Video: Proteins and DNA Polymerase Vocabulary

Vocabulary flashcards covering key terms from the protein structure lesson and DNA polymerase discussion.

DNA polymerase

An enzyme that synthesizes new DNA strands; mutations can impair or alter DNA synthesis.

A defective version of DNA polymerase that may reduce or change the ability to make new DNA.

Mutated DNA polymerase

Protein

A macromolecule made of amino acids that performs many cellular functions (structure, enzymes, transport, movement).

Amino acid

The basic building block of proteins; contains an amino group, a carboxyl group, a hydrogen, and a variable R group.

R group (side chain)

The variable side chain of an amino acid that determines its chemical properties (hydrophobic, hydrophilic, acidic, basic).

Monomer

A single subunit that can join to form polymers (e.g., amino acids are the monomers of proteins).

Polypeptide

A polymer composed of many amino acids linked by peptide bonds.

Primary structure

The linear sequence of amino acids in a protein; described as beads-on-a-string.

Beads on a string

A metaphor for the primary structure: amino acids linked in a chain.

Secondary structure

Local folding patterns of the polypeptide backbone, including alpha helices and beta pleated sheets.

Alpha helix

A right-handed coiled structure stabilized by hydrogen bonds along the backbone.

Beta pleated sheet

A folded, zigzag arrangement of segments stabilized by hydrogen bonds between strands.

Tertiary structure

The overall three-dimensional folding of a single polypeptide due to interactions among side chains.

Quaternary structure

A complex of multiple folded polypeptides (subunits) forming a functional protein.

Disulfide bridge

A covalent bond between sulfur atoms (often from cysteine residues) that strengthens protein structure.

Hydrophobic collapse

Process where nonpolar parts of a protein fold away from water to drive compact folding.

Hydrogen bond

A weak bond between a hydrogen attached to an electronegative atom (O, N) and another electronegative atom.

Hydrophilic

Water-loving; amino acids with polar or charged side chains that interact with water.

Hydrophobic

Water-fearing; amino acids with nonpolar side chains that avoid water.

Positive charged amino acid

An amino acid with a basic, positively charged side chain.

Negative charged amino acid

An amino acid with an acidic, negatively charged side chain.

N-terminus

The end of a protein or polypeptide with the free amino group.

C-terminus

The end of a protein or polypeptide with the free carboxyl group.

Peptide bond

The covalent bond formed between amino acids during dehydration synthesis.

Dehydration synthesis

A condensation reaction that links amino acids by removing water.

20 common amino acids

The standard set of amino acids found in proteins across organisms, each with a characteristic side chain.

Amino group

The -NH2 or -NH3+ group on an amino acid; involved in peptide bonds and hydrogen bonding.

Carboxyl group

The -COOH group on an amino acid; participates in peptide bond formation and acid–base chemistry.

Directionality of proteins

Proteins are read/synthesized from N-terminus to C-terminus.

Structure determines function

The concept that a protein’s three-dimensional shape dictates its activity and role.

Coronary structure

Informal term used in notes for quaternary structure (protein complexes).

Hemoglobin

A quaternary structure protein composed of multiple subunits that transports oxygen in red blood cells.