Question

Lab 6: Cellular Respiration Exercise 6.2: Succinic dehydrogenase 6. Record your dats in the table below Tube EnzymeSubs rateColor A Supermatant Succinate with b Pellet Succinate wik D Pellet HiO E Supernatant Malonate Roite H2O Succinate 7. Where were most of the mitochondria: in the supernatant or in the pellet? Why is this? 8. Where is the enzyme: in the supernatant or in the pellet? How do you know? 9. Which substrate is "best" for this enzyme? Explain your answer

Answer 1

6).

( A) Will be colorless, if 2,6-dichloropenolindolphenol (DCPIP) is used as an artificial electron acceptor. Supernatant will not have mitochondrial.

( B ) Will be colorless. Supernatant will not have mitochondrial.

( C ) Will be blue in color, if 2,6-dichloropenolindolphenol (DCPIP) is used as an artificial electron acceptor. Supernatant will not have mitochondrial.

( D) Will be colorless. Water will not initiate SDH reaction.

( E ) Will be blue in color, Supernatant have subtle SDH enzyme which react with its competitive inhibitor.

( F ) Will be colorless. Water will not initiate SDH reaction.

7). Mitochondria will be seen in the pellet. After homogenization, the first centrifugation will pellet down nuclei and debris. From this supernatant having mitochondria will be centrifuged. The resultant pellet will have mitochondria.

8). The enzyme is present in pellet (mitrochindrial) portion. Succinate Dehydrogenase (SDH) complexes present in inner mitochondrial membranes. SDH enzyme participates in TCA cycle and resoiratory complexes.

9). The succinate is the best substrate used for SDH activity. Malonate is the competitive inhibitor of succinate.

10) Oxidation is observed during the conversion of succinate to fumarate to malate. Where reduced DCPIP is oxidized DCPIP (change in color from blue to colorless is observed).

11) The electrons are transferred from succinate to coenzyme Q. FAD+ is oxidized to FADH2.