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

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

Question 1

Which property of water allows insects such as water striders to walk on the surface of a pond without sinking?

Accepted Answer

Surface tension due to hydrogen bonding

Question 2

A scientist adds a strong acid to a solution containing a biological buffer. What is the primary function of the buffer in this scenario?

Accepted Answer

To maintain a relatively constant pH by accepting excess H$$^+$$ ions

Question 3

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

Accepted Answer

Ice is less dense than liquid water because its hydrogen bonds form a lattice that spaces molecules farther apart

Question 4

Which of the following statements about carbon is correct and explains its versatility in forming large, complex molecules?

Accepted Answer

Carbon can form up to four covalent bonds with other atoms

Question 5

A dehydration reaction is used to build a polymer from monomers. Which of the following best describes what happens during this process?

Accepted Answer

A water molecule is removed, forming a new covalent bond between monomers

Question 6

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

Accepted Answer

Glucose and fructose, which have the same molecular formula $$C_6H_{12}O_6$ but different structures

Question 7

A patient is suffering from a fever, and their enzymes begin to lose function. Which process is most likely occurring at the molecular level?

Accepted Answer

The enzymes are denaturing, losing their three-dimensional shape

Question 8

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA contains the sugar deoxyribose, while RNA contains the sugar ribose

Question 9

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

Accepted Answer

Carboxyl group $$-COOH$$

Question 10

A plant cell is placed in a hypotonic solution. Which organelle is primarily responsible for storing the excess water that enters the cell?

Accepted Answer

Central vacuole

Question 11

Which of the following statements correctly distinguishes between animal and plant cells?

Accepted Answer

Plant cells contain chloroplasts, while animal cells do not

Question 12

Which property of water is most important for maintaining a stable temperature in lakes and oceans, thus supporting aquatic life?

Accepted Answer

High specific heat

Question 13

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

Accepted Answer

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

Question 14

Which of the following best describes the process of hydrolysis in biological systems?

Accepted Answer

A water molecule is added to break a covalent bond in a polymer

Question 15

Which macromolecule is primarily responsible for storing genetic information in living organisms?

Accepted Answer

Nucleic acids

Question 16

Which of the following is a correct pairing of a cell organelle with its function?

Accepted Answer

Golgi apparatus: modification and packaging of proteins

Question 17

Which of the following best explains why oil and water do not mix?

Accepted Answer

Oil molecules are nonpolar and hydrophobic, while water molecules are polar and form hydrogen bonds

Question 18

A polysaccharide is broken down into monosaccharides in the human digestive tract. Which type of reaction is responsible for this process?

Accepted Answer

Hydrolysis

Question 19

Which of the following best describes the role of functional groups in organic molecules?

Accepted Answer

They determine the chemical reactivity and properties of the molecule

Question 20

A researcher observes that a certain protein loses its function when exposed to high heat, but regains function when cooled. What does this suggest about the protein's structure?

Accepted Answer

The protein's tertiary structure is disrupted by heat but can refold when cooled

BIOS107-01 Exam 2 Study Guide

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