BIO 241 Terms Sheet 1

Hydrogen Bond

The weak attraction between a slightly positive hydrogen atom and a slightly negative atom on another molecule

Ex: Water mcs & DNA bases are held by h-bonds

Covalent Bond

Strong chemical bond formed when 2 or more atoms share 1 or more pairs of electrons

Ex: Hydrogen and Oxygen in water are covalently bonded

Polar Covalent Bond

Unequal sharing of electrons between atoms with different electronegativities (bc 1 atom attracts the shared electrons more strongly than the other)

Ex: in water, oxygen pulls shared e-s closer to itself; oxygen is slightly negative and hydrogen is slightly positive

Electronegative

An atom’s ability to attract electrons towards itself in a chemical bond

Ex: oxygen is more electronegative than hydrogen, so it pulls te shares elecrrons closer to itself (in a water mc)

Kinetic Energy

Energy gained from motion; also associated with random motion of molecules

• Faster a mc moves, the greater kinetic energy it possesses

Hydrophilic

When a substance has a chemical attraction to water; dissolves/interacts easily with water because it is polar/charged

Hydrophobic

Substance does NOT interact with/dissolve in water because it is non-polar

Dehydration Synthesis Reaction

Chemical reaction that joins 2 mcs together by removing a molecule of water.

• Builds polymers from monomers

Hydrolysis

Chemical reaction that breaks a bond in a larger mc by adding water

• Breaks polymers into smaller mcs

Macromolecules

Large biological molecules that are essential for life

1. carbs

2. lipids

3. proteins

4. nucleic acids

Polymer

Large mc made by linking many smaller repeating units (monomers) together; usually through covalent bonds

• Not all Macromcs are polymers! (ex: Lipids are not)

Monomer

Small molecular subunit that can be linked to other monomers to form a polymer

Carbohydrates

Biological mc made of C, H, O that function as energy storage and use, and structural support

• Building blocks are monosaccharides (ex: glucose)

Lipids

Group of biological mcs that are hydrophobic; includes fats, oils, phospholipids, and steroids. Function as long-term energy storage, cell membranes, insulation, and signaling

Proteins

Macromolecule made of amino acids that catalyses reactions, cell communication, transport, and provides structural support; function depends alot on ther 3D structure

Nucleic Acid

Macromolecule made of nucleotides; store, transmit and express genetic information

• DNA

• RNA