Chapter 3: Chemical Building Blocks of Life

A set of Q&A flashcards covering the key concepts from the chapter on carbohydrates, nucleic acids, proteins, and lipids.

What are the four major macromolecules discussed in Chapter 3?

Carbohydrates, proteins, nucleic acids, and lipids.

What is the monomer of carbohydrates?

Monosaccharide.

What is the polymer form of carbohydrates?

Polysaccharide.

Do lipids form polymers?

No. Lipids do not form polymers; their building blocks are glycerol and fatty acids.

What are the building blocks of fats?

Glycerol and fatty acids.

What is a triglyceride?

A fat molecule composed of glycerol bound to three fatty acids.

What is the monomer of proteins?

Amino acid.

What is a peptide bond?

A covalent bond linking amino acids in a protein, formed by a dehydration reaction.

How many levels of protein structure exist?

Four: primary, secondary, tertiary, and quaternary.

Name two common secondary structures of proteins.

Alpha helix and beta pleated sheet.

What interactions stabilize protein tertiary structure?

Hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic interactions and van der Waals forces.

What is denaturation?

Loss of a protein’s native structure and biological activity.

What is an essential amino acid?

An amino acid that must be obtained from the diet; the body cannot synthesize it.

What are the three main types of carbohydrates?

Monosaccharides, disaccharides, and polysaccharides.

What is the monomer of nucleic acids?

Nucleotide.

What are the building blocks of lipids?

Glycerol and fatty acids.

Do nucleic acids have monomers? If so, what are they?

Yes. The monomer is the nucleotide.

Name the purine bases.

Adenine (A) and Guanine (G).

Name the pyrimidine bases.

Cytosine (C), Thymine (T) in DNA, and Uracil (U) in RNA.

What sugar is in DNA?

Deoxyribose.

What sugar is in RNA?

Ribose.

What base pairs with A in DNA?

Thymine (T) (A pairs with T; in RNA, A pairs with Uracil).

Are DNA strands antiparallel?

Yes; the two strands run in opposite directions.

What forms the backbone of DNA?

Deoxyribose-phosphate backbone.

What is the primary function of DNA?

Store and transmit hereditary information.

What are the two types of nucleic acids?

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

Give an example of a disaccharide formed by glucose and fructose.

Sucrose.

Give an example of a disaccharide formed by glucose and glucose.

Maltose.

Give an example of a disaccharide formed by glucose and galactose.

Lactose.

Which polysaccharide is the storage form in plants?

Starch (amylose and amylopectin).

Which polysaccharide is the major structural component of plant cell walls?

Cellulose.

What type of glycosidic linkages are in cellulose?

Beta-1,4 glycosidic linkages.

What are the two forms of glucose called?

Alpha (α) and Beta (β) forms, i.e., α-glucose and β-glucose.

What are the components of starch?

Amylose and amylopectin.

What are the linkages inside amylose and amylopectin?

Amylose has mainly α-1,4 linkages; amylopectin has α-1,4 linkages with α-1,6 branches.

Which polysaccharide is highly branched and used for quick energy storage in animals?

Glycogen.

What is the basic structure of a phospholipid?

Glycerol backbone, two fatty acid tails (nonpolar) and a phosphate-containing head (polar).

What structure do phospholipids form in water?

A lipid bilayer (and can form micelles).

What characteristic defines steroids like cholesterol?

They have a carbon skeleton of four fused rings.

Name an example of a steroid.

Cholesterol (others include cortisol, testosterone, vitamin D2).

Do lipids generally dissolve in water?

No; they are nonpolar and have little or no affinity for water.

What are the four major roles of proteins?

Catalysts (enzymes), structural support, storage, transport, movement, defense, and receptors (any one of these is a correct example).