Biology 1406 Chapter 5

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of

120 thymine and 120 adenine molecules.

Which of the following statements is true regarding the molecule illustrated in Figure 5.2?

A & B only

Dehydration reactions are used in forming which of the following compounds?

A, B, and C

Which of the following best describes the flow of information in eukaryotic cells?

DNA → RNA → proteins

Which of the following is true of cellulose?

It is a major structural component of plant cell walls.

For this pair of items, choose the option that best describes their relationship. (A) The probability of finding chitin in fungal cell walls (B) The probability of finding chitin in arthropod exoskeletons

Item (A) is exactly or very approximately equal to item (B).

For this pair of items, choose the option that best describes their relationship. (A) The number of purines in the DNA strand 5'-AAGAGGAGAAA-3' (B) The number of pyrimidines in the DNA strand 5'-AAGAGGAGAAA-3'

Item (A) is greater than item (B).

For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with nonpolar side chains are hydrophobic. (B) The probability that amino acids with side chains containing a carboxyl group are hydrophobic.

Item (A) is greater than item (B).

Which of the following is true of both starch and cellulose?

They are both polymers of glucose.

What method did Frederick Sanger use to elucidate the structure of insulin?

analysis of amino acid sequence of small fragments

There are 20 different amino acids. What makes one amino acid different from another?

different side chains (R groups) attached to an alpha (α) carbon

A strong covalent bond between amino acids that functions in maintaining a polypeptide's specific three-dimensional shape is a (an)

disulfide bond

In the double helix structure of nucleic acids, cytosine hydrogen bonds to

guanine

Which of the following are nitrogenous bases of the purine type?

guanine and adenine

Humans can digest starch but not cellulose because

humans have enzymes that can hydrolyze the alpha (α) glycosidic linkages of starch but not the beta (β) glycosidic linkages of cellulose.

A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism

is more closely related to frogs than to humans.

Which bonds are created during the formation of the primary structure of a protein?

peptide bonds