Structure and Function of Large Biological Molecules Lesson 5

Vocabulary flashcards covering the major macromolecules (carbohydrates, lipids, proteins, nucleic acids), their structures, functions, and key concepts such as polymer synthesis, denaturation, and genetic information flow.

Monomer

A small subunit that can join with other monomers to form a polymer.

Polymer

A large molecule built from repeating monomer units.

Macromolecule

A large biological molecule made up of smaller subunits; many are polymers (lipids are not).

Carbohydrate

A biomolecule consisting of sugars or polymers of sugars.

Lipid

Hydrophobic biomolecule not formed by repeating monomer units; includes fats, phospholipids, steroids.

Protein

A functional molecule made of one or more polypeptides folded into 3D shape.

Nucleic Acid

DNA or RNA; stores, transmits, and/or expresses genetic information.

Monosaccharide

A single sugar unit; the building block of carbohydrates.

Disaccharide

Two monosaccharides joined by a covalent bond.

Polysaccharide

Many monosaccharides linked together; used for energy storage or structural support.

Glucose

Most common hexose monosaccharide (C6H12O6).

Aldose

Sugar with an aldehyde group at the carbonyl carbon.

Ketose

Sugar with a ketone group at the carbonyl carbon.

Glycosidic linkage

Covalent bond joining monosaccharides in disaccharides and polysaccharides.

Dehydration reaction

Chemical reaction that forms bonds by removing a water molecule.

Hydrolysis

Chemical reaction that breaks bonds by adding water.

Maltose

Disaccharide composed of two glucose units.

Sucrose

Disaccharide of glucose and fructose; table sugar.

Lactose

Disaccharide of glucose and galactose; milk sugar.

Glycogen

Animal storage polysaccharide stored in liver and muscles.

Starch

Plant storage polysaccharide.

Cellulose

Structural polysaccharide in plant cell walls.

Chitin

Structural polysaccharide in exoskeletons of arthropods.

Fat (triglyceride)

Glycerol bound to three fatty acids; main form of stored energy.

Glycerol

Three-carbon alcohol; backbone for fats.

Fatty acid

Hydrocarbon chain with a terminal carboxyl group.

Ester linkage

Bond connecting glycerol to fatty acids in fats.

Saturated fatty acid

Fatty acid with no double bonds; straight chain.

Unsaturated fatty acid

Fatty acid with one or more double bonds; kinked chain.

Cis fatty acid

Double bond with hydrogens on the same side.

Trans fatty acid

Double bond with hydrogens on opposite sides.

Phospholipid

Lipid with two fatty acids, glycerol, and a phosphate group.

Lipid bilayer

Phospholipid arrangement forming cell membranes: hydrophobic tails inward, hydrophilic heads outward.

Steroid

Hydrophobic lipid with four fused carbon rings.

Cholesterol

Steroid component of membranes and precursor for other steroids.

Amino acid

Monomer of proteins; contains amino and carboxyl groups and a variable side chain (R).

Peptide bond

Bond between amino acids formed by dehydration.

N-terminus

Amino end of a polypeptide; the first amino acid.

C-terminus

Carboxyl end of a polypeptide; the last amino acid.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Regular folding patterns (α-helixes and β-sheets) in the backbone.

Tertiary structure

3D shape of a protein formed by side chain interactions.

Quaternary structure

Assembly of multiple polypeptides into a functional protein.

Sickle-cell disease

Inherited disorder caused by a single amino acid substitution in hemoglobin.

Denaturation

Loss of protein structure and function due to disrupted bonds (pH, temperature, salts); protein can often refold.

DNA

Deoxyribonucleic acid; stores hereditary information and forms a double helix.

RNA

Ribonucleic acid; helps synthesize proteins; usually single-stranded.

Nucleotide

Monomer of nucleic acids: a nitrogenous base, a five-carbon sugar, and a phosphate group.

Nitrogenous base

Part of a nucleotide; Purines (A, G) have two rings; Pyrimidines (C, T, U) have one ring.

Purine

Two-ring nitrogenous bases: Adenine (A) and Guanine (G).

Pyrimidine

One-ring nitrogenous bases: Cytosine (C), Thymine (T), Uracil (U).

Deoxyribose

Five-carbon sugar in DNA.

Ribose

Five-carbon sugar in RNA.

Antiparallel

DNA strands run in opposite 5'→3' and 3'→5' directions.

Complementary base pairing

A pairs with T (DNA) or U (RNA); C pairs with G.

Flow of genetic information

DNA is transcribed into RNA, which is translated into protein.