Porphyrins | Processing of Heme b to Heme a & Heme c

The video tutorial explores the synthesis and transformation of heme B into heme A and heme C, detailing the enzymatic processes involved. It highlights the roles of Cox 10 and Cox 15 enzymes in the assembly of cytochrome C oxidase and compares mitochondrial structures with gram-negative bacteria. The tutorial provides insights into the complex biochemical pathways and protein assemblies essential for cellular respiration.

What is the primary precursor molecule for the synthesis of Heme B?

• Copper A

• Cytochrome C

• Farnesyl pyrophosphate

• Delta aminolevulinic acid

Which enzyme is responsible for adding a farnesyl group to Heme B?

• Cytochrome C heme lyase

• Protoheme 9 farnesyl transferase

• Heme A synthase

• Ferrochelatase

What is the role of Cox 15 in the conversion of Heme B to Heme A?

• It reduces disulfide bridges in cytochrome C

• It adds cysteine residues to Heme B

• It hydroxylates and oxidizes the methyl group on the D ring

• It transports Heme B to the mitochondria

What is the main function of cytochrome C heme lyase?

• To transport Heme B to the inner membrane space

• To catalyze the addition of cysteine residues to Heme C

• To add a farnesyl group to Heme B

• To hydroxylate the methyl group on Heme A

In which complex of the mitochondria is Heme A primarily found?

• Complex I

• Complex II

• Complex III

• Complex IV

How do Cox 10 and Cox 15 contribute to cytochrome C oxidase assembly?

• They transport copper ions to the complex

• They become part of the final protein complex

• They reduce disulfide bridges in cytochrome C

• They deliver Heme A to the assembling protein

What structural similarity do gram-negative bacteria share with mitochondria?

• Equivalent inner and outer membrane structures

• Similar electron transport chain components

• Identical DNA sequences

• Presence of a single membrane

What is the role of the oxidoreductase protein in the synthesis of Heme C?

• To add a farnesyl group to Heme B

• To hydroxylate the methyl group on Heme A

• To reduce disulfide bridges in cytochrome C

• To transport Heme B to the inner membrane space

Which enzyme is responsible for the final step of Heme B synthesis in mitochondria?

• Cytochrome C heme lyase

• Heme A synthase

• Ferrochelatase

• Protoheme 9 farnesyl transferase

What is the function of the thioredoxin-dependent enzyme complex in Heme C synthesis?

• To add cysteine residues to Heme C

• To reduce disulfide bridges in cytochrome C

• To transport Heme B to the inner membrane space

• To hydroxylate the methyl group on Heme A