CH 3: The Chmical Basis of Life ll: Organic Molecules

Organic Chemistry

The science of carbon-containing molecules

What can carbon form? What are the bonding properties?

Carbon can form 4 covalent bonds, either polar or nonpolar

Most organic molecules contain ____ groups.

Functional groups - groups of atoms with characteristic structure and properties

Organic molecules may exist as ____.

Isomers- two or more molecules with the same chemical formula but different structures and characteristics

What are the two types Isomers can be?

Structural or stereoisomers

What are the biological macromolecules that make up cells?

Carbohydrates, proteins, lipids, nucleic acids

What is the monomer for carbohydrates?

Monosaccharides

What is the monomer for lipids?

Fatty acids and glycerol

What is the monomer for proteins?

Amino acids

What is the monomer for nucleic acids?

Nucleotides (A,T,C,G)

What chemical reaction breaks down polymers?

Hydrolysis reaction (hydration)

What chemical reaction synthesizes polymers?

Dehydration reactions (lose water)

What are the classification of carbohydrates?

Monosaccharides, disaccharides, and polysaccharides

What are the examples of monosaccharides?

Glucose, fructose, and galactose

What are examples of disaccharides?

Sucrose, lactose, and and maltose

What are examples of polysaccharides?

Starch, glycogen, cellulose, chitin, and peptidoglycan

What are the classifications of lipids?

Triglycerides, phospholipids, and steroids

Structure of triglycerides

Classified as saturated and unsaturated:

• saturated is single covalent bonding

• Unsaturated is double covalent bonding

Structure of phospholipids

• Are amphipathic and important components of cell membranes

• Head = hydrophilic (polar)

• Tail = hydrophobic (nonpolar)

Structure of steroids

• include cholesterol and steroid hormones

• Have 4 ring structures

What is the primary structure of proteins?

Polypeptide bonds (a linear shape)

What is the secondary structure of proteins?

Either a spiral (alpha helix) or a beta pleated sheet

What is the tertiary structure of proteins?

Secondary structures coil into a random 3-D shape

What is the quaternary structure of proteins?

Two or more polypeptide chains bind together to form a complex functional protein

What are the critical roles proteins play in living organisms?

Gene expression, motor proteins, defense proteins, metabolic enzymes, cell signaling proteins, structural proteins, and transporters, hormones

Contrast the structure and nucleotide composition of DNA and RNA.

DNA:

• double stranded

• Purine nucleotides (adenine and guanine) pair with pyrimidine nucleotides (thymine and cytosine)

RNA:

• single stranded

• Composed of adenine, uracil, guanine, and cytosine nucleotides