Carbohydrates

Flashcards for Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition

Carbohydrates

A major source of energy from our diet, made from carbon, hydrogen, and oxygen, also called saccharides, which means sugars.

Photosynthesis

Process by which plants produce carbohydrates such as glucose, from CO2, H2O, and energy from the sun.

Monosaccharides

The simplest carbohydrates consisting of three to eight carbon chains with one carbon in a carbonyl group.

Aldose

A monosaccharide containing an aldehyde group.

Ketose

A monosaccharide containing a ketone group.

Triose

A monosaccharide with three carbon atoms.

Tetrose

A monosaccharide with four carbon atoms.

Pentose

A monosaccharide with five carbon atoms.

Hexose

A monosaccharide with six carbon atoms.

Structural Isomers

Molecules with the same molecular formula but different bonding arrangements.

Stereoisomers

Molecules with identical molecular formulas that are not structural isomers, with atoms bonded in the same sequence but differ in their arrangement in space.

Chiral Molecules

Molecules that have nonsuperimposable mirror images.

Achiral Molecules

Molecules with mirror images that are superimposable.

Chiral Carbon Atoms

A carbon atom bonded to four different groups.

Enantiomers

Stereoisomers that cannot be superimposed.

Fischer Projection

A two-dimensional representation of a three-dimensional molecule, useful for representing carbohydrates.

D and L Notations

System to assign isomers based on the position of the —OH group on the chiral carbon farthest from the carbonyl carbon.

D-Glucose

An aldohexose found in fruits, corn syrup, and honey, also known as dextrose and blood sugar.

D-Fructose

A ketohexose obtained from sucrose and the sweetest of the carbohydrates.

D-Galactose

An aldohexose obtained from the disaccharide lactose.

Haworth Structures

Cyclic structures of monosaccharides, usually pentose and hexose sugars.

Disaccharide

Two monosaccharides linked together by glycosidic bonds.

Glycosidic Bond

The bond that links two monosaccharides to form a disaccharide.

Maltose

A disaccharide composed of two D-glucose molecules, also known as malt sugar.

Lactose

A disaccharide found in milk and milk products, composed of β-D-galactose and α- or β-D-glucose.

Sucrose

A disaccharide, commonly known as table sugar, consisting of α-D-glucose and β-D-fructose.

Polysaccharides

Polymers formed when many monosaccharides are joined together.

Amylose

A straight-chain polysaccharide composed of α-D-glucose molecules connected by α-1,4-glycosidic bonds.

Amylopectin

A branched-chain polysaccharide composed of glucose molecules connected by α-1,4- and α-1,6-glycosidic bonds.

Glycogen

A polymer of glucose stored in the liver and muscle of animals.

Cellulose

A polysaccharide of glucose units in unbranched chains with β-1,4-glycosidic bonds, providing structure to plant cell walls.