Macromolecules

Monosaccharide

One carbohydrate unit

Disaccharide

Two carbohydrate units linked together

Oligosaccharide

Three to ten carbohydrate units linked together

Polysaccharide

More than ten carbohydrate units linked together

Fischer Projection

Represents the carbohydrate molecule in a straight-chain configuration

Haworth Projection

Represents the cyclical structure of a carbohydrate molecule

Chair Conformation

A chair-like representation of the most stable conformation of a carbohydrate molecule

D- and L-isomers

Molecules with the same chemical components but are mirror images of each other

Dextrorotatory

Molecules that rotate light to the right

Levorotatory

Molecules that rotate light to the left

Pyranose

A six-membered carbohydrate ring

Furanose

A five-membered carbohydrate ring

α-anomer

The hydroxyl group (-OH) in C1 is positioned downward

β-anomer

The hydroxyl group (-OH) in C1 is positioned upward

Aldose

Carbohydrate molecule with an aldehyde group at its C1

Ketose

Carbohydrate molecule with a ketone group at its C2

Glycoside

A carbohydrate molecule that has its hydroxyl group (-OH) bonded to another compound

Deoxy Sugars

Sugars where oxygen is removed, such as deoxyribose found in DNA

Amylose

A helical, non-branching polysaccharide composed of glucose units

Amylopectin

A polysaccharide with both α(1→4) and α(1→6) glycosidic bonds, forming a branched structure

Glycogen

A highly branched polysaccharide composed of glucose units, used for energy storage in humans

Cellulose

A polysaccharide that makes up plant cell walls, composed of β-D-glucopyranose units

Inulin

A polysaccharide of fructose found in tubers and roots of plants, used to assess kidney function

Chitin

A polysaccharide that forms the exoskeletons of insects, crustaceans, and fungi

Glycosaminoglycan

Complex carbohydrates containing amino sugars and uronic acids, which may form proteoglycans

Hyaluronic Acid

A glycosaminoglycan found in joints, helping with lubrication

Chondroitin Sulfate

A glycosaminoglycan that lubricates joints and reinforces cartilage

Heparin

A naturally occurring anticoagulant found in the liver

Glycoproteins

Proteins that contain oligosaccharide chains, important for cell recognition and communication

ABO Blood Group Antigens

Carbohydrate chains on glycoproteins that determine blood type and are synthesized by glycosyltransferases

Glycosyltransferase

Enzymes that add sugar molecules to proteins or lipids, playing a role in blood group antigen synthesis

Lipids

Nonpolar heterogeneous group of compounds such as fats, oils, steroids, and waxes

Simple Lipids

Esters of fatty acids with various alcohols

Compound Lipids

Esters of fatty acids that have alcohol and possess additional groups

Derived Lipids

Formed from hydrolysis of both simple and complex lipids

Delta (Δ) Nomenclature

Indicates the position of double bonds in a fatty acid relative to the carboxyl (COOH) end of the molecule

Omega (ω) Nomenclature

Indicates the position of double bonds relative to the methyl (CH3) end of the fatty acid

Saturated Fatty Acids

Fatty acids that contain only single C−C bonds and have high melting points, being solid at room temperature

Unsaturated Fatty Acids

Fatty acids that contain one or more double C=C bonds and have low melting points, being liquid at room temperature

Cis Double Bond

Acyl chains are on the same side of the bond, resulting in kinks that make the fatty acid more fluid

Trans Double Bond

Acyl chains are on opposite sides of the bond, making the fatty acid more rigid and similar to saturated fatty acids

Triglycerides

Lipids composed of three fatty acid chains attached to a glycerol backbone

Phospholipids

Lipids containing a phosphate group, glycerol, and two fatty acids, with amphipathic properties

Cholesterol

A sterol compound consisting of four fused hydrocarbon rings, important for cell membrane structure and as a precursor for steroid hormones

Eicosanoids

Chemical messengers derived from 20-carbon polyenoic fatty acids, including prostaglandins, thromboxanes, and leukotrienes

Prostaglandins

Eicosanoids that act as local hormones and are involved in inflammation and blood flow regulation

Thromboxanes

Eicosanoids involved in blood clotting and vascular constriction

Leukotrienes

Eicosanoids that cause bronchoconstriction and play a role in asthma

Lipoxins

Eicosanoids similar to leukotrienes but with four conjugated double bonds

Glycolipids

Lipids attached to carbohydrates, often functioning as receptors or recognition sites on cell membranes

Sphingolipids

Lipids with a sphingosine backbone and fatty acid residues attached via amide linkage, important in cell signaling and membrane structure

Phosphoglycerides

Phospholipids that contain glycerol as the backbone and a phosphate group

Sphingomyelins

Sphingolipids found in the myelin sheath of nerve cells, important for electrical insulation

Cardiolipin

Phospholipid found in the mitochondria, essential for mitochondrial function

Lysophosphatidylcholine

A component of phospholipid metabolism, involved in the interconversion of phospholipids

