Transport into and out of mitochondria

Mitochondria possess an inner and an onter membrane (see Fignre 9.1). The outer membrane contains proteins known as porins that act as pores for entry into the inter-membrane 

The transport is, therefore, electronentral. If the transport does, in fact, resnlt in the transfer of a net charge, it is termed electrogenic (e.g. the proton pnmps in the inner membrane). 

The three major fnels for oxidation within the mitochondria are pymvate, fatty acids in the form of fatty acyl-camitine, and glntamine - all of which require specific transport processes (Fignre 9.14). The hydrogen atoms in the NADH in the cytosol comprise a fonrth fnel that mnst also be transported into the mitochondria for oxidation. 

The conversion of glncose to pymvate (glycolysis) generates NADH from NAD+ in the cytosol so that, to maintain 

Glutamine, which has no net charge, is transported by a specific glutamine transporter. 

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In the absence of a demonstrable yeast iron-storage protein (ferritin), we have to recognize that, despite our substantial advances in understanding iron uptake in yeast, we know practically nothing about intracellular iron metabolism - except that is for iron transport into, and out of, mitochondria. 

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