Group 1: Fatty Acid

Wrong:
A: Both saturated and unsaturated FAs can have variable lengths (typically 12 - 20 carbons)
C: Both types are found in plants and animals; for example, Stearic acid (saturated) is found in animals, and Oleic acid (unsaturated) is found in olive oil (plant source)
D: All fatty acids are monocarboxylic acids and therefore have a terminal carboxyl group

D. SFA has a terminal carboxyl group, while UFA has a terminal methyl group

C. SFA is only found in plants, while UFA is only found in animals

A. SFA has a shorter carbon chain (less than 12 carbons), while UFA has a longer chain (more than 20 carbons)

B. LA serves as necessary precursor for important metabolism like PGs

Cis double bonds introduce kinks (twist) that prevent tight packing of hydrocarbon chains.

Correct:
Those bent chains cannot pack neatly together as the straight chains of saturated fats. The intermolecular interactions are much weaker than saturated molecules, thus it requires lower temperature to break them out of a packed-together solid structure and melt them.

Wrong:
Polyunsaturated and saturated fatty acids with similar length have same number of carbon atoms.

They contains fewer carbon atoms available for Van der Waals interactions.

Wrong:
Double bonds do not significantly increase molecular weight. In fact, for a given carbon chain length, an unsaturated fatty acid has fewer hydrogen atoms, thus it has lower molecular weight.

Melting point depends on how well molecules pack together in a solid, not chemical stability.

Double bonds increase the molecular weight, making them less stable.

Wrong:
Melting point is to measure pure fatty acid, not blood or cytosol.

Both saturated and unsaturated fatty acid has one carbocyl group. There is no difference ionization between them.

Differences in melting point come from hydrocarbon tail, not carboxyl group.

Their carboxyl group becomes fully ionized at physiological pH.

Wrong:
A. Both essential and nonessential fatty acids can have similar carbon chain lengths.

B. Essential fatty acids can have FEW or MANY double bonds; Nonessential fatty acids can ALSO have multiple double bonds

D. All fatty acids have a carboxyl group (–COOH).

B. Number of double bonds present

D. Presence of a carboxyl group

A. Total number of carbon atoms

Correct:
C. Methyl end (–CH₃), this is called the omega (ω) end

• Omega-3 (linolenic acid) → first double bond at carbon 3

• Omega-6 (linoleic acid) → first double bond at carbon 6

• Omega-9 (oleic acid) → first double bond at carbon 9
  
  Cannot make ω-3 or ω-6 → must eat them → essential
  Can make ω-9 → no need to eat → nonessential

C. Position of the first double bond from the omega (methyl) end

​More rapidly β-oxidized

Correct:
1. Metabolic prioritization: Prioritization as an immediate energy source
2. Structural: The degree of the unsaturated of the lipid affects the oxidation sensitivity.
3. Limited storage: Less easily replaced in tissue lipids
ALA is the highest oxidation rate of the unsaturated fats!!

Wrong:
Limited storage: Less easily replaced in tissue lipids.

More easily replaced in tissue lipids

​​Less rapidly metabolized

Wrong:
Essential fatty acids cannot be synthesized by the human body, it must be obtained from diet.

Synthesized in larger quantities