Week 2 Quiz

Which count decides which element an atom is?

Select one.

• The number of protons in its nucleus
• The number of electrons around its nucleus
• The number of neutrons in its nucleus
• The size of its electric charge

In table salt, sodium gives one electron to chlorine, and the resulting Na⁺ and Cl⁻ attract. Which bond is this?

Select one.

• Polar covalent bond
• Nonpolar covalent bond
• Ionic bond
• Hydrogen bond

Inside a single water molecule, which bond holds each hydrogen to the oxygen?

Select one.

• A hydrogen bond, drawn as a dotted line
• A polar covalent bond, with uneven sharing
• An ionic bond, with a transferred electron
• A nonpolar covalent bond, with even sharing

Sweat leaving a runner's skin on a hot trail carries heat away. Which of water's four jobs is at work?

Select one.

• Solvent
• Lubricant
• Reactant
• Heat sink

Using the count-the-steps rule, compare pH 4 with pH 7. How many hydrogen ions does each carry, relative to the other?

Select one.

• pH 4 carries 1,000 times more
• pH 4 carries 3 times more
• pH 4 carries 30 times more
• pH 7 carries 1,000 times more

Compare pH 5 with pH 7. How many times more hydrogen ions does pH 5 carry?

Select one.

• 20 times more
• 100 times more
• 2 times more
• 200 times more

Blood is held between 7.35 and 7.45. An illustrative chart value reads 7.0. Where does that value fall?

Select one.

• Inside the defended range
• Above the range, on the alkalosis side
• Below the range, on the acidosis side
• At neutral, which is the blood's target

A buffer holds blood at exactly pH 7 and never lets its pH change.

True or false.

• True
• False

Select every correct pairing of an organic compound with its building block.

Select every option that applies.

• Carbohydrate: monosaccharides
• Protein: amino acids
• Nucleic acid: nucleotides
• Lipid: one single repeating monomer
• Protein: nucleotides

Heat unfolds a protein's shape. Which statement describes this denaturation?

Select one.

• Its amino-acid sequence is rearranged
• It gains a third phosphate group
• It becomes a lipid
• Its shape is lost and it can lose its function