The Chemical Level of Organization Flashcards

Flashcards covering chemical elements, atomic structure, bonding, chemical reactions, pH, and organic macromolecules (carbohydrates, lipids, proteins, and nucleic acids).

Chemical Elements

Substances that cannot be split into simpler substances by ordinary chemical means.

Atoms

The units of elements; a quantity of matter composed of atoms of the same type.

Nucleus

The central part of an atom containing protons with a positive charge and neutrons which are not charged.

Electrons

Sub-atomic particles with a negative charge that surround the nucleus in energy levels called clouds (orbits).

Atomic Number

The number of protons in the nucleus of an atom; in neutral atoms, this also represents the number of electrons.

Mass Number

The sum of the protons and neutrons in an atom.

Atomic Mass

The atomic weight, which is close to the mass number of its most abundant isotope (roughly the number of protons and neutrons).

Isotopes

A specific version of an element based on its mass number; they differ in the number of neutrons.

Ions

Atoms that have gained or lost an electron, resulting in a charge.

Anion

A negative-ion formed by gaining an electron.

Cation

A positive-ion formed by losing an electron.

Molecules/Compounds

Formed when atoms combine (bond together); written using chemical symbols and subscripts to indicate atom counts, such as $H_2O$.

Valence Electrons

The outer most electrons that interact to establish stability in the outer shell.

Rule of Octets

The principle stating that an outer shell is stable when it has 8 electrons.

Ionic Bonding

A bond formed when atoms gain or lose electrons and the resulting ions of opposite charge are attracted to each other.

Covalent Bonding

A bond formed when atoms share electrons in their outer shells to achieve stability.

Non-polar Covalent Bond

A covalent bond where the sharing of electrons is equal.

Polar Covalent Bond

A covalent bond where atoms of unequal size have unequal sharing, creating a slight differential charge (e.g., $H_2O$).

Hydrogen Bonding

Attraction where the positive end of one polar molecule is attracted to the negative end of another molecule.

Activation Energy

The certain amount of energy required for every chemical reaction to begin.

Enzymes

Catalysts in living cells that lower the activation energy needed for a reaction to occur without injuring the cell.

Synthesis Reactions (Anabolism)

Chemical reactions that put things together; represented as $A + B \rightarrow AB$.

Decomposition Reactions (Catabolism)

Chemical reactions that break things down; represented as $AB \rightarrow A + B$.

Exchange Reactions

Chemical reactions that mix things up; represented as $AB + CD \rightarrow AC + BD$.

Reversible Reactions

Chemical reactions that can go in either direction; represented as $AB + CD \rightleftharpoons AC + BD$.

pH

A measure of acidity based on the amount of hydrogen ions ($H^+$).

pH Scale

A range from 0 to 14, where 0 is acidic, 14 is alkaline, and 7 is neutral (pure water).

Buffer Systems

Systems used by the body to maintain pH relatively near neutral to prevent denaturing proteins.

Monomers

Similar carbon chains or groupings that serve as building blocks.

Polymers

Large macromolecules created by putting similar monomers together.

Isomers

Molecules that have the same molecular formula but different structural arrangements (e.g., glucose and fructose: $C_6H_{12}O_6$).

Carbohydrates

Substances providing most energy for life, following the formula $(CH_2O)_n$; grouped as monosaccharides, disaccharides, and polysaccharides.

Triglyceride

The most plentiful lipid in the body, consisting of a glycerol molecule with 3 fatty acids; provides protection, insulation, and energy.

Phospholipids

Complex lipids with a glycerol, 2 fatty acids, and a phosphate group; important components of cell membranes with a polar head and hydrophobic tails.

Amino Acids

The building blocks of proteins, consisting of a central carbon, hydrogen, carboxyl group, amino group, and variable R-group.

Primary Level of Protein Organization

The sequence of amino acids in a protein established according to the DNA code.

Nucleotides

Subunits of nucleic acids composed of a nitrogen base, a pentose sugar, and a phosphate group.

DNA (Deoxyribonucleic acid)

The genetic code that regulates cellular activity using deoxyribose sugar and bases adenine, guanine, thymine, and cytosine.

RNA (Ribonucleic acid)

Molecule that relays information from genes to ribosomes using ribose sugar and bases adenine, guanine, uracil, and cytosine.

mRNA (Messenger RNA)

The type of RNA that carries the genetic code from the gene to the ribosome.

rRNA (Ribosomal RNA)

The type of RNA that is part of the structure of the ribosome.

tRNA (Transfer RNA)

The type of RNA that carries amino acids to the ribosomes during protein synthesis.

ATP (Adenosine Triphosphate)

The energy storage molecule in cells; produced by phosphorylating ADP ($ADP + \text{energy} + P \rightarrow ATP$).