Question 1

Which property of water is primarily responsible for the ability of some insects, such as water striders, to walk on the surface of water without sinking?

Accepted Answer

Surface tension

Question 2

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom

Question 3

Why is water considered a polar covalent molecule?

Accepted Answer

Because the oxygen atom is more electronegative than hydrogen, creating a partial negative charge on oxygen and a partial positive charge on hydrogen

Question 4

Which of the following is an example of a physiological buffer that helps maintain pH in human blood?

Accepted Answer

Bicarbonate ion ($$ \mathrm{$$HCO_3$$^-} )$$

Question 5

Which of the following statements about dehydration and hydrolysis reactions is correct?

Accepted Answer

Dehydration reactions join monomers to form polymers by removing water, while hydrolysis reactions break polymers into monomers by adding water.

Question 6

Which type of bond is found between the monomers of cellulose, and what is the significance of this bond for human digestion?

Accepted Answer

Beta-1,4-glycosidic bond; not digestible by humans due to lack of appropriate enzymes

Question 7

A patient is found to have a mutation that prevents the formation of peptide bonds. Which macromolecule would be most directly affected?

Accepted Answer

Proteins

Question 8

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules require a large amount of energy to break.

Question 9

Which of the following functional groups is most likely to act as a base in a biological molecule?

Accepted Answer

Amino group ($$ -\mathrm{NH_2$} )$$

Question 10

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain

Question 11

A scientist is studying a nucleic acid that contains uracil, is single-stranded, and has ribose as its sugar. Which nucleic acid is being studied?

Accepted Answer

RNA

Question 12

Which of the following statements about the denaturation of proteins is correct?

Accepted Answer

Denaturation disrupts secondary, tertiary, and quaternary structures but not the primary structure.

Question 13

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice structure that is less dense than liquid water.

Question 14

Which of the following best describes the difference between starch and cellulose?

Accepted Answer

Starch is composed of alpha-glucose monomers with alpha-1,4 and alpha-1,6 linkages, while cellulose is composed of beta-glucose monomers with beta-1,4 linkages.

Question 15

Which of the following statements about Chargaff's rules is correct?

Accepted Answer

The amount of adenine equals the amount of thymine, and the amount of cytosine equals the amount of guanine in DNA.

Question 16

A researcher heats a DNA sample and observes that it melts at a higher temperature than another sample. What is the most likely explanation?

Accepted Answer

The sample has a higher proportion of G-C base pairs, which have three hydrogen bonds.

Question 17

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The association of multiple polypeptide subunits into a functional protein

Question 18

Which of the following is a correct statement about the directionality of DNA and RNA?

Accepted Answer

Both DNA and RNA are synthesized in the 5' to 3' direction.

Question 19

Which of the following best explains the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in pH by accepting or donating hydrogen ions ($$ \mathrm{H^+} ) $$when acids or bases are added.

Question 20

Which of the following is a correct description of an isomer?

Accepted Answer

Molecules with the same chemical formula but different structures

General Biology: Chemical Foundations, Macromolecules, and Nucleic Acids Study Guide

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