Lecture Review: Buffers, pH, and Organic Molecules

Vocabulary flashcards covering chapter topics on blood pH ranges, buffer systems, chemical reactions, organic molecules, functional groups, carbohydrates, fatty acids, triglycerides, phospholipids, steroids, and lipoproteins.

Acidosis

A life-threatening condition in which blood pH drops below $7.35$.

Alkalosis

A life-threatening condition in which blood pH rises above $7.45$.

Buffer

A system or molecule that resists changes in pH by releasing or binding hydrogen ions ($\text{H}^+$).

Carbonic Acid-Bicarbonate Buffer System

The primary buffer system in the blood that maintains blood pH within the narrow range of $7.35$ to $7.45$.

Carbonic Acid

A molecule with the chemical formula $\text{H}_2\text{CO}_3$ that acts as the weak acid component in the primary blood buffer system.

Bicarbonate

An ion with the chemical formula $\text{HCO}_3^-$ that acts as the base component in the primary blood buffer system.

Dissociation Reaction

A buffer reaction where carbonic acid ($\text{H}_2\text{CO}_3$) breaks apart into bicarbonate ($\text{HCO}_3^-$) and releases a hydrogen ion ($\text{H}^+$) to replace lost hydrogen ions when a base is added.

Association Reaction

A buffer reaction where bicarbonate ($\text{HCO}_3^-$) and a hydrogen ion ($\text{H}^+$) combine to reform carbonic acid ($\text{H}_2\text{CO}_3$), binding and removing excess hydrogen ions when an acid is added.

Equilibrium

The state of balance between association and dissociation reactions that maintains a relatively stable concentration of hydrogen ions.

Organic Molecules

Molecules that contain the element carbon as part of their structure.

Carbon Skeleton

A structural framework of carbon atoms arranged in chains, branched chains, or rings within organic molecules.

Functional Groups

Specific groups of atoms attached to a carbon skeleton that help determine a molecule's water solubility and pH.

Hydroxyl Group

A functional group containing an oxygen atom bonded to a hydrogen atom ($\text{-OH}$).

Sulfhydryl Group

A functional group containing a sulfur atom bonded to a hydrogen atom ($\text{-SH}$).

Methyl Group

A functional group consisting of a carbon atom bonded to three hydrogen atoms ($\text{-CH}_3$).

Carboxyl Group

A functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group ($\text{-COOH}$).

Amino Group

A functional group consisting of a nitrogen atom bonded to two hydrogen atoms ($\text{-NH}_2$).

Phosphate Group

A functional group containing a central phosphorus atom bonded to oxygen atoms.

Monomer

A single molecular building block that can be linked with others to form long chains.

Polymer

A long chain molecule formed by linking together multiple monomer building blocks.

Dehydration Reaction

A chemical reaction that links monomers together via strong covalent bonds to lengthen a polymer, yielding water as a product.

Hydrolysis Reaction

A chemical reaction that uses water as a reactant to break covalent bonds between monomers to shorten a polymer chain.

Macromolecule

A large, complex molecule that is typically a polymer, such as DNA or proteins.

Monosaccharide

A carbohydrate containing a single sugar unit, usually structured as a ring of 5 or 6 carbon atoms with attached hydroxyl groups.

Disaccharide

A carbohydrate formed by two linked sugar units, such as sucrose or lactose.

Polysaccharide

A carbohydrate composed of a long chain of sugar units linked together, such as glycogen, starch, or cellulose.

Glucose

A monosaccharide that acts as the primary sugar in blood.

Glycogen

An animal polysaccharide that functions to store energy, located in organs such as the liver.

Starch

A plant polysaccharide that functions to store energy.

Cellulose

A plant polysaccharide that provides structural support and acts as dietary fiber.

Glycosidic Bond

A strong covalent bond that links sugar units together in carbohydrates.

Fatty Acid

A lipid structure consisting of a long hydrocarbon chain attached to a carboxyl group.

Saturated Fatty Acid

A fatty acid that contains only single covalent bonds between the carbon atoms in its hydrocarbon chain.

Unsaturated Fatty Acid

A fatty acid containing one or more double covalent bonds between the carbon atoms in its hydrocarbon chain.

Trans Fatty Acid

An unhealthy form of fatty acid found in fast food and baked goods that increases the risk of cardiovascular disease.

Omega-3 Fatty Acid

A healthy form of fatty acid found in fish, spinach, and walnuts that lowers the risk of cardiovascular disease.

Triglyceride

A fat molecule composed of a three-carbon glycerol molecule attached to three fatty acids.

Ester Bond

The strong covalent bond that links a glycerol molecule to a fatty acid in lipids.

Lipogenesis

The process that synthesizes a triglyceride by joining glycerol to three fatty acids with ester bonds.

Lipolysis

The process that breaks down a triglyceride to release its free fatty acids.

Phospholipid

An amphipathic lipid composed of a glycerol molecule, two fatty acids, a phosphate group, and a polar molecule, forming the structural basis of cell membranes.

Amphipathic

Describing a molecule that has both polar (hydrophilic) and nonpolar (hydrophobic) regions.

Steroid

A class of lipids built upon a four-ring cholesterol structure, most of which function as hormones such as estradiol, testosterone, and cortisol.

Lipoprotein

A protein-lipid complex that transports hydrophobic lipids and cholesterol through the bloodstream.

LDL (Low-Density Lipoprotein)

The bad cholesterol carrier that delivers cholesterol from the liver to blood vessels, increasing the risk of atherosclerosis.

HDL (High-Density Lipoprotein)

The good cholesterol carrier that removes cholesterol from blood vessels and transports it back to the liver, lowering the risk of atherosclerosis.

Atherosclerosis

A condition caused by the buildup of cholesterol in blood vessel walls, leading to vessel narrowing and increased risk of cardiovascular disease.

Statins

A class of medications that lower the levels of bad cholesterol (LDL) in the blood.