BIO 155 - Chapter 3 Study Guide: The Chemistry of Organic Molecules

Vocabulary flashcards covering the key terms and concepts from Chapter 3: The Chemistry of Organic Molecules.

Organic Molecule

A molecule containing carbon and hydrogen atoms bonded to other atoms.

Carbon Skeleton

The carbon chain of an organic molecule, also called its backbone.

Functional Group

A cluster of specific atoms attached to a carbon skeleton that gives molecules characteristic structures and functions.

Hydroxyl Group

An $-OH$ functional group that can turn a molecule into an alcohol.

Carboxyl Group

A functional group that can release $H^+$ and make a molecule acidic and polar.

Hydrophilic

The property of being able to dissolve in water, often imparted by polar functional groups.

Hydrophobic

The property of not dissolving in water, characteristic of nonpolar molecules.

Isomer

A molecule with the same molecular formula as another but a different arrangement of atoms, leading to different chemical properties.

Monomer

A small subunit used to build larger molecules (polymers).

Polymer

A large biomolecule made by linking many similar monomers.

Dehydration Synthesis

A chemical reaction that builds biomolecules by removing water and forming a covalent bond.

Hydrolysis

A chemical reaction that breaks polymers apart by adding water.

Monosaccharide

A simple sugar containing $3$ to $7$ carbon atoms.

Hexose

A six-carbon sugar, such as glucose, fructose, or galactose.

Pentose

A five-carbon sugar, such as ribose found in RNA or deoxyribose found in DNA.

Glucose

A six-carbon monosaccharide found in animal blood that serves as a source of biochemical energy for nearly all organisms.

Disaccharide

A carbohydrate containing two monosaccharides joined by a dehydration reaction.

Maltose

A disaccharide composed of glucose + glucose.

Sucrose

Table sugar; a disaccharide composed of glucose + fructose.

Lactose

A disaccharide composed of galactose + glucose.

Polysaccharide

A polymer made of monosaccharides.

Starch

A plant storage form of glucose that includes amylose and amylopectin.

Glycogen

A highly branched storage form of glucose found in animals.

Cellulose

A glucose polymer that forms plant cell walls and provides structural support; humans cannot digest it.

Chitin

A structural polymer found in the exoskeletons of insects, crabs, and related animals.

Peptidoglycan

A polymer found in bacteria.

Lipid

A varied group of organic molecules that are generally insoluble in water because they lack polar groups.

Fatty Acid

A long hydrocarbon chain with a carboxyl group at one end.

Saturated Fatty Acid

A fatty acid with no double bonds between carbon atoms.

Unsaturated Fatty Acid

A fatty acid with double bonds in its carbon chain.

Triglyceride

A lipid composed of glycerol joined to three fatty acids by dehydration reactions.

Glycerol

A molecule with three hydroxyl groups that combines with fatty acids to form triglycerides.

Phospholipid

A lipid with a polar, hydrophilic phosphate head and nonpolar, hydrophobic fatty acid tails, which forms plasma membranes.

Steroid

A lipid with four fused carbon rings that acts as a cell messenger or membrane component.

Cholesterol

A steroid that is part of animal plasma membranes and serves as a precursor of several other steroids.

Wax

A lipid made of long-chain fatty acids bonded to long-chain alcohols that is waterproof and resists degradation.

Enzyme

A protein that speeds up chemical reactions without being changed by the reaction.

Amino Acid

The monomer of proteins containing an acidic group ($-COOH$), an amino group ($-NH_2$), and a variable R group.

Cysteine

An amino acid that can form a disulfide bond ($-S-S-$) between amino acid chains.

Peptide Bond

A covalent bond joining two amino acids.

Polypeptide

A chain of many amino acids joined by peptide bonds.

Primary Structure

The specific sequence of amino acids in a protein.

Secondary Structure

The level of protein structure where a polypeptide coils or folds, such as an alpha helix or beta sheet.

Tertiary Structure

The final three-dimensional shape of a protein caused by interactions among R groups.

Quaternary Structure

The level of protein structure formed when two or more polypeptide chains combine.

Denaturation

The loss of a protein's normal shape, such as from high temperatures.

Chaperone Protein

A protein that helps newly made proteins fold correctly and can help correct misfolding.

Prion

A misfolded protein associated with certain diseases.

Nucleotide

The monomer of nucleic acids composed of a phosphate, a pentose sugar, and a nitrogen-containing base.

Nucleic Acid

A polymer of nucleotides that stores information in cells (e.g., DNA and RNA).

DNA

A double-stranded double helix nucleic acid containing deoxyribose sugar and thymine base that stores the genetic code.

RNA

A single-stranded nucleic acid containing ribose sugar and uracil base that helps translate the genetic code into amino acid sequences for proteins.

ATP

Adenosine triphosphate; a nucleotide made with adenine, ribose, and three phosphate groups that supplies usable energy for cellular activities.