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Bio 103
Bio 103 Final Exam Questions with Correct
Verified Answers Latest Update (2025/2026)
Guaranteed Pass
1. What is the precursor for sphingomyelin and glycolipid
synthesis in the Golgi?: Ceramide, which is synthesized in the ER,
serves as a precursor for sphingomyelin and glycolipid synthesis in the
Golgi.
2. How is ceramide modified in the Golgi?: Ceramide is modified
in the Golgi to form sphingomyelin by adding a phosphorylcholine
group and glycolipids by adding sugars.
3. What is the function of the KDEL sequence in ER proteins?:
The KDEL sequence (Lys-Asp-Glu-Leu) signals for ER proteins (such
as BiP and calreticulin) to be returned to ER
4. What are the two main mechanisms of N-linked
oligosaccharide processing in the Golgi?: 1. Mannose removal,
followed by additional sugars
Bio 103
, 2
Bio 103
2. Mannose phosphorylation by N-acetylglucosamine (lysosomal
targeted enzymes)
5. What is the initial step common to both Golgi processing
mechanisms of N-linked oligosaccharides?: A core oligosaccharide
is attached to asparagine residues in the ER.
6. What are the steps of Mechanism 1: Mannose Removal + Sugar
Addition in the Golgi?: 1. Mannose residues are trimmed.
2. Additional sugars like GlcNAc, galactose, and sialic acid are added.
7. The pathway of mechanism 1 is specific to?: secreted and
membrane-bound proteins
8. What are the steps of Mechanism 2: Mannose
Phosphorylation by N-acetylglucosamine (Lysosomal
Targeting)?: 1. In the ER: Initial glycosylation of lysosomal enzymes
occurs.
2. Mannose residues are phosphorylated by N-acetylglucosamine
phosphotransferase.
3. N-acetylglucosamine is then removed, leaving mannose-6-
phosphate.
Bio 103
Bio 103
Bio 103 Final Exam Questions with Correct
Verified Answers Latest Update (2025/2026)
Guaranteed Pass
1. What is the precursor for sphingomyelin and glycolipid
synthesis in the Golgi?: Ceramide, which is synthesized in the ER,
serves as a precursor for sphingomyelin and glycolipid synthesis in the
Golgi.
2. How is ceramide modified in the Golgi?: Ceramide is modified
in the Golgi to form sphingomyelin by adding a phosphorylcholine
group and glycolipids by adding sugars.
3. What is the function of the KDEL sequence in ER proteins?:
The KDEL sequence (Lys-Asp-Glu-Leu) signals for ER proteins (such
as BiP and calreticulin) to be returned to ER
4. What are the two main mechanisms of N-linked
oligosaccharide processing in the Golgi?: 1. Mannose removal,
followed by additional sugars
Bio 103
, 2
Bio 103
2. Mannose phosphorylation by N-acetylglucosamine (lysosomal
targeted enzymes)
5. What is the initial step common to both Golgi processing
mechanisms of N-linked oligosaccharides?: A core oligosaccharide
is attached to asparagine residues in the ER.
6. What are the steps of Mechanism 1: Mannose Removal + Sugar
Addition in the Golgi?: 1. Mannose residues are trimmed.
2. Additional sugars like GlcNAc, galactose, and sialic acid are added.
7. The pathway of mechanism 1 is specific to?: secreted and
membrane-bound proteins
8. What are the steps of Mechanism 2: Mannose
Phosphorylation by N-acetylglucosamine (Lysosomal
Targeting)?: 1. In the ER: Initial glycosylation of lysosomal enzymes
occurs.
2. Mannose residues are phosphorylated by N-acetylglucosamine
phosphotransferase.
3. N-acetylglucosamine is then removed, leaving mannose-6-
phosphate.
Bio 103
