Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$the solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ \mathrm{M}$$

Question 1

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

Accepted Answer

Water molecules are polar, allowing them to surround and stabilize both positive and negative ions through hydrogen bonding.

Question 2

A patient is diagnosed with a genetic disorder that affects the structure of their phospholipids. Which cellular process is most likely to be directly impacted?

Accepted Answer

Active transport across the plasma membrane

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 4

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$the solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{M}$$

Question 5

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids are solid at room temperature due to the absence of double bonds, while unsaturated fatty acids are liquid due to the presence of one or more double bonds.

Question 6

Which of the following is a correct sequence of protein structure levels from simplest to most complex?

Accepted Answer

Primary, secondary, tertiary, quaternary

Question 7

A scientist is studying a molecule with the formula $$C_6H_{12}O_6$. Which class of biomolecule does this most likely represent, and what is its primary function?

Accepted Answer

Monosaccharide; immediate energy source

Question 8

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 9

Which of the following scenarios best illustrates the concept of a condensation (dehydration synthesis) reaction?

Accepted Answer

Linking two amino acids together to form a dipeptide and releasing a molecule of water

Question 10

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

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

Question 11

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

The cell will swell and possibly burst because water will move in by osmosis.

Question 12

Which of the following is a correct comparison between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 13

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules from high to low concentration through a membrane protein without energy input

Question 14

Which of the following functional groups is found in all amino acids?

Accepted Answer

Both carboxyl group $$(-COOH)$$ and amino group $$(-NH_2$)$$

Question 15

A cell is observed to have a large number of tight junctions. Which tissue type is this cell most likely a part of?

Accepted Answer

Epithelial tissue

Question 16

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Their hydrophobic tails avoid water while their hydrophilic heads interact with water.

Question 17

Which of the following is an example of active transport?

Accepted Answer

Sodium-potassium pump moving $$Na^+$$ out of and $$K^+$$ into the cell using ATP

Question 18

Which of the following best describes a glycosidic linkage?

Accepted Answer

A bond formed between two monosaccharides by a dehydration reaction

Question 19

A protein is exposed to high heat and loses its three-dimensional structure but not its primary sequence. What process has occurred?

Accepted Answer

Denaturation

Question 20

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A dynamic structure with proteins and lipids able to move laterally within the layer

General Biology: Core Concepts and Molecular Foundations

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