AP Biology - Chemistry of Life

Trace Elements

Required by an organism in small quantities. Examples are iron (Fe), iodine (I) + copper (Cu)

Atom

Smallest unit of the world

Proton

Positively charged particle in the nucleus

Neutron

Neutrally charged particle in the nucleus

Electron

Negatively charged massless particle orbiting around the nucleus

Isotopes

Molecules that have the same number of protons and electrons, but different numbers of neutrons

Compound

Two or more elements combined in ratio

Chemical Reaction

When two elements combine together

Chemical Bonds

How atoms of a compound are kept together

Ionic Bonds

Bond between two atoms, when one or more electrons are given from one atom to another. One atom becomes positive, one becomes negative.

Ions

The charged forms of atoms

Covalent Bond

When electrons are shared between atoms

Nonpolar Covalent

In the bond, electrons are shared equally

Polar Covalent

Electrons shared unequally

Double Covalent Bond

Two pairs of electrons shared

Triple Covalent Bond

Three pairs of electrons shared

Polar

Partially positive and partially negative charges

Hydrogen Bonds

Weak chemical bonds that form when a hydrogen ion that is bonded to a negatively charged molecule is attracted to another negatively charged molecule

Cohesion

Water demonstrates this by sticking together. During transpiration water pulls on other water molecules to bring them up the stem using this force.

Adhesive

Water sticks to other surfaces

Capillary Action

The ability of water to rise up in roots, trunks + branches of trees

Surface Tension

Water molecules sticking together on the top

Acidic

Contains lots of hydrogen ions (H+).

Basic

Contains lots of hydroxide ions (OH-). Have a slippery consistency.

Alkaline

Basic solution

pH scale

Numbered from 1-14. 7 is thought of as neutral pH. Concentration of hydrogen ions determines number. Acidic gives low pH, basic gives high. Change in 1 pH number shows 10 times change in hydrogen ions.

Organic Compounds

Molecules with carbon and hydrogen

Inorganic Compounds

Molecules without carbon

Polymers

Chains of monomers

Monomer

The individual parts of a polymer

Dehydration Synthesis/Condensation

Creation of polymer from two monomers and loss of a water molecule

Hydrolysis

Creation of two monomers from a polymer and gaining of water molecule

Carbohydrates

Contains carbon, hydrogen and oxygen. The ratio of those elements is 1:2:1.

Monosaccharide

One sugar carbohydrate. Two most common are glucose + fructose.

Glucose

Has formula C₆H₁₂O₆. Important sugar in cellular respiration

Fructose

Has formula C₆H₁₂O₆. Most commonly found in fruits

Disaccharide

Two sugar carbohydrate

Glycosidic Linkage

Bond between two monosaccharides

Maltose

Disaccharide formed from two glucose molecules

Polysaccharide

Many sugar carbohydrate

Starch

Sugar storage molecule in plants

Amino Acid

Organic molecule that makes up proteins. Contains carbon, hydrogen, oxygen + nitrogen. 20 different ones. Has four different parts around a carbon: amino group, carboxyl group, hydrogen and R-group

Amino Group

-NH₂

Carboxyl Group

-COOH

R-group

Also known as the side chain, only part of the amino acid that differs between types. Can determine the molecule’s polarity, charge, composition of elements and shape

Hydrophobic

Non-polar and uncharged.

Hydrophilic

Polar and uncharged

Ionic

Polar and charged.

Dipeptide

Two amino acids join together. Carboxyl group of one joins with the amino acid of another. Uses the process of dehydration synthesis.

Peptide Bond

Bond between two amino acids

Polypeptide

Group of amino acids joined in a string

Protein

A twisted three-dimensional polypeptide chain

N-terminus/amino terminus

Amino group

C-terminus/carboxyl terminus

Carboxyl group

Primary Structure

Linear sequence of amino acids

Secondary Structure

How a protein twists, due to how different R-groups interact

Tertiary Structure

Amino acids that were previously far away can now interact, due to secondary structure. Hydrophilic amino acids typically found on the outside of the protein, hydrophobic amino acids are found on the inside. Puts the protein in a 3D shape.

Quaternary Structure

Multiple polypeptide chains that interact with one another, ex: hemoglobin. The different chains are sometimes called subunits.

Chaperone Proteins (Chaperonins)

Folding of proteins sometimes involves help from these to help the proteins fold effectively

Lipids

Consists of carbon, hydrogen and oxygen. 3 common types are triglycerides, phospholipids and steroids. They are nonpolar, so are found in the structure of the cell membrane, in insulation, help to signal molecules and energy storage. Bond is an ester bond

Triglycerides

The fat cells of the human body are filled with these. Made up of singular glycerol molecule, along with three fatty acid chains attached.

Fatty Acid

Long chain of carbons, where each have hydrogens surround them. Can either be saturated or unsaturated. Has a carboxyl group at the end of the chain

Saturated Fatty Acids

Has no double bonds present in the chain. Tends to forms a solid at room temperature.

Unsaturated Fatty Acid

Has one or more double bonds present in the chain. Tends to form a liquid at room temperature. One exception is when there is a trans-double bond, so more likely to be solid.

Phospholipids

These have two fatty acid chains attached to a phosphate head. The fatty acid tails are hydrophobic because they’re nonpolar. The head is hydrophilic.

Amphipathic Molecule

A molecule with both a hydrophilic region and a hydrophobic region

Cholesterol

Four ringed molecule, often found in membranes. Increases membrane fluidity except in very high temperatures, where it helps hold the membrane together. Also makes certain hormones, like testosterone, estradiol, as well as Vitamin D.

Nucleic Acid

Made up of carbon, hydrogen, oxygen, nitrogen and phosphorus. Monomer is a nucleotide and the 2 important kinds are deoxyribonucleic acid and ribonucleic acid. The bond is a sugar-phosphate phosphodiester bond.