Carbohydrates Overview

Carbohydrates

• Carbohydrates are organic macromolecules built from chains of simple sugars covalently bonded together.
• These polymers can be linear or branched, and function in energy storage or building structural components.
• Simple sugars contain carbon, hydrogen, and oxygen.
• The arrangement of atoms in a sugar monomer determines its structure and properties (e.g., glucose and fructose are isomers with the same chemical formula C₆H₁₂O₆ but different arrangements).
• Sugar monomers join via dehydration synthesis, where water is lost and covalent bonds form.
• Different arrangements of glucose monomers create various complex carbohydrates like starch, glycogen, and cellulose.
• Cellulose (linear chains) forms plant cell walls; starch (branched) stores energy in plants, and is digested to glucose in animals.
• Glycogen (branched) is an animal energy storage carbohydrate.
• Hydrolysis breaks complex carbs into simple sugars by adding water and breaking covalent bonds.

Water

• Water is essential for all known life forms.
• A water molecule (H₂O) has two hydrogen atoms and one oxygen atom covalently bonded.
• Covalent bonds result from atoms sharing electrons.
• Water is polar due to unequal electron sharing (oxygen is more electronegative).
• This polarity creates partial positive and negative charges on the water molecule.
• Hydrogen bonding occurs between water molecules due to their polarity.
• Cohesion is water's attraction to itself, leading to high surface tension.
• Surface tension results from hydrogen bonds at the surface.
• Adhesion is water's attraction to other polar molecules or charged ions.
• Cohesion and adhesion combined help water move in plants against gravity.
• Water interacts with hydrophilic (water-loving) and hydrophobic (water-fearing) molecules.
• Aqueous fluids in cells and their environments are affected by water properties that allow for material balance and transport.