Macromolecules and Their Functions

Study Notes

Macromolecules

Four main macromolecules are essential for cell survival: carbohydrates, lipids, proteins, and nucleic acids.
Each macromolecule is a large molecule composed of smaller repeating units called monomers.

Carbohydrates

Function: Provide quick energy for the body.
Structural components: Carbon, hydrogen, and oxygen (CH₂O ratio).
Monomer: Monosaccharide (e.g., glucose).
Examples: Glucose (most common monosaccharide), glycogen (animal energy storage), starch (plant energy storage), cellulose (plant structural component).
Polysaccharides are long chains of monosaccharides.

Lipids

Functions: Long-term energy storage, insulation, and plasma membrane formation.
Structural components: Carbon, hydrogen, and oxygen (more carbons than oxygens).
Monomer: Fatty acid.
Examples: Phospholipids (plasma membrane component), cholesterol (can contribute to heart problems), steroids (sex hormones).
Lipids are also known as fats.
Lipids are hydrophobic (don't mix with water).

Proteins

Functions: Act as the "workers" of the cell.
Structural components: Carbon, hydrogen, oxygen, and nitrogen (CHON).
Monomer: Amino acid.
Examples: Hemoglobin (oxygen transport), insulin (blood sugar regulation), enzymes (catalyze chemical reactions).
Many proteins end in "-ion" (e.g., insulin, collagen).

Nucleic Acids

Functions: Store and transmit genetic information.
Structural components: Carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP).
Monomer: Nucleotide.
Examples: DNA (deoxyribonucleic acid), RNA (ribonucleic acid).

Enzymes

Proteins that speed up chemical reactions.
Also known as catalysts.
Function by lowering activation energy, the amount of energy needed for a reaction to occur.
Involved in breaking down and building molecules.

Enzyme Reactions

Substrate: The molecule that the enzyme acts upon.
Enzyme-substrate complex: The temporary combination of the enzyme and substrate.
Products: The molecules resulting from the chemical reaction catalyzed by the enzyme.

5 Key Facts About Enzymes

Shape and Function: The shape of an enzyme determines its function. The substrate fits perfectly into the enzyme's active site.
Specificity: Enzymes are specific, meaning they only bind to one type of substrate.
Reusability: Enzymes are not consumed during a reaction and can be used repeatedly.
Denaturation: Enzymes can lose their shape (denature) due to high temperatures (fevers) or low pH (acidity).
Activation Energy: Enzymes reduce the activation energy required for a reaction to occur, speeding up the process.

Enzyme Activity

Enzymes speed up chemical reactions by lowering the activation energy needed for the reaction to occur.
This makes the reactions happen faster.
The graph illustrates this: the blue line represents a reaction without an enzyme (high activation energy, slow process), while the pink line depicts a reaction with an enzyme (lower activation energy, faster process).

Description

Test your knowledge on the four main macromolecules essential for cell survival, including carbohydrates, lipids, proteins, and nucleic acids. Explore their structures, monomers, and examples to understand their functions in biology.