Question 1

Which four elements make up the majority of living matter in biological organisms?

Accepted Answer

Carbon, Hydrogen, Oxygen, Nitrogen

Question 2

Why is water considered a versatile solvent in biological systems?

Accepted Answer

Because its polar covalent bonds allow it to dissolve both ionic and polar compounds

Question 3

Which type of chemical bond involves the sharing of valence electrons between two atoms?

Accepted Answer

Covalent bond

Question 4

In a water molecule, why are the covalent bonds considered polar?

Accepted Answer

Because oxygen is more electronegative than hydrogen, pulling shared electrons closer to itself

Question 5

Which equation correctly represents the chemical reaction for the formation of water from its elements?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 6

Which statement best explains why ionic compounds dissolve well in water?

Accepted Answer

Water's partial charges attract the positive and negative ions, separating them

Question 7

What is the main reason non-polar compounds are hydrophobic?

Accepted Answer

Their electrons are evenly distributed, so they do not interact favorably with water's partial charges

Question 8

Which of the following best describes the structure of a phospholipid in a cell membrane?

Accepted Answer

A hydrophilic head and two hydrophobic tails

Question 9

Which type of bond is responsible for holding together the sodium and chloride ions in table salt ($$NaCl$$)?

Accepted Answer

Ionic bond

Question 10

Why are weak chemical bonds important for the functions of life?

Accepted Answer

They allow for reversible interactions necessary for biological processes

Question 11

A mutation causes a change in the fatty acid tails of a phospholipid, making them saturated instead of unsaturated. What effect would this have on the cell membrane?

Accepted Answer

The membrane would become less fluid and more rigid

Question 12

Which of the following macromolecules contains both hydrophilic and hydrophobic regions, allowing it to form membranes?

Accepted Answer

Phospholipids

Question 13

Which property of water is most important for its role as a solvent in biological systems?

Accepted Answer

Its polarity

Question 14

Which of the following best describes the behavior of valence electrons in a covalent bond?

Accepted Answer

They are shared between two atoms

Question 15

A patient is diagnosed with anemia due to a mutation in the hemoglobin molecule. Which chemical property of hemoglobin is most directly affected?

Accepted Answer

Its ability to bind oxygen via the iron atom in the heme group

Question 16

Which of the following is a correct statement about chemical reactions in cells?

Accepted Answer

They involve the rearrangement of electrons to form new products

Question 17

Which of the following best explains why carbohydrates are important for energy in living organisms?

Accepted Answer

Their covalent bonds are relatively weak and can be broken to release energy

Question 18

Which of the following is true about the chemical behavior of an atom?

Accepted Answer

It is mostly determined by the number of valence electrons

Question 19

Which scenario best describes the formation of an ionic bond?

Accepted Answer

One atom transfers an electron to another, resulting in oppositely charged ions that attract each other

Question 20

Which of the following molecules is most likely to be hydrophobic?

Accepted Answer

A lipid

Chemistry of Life: The Molecular Basis of Biology

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