Which of the following statements about the 5 end of a polynucleotide strand of RNA is correct?

The 5 end has a phosphate group attached to the number 5 carbon of ribose.

When nucleotides polymerize to form a nucleic acid, ________.

a covalent bond forms between the sugar of one nucleotide and the phosphate of a second

Which of the following is a major difference between RNA and DNA?

type of sugar

The relation between amino acid and polypeptide is similar to the relation between ________.

nucleotide and nucleic acid

Use the following figure to answer the question.

The chemical reaction illustrated ________.

results in a peptide bond

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Alzheimer's and Parkinson's

Which of the following provides the information necessary to stipulate a protein's 3-D shape?

sequence of amino acids in the polypeptide chain

Use the following information to answer the question.

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)

Hemoglobin, when subjected to 40% acetonitrile at pH 10.0, loses its quaternary structure, which means the ________.

four α and β polypeptides dissociate

In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits ________.

altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered

Use the following information to answer the question.

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)

How many heme groups are present in three hemoglobin protein molecules?

12

Use the following information to answer the question.

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)

Hemoglobin is ________.

a quaternary protein with four polypeptides

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. What is the significance of this finding?

Cysteine residues are involved in disulfide bridges that help form tertiary structure.

Which of the following statements is true about proteins?

Some proteins form a complete 3-D structure only when they interact with their targets

You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?

primary structure

What component of amino acid structure varies among different amino acids?

the components of the R group

A tripeptide has ________.

three amino acids and two peptide bonds

Which parts of the amino acids X and Y are involved in the formation of a peptide bond?

X—Y

carboxyl group of X and amino group of Y

Use the following figure to answer the question.

The molecule shown the figure is a ________.

steroid

Use the following figure to answer the question.

The molecule illustrated in the figure ________.

will be liquid at room temperature

Which of the following could be responsible for atherosclerosis and should be eliminated from diet for health reasons?

butter, liver, and kidney organ meat

The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. Hydrogenated vegetable oil ________.

is solid at room temperature

Saturated fats ________.

contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms

Phospholipids and triglycerides both ________.

have a glycerol backbone

How do phospholipids interact with water molecules?

The polar heads interact with water; the nonpolar tails do not.

For lipids to be fluid at room temperature, they should have ________.

a higher number of cis double bonds

Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they ________.

do not have a polar or charged region

What makes lipids/fats hydrophobic?

presence of relatively nonpolar C—H bonds

Which of the following statements is true for lipids?

Lipids mix poorly with water.

A glycosidic linkage is analogous to which of the following in proteins?

a peptide bond

Use the following figure to answer the question.

The molecule shown is ________.

a hexose

Humans can digest starch but not cellulose because ________.

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

Starch and cellulose ________.

are polymers of glucose

People who are lactose intolerant cannot extract energy from milk because ________.

they are missing an enzyme

In carbohydrates, the ratio of hydrogen (H) to oxygen (O) is ________.

2:1

A molecule with the chemical formula C6H12O6 is probably a ________.

monosaccharide

What does the term insoluble fiber refer to on food packages?

cellulose

Which polysaccharide is an important component in the structure of many animals and fungi?

chitin

Starch is composed of ________.

branched amylopectin and unbranched amylose

What is the major structural difference between starch and glycogen?

the amount of branching that occurs in the molecule

You would like to lose weight. Which of the following should be your preferred food group?

Cellulose and fructose

Maltose is a disaccharide that can easily be digested into glucose molecules. The glycosidic linkage between glucose molecules in maltose is ________.

α 1—4

The difference between an aldose sugar and a ketose sugar is ________.

the position of the carbonyl group

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18H32O16

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.

How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?

19

Which of the following is not a polymer?

glucose