1. Indicate the correct cellular compartment(s) for each of the following events

Question

1. Indicate the correct cellular compartment(s) for each of the following events. If an organelle has more than one part, specify the precise location in the organelle. Assume metabolism is aerobic, not anaerobic.

reduction of oxygen

generation of pyruvate

dissipation of H+ gradient to create ATP

reduction of NAD+

oxidation of NADPH

oxidation of water

2. How is it possible for some molecules to be at equilibrium across a biological membrane and yet not be at the same concentration on both sides?

3. Why are the maximum rates of transport by carriers and channels thought to be so different?

4. Which of the ions listed in the table below could be used to drive an electrically neutral coupled transport of a solute across the plasma membrane? (Notice that there are many more cations than anions listed in the table, but cells are electrically neutral overall. What anions are missing from the table?)

please help:)

Explanation / Answer

1. Aerobic processes:

A) reduction of oxygen :

B) generation of pyruvate: Pyruvate is formed from Glucose through a process called Glycolysis in cytosol.

C6H12O6 (GLUCOSE)+ 2 NAD+ + 2ADP + 2Pi --------------> 2C3H4O3 (pYRUVATE)+ 2 NADH+ 2H+ +2 ATP+ 2 H2O

C) Dissipation of H+ gradient to create ATP: Chemiosmosis uses the energy of the electrochemical proton gradient across mitochondria membrane and produces ATP through oxidative phosphorylation. In this process free energy from series of redox reactions that make up electron transport chain is used to pump hydrogen ions across membrane establishing electrochemical gradient. Hydrogen ions in the matrix can only pass through the inner mitochondrial membrane through ATP synthase. As protons move through ATP synthase ADP is turned to ATP.

D) reduction of NAD+: Reduction of NAD+ occurs in Glycolysis in cytosol and Citric acid cycle in mitochondria

E) oxidation of NADPH :

F) oxidation of water

2.) The equilibrium distribution of a molecule acrossa membrane depends on the chemical gradient concentration and on memvrane potential. An uncharged molecule doesnt experience the membrane potential or electrical gradient awhen it is at same concentration nd will be at equilibrium on both sides of the meF) mbrane. A charged molecule responds to both components of concentration and membrane potential gradients and will distribute accordingly. Gor example K+ ions are at equilibrium distribution across the plasma membrane even they are more concentrated inside the cell. The difference in concentration is balanced by the membrane potential which posess the movement of cations across the cell.

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