Question 1

Which of the following statements best explains why water is considered a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, resulting in an unequal sharing of electrons.

Question 2

A sodium atom (Na) has an atomic number of 11 and an atomic mass of 23. How many neutrons does a typical sodium atom have?

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 3

Which of the following best describes the difference between covalent and ionic bonds?

Accepted Answer

Covalent bonds involve the sharing of electrons, while ionic bonds involve the transfer of electrons.

Question 4

Which property of water allows insects to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 5

A solution has a pH of 5. How does its hydrogen ion concentration compare to a solution with a pH of 7?

Accepted Answer

It is 100 times higher.

Question 6

Which of the following is a correct example of an endergonic reaction?

Accepted Answer

The synthesis of proteins from amino acids

Question 7

Which functional group is found in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 8

Which of the following statements about saturated and unsaturated fats is TRUE?

Accepted Answer

Saturated fats contain only single bonds between carbon atoms and are solid at room temperature.

Question 9

What is the primary function of glycogen in animals?

Accepted Answer

Long-term energy storage

Question 10

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

Accepted Answer

Hydrogen bonds in ice create a rigid, less dense structure than liquid water.

Question 11

Which of the following is NOT a property of water that is critical for life?

Accepted Answer

High density as a solid

Question 12

Which of the following best describes a buffer in biological systems?

Accepted Answer

A substance that resists changes in pH by donating or accepting $$H^+$$ ions

Question 13

Which of the following is a correct pairing of a macromolecule and its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 14

Which level of protein structure is primarily determined by the sequence of amino acids?

Accepted Answer

Primary structure

Question 15

Which of the following statements about phospholipids is TRUE?

Accepted Answer

They are amphipathic, with a hydrophilic head and hydrophobic tails.

Question 16

Which of the following best describes the role of hydrogen bonds in protein structure?

Accepted Answer

They stabilize secondary structures such as alpha helices and beta sheets.

Question 17

Which of the following is a real-life consequence of protein denaturation?

Accepted Answer

A fever above 104°F can cause proteins in the body to lose their function.

Question 18

Which of the following is TRUE about isomers?

Accepted Answer

Isomers have the same molecular formula but different structures.

Question 19

Which of the following best explains why carbon is central to life?

Accepted Answer

Carbon can form up to four stable covalent bonds with a variety of atoms.

Question 20

Which of the following statements about nucleic acids is correct?

Accepted Answer

DNA and RNA are composed of nucleotides linked by phosphodiester bonds.

Chemistry for Microbiology: Essential Principles and Biological Molecules

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