Question 1

Which of the following statements best describes the difference between an atom and an element?

Accepted Answer

An element is made up of atoms that all have the same number of protons, while an atom is the smallest unit of an element that retains its chemical properties.

Question 2

A carbon atom has 6 protons, 6 neutrons, and 6 electrons. What is its atomic number and mass number?

Accepted Answer

Atomic number: 6, Mass number: 12

Question 3

Which of the following best explains why radioisotopes are useful in medical imaging?

Accepted Answer

They emit high-energy radiation that can be detected to visualize the size, shape, and activity of organs.

Question 4

Which of the following is true regarding ionic bonds?

Accepted Answer

Ionic bonds are formed when electrons are transferred from a metal to a nonmetal, resulting in oppositely charged ions.

Question 5

A molecule of water ($$H_2O) is $$described as a polar covalent molecule. What property does this give water?

Accepted Answer

It enables water to dissolve both ionic and polar solutes, making it a universal solvent.

Question 6

Which of the following best describes the role of enzymes in chemical reactions within the human body?

Accepted Answer

Enzymes lower the activation energy, increasing the likelihood of strong collisions between reactants and speeding up reaction rates.

Question 7

A patient is diagnosed with Tay-Sachs disease, which is caused by a deficiency of hexosaminidase. What is the direct consequence of this enzyme deficiency?

Accepted Answer

Accumulation of gangliosides around neurons, leading to neurological damage.

Question 8

Which of the following best explains why saturated fats are solid at room temperature?

Accepted Answer

Their hydrocarbon chains are straight, allowing them to pack closely together.

Question 9

Which equation correctly represents the relationship between pH and hydrogen ion concentration?

Accepted Answer

$$pH = -\log[H^+]$$

Question 10

A buffer system in the blood helps maintain pH homeostasis. Which reaction represents the bicarbonate buffer system?

Accepted Answer

$$H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-$$

Question 11

Which of the following is a correct statement about the structure of DNA?

Accepted Answer

DNA consists of two complementary strands held together by hydrogen bonds between purines and pyrimidines.

Question 12

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction that links monomers together to form polymers, releasing water as a byproduct.

Question 13

Which of the following is a property of water that is critical for temperature regulation in the human body?

Accepted Answer

High heat capacity, enabling water to absorb heat without significant temperature change.

Question 14

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms chemically bonded, while a compound consists of two or more atoms from different elements bonded together.

Question 15

Which of the following is true about ATP (adenosine triphosphate) in human cells?

Accepted Answer

ATP contains three phosphate groups, and the bond between the second and third phosphate is highly exergonic.

Question 16

Which of the following best explains why phospholipids are critical for cell membrane structure?

Accepted Answer

They have both polar and nonpolar regions, allowing the membrane to interact with both water and hydrophobic molecules.

Question 17

Which of the following is a correct example of a redox (oxidation-reduction) reaction?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$

Question 18

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The linking together of multiple polypeptide chains in a specific arrangement.

Question 19

Which of the following statements about acids and bases is correct?

Accepted Answer

Bases are proton acceptors that decrease the concentration of $$H^+ in $$solution.

The Chemistry of Life: Atoms and Elements in Anatomy & Physiology

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