Biological Macromolecules and Proteins

These flashcards cover key terms and concepts related to biological macromolecules and proteins, as discussed in the lecture notes.

alpha-helix structure (α-helix)

A type of secondary protein structure formed by folding the polypeptide into a helix shape with hydrogen bonds stabilizing the structure.

amino acid

A protein's monomer; has a central carbon (alpha carbon) to which an amino group, a carboxyl group, a hydrogen, and an R group (side chain) is attached.

beta-pleated sheet (β-pleated)

A secondary structure in proteins in which hydrogen bonding forms 'pleats' between atoms on the polypeptide chain's backbone.

biological macromolecule

A large molecule necessary for life that is built from smaller organic molecules.

carbohydrate

A biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; serves as energy sources and provides structural support.

cellulose

A polysaccharide that comprises the plant's cell wall; provides structural support to the cell.

chaperone (chaperonin)

A protein that helps nascent proteins in the folding process.

chitin

A carbohydrate that forms the outer skeleton of arthropods, including crustaceans and insects, and also forms fungal cell walls.

dehydration synthesis (condensation)

A reaction that links monomer molecules by releasing a water molecule for each bond formed.

denaturation

The loss of shape in a protein as a result of changes in temperature, pH, or chemical exposure.

deoxyribonucleic acid (DNA)

A double-helical molecule that carries the cell's hereditary information.

disaccharide

Two sugar monomers linked by a glycosidic bond.

enzyme

A catalyst in a biochemical reaction that is usually a complex or conjugated protein.

glycogen

A storage carbohydrate in animals.

glycosidic bond

A bond formed by a dehydration reaction between two monosaccharides, eliminating a water molecule.

hormone

A chemical signaling molecule, usually protein or steroid, secreted by endocrine cells that regulate specific physiological processes.

hydrolysis

A reaction that causes the breakdown of larger molecules into smaller molecules by utilizing water.

lipid

A macromolecule that is nonpolar and insoluble in water.

messenger RNA (mRNA)

RNA that carries information from DNA to ribosomes during protein synthesis.

monomer

The smallest unit of larger molecules that are polymers.

monosaccharide

A single unit or monomer of carbohydrates.

nucleic acid

A biological macromolecule that carries the cell's genetic blueprint and instructions for the cell's functioning.

nucleotide

The monomer of nucleic acids; contains a pentose sugar, one or more phosphate groups, and a nitrogenous base.

omega fat

A type of polyunsaturated fat that the body requires.

peptide bond

A bond formed between two amino acids by a dehydration reaction.

phosphodiester linkage

A covalent bond that holds together the polynucleotide chains with a phosphate group linking neighboring nucleotides.

phospholipid

Membranes' major constituent; comprised of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

polymer

A chain of monomer residues that covalent bonds link.

polynucleotide

A long chain of nucleotides.

polypeptide

A long chain of amino acids that peptide bonds link.

polysaccharide

A long chain of monosaccharides that may be branched or unbranched.

primary structure

The linear sequence of amino acids in a protein.

protein

A biological macromolecule comprised of one or more amino acid chains.

purine

A type of nitrogenous base in DNA and RNA; adenine and guanine are purines.

pyrimidine

A type of nitrogenous base in DNA and RNA; cytosine, thymine, and uracil are pyrimidines.

quaternary structure

The association of discrete polypeptide subunits in a protein.

ribonucleic acid (RNA)

A single-stranded, often internally base paired, molecule involved in protein synthesis.

ribosomal RNA (rRNA)

RNA that ensures the proper alignment of mRNA and ribosomes during protein synthesis and catalyzes the formation of peptide linkages.

saturated fatty acid

A long-chain hydrocarbon with single covalent bonds in the carbon chain.

secondary structure

The regular structure that proteins form by intramolecular hydrogen bonding between amino acid residues.

starch

A storage carbohydrate in plants.

steroid

A type of lipid comprised of four fused hydrocarbon rings forming a planar structure.

tertiary structure

A protein's three-dimensional conformation, including interactions between secondary structural elements.

trans fat

Fat formed artificially by hydrogenating oils, leading to a different arrangement of double bonds.

transcription

The process through which messenger RNA forms on a template of DNA.

transfer RNA (tRNA)

RNA that carries activated amino acids to the site of protein synthesis on the ribosome.

translation

The process through which RNA directs the formation of proteins.

triacylglycerol (triglyceride)

A fat molecule; consists of three fatty acids linked to a glycerol molecule.

unsaturated fatty acid

A long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain.

wax

A lipid comprised of a long-chain fatty acid that is esterified to a long-chain alcohol; serves as a protective coating.