Biochemistry

AP biology unit 2

Proton

positive charge, located in the nucleus

Ionic Bonding

A bond formed by the transfer of electrons between atoms, resulting in electrostatic attraction between oppositely charged ions.

Neutron

neutral charge, located in the nucleus

Electron

negative charge, located in orbitals/shells

What determines an element's identity and its chemical properties?

The Atomic Number (number of protons)

Isotopes

Atoms of the same element that have a different number of neutrons leading to different masses.

Octet Rule

Atoms want to have a stable outer electron shell, typically filled with 8 electrons (or 2 for the first shell).

Covalent Bonding

A bond formed by the sharing of electrons between atoms.

Nonpolar Electrons

Electrons are shared equally.

Hydrogen Bonding

A weak attraction between a slightly positive Hydrogen atom of one molecule and a slightly negative O or N atom of another molecule.

Six most common elements in living things

C, H, N, O, P, S (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur).

What two properties of water help to moderate Earth's temperature?

High specific heat and High heat of vaporization.

Universal Solvent (as it relates to water)

Water dissolves many substances, especially polar or ionized ones.

Hydrophilic

water-loving (polar or ionized molecules)

Hydrophobic

water-fearing (nonpolar molecules)

Cohesion

Water molecules stick to each other (due to H-bonds).

Adhesion

Water molecules sticking to other polar surfaces

Why is the density anomaly of water important for aquatic life?

Ice is less dense than liquid water, so it floats, insulating the water below and allowing aquatic life to survive frozen conditions.

Acidic pH range and relative H+ concentration.

pH<7. It has a higher H+ concentration.

Buffer

Systems that resist changes in pH, crucial for maintaining stable internal environments.

Major classes of Organic Molecules (Polymers/Macromolecules)

Carbohydrates, Lipids, Proteins, Nucleic Acids

Characteristic of Carbon that allows it to form diverse molecular structures

Carbon can form chains and rings, as it can bond up to four other atoms.

Functional Groups

Clusters of atoms that determine a molecule's chemical properties and reactivity.

Monomer

A small, repeating unit.

Polymer

A large macromolecule built from many monomers.

A process that joins monomers to form polymers, and removes a molecule.

Dehydration Synthesis; a molecule of water is removed.

A process that breaks down polymers into monomers, adding what molecule?

Hydrolysis; a molecule of water is added.

What is the monomer of a Carbohydrate?

Monosaccharide (e.g., glucose, fructose, ribose).

Polysaccharides used for energy storage in plants and animals.

Starch (plants) and Glycogen (animals).

Polysaccharides that are used for structure + location

Cellulose (plant cell walls) and Chitin (arthropod exoskeletons/fungal cell walls).

What is the primary characteristic that makes Lipids insoluble in water?

They are generally hydrophobic due to a lack of polar groups.

Triglyceride (Fat/Oil)

Glycerol + 3 fatty acids.

Saturated Fatty Acid

Contains no double bonds in the carbon chain.

Unsaturated Fatty acid

Contains double bonds in the carbon chain.

Structure of a Phospholipid

Glycerol + 2 fatty acids + phosphate group.

What is the function of a Phospholipid?

Forms the plasma membrane bilayer (hydrophilic heads, hydrophobic tails).

Monomers of Protein

Amino Acids.

What are the two major types of Nucleic Acids?

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).

Monomers of Nucleic Acid

Nucleotides.

Function of Nucleic Acids (DNA and RNA)?

They store and transmit genetic information.

Isomer

Molecules with the same molecular formula but different structural arrangements.

Matter

Anything that takes up space and has mass.

Polar Electrons

Electrons are shared unequally due to differences in electronegativity.