure.

    • Energy Storage:

    • Lipids serve as long-term energy storage after carbohydrates' energy sources are exhausted.

    • Insulation:

    • Aids in carrying electrical impulses in neurons via myelin sheath made of lipids.

    • Provides thermal insulation (e.g., blubber in seals).

    • Hormones:

    • Many lipids function as hormones, acting as chemical messengers in various processes.

Proteins

  • Protein-rich food sources include beans, meat, nuts, and eggs.

  • Monomer of proteins: Amino acid.

  • Proteins are typically composed of various amino acids bonded together.

  • Importance of proteins in organisms and cells:

    • Structural:

    • Muscle tissues consist heavily of proteins; proteins also form structures such as hair and collagen.

    • Membrane Proteins:

    • Proteins function as channels and receptors within cell membranes, crucial for signaling and substance transport.

    • Enzymes:

    • Most enzymes are proteins, facilitating metabolic processes by building up or breaking down substances.

    • Defensive Proteins:

    • Antibodies made by immune cells are proteins that protect the body.

    • Hormonal Proteins:

    • Some hormones, like insulin, are proteins.

    • Genetic Role:

    • Genes, which are composed of DNA, often code for proteins.

Nucleic Acids

  • Nucleic acids include DNA and RNA.

  • Monomer of nucleic acids: Nucleotide.

  • Are nucleic acids found in food? Yes, they are present in cells of living organisms.

    • Example: Eating a strawberry includes consuming the cells that contain DNA in their nuclei.

  • Importance of nucleic acids in cells:

    • Cells carry genetic information necessary for trait coding (involves both DNA and RNA).

Summary of Biomolecules

  • General overview of four biomolecule classes: carbohydrates, lipids, proteins, and nucleic acids.

  • Mnemonic for common elements: CHO, CHO, CHON, CHONP

    • C: Carbon

    • H: Hydrogen

    • O: Oxygen

    • N: Nitrogen

    • P: Phosphorus

  • Structural arrangements of these elements significantly impact biomolecule functions.

  • Encourage further reading and exploration of biomolecule structures due to their complexity and beauty.