Bio 168 Anatomy and Physiology at Piedmont Community College

Correct Answer: False

Explanation:

The first part is correct: the thigh is proximal to the foot, meaning it is closer to the body’s center. However, the second part is incorrect. Moving proximally from the wrist brings you toward the elbow and shoulder, not the thumb. The thumb is distal to the wrist.

Correct Answer A: anabolic

Explanation:

An anabolic reaction builds larger molecules from smaller ones. In this case, the liver joins multiple glucose molecules together to form glycogen, a storage form of energy. This energy-requiring process is a classic example of anabolism.

Why the Other Options Are Incorrect:

B. catabolic

Catabolic reactions involve the breakdown of larger molecules into smaller ones, which is the opposite of what is happening here.

C. hydration

Hydration involves adding water to a molecule, which is not the process being described.

D. exchange

Exchange reactions involve swapping components between molecules, not building glycogen from glucose.

Correct Answer A: donate a hydrogen ion

Explanation:

Carbonic acid (H₂CO₃) is a weak acid formed when carbon dioxide dissolves in water. As an acid, it can donate hydrogen ions (H⁺), which plays a key role in the body's pH buffering system, helping to maintain acid-base balance in the blood.

Why the Other Options Are Incorrect:

B. accept a hydrogen ion – Accepting H⁺ is characteristic of a base, not an acid.

C. function has nothing to do with hydrogen ions – Incorrect; carbonic acid's primary function is buffering pH by releasing or holding H⁺ ions.

D. a fatty acid having no single, double, nor triple bonds – This describes a nonexistent chemical structure, and carbonic acid is not a fatty acid.

Correct Answer B: Decrease the pH

Explanation:

An increase in hydrogen ion (H⁺) concentration makes a solution more acidic, which lowers its pH. Without a buffer to stabilize the hydrogen ion levels, the solution cannot resist this change, and the pH drops significantly. This makes buffers essential for maintaining a stable internal environment in biological systems.

Why the Other Options Are Incorrect:

A. Will not affect the pH

This is incorrect because hydrogen ion concentration directly affects pH. An increase in H⁺ will always lower pH unless buffered.

C. Gravity

This is irrelevant to the chemical property of pH and has no role in acid-base balance.

D. Will both raise and lower the pH in equal amounts

pH does not fluctuate randomly. An increase in H⁺ will specifically decrease pH, not cause it to go up and down equally.

Correct Answer E: acidic

Explanation:

A pH of 2.0 is very acidic. The pH scale ranges from 0 to 14, where 7 is neutral, below 7 is acidic, and above 7 is alkaline (basic). A pH of 2.0 is close to that of stomach acid and is far from neutral or alkaline.

Why the Other Options Are Incorrect:

A. all choices are correct – Incorrect because only one choice (acidic) accurately describes a pH of 2.0.

B. neutral – Neutral pH is 7, not 2.0.

C. alkaline – Alkaline refers to pH above 7, not below.

D. esophageal cancer – pH is a measure of acidity or alkalinity, not a disease.

Correct Answer: False

Explanation:

While it's true that a tissue is a group of similar cells working together to perform a specific function, the heart is not an example of a tissue — it is an organ. An organ is made up of multiple tissue types (muscle tissue, connective tissue, epithelial tissue, etc.) working together. Therefore, using the heart as an example of a tissue is incorrect.

Correct Answer D: it removes a hydrogen ion out of solution

Explanation:

Bicarbonate (HCO₃⁻) acts as a weak base in the body’s buffering system. It helps maintain pH balance by removing excess hydrogen ions (H⁺) from the solution, thereby reducing acidity. This is a key part of the carbonic acid–bicarbonate buffer system, which helps regulate blood pH.

Why the Other Options Are Incorrect:

A. bicarbonate has nothing to do with hydrogen ions, nor pH – Incorrect, because bicarbonate plays a central role in pH regulation through its interaction with hydrogen ions.

B. it adds hydrogen ions into the solution – This would make it an acid, not a base.

C. it both adds and takes away hydrogen ions – Bicarbonate’s primary role is to remove hydrogen ions, not to add them.

Correct Answer C: appendicitis

Explanation:

Appendicitis is the inflammation of the appendix, which is located in the lower right quadrant of the abdomen. Pain in this area is a classic symptom and often requires urgent medical evaluation and possible surgical removal of the appendix.

Why the Other Options Are Incorrect:

A. hepatitis – This affects the liver, which is located in the right upper quadrant, not the lower right.

B. kidney stones – Pain from kidney stones usually occurs in the flank or lower back, not specifically in the lower right quadrant.

D. esophageal cancer – This affects the esophagus, located in the chest, not the abdomen.

E. stomach ulcer – Ulcers typically cause epigastric pain (upper middle abdomen), not lower right quadrant pain.

Correct Answer C: a fatty acid having one or more double bonds

Explanation:

An unsaturated fatty acid contains one or more double bonds between carbon atoms in its hydrocarbon chain. These double bonds create kinks in the chain, affecting the structure and fluidity of fats.

If it has one double bond, it's called monounsaturated; if it has two or more, it's polyunsaturated.

Why the Other Options Are Incorrect:

A. a fatty acid having no single or double bonds – This is chemically impossible, as all fatty acids require some form of bonding.

B. a fatty acid having no double bonds – This describes a saturated fatty acid, not an unsaturated one.

D. a fatty acid having no single, double, nor triple bonds – A molecule without any bonds cannot exist; this is not a valid description of any fatty acid.