Question 1

Which of the following statements best explains why atoms are electrically neutral?

Accepted Answer

Atoms have equal numbers of protons and electrons.

Question 2

A radioactive isotope of carbon has a half-life of 5,730 years. If you start with 100 grams, how much will remain after 11,460 years?

Accepted Answer

25 grams

Question 3

Which type of chemical bond is responsible for the high surface tension of water?

Accepted Answer

Hydrogen bonds

Question 4

A sodium atom (Na) loses one electron to a chlorine atom (Cl) during the formation of sodium chloride (NaCl). What type of bond is formed?

Accepted Answer

Ionic bond

Question 5

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction that assembles larger molecules from smaller ones by removing water

Question 6

The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration. Which equation correctly represents this relationship?

Accepted Answer

$$pH = -\log_{10}[H^+]$$

Question 7

Which of the following is a property of hydrophobic molecules?

Accepted Answer

They do not interact readily with water.

Question 8

A patient’s blood pH drops to 7.20. Which of the following best describes this condition?

Accepted Answer

The blood is acidic and has a high hydrogen ion concentration.

Question 9

Which of the following best describes the role of enzymes in biochemical reactions?

Accepted Answer

Enzymes lower the activation energy and speed up reactions.

Question 10

Which of the following is true about the structure of DNA?

Accepted Answer

DNA consists of two complementary strands held together by hydrogen bonds.

Question 11

Which of the following is a correct example of a decomposition reaction involving water?

Accepted Answer

$$AB + H_2O \rightarrow AH + BOH$$

Question 12

Which of the following statements about protein structure is correct?

Accepted Answer

Tertiary structure results from interactions between R groups, forming the final 3D shape.

Question 13

Which of the following is a function of proteins in the human body?

Accepted Answer

Acting as enzymes to regulate metabolic reactions

Question 14

Which of the following best describes the difference between organic and inorganic compounds?

Accepted Answer

Organic compounds contain carbon bonded to hydrogen; inorganic compounds do not.

Question 15

Which of the following is a correct representation of a synthesis reaction?

Accepted Answer

$$A + B \rightarrow AB$$

Question 16

Which of the following is true about the structure of phospholipids?

Accepted Answer

Phospholipids have hydrophilic heads and hydrophobic tails.

Question 17

Which of the following best explains why buffers are important in human physiology?

Accepted Answer

Buffers stabilize pH by neutralizing acids and bases.

Question 18

Which of the following is a correct statement about ATP?

Accepted Answer

ATP is a nucleotide with three phosphate groups and is the main energy storage molecule in the body.

Question 19

Which of the following is true about monosaccharides?

Accepted Answer

Monosaccharides are simple sugars, hydrophilic, and include glucose and fructose.

Question 20

A protein loses its three-dimensional structure due to high temperature or extreme pH. What is this process called?

Accepted Answer

Denaturation

The Chemical Level of Organization – Study Notes for Anatomy & Physiology

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