Question 1

Which of the following statements best explains why water is an excellent solvent for ionic compounds such as NaCl?

Accepted Answer

Water is a polar molecule, so its partial charges can surround and separate the positive and negative ions in ionic compounds.

Question 2

A solution has a pH of 4. How many times more acidic is it compared to a solution with a pH of 6?

Accepted Answer

$$100$$ times more acidic

Question 3

Which of the following best describes the difference between a saturated and an unsaturated fatty acid?

Accepted Answer

Saturated fatty acids have only single bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 4

Which of the following is a correct example of a condensation (dehydration synthesis) reaction?

Accepted Answer

Joining two monosaccharides to form a disaccharide and releasing a molecule of water.

Question 5

A radioactive isotope of carbon, $$^{14}C$$, is used in radiometric dating. What makes $$^{14}C$$ different from the more common $$^{12}C$$ isotope?

Accepted Answer

$$^{14}C$$ has more neutrons than $$^{12}C.$$

Question 6

Which property of water allows it to help maintain a stable body temperature in organisms?

Accepted Answer

Water's high heat capacity

Question 7

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

Accepted Answer

Buffers maintain pH by binding or releasing hydrogen ions as needed.

Question 8

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electron pairs between atoms.

Question 9

A patient is given an intravenous solution of glucose ($$C_6H_{12}O_6$) in water. Which property of glucose allows it to dissolve in water?

Accepted Answer

Glucose is polar and hydrophilic.

Question 10

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 11

Which of the following is a correct description of a phospholipid's structure and its role in cell membranes?

Accepted Answer

Phospholipids have a hydrophilic head and hydrophobic tails, forming a bilayer that acts as a selectively permeable barrier.

Question 12

A strong acid, such as HCl, is added to water. What happens at the molecular level?

Accepted Answer

HCl completely dissociates, releasing $$H^+$$ ions and $$Cl^-$$ ions into the solution.

Question 13

Which of the following best describes the difference between a monosaccharide and a disaccharide?

Accepted Answer

Monosaccharides are simple sugars, while disaccharides are composed of two monosaccharides joined by a glycosidic linkage.

Question 14

Which of the following is a real-life example of a hydrolysis reaction?

Accepted Answer

The breakdown of starch into glucose molecules during digestion.

Question 15

Which of the following best explains why trans fats are considered unhealthy compared to cis unsaturated fats?

Accepted Answer

Trans fats are partially hydrogenated, making them more solid and increasing LDL cholesterol.

Question 16

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds are weak attractions between a hydrogen atom and an electronegative atom like oxygen or nitrogen.

Question 17

A cell is placed in a solution and water moves out of the cell, causing it to shrink. What type of solution is the cell in?

Accepted Answer

Hypertonic solution

Question 18

Which of the following best describes the function of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol increases membrane fluidity at high temperatures and decreases it at low temperatures.

Question 19

Which of the following is a correct statement about the atomic number and mass number of an atom?

Accepted Answer

The atomic number is the number of protons, and the mass number is the sum of protons and neutrons.

Module 1: Chemistry of Life, Major Macromolecules, Membranes and the Cell

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