Biological Molecules Review

Flashcards covering key concepts in biological molecules.

How are monosaccharides classified?

The location of the carbonyl group (as aldose or ketose) and the number of carbons in the carbon skeleton.

What are the four classes of large biological molecules?

Carbohydrates, lipids, proteins, and nucleic acids.

What is a polymer?

A long molecule consisting of many similar building blocks held together by covalent bonds.

What is the difference between anabolic and catabolic reactions?

Anabolic reactions build organic molecules through condensation reactions (removing water to form a bond), while catabolic reactions break down organic molecules through hydrolysis reactions (adding water to break a bond).

What are monomers and polymers?

Monosaccharides are the basic units, or building blocks and Polymers are many monomers strung together to create a more complex structure.

What is the structure of sugars in aqueous solutions?

Sugars form rings in aqueous solutions.

What is the covalent bond formed when a dehydration reaction joins two monosaccharides?

Glycosidic linkage.

What are the functions of glycogen, starch, and cellulose?

Glycogen is a branched polymer of glucose used for energy storage in animals, starch is a polymer used for energy storage in plants, and cellulose is a structural polymer in plant cell walls.

What is the difference between polymers with alpha glucose and polymers with beta glucose

Polymers with α glucose are helical and Polymers with β glucose are straight.

What is the difference between saturated and unsaturated fatty acids?

Saturated fatty acids have the maximum number of hydrogen atoms and no double bonds (solid at room temperature), while unsaturated fatty acids have one or more double bonds (liquid at room temperature).

What is the difference between cis- and trans- isomers?

cis-isomers are on the same side of the two carbon atoms, while trans-isomers are on different sides of the two carbon atoms.

Which type of fat may contribute more than saturated fats to cardiovascular disease?

Trans fats.

What are the characteristics of a phospholipid?

The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head.

What are the functions of proteins?

Proteins include structural support, storage, transport, cellular communications, movement, and defense against foreign substances.

How are amino acids linked?

Amino acids are linked by peptide bonds.

If a polypeptide can function by itself, then what is it?

A protein.

What determines the three-dimensional conformation of a protein?

The amino acid sequence.

What are the four levels of protein structure?

Primary structure is the sequence of amino acids, secondary structure is the folding or coiling of the polypeptide chain, tertiary structure is the overall 3D shape of the protein, and quaternary structure is the interaction between multiple polypeptides or prosthetic groups.

What is the difference between fibrous and globular proteins?

Fibrous proteins have structural roles whereas globular proteins are functional (active in a cell’s metabolism).

What causes sickle-cell disease?

Sickle-cell disease results from a single amino acid substitution in the protein hemoglobin.

What is the loss of a protein’s native structure called?

Denaturation.

What roles do nucleic acids play?

DNA provides directions for its own replication and directs the synthesis of proteins by creating messenger RNA (more on this in a later chapter!).

What is the difference between a nucleoside and a nucleotide?

Nucleoside = nitrogenous base + sugar; Nucleotide = nucleoside + phosphate group.

What is the sugar in DNA and RNA?

In DNA, the sugar is deoxyribose; in RNA, the sugar is ribose.

What are the two families of nitrogenous bases?

Pyrimidines (cytosine, thymine, and uracil) have a single six-membered ring; Purines (adenine and guanine) have a six-membered ring fused to a five-membered ring.

How does DNA differ from RNA?

DNA differs from RNA in the number of strands present, the base composition and the type of pentose.