The Cell

Question 1

Pseudohypoparathyroidism

Answer 1

• Nonfunctioning parathyroid receptors.

- Glands produce the hormone, but the target cells do not respond because they lack normal receptors.

Question 2

Dwarfism

Answer 2

• Nonfucntioning growth hormone receptors

- Glands produce the hormone, but the target cells do not respond because they lack normal receptors.

Question 3

I- Cell disease

Answer 3

• Phosphorylation of mannose in glycoproteins targets proteins to lysosomes.
• Phosphate is added in a two-step sequence of reactions that are catalyzed by N-acetylglucosamine-phosphotransferase and N-acetylglucosaminidases.
• A deficiency in N-acetylglucosamine-phosphotransferase results In I-cell dieease .

Question 4

Hyperproinsulinemia

Answer 4

Hyperprolnsulinemia is characterized by elevated levels of proinsulin in the serum resulting from the failure of a peptidase to cleave proinsulin to insulin and C-peptide in the golgi apparatus.

Question 5

Glycogen-storage disease type 2 (Pompe’s disease)

Answer 5

• an autosomal recessive disorder that results from the deficiency of acid alpha-glucosidase, a lysosomal hydrolase , is required for the degradation of a small percentage of cellular glycogen.
• Results in the accumulation of structurally normal glycogen in lysosomes and cytoplasm.
• Excessive glycogen storage within lysosomes may interrupt normal functioning of other organelles and leads to enlargement and dysfunction of the entire organ involved (eg, cardiomyopathy).

Question 6

Zellweger (cerebrohepatorenal) syndrome
Neonatal adrenoleukodystrophy
Infantile Refsum disease
Hyperlipopecolaternia

Answer 6

• Associated with the impairment or absence of peroxisomes.

- These patients fail to oxidize very long chain fatty acids and accumulate bile acid precursors.

Question 7

Chediak-Higashi Syndrome

Answer 7

• Defect in microtubule polymerization .
• Is an autosomal recessive immunodeficiency disorder characterized by abnormal intracellular protein transport.
• Leads to delayed fusion of phagosomes with lysosomes in leukocytes

Question 8

Muscular dystrophy

Answer 8

Genetic disorder due to mutation in gene coding for the Actin binding protein, dystrophin.

Question 9

Epidermolysis bullosa

Answer 9

- Genetic disorder due to 
mutation in gene coding for 
keratin (intermediate filaments).
- Results in increased skin 
fragility & blister formation