Water, Acids, Bases, and Functional Groups Lecture Notes

Practice flashcards covering the role of water, fluid compartments, pH, weak acids, buffers, and functional groups based on the lecture transcript.

What is the approximate percentage of total body water in an adult's body weight?

$$\sim 50-60\%$$

What are the two main fluid compartments in the body and their respective percentages of total body fluid?

Intracellular fluid ($\sim 60\%$) and Extracellular fluid ($\sim 40\%$)

How is interstitial fluid defined in the lecture notes?

Fluid in tissue spaces, lying between cells.

Why is water considered a dipolar molecule?

Electrons are unevenly distributed and spend more time around oxygen than hydrogen.

What is a hydrogen bond as described in the notes?

A weak, non-covalent attraction between a hydrogen atom and lone electron pairs on another atom, such as $-NH$ or $-OH$.

What are the criteria for a molecule to be highly soluble in water according to the hydrogen bonding rule?

Organic molecules that can participate in hydrogen bonding with water (acting as H-bond acceptors or donors) are highly soluble.

What are the concentrations of $Na^+$ and $K^+$ in the Extracellular Fluid (ECF) versus the Intracellular Fluid (ICF)?

$Na^+$ is $145\,mM/L$ (ECF) vs $12\,mM/L$ (ICF); $K^+$ is $4\,mM/L$ (ECF) vs $150\,mM/L$ (ICF).

How much acid does the body produce daily from metabolism?

Approximately $13-22\,mol/day$.

What is the mathematical formula for pH?

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

What is the ion product of water ($K_w$)?

$$[H^+] \times [OH^-] = 10^{-14}\,M^2$$

Name three examples of strong acids mentioned in the notes.

$HCl$, $HI$, and $H_2SO_4$.

What is the Henderson-Hasselbalch equation used for weak acid equilibrium?

$$pH = pK_a + \log_{10} \frac{[A^-]}{[HA]}$$

According to the Henderson-Hasselbalch relationship, what is the state of the acid when $pH > pK_a$?

$[A^-] > [HA]$ (The conjugate base concentration is greater than the conjugate acid).

What is the $pK_a$ of acetic acid?

$$4.76$$

What are the three $pK_a$ values for Phosphoric acid ($H_3PO_4$) and its derivatives?

$pK_{a1} = 2.14$, $pK_{a2} = 6.86$, and $pK_{a3} = 12.4$.

What are the two components that make up a buffer?

A weak acid ($HA$) and its conjugate base ($A^-$).

Which enzyme accelerates the hydration of $CO_2$ to $H_2CO_3$ in the bicarbonate buffer system?

Carbonic anhydrase

What is the bicarbonate buffer equation for blood pH as a function of $HCO_3^-$ and $PaCO_2$?

$$pH = 6.1 + \log_{10} \frac{[HCO_3^-]}{0.03 \times PaCO_2}$$

Distinguish between aliphatic and aromatic carbon structures.

Aliphatic groups are straight or branched carbon structures, while aromatic groups are carbon rings with alternating double bonds.

What is the difference between Dopamine and Choline regarding their interaction with protons?

Dopamine is a primary amine that can pick up an $H^+$ to become positively charged; Choline is a quaternary amine that cannot pick up or lose protons or form hydrogen bonds.

How is an amide formed?

When a carboxylic acid combines with an amine group and water is released.

In the Greek lettering system for identifying carbon atoms, which label is given to Carbon 2 and Carbon 3?

Carbon 2 is the $\alpha$-carbon and Carbon 3 is the $\beta$-carbon.