BIOCHEM: Biomolecules and Biochemical Method

Vocabulary flashcards covering key biomolecule concepts, protein and carbohydrate structure, isomerism, and biochemical methods from the lecture notes.

Biomolecule

Large, complex organic molecules produced by living organisms that perform essential life processes.

Proteins

Biomolecules made of amino acids; perform diverse roles such as enzymes, structural support, transport, defense, hormones, and movement.

Carbohydrates

biomolecules that serve as energy sources and structural components; classified as monosaccharides, oligosaccharides, and polysaccharides.

Lipids

One of the four major biomolecule types; fats, oils, and related molecules that store energy and form cell membranes.

Nucleic Acids

Biomolecules that store and transmit genetic information (DNA and RNA).

Amino acids

Building blocks of proteins; there are 20 common types with unique side chains (R-groups).

R-group

The side chain of an amino acid that determines its properties and protein folding.

L-Amino acids

Most amino acids in human proteins are in the L-form, the arrangement recognized by biological systems.

Peptide bond

Covalent bond linking amino acids in a protein chain.

Polypeptide

Long chain of amino acids formed by connected peptide bonds; folds into a functional protein.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Local folding patterns of the polypeptide backbone, including α-helix and β-pleated sheet.

Alpha-helix

Right-handed coiled secondary structure stabilized by hydrogen bonds.

Beta-pleated sheet

Secondary structure with sheet-like folding stabilized by hydrogen bonds.

Tertiary structure

Overall 3D shape of a single polypeptide, formed by interactions among R-groups.

Disulfide bond

Covalent bond between cysteine residues that stabilizes protein folding.

Quaternary structure

Assembly of multiple polypeptide chains into a functional protein (e.g., hemoglobin).

Hemoglobin

A four-chain protein in red blood cells that carries oxygen.

Denaturation

Loss of a protein’s 3D structure and function due to heat, pH change, or heavy metals.

Enzymes

Proteins that catalyze biochemical reactions.

Structural proteins

Proteins that provide support, such as collagen and keratin.

Transport proteins

Proteins that carry substances; e.g., hemoglobin, membrane transporters.

Antibodies

Defensive proteins that recognize and neutralize pathogens.

Hormones

Signaling proteins that regulate body processes (e.g., insulin).

Actin and myosin

Proteins essential for muscle movement; form sarcomeres.

Protein shape-function relationship

A protein’s function is highly dependent on its precise 3D shape.

Carbohydrates

Sugars and their polymers; main energy source and structural components.

Aldose

A carbohydrate with an aldehyde group (-CHO) at the end of the chain.

Ketose

A carbohydrate with a ketone group (C=O) usually within the chain.

Monosaccharide

Single sugar unit; glucose, fructose, and galactose are examples.

Disaccharide

Two monosaccharides linked together; examples include sucrose, lactose, maltose.

Oligosaccharide

Carbohydrates containing 2–10 monosaccharide units.

Polysaccharide

Large polymers of monosaccharides; used for energy storage or structure.

Glucose

A key monosaccharide, the body’s main blood sugar and energy source.

Fructose

Monosaccharide found in fruits and honey.

Galactose

Monosaccharide that is part of lactose (glucose + galactose).

Sucrose

Disaccharide of glucose + fructose (table sugar).

Lactose

Disaccharide of glucose + galactose (milk sugar).

Maltose

Disaccharide of glucose + glucose (malt sugar).

Starch

Plant polysaccharide used for energy storage; primarily α-glycosidic bonds.

Glycogen

Animal polysaccharide for energy storage; highly branched, α-linkages.

Cellulose

Plant polysaccharide with β-glycosidic bonds; indigestible by humans but fiber-rich.

Linear form

Open-chain form of a monosaccharide.

Cyclic form

Ring form of a monosaccharide; biologically common in solution.

D-sugars

Sugars in which the terminal -OH of the furthest asymmetric carbon is on the right in Fischer projections; predominant in biology.

L-sugars

Sugars with the opposite configuration; less common in biology and often not metabolized.

Optical activity

Ability of chiral molecules to rotate plane-polarized light.

Polarimeter

Instrument used to measure the angle of optical rotation.

Chiral center

An asymmetric carbon atom bonded to four different groups; creates stereoisomerism.

Enantiomer

Non-superimposable mirror-image isomers; D- and L- forms have identical properties except for optical activities and interactions with other chiral molecules.

D-glucose

A D-sugar and primary energy source in humans.

L-glucose

An L-sugar; not commonly metabolized by humans.

Diastereomer

Stereoisomers that are not mirror images and have different physical properties.

Epimer

Diastereomer differing at exactly one chiral center (e.g., glucose vs galactose at C4).

Mannose

Epimer of glucose at C2.

Anomer

Isomers of cyclic sugars differing at the anomeric carbon (α or β form).

Alpha anomer

Anomer where the OH at the anomeric carbon is below the plane of the ring.

Beta anomer

Anomer where the OH at the anomeric carbon is above the plane of the ring.

Mutarotation

Interconversion between α and β anomers in solution until equilibrium is reached.

Anomeric carbon

New asymmetric carbon created when a sugar cyclizes.

Glycosidic bond

Bond linking carbohydrate units; can be α or β depending on linkage.

Alpha glycosidic bond

Glycosidic linkage where the anomeric OH is down in the ring form.

Beta glycosidic bond

Glycosidic linkage where the anomeric OH is up in the ring form.

Isomerism

Molecules with the same formula but different arrangements.

Structural isomer

Isomers with different connectivity of atoms.

Stereoisomer

Isomers with identical connectivity but different 3D arrangement.

Enzymatic assays

Biochemical methods using enzymes to detect or quantify specific substrates.

Chromatography

Separation technique used to separate components of a mixture.

Biochemical methods

Techniques to analyze the chemistry of life, including identification, separation, and quantification of biomolecules.