Unit 1 Flashcards AP Biology

unit 1 ap bio

Covalent bond

Sharing of electrons by two atoms

• Forms molecules and compounds

• Single bonds, double bonds, triple bonds, etc …

Nonpolar covalent bond

A type of bond where electrons are shared equally between the two atoms

Polar covalent bond

A type of bond where electrons are not shared equally between two atoms

Ionic bond

The attraction between oppositely charged atoms, where one atom steals electrons from another * Forms compounds and salts * NaCl (sodium chloride) * LiF (lithium fluoride)

Cation

Positively charged ion

Anion

Negatively charged ion

Cohesion

Two of the same molecules forming hydrogen bonds with each other.

• Responsible for surface tension by allowing liquids to resist forces

Adhesion

Two different molecules forming hydrogen bonds with each other.

• Allows water to cling to cell walls

Capillary action

The upward movement of water due to the forces of cohesion, adhesion, and surface tension

• Adhesion > Cohesion

Temperature control

H₂O resists changes in temperature through hydrogen bonds.

• Heat must be absorbed to break bonds, but heat is released when bonds form

Evaporative Cooling

Responsible for:

• Moderating the Earth’s climate

• Stabilizing temperatures in lakes and ponds

• Preventing terrestrial organisms from overheating

• Preventing leaves from becoming too warm

Floating Ice

Through water solidifying and becoming less dense / expanding:

• Allows marine life to survive under the sheets of ice

Organic Chemistry

The study of compounds with covalently bonded carbon

Organic compounds

Compounds that contain carbon and hydrogen

Hydrocarbon

Organic molecules consisting only of carbon and hydrogen

• Framework/skeletons for more complex molecules

Varies in length, branching, double bond positions, and presence of rings.

Dehydration Synthesis Reaction

Bonds two monomers with the loss of water

• -OH of one monomer bonds to the -H of another, forms H₂O, which is then released.

• A + B → AB + H₂O

Hydrolysis

Breaks bonds by adding H₂O

• -H of the H₂O bonds to one monomer and the remaining -OH attaches to the other monomer.

• Covalent bonds are cleaved (broken).

• AB + H₂O → A + B

Carbohydrates

Includes sugars and polymers of sugars; a major energy source for organisms

• Carbonyl and hydroxyl groups

  • Composed of carbon, hydrogen, and oxygen (CHO)

Monosaccharides

Simple sugars; monomers of carbohydrates

• Composed of multiples of the unit CH₂O

Glucose

• Most common monosaccharides

• Nutrients and fuels for cells

• Used in cellular respiration

Fructose

• “Fruit” sugar

Sucrose

Most common disaccharide

• Made up of glucose and fructose

• Plants transfer carbs from roots to leaves in this form

Cellulose

• Polymer of glucose

• Tough substance that forms cell walls

Lipid

Diverse group of molecules; generally won’t dissolve in water; does not include true polymers

• Generally small in size

• Nonpolar-hydrophobic

Fats

Lipids - Composed of glycerol (1) and fatty acids (3)

Glyercol

Classified as an alcohol (hydroxyl groups)

Fatty acids

Long carbon chains with a carboxyl group at one end

Saturated fatty acid

Type of fatty acid; No double bonds between carbons in the carbon chain; contains more hydrogen (saturated w/ hydrogen)

Unsaturated fatty acid

Fatty acid that contains one or more double carbon bonds, leaving less room for hydrogen molecules

Phospholipids

Major components of cell membranes

• Two fatty acids - glycerol - phosphate

Assembled as a bilayer in H₂O

• Tails are hydrophobic

• Head is hydrophillic

Steroids

Lipids that have four fused rings

• Unique groups attached to the ring determine the type of steroid

Lipid

• Moving and storing energy

• Absorbing vitamins

• Making hormones

Protein

Molecule consisting of polypeptides (polymers of amino acids) folded in a 3D space

• Includes sulfur

• Shape determines function

Amino acids

Molecules that have an amino group and a carboxyl group

Polypeptides

Many amino acids linked by peptide bonds

• Each has a unique sequence of amino acids and directionality

• Each end is chemically unique (one end is a free amino group, N-terminus; one is a free carboxyl group, C-terminus)

• Sequence of AAs determine shape (and shape determines functions)

Primary

Protein level

• Linear chain of amino acids

• Determined by genes

• Dictates secondary and tertiary forms

Secondary

Coils and folds due to hydrogen bonding within the polypeptide backbone

• β pleated sheets - hydrogen bonds between chains lying side to side

• α helix - hydrogen bonding between every 4th AA

Tertiary

3D folding due to interactions between the side chains

• Reinforced by hydrophobia interactions and disulfide bridges of the side chains

• Covalent bond formed between sulfur atoms of the cysteine monomers

Quaternary

Association of two or more polypeptides

• Found only in some polypeptides

Protein

• Antibodies

• Enzymes

• Hormones

• Provides structure and support

• Transport/Storage

Nucleic acids

Made from nucleotides; DNA/RNA

• Stores, transmits, and expresses hereditary information

A nitrogenous base, a five carbon sugar (pentose), and phosphate group(s)

Parts of a nucleotide

Nucleoside

A nitrogenous base and a five carbon sugar

Pyrimidine and purine

Types of nitrogenous bases

Purine

One ring with 6 atoms bonded to one ring with five atoms

• Adenine, guanine

Pyrimidine

One ring with 6 atoms

• Cytosine, thymine (only found in DNA), uracil (only found in RNA)

Five carbon sugar

A sugar is bonded to the base \n In DNA the sugar is deoxyribose. \n In RNA the sugar is ribose.

Phosphate group

Polynucleotides

Phosphate groups that link adjacent nucleotides produce…

DNA

Consists of two polynucleotides

• Forms the double helix

• Strands are antiparallel (parallel but moving in opposite directions) and held by hydrogen bonds between bases

• Cytosine - guanine; adenine - thymine

RNA

A single stranded polynucleotide

• Varied in shape

• Adenine - uracil; cytosine - guanine

glysodic link

two monopsaccardies