Bio Chapter 2

Cells require one particular monosaccharide as a starting material to synthesize nucleotide building blocks. Which of the monosaccharides below fills this important role? Select one: a. ribulose b. fructose c. glucose d. ribose

d

Which subatomic particles contribute to the atomic number for any given element? Select one: a. protons and electrons b. neutrons c. protons and neutrons d. protons

d

Which subatomic particles can vary between isotopes of the same element, without changing the observed chemical properties? Select one: a. electrons b. neutrons c. neutrons and electrons d. protons and neutrons

b

Polar covalent bonds are formed when the electrons in the bond are not shared equally between the two nuclei. Which one of these molecules contains polar bonds? Select one: a. water b. propane c. molecular oxygen d. methane

a

Which of the following elements is least abundant in living organisms? Select one: a. sulfur b. oxygen c. nitrogen d. carbon

a

A covalent bond between two atoms is formed as a result of the ______________. Select one: a. transfer of electrons from one atom to the other. b. sharing of electrons. c. loss of a proton from one atom. d. loss of electrons from both atoms.

b

Both DNA and RNA are synthesized by covalently linking a nucleoside triphosphate to the previous nucleotide, constantly adding to a growing chain. In the case of DNA, the new strand becomes part of a stable helix. The two strands are complementary in sequence and antiparallel in directionality. What is the principal force that holds these two strands together? Select one: a. covalent bonds b. hydrogen bonds c. van der Waals interactions d. ionic interactions

b

Which combination of answers best completes the following statement: When atoms are held together by ___________ __________, they are typically referred to as _________. Select one: a. hydrogen bonds, molecules. b. ionic interactions, salts. c. ionic interactions, molecules d. double bonds, nonpolar

b

Choose the answer that best fits the following statement: Cholesterol is an essential component of biological membranes. Although it is much smaller than the typical phospholipids and glycolipids in the membrane, it is a(n) _________________ molecule, having both hydrophilic and hydrophobic regions. Select one: a. hydrophobic b. polar c. amphipathic d. oxygen-containing

c

DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but not true of RNA? Select one: a. It has 5′-to-3′ directionality. b. It is single-stranded. c. It contains thymine. d. It contains uracil.

c