BIO 1110 - Chapter 3: The Molecules of Life

Organic Compounds

• ORGANIC COMPOUNDS: carbon-cased molecules

  • Carbon = most important element for life

• Unique properties of an organic compound depend on:

  • Carbon skeleton

  • Other functional groups attached

Building Macromolecules

• MACROMOLECULES: polymers made up of smaller molecules (subunits/monomers) linked via covalent bonds

• Examples:

  • Carbohydrates: (sugar )

  • Lipids (fats, oilds, waxes, steroids, phospholipids)

  • Proteins (enzymes)

  • Nucleic Acids (DNA, RNA)

Carbohydrates

• CARBOHYDRATES: Sugars and polymers of sugar

• Composed of C, H, and O

• MONOMER: monosaccharide (simple sugar)

• POLYMER: polysaccharides

• Functions:

  • Source of dietary energy

  • Is raw material for manufacturing other kinds of organic compounds

  • building material for plants

Monosaccharides

• Simple sugars

• Command examples are glucose and fructose

  • GLUCOSE: is the main source of fuel for cellular energy

Disaccharides

• Made from two monosaccharides

• Example

  • Lactose

  • Sucrose

• US is the leading market for sweeteners

Polysaccharides

• Complex carbohydrates

• Made of long chain of monosaccharides

• Examples:

  • STARCH\

    • Used by plant cells to store energy

    • Potatoes and grain

  • GLYCOGEN

    • Used by animal cells to store energy

  • CELLULOSE

    • Cannot be broken apart

    • Dietary fiber

Simple vs Complex Carbs

Lipids

• Very diverse group means no monomer

• Common property: does no dissolve in water; hydrophobic

  • HYDROPHOBIC: no effect by water

  • HYDROPHILIC: do dissolve in water

• FATS:

  • Glyceral head

  • Three fatty acid tails (C-H chain)

  • Functions in the human body as:

    • cushioning

    • insulation

    • long term energy storage

• STEROIDS:

  • Different from fats in structure and functions

  • CHOLESTEROL

    • key component of cell membranes

    • used by the body to produce other steroid

• Phospholipids

  • Composed of a hydrophobic head and two hydrophobic fatty acid tails

  • Main component of cell membranes

Saturated vs Unsaturated Fats

• Fatty acids can be saturated or unsaturated

  • SATURATED: single bonds between the carbons

  • UNSATURATED: one or more double bonds exist between the carbons

Proteins

• Account for more than 50% of the dry weight of most cells

• Very diverse in structure and function

• MONOMERS: amino acids

• AMINO ACIDS:

  • central carbon atom

  • SIDE CHAIN: gives amino acids their unique chemical identity

  • There are 20 different amino acids (so 20 different side chains)

Proteins as Polymers

• Amino acids are linked together by a covalent bond called a peptide bond

• POLYPEPTIDE: A long chain of amino acids connected together

  • The sequence of the amino acids determines the structure

Protein Shape

• A slight change in the amino acids sequence can affect a protein's ability to function

• proteins can be denatured

  • DENATURED: lose their shape and function due to unfavorable changes in the environment

  • can be temporary of permanent

Nucleic Acids

• Monomers:

  • Nucleotides

• Functions:

  • Serve as the building blocks of nucleic acids, which are essential for storing and transmitting genetic information.

  • Act as coenzymes in various biochemical reactions, facilitating metabolic processes.

  • provide instructions for building proteins

• Examples

  • DNA

  • RNA

• Has three parts

  • Adenine

  • Guanine

  • Cystosine

  • Thymine (DNA only)

  • Uracil (RNA only)

• A only pairs with T

• G only pairs with C

• RNA replaces T with U, which allows for the formation of complementary base pairs during transcription. This unique pairing mechanism is crucial for the synthesis of RNA from DNA, ensuring that genetic information is accurately transcribed.