What are the four types of macromolecules found in living organisms?
Proteins, nucleic acids, carbohydrates, and lipids.
What is a monomer?
A small subunit that links together with other monomers to form a polymer.
What is a polymer?
A long chain of repeating monomer subunits linked together by covalent bonds.
What is the monomer of proteins?
Amino acids.
What is the monomer of nucleic acids?
Nucleotides.
What is the monomer of carbohydrates?
Monosaccharides.
What is the monomer of fats (lipids)?
Fatty acids.
What is a dehydration reaction?
A reaction that links monomers together by forming a covalent bond while removing a water molecule.
What is hydrolysis?
The breakdown of a polymer by adding a water molecule to break the covalent bond between subunits.
What are the five functional categories of proteins?
Enzymes, structural proteins, contractile proteins, transport proteins, and defensive proteins.
Give an example of each functional category of protein.
Enzymes (globular proteins); structural (collagen in bones/tendons, keratin in hair); contractile (actin and myosin in muscles); transport (hemoglobin carries oxygen); defensive (antibodies made by white blood cells).
What is the basic structure of an amino acid?
A central carbon attached to an amino group (–NH2), a carboxyl group (–COOH), a hydrogen atom, and a variable R group.
How many common amino acids are there?
20
What determines the chemical properties of an amino acid?
Its R group (functional group).
What is a peptide bond?
The covalent bond linking two amino acids together, formed by a dehydration reaction.
What is a polypeptide?
A long chain of amino acids linked by peptide bonds.
What are the four levels of protein structure?
Primary, secondary, tertiary, and quaternary.
What is the primary structure of a protein?
The specific sequence of amino acids in the polypeptide chain.
What is the secondary structure of a protein?
The initial folding of the polypeptide chain due to hydrogen bonds along the backbone — forming α-helices or β-pleated sheets.
What is the tertiary structure of a protein?
The final three-dimensional shape of the polypeptide, determined by where nonpolar amino acids occur and their tendency to be pushed away from the watery environment.
What is the quaternary structure of a protein?
The spatial arrangement of two or more polypeptide chains that together form a single protein — for example hemoglobin has four subunits.
What is denaturation?
The unfolding of a protein caused by disruption of hydrogen bonds — for example by increased temperature or decreased pH.
What happens to a denatured protein’s function?
It loses its ability to function properly; most cannot refold and are permanently denatured.
What is the active site of an enzyme?
The groove or depression on the enzyme’s surface that precisely fits and binds a specific molecule to facilitate a chemical reaction.
