Chapter 3: Overview of Biological Macromolecules

Vocabulary flashcards covering key concepts from Chapter 3: biological macromolecules, their structures, and related reactions.

Organic molecules

Molecules with a carbon backbone that enable diverse structures and functions; often contain functional groups such as -OH (hydroxyl) and -CH3 (methyl) that influence properties.

Functional groups

Specific groups (e.g., hydroxyl -OH, methyl -CH3) that modify solubility, acidity, and hydrogen bonding in organic molecules.

Carbohydrates

Class of macromolecules including simple sugars and polysaccharides; primarily composed of carbon, hydrogen, and oxygen; provide energy and structural support.

Proteins

Polymers of amino acids linked by peptide bonds; four levels of structure: primary, secondary, tertiary, and quaternary.

Lipids

Hydrophobic, nonpolar molecules including triglycerides, phospholipids, and cholesterol; roles in energy storage, membranes, and signaling.

Nucleic acids

DNA and RNA polymers made of nucleotides; store and transfer genetic information; backbone formed by phosphodiester bonds.

Amino acids

Building blocks of proteins; contain an amino group, a carboxyl group, and a distinctive side chain; some contain sulfur.

Peptide bonds

Bonds linking amino acids in proteins to form polypeptide chains.

Primary structure

Linear sequence of amino acids in a protein; determines eventual shape and function.

Secondary structure

Local folding patterns such as alpha helices and beta sheets stabilized by hydrogen bonds.

Tertiary structure

Overall 3D folding driven by interactions among R groups and backbone elements; determines function.

Quaternary structure

Association of multiple polypeptide chains into a functional protein.

Denaturation

Loss of native protein structure due to heat or pH changes; disrupts secondary/tertiary structure but not the primary sequence.

Monosaccharides

Simple sugars (e.g., glucose, fructose, galactose) that provide immediate energy and serve as building blocks.

Disaccharides

Two monosaccharides linked together (e.g., lactose); digested by specific enzymes.

Polysaccharides

Complex carbohydrates like cellulose and starch; provide energy storage or structural support.

Cellulose

Plant structural polysaccharide; humans cannot digest due to lack of cellulase.

Lactose

Disaccharide composed of glucose and galactose; digestion requires lactase; lactose intolerance results from lactase deficiency.

Lactase

Enzyme that hydrolyzes lactose into glucose and galactose.

Triglycerides

Primary form of energy storage in animals; glycerol bound to three fatty acids via dehydration synthesis.

Glycerol

Three-carbon molecule with three hydroxyl groups that forms triglycerides with fatty acids.

Phospholipids

Major component of cell membranes with hydrophilic heads and hydrophobic tails; form bilayers.

Hydrogenation

Addition of hydrogen to unsaturated fats to make them more saturated and solid; can produce trans fats.

Trans fats

Fats formed during hydrogenation; associated with health risks; less favorable than natural unsaturated fats.

Nucleotides

Monomers of nucleic acids consisting of a sugar, phosphate group, and nitrogenous base; ATP is a nucleotide used for energy transfer.

DNA bases

Adenine (A), Thymine (T), Cytosine (C), Guanine (G); in RNA, uracil (U) replaces thymine.

RNA

Nucleic acid involved in protein synthesis; uses uracil instead of thymine; contains ribose sugar.

Chargaff's rule

In double-stranded DNA, A pairs with T and C pairs with G; amounts of A=T and C=G are equal.

Antiparallel

DNA strands run in opposite directions (5'→3' and 3'→5'); essential for replication and transcription.

Phosphodiester bonds

Backbone linkages that connect nucleotides in DNA and RNA via sugar-phosphate bonds.

Hydrolysis

Reaction using water to break down polymers into monomers; catalyzed by enzymes like amylase and proteases.

Dehydration synthesis

Reaction that joins monomers to form polymers with the release of water.

Starch

Plant energy storage polysaccharide; hydrolyzed to glucose for cellular respiration.

Amylase

Enzyme that catalyzes the hydrolysis of starch into sugar molecules.

Proteases

Enzymes that catalyze the hydrolysis of proteins into peptides and amino acids.

Cellulase

Enzyme that digests cellulose; humans lack this enzyme, contributing to cellulose indigestion.

Cholesterol

Lipid component of membranes; precursor to steroids and bile acids; helps maintain membrane fluidity.