Plasmalogens

Phospholipids involved in membrane structure and cell signaling, suggested to have protective effects against oxidative stress

Steroids

Nonpolar, asymmetric molecules synthesized from cholesterol that function as hormones and other important signaling molecules

Cholesteryl Esters

Esterified form of cholesterol found in plasma, more hydrophobic than non-esterified cholesterol

Ergosterol

A sterol found in fungal membranes and a precursor for Vitamin D2 synthesis upon UV exposure

Terpenes

Hydrocarbon compounds with a formula of C5H8, present in both animals and plants, with various medicinal uses

Carotenoids

Tetraterpenoids with antioxidant and anti-inflammatory properties, including lycopene, found in various fruits and vegetables

Lycopene

A non-provitamin A carotenoid responsible for the red color in tomatoes, linked to reduced cardiovascular disease risk

Neutral Lipids

Lipids such as triglycerides and cholesterol that are uncharged and nonpolar

Amino Acids

Hydrocarbons containing an amino group (NH2) and a carboxyl group (COOH) attached to an α-carbon

Polypeptides

Chains of amino acids linked by peptide bonds

Proteins

Linear polymers of amino acids that perform diverse functions in living systems

Zwitterion

Molecule with both a positive and a negative charge, typically at physiological pH

Alpha Carbon (α-carbon)

Central carbon in an amino acid to which the amino group, carboxyl group, hydrogen, and side chain (R group) are attached

Essential Amino Acids

Amino acids that cannot be synthesized by the body and must be obtained from dietary sources

Nonessential Amino Acids

Amino acids that can be synthesized by the body

Peptide Bond

Covalent bond linking the amino group of one amino acid to the carboxyl group of another, formed through a dehydration reaction

Hydrophobic Interactions

Interaction between nonpolar side chains of amino acids that tend to cluster away from water

Disulfide Bonds

Covalent bonds formed between the thiol groups of cysteine residues, stabilizing protein structure

Isoelectric Point (pI)

The pH at which an amino acid has no net charge, the sum of positive and negative charges is equal

Chiral

Molecules that are asymmetric and exist as enantiomers, like amino acids, except for glycine

D- and L-isomers

Two enantiomers of amino acids that are mirror images of each other

Ketogenic Amino Acids

Amino acids whose catabolic products are ketone bodies like acetoacetate or acetyl-CoA

Glucogenic Amino Acids

Amino acids that can be converted into glucose through gluconeogenesis

Selenocysteine

A variant of cysteine where sulfur is replaced by selenium, found in certain enzymes with antioxidant activity

Amino Acid Side Chains

The unique functional groups attached to the α-carbon that determine the chemical properties of amino acids

Nonpolar Side Chains

Amino acids with side chains that are hydrophobic and do not participate in hydrogen or ionic bonds

Polar Side Chains

Amino acids with side chains that are hydrophilic and can participate in hydrogen bonding

Acidic Amino Acids

Amino acids with side chains that are negatively charged at physiological pH, such as aspartic acid and glutamic acid

Basic Amino Acids

Amino acids with positively charged side chains at physiological pH, such as lysine, arginine, and histidine

Peptide Bond Formation

A dehydration reaction where an amino group from one amino acid bonds with a carboxyl group of another, releasing water

Protein Folding

The process by which a polypeptide chain folds into its functional three-dimensional structure

Primary Protein Structure

The linear sequence of amino acids in a polypeptide chain

Secondary Protein Structure

The localized folding of a polypeptide chain into structures such as alpha helices and beta sheets, stabilized by hydrogen bonds

Tertiary Protein Structure

The three-dimensional arrangement of all atoms in a protein, influenced by side chain interactions

Quaternary Protein Structure

The interaction between two or more polypeptide chains to form a functional protein

Fibrous Proteins

Long, thin proteins that provide structural support, such as collagen and keratin

Globular Proteins

Proteins that fold into spherical shapes and are soluble in water, like enzymes and antibodies

Amino Acid Isomers

D- and L-forms of amino acids, with L-forms being predominantly used in proteins

Hydrogen Bonds

Weak bonds that form between the hydrogen atom of one molecule and an electronegative atom (like oxygen or nitrogen) of another

Alpha-Helix

A secondary structure of proteins where the polypeptide chain coils into a right-handed spiral, stabilized by hydrogen bonds

Beta-Sheets

A secondary structure of proteins where the polypeptide chain folds into pleated sheets, stabilized by hydrogen bonds

Peptide Bond

Rigid, planar, with partial double bond character, and typically in the trans configuration

Amphoteric Amino Acids

Amino acids that can act as both acids and bases, depending on the pH of the environment

Henderson-Hasselbalch Equation

Equation that relates pH, pKa, and the concentrations of an acid and its conjugate base, useful for understanding buffer capacity

Amino Acid Catabolism

The process of breaking down amino acids to remove the α-amino group and convert the carbon skeleton into various metabolic intermediates