Biology 181 Exam 2 Review

Which level of protein structure is characteristic of some, but not all, proteins? a) Quaternary level of protein structure b) Secondary level of protein structure c) Tertiary level of protein structure

A) QUATERNARY structure results from the aggregation of two or more polypeptide subunits, and not all proteins are composed of more than one polypeptide.

What are monomer/polymer pairings?

- deoxyribonucleotide/DNA - monosaccharide/polysaccharide - amino acid/protein - ribonucleotide/RNA NOT a monomer/polymer pairing: - triglyceride/phospholipid bilayer

Saturated Fats:

- generally solidify at room temperature. - are one of several factors that contribute to atherosclerosis. - more common in animals than in plants. - contain more hydrogen than unsaturated fats having the same number of carbon atoms. They DO NOT have multiple double bonds in the carbon chains of their fatty acids.

A hydrophobic amino acid R group (side group) would be found where in a protein? a) only at one end of a protein chain b) on the outside of the folded chain, in the water c) on the inside of the folded chain, away from water d) forming a peptide bond with the next amino acid in the polypeptide chain e) forming hydrogen bonds with other R groups

A hydrophobic amino acid R group (side group) would be found where in a protein? C) on the inside of the folded chain, away from water Hydrophobic R groups are nonpolar. By orienting within the folded chain they associate with other nonpolar R groups or side chains and avoid coming into contact with water

Which of the following correctly matches an organelle with its function? a) central vacuole ... storage b) mitochondrion ... photosynthesis c) lysosome ... movement d) nucleus ... cellular respiration e) ribosome ... manufacture of lipids

A) central vacuole ... storage

Which molecule is a nucleotide? a) Deoxyribose b) ATP c) The amino acid glycine

B) ATP - A nucleotide consists of three parts: a nitrogenous base, a pentose sugar, and one or more phosphate groups. - ATP consists of a nitrogenous base (adenine), a pentose sugar, and three phosphate groups.

Which level of protein structure do the α helix and the β pleated sheet represent? a) primary b) secondary c) tertiary d) quaternary e) primary, secondary, tertiary, and quaternary

B) the α helix and the β pleated sheet represent the SECONDARY level of protein structure

In order for a protein to be an integral membrane protein it would have to be a) completely covered with phospholipids. b) exposed on only one surface of the membrane. c) hydrophilic. d) amphipathic, with at least one hydrophobic region. e) hydrophobic.

In order for a protein to be an integral membrane protein it would have to be (D) AMPHIPATHIC with at least one hydrophobic region.

The tertiary structure of a protein is the: a) organization of a polypeptide chain into an α helix or β pleated sheet. b) bonding together of several polypeptide chains by weak bonds. c) unique three-dimensional shape of the fully folded polypeptide. d) order in which amino acids are joined in a polypeptide chain. e) overall protein structure resulting from the aggregation of two or more polypeptide subunits.

The tertiary structure of a protein is the (C) unique three-dimensional shape of the fully folded polypeptide.

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? a) Hydrolysis creates monomers, and dehydration reactions break down polymers. b) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. c) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. d) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. e) Dehydration reactions can occur only after hydrolysis.

What best summarizes the relationship between dehydration reactions and hydrolysis? C) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Molecules that have the same chemical formula (same numbers of each atom) but different three-dimensional shapes are called _____. a) functional groups b) isomers c) isotopes d) hydrocarbons e) enantiomers

b) ISMOMERS of carbon compounds can arise in several different ways