Fructose is still a reducing sugar. Many students think ketoses are non-reducing. Free fructose IS reducing (its hemiketal can open to expose the ketone). Only sucrose is non-reducing, and that is because BOTH anomeric carbons are blocked, not because fructose is a ketose.

Sucrose is NOT a polysaccharide. Sucrose is a disaccharide (two monosaccharides). Students sometimes call large, complex molecules "polysaccharides" loosely.

$\alpha$ vs $\beta$ anomer confusion. $\alpha$-D-glucose has C1-OH below the ring (axial) in Haworth projection. $\beta$-D-glucose has C1-OH above the ring. Do not reverse this.

Denaturation ≠ hydrolysis. Denaturation does not break peptide bonds and does not release amino acids. Hydrolysis (by acid, base, or enzymes) breaks peptide bonds and releases amino acids. Denaturation only disrupts 2°/3°/4° structure.

A–T has 2 H-bonds, G–C has 3 H-bonds. Students frequently swap these. Mnemonic: GC is three letters when you say "G–C–three."

Cellulose vs starch linkage. Both are glucose polymers. Starch uses $\alpha$-1,4 linkages (digestible). Cellulose uses $\beta$-1,4 linkages (indigestible). The $\alpha$/$\beta$ difference at C1 causes completely different 3D shapes and digestibility.

Vitamin K is fat-soluble, NOT water-soluble. Remember ADEK for fat-soluble. Vitamin K is often mistakenly placed in the water-soluble group.

mRNA vs tRNA function. mRNA carries the genetic code (sequence of codons); tRNA carries the amino acid and has the anticodon. Do not swap their roles in protein synthesis.

Glycogen is not identical to amylopectin. Both are branched with $\alpha$-1,4 + $\alpha$-1,6, but glycogen is MORE branched (branch every 8–12 units) vs amylopectin (every 24–30 units). Glycogen is found in animals; amylopectin in plants.

Isoelectric point ≠ neutral pH. At pI, the amino acid has no net charge (zwitterion). The pI value is not necessarily 7; it depends on the side chain (R group) of each amino acid.