AP Biology- Unit 1: Chemsitry of Life

Elements

substances that cannot be broken down into simpler substances by chemical means

Essential Elements of Life

Hydrogen, Oxygen, Carbon, and Nitrogen

Trace Elements

Elements required by an organism but only in small quantities; ex: iron, iodine, copper

Compound

Two or more individual elements combined in a fixed ratio

Chemical Reaction Bonds

Ionic, covalent

Ionic Bond

Bond where the molecules give away ions

Covalent Bond

Bond where molecules share ions between themselves

Polar Bond

Bond where the sharing of ions in the bond is unequal

Non-polar Bond

Bond where the sharing of ions is equal

What type of molecule is water?

Polar!

Hydrogen Bonds

The weakest bond, yet most stable; happens when a hydrogen atom, that is covalently bonded to one electronegative atom, is also attracted to another electronegative atom

Traits of Water

• cohesion

• adhesion

• surface tension

• high heat capacity

• expanding on freezing (and less dense when solid)

Cohesion

Water’s tendency to stick to itself; ex: water forming droplets

Adhesion

Water’s tendency to stick to other objects; ex: hair or leaves

Capillary Action

Phenomenon where cohesion and adhesion work together to cause water to rise up roots/thin vessels

Surface Tension

Water’s trait to allow certain objects to stay on top of it with out sinking; ex: a leaf, water strider

Acidic Solutions

Solutions that contain positive hydrogen ions (H+)

Basic Solutions

Solutions that contain negative alkaline ions (OH-)

Organic Compounds

Compounds that contain carbon surrounded by hydrogen or other elements

Inorganic Compounds

Compounds with no carbons

Polymers

Chains of building blocks that form macromolecules

Monomer

Building block of a polymer

Dehydration Synthesis

Reactions that forms polymers; water is lost and a larger compound is formed

Hydrolysis

Reaction that breaks down polymers into monomers; adding water to compound makes smaller compounds

Carbohydrates

• Sugar molecules that provide energy for the body

• Contains carbon, hydrogen, and oxygen

Monosaccharides

• Organic compounds that contain carbon, hydrogen, and oxygen (often in a ration of 1:2:1)

• The simplest sugars: energy source for cells

• Ex: glucose and fructose

• Formula of C6H12O6

Glucose

Compound broken down to provide energy

Fructose

Sugar common in fruit

Disaccharide

2 monosaccharides joined together; glycosidic linkage bond

Polysaccharides

• Repeated units of monosaccharides

• Ex: Starch (storage molecule in plants), Glycogen (storage molecule in animals), and Cellulose (glucose in cell walls of plant cells)

Proteins

• Preform most of the work in cells

• Essential for structure, function, and regulation of tissues and organs

• Contains carbon, hydrogen, oxygen, nitrogen, and sulfur

Animo Acids

• The buildings blocks of proteins

• They have 4 important parts around a central carbon: animo group, carboxyl group, a hydrogen, and an R group (compound)

  • R group (side chain) can differ in: composition of elements, polarity, charge, and shape

  • Can be hydrophobic, hydrophilic, and ionic (animo acids)

Polypeptides

• Uses the same dehydration synthesis

• Uses peptide bond

  • String=Polypeptide chain

  • 3D=Protein structure

• All peptides end with an animo group

Protein Structures

Primary, Secondary, Tertiary, and Quaternary

Primary Protein Structure

A linear sequence of polypeptides

Secondary Protein Structure

A twisted, coiled, or zigzagged pattern of polypeptides

• Alpha Helix= coiled

• Beta-Pleated Sheets= zigzagged pattern

Tertiary Protein Structure

Structure where the secondary protein structure reshapes the polypeptide and originally far apart animo acids can interact each other; 3D shape

Quaternary Structure

Structure where large polypeptide chains interact with each other; ex: hemoglobin protein

Chaperonins

Proteins that assist other proteins with folding properly; if not done correctly protein can lose function

Lipids

• Fatty compounds that are structural components of cell membranes, sources of insulation, signaling molecules and energy storage; ex: triglycerides, phospholipids, steroids

• Made up of carbon, hydrogen, oxygen, and sometimes phosphorus

• Can be saturated or non saturated (having no double bonds vs. with double bonds)

  • Saturated structures are kinked, with the exception of fatty acids with trans-double bonds

Cholesterol

Lipids important for creation of hormones and making vitamins D

• 4 ringed and increases membrane fluidity

Nucleic Acids

Molecules made of up nucleotides

• made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus

Two types of Nucleic Acids

• deoxyribose (DNA)

• ribose (RNA)