General

Question 1

What is co-dominance?

Answer 1

A pair of alleles in a heterozygote are equally dominant and result in a mixed phenotype

Question 2

What is NADPH required for?

Answer 2

• reducing power for biosynthesis
• maintenance of GSH levels
• detoxification reactions

Question 3

What does the pentose phosphate pathway produce?

Answer 3

• NADPH
• C5-sugar ribose
• CO2

Question 4

What rate-limiting enzyme is used in the pentose phosphate pathway?

Answer 4

Glucose-6-phosphate dehydrogenase

Question 5

What is the pattern of inheritance in glucose-6-phosphate dehydrogenase deficiency?

Answer 5

X-linked recessive

Question 6

Which cell gets it’s only NADPH source from the pentose phosphate pathway?

Answer 6

RBCs

Question 7

What abnormality if found in a blood sample of a patient with glucose-6-phosphate dehydrogenase deficiency? Why do they form?

Answer 7

Heinz bodies

Hb becomes cross-linked due to inappropriate disulphide bond formation - forms an insoluble aggregate called Heinz bodies

Question 8

What are the differences between fibrous and globular proteins?

Answer 8

Fibrous - support, shape and protect. Long strands/sheets. Have a single type of repeating secondary structure.

Globular - involved in catalysis and regulation. Compact shape. Have several types of secondary structures