Finally, cells control metabolic processes by restricting the location of enzymes and enzyme complexes to certain locations within the cell. In some cases, enzymes are incorporated into specific membranes or fluid-filled spaces in the cell. Some of the enzymes for cellular respiration are inside the mitochondria, whereas others are dissolved in the cell’s cytoplasm. Thus, the rate of the inner mitrochondrial reactions can be controlled by restricting the movement into the mitochondrion of intermediates that are formed in the cytoplasm
What this means is that your body's metabolic process is controlled on the cellular level: your cells control your metabolism. The way they do this is by restricting where enzymes and enzyme complexes may go. Enzymes may become part of cells' membrane or part of fluid-filled sacs in the cell.
An example is given from the process of cellular respiration in which enzymes are (1) inside the mitochondria or (2) liquefied in the cytoplasm.
The point is then made that cellular respiratory metabolic rates in the inner mitochondria may be controlled by the number of enzymes allowed to enter and be liquefied in the cytoplasm: few enzymes in and liquefied in the cytoplasm, the lower the respiratory metabolic rate; the more enzymes allowed and liquefied in the cytoplasm, the higher the respiratory metabolic rate.
This is also a method of internal control over metabolism, which is a major part of all organic life. Without a method of slowing or speeding metabolism, respiration and storage of glucose could get out of control. Many cells have their metabolism regulated by enzymes.
Inside the cell is a fluid known as cytoplasm. Swimming around inside the cytoplasm are free enzymes, and groups of enzymes inside their own covering, or a little bag known as a vacuole. Some of these enzymes and vacuoles are created by the cell itself. The mitochondria are a special form of vacuole, which produces energy for the cell by the process known as respiration, which is one of the metabolic processes a cell performs.
What the paragraph is saying is that by the cell itself restricting the movement of the free enzymes, or the little bags of enzymes swimming around the cytoplasm, the rate of respiration by the mitochondria can be decreased. Conversely, by the cell allowing for increased movement of the enzymes or vacuoles, the respiration rate can be increased.
So the cell itself can regulate some of its metabolic processes.
Please be sure to understand the definitions of all of the italicized words.
It's discussing the location of enzymes within the cells and how the enzymes move or change location within the cells, which impacts the function of the enzymes. It might be helpful to go phrase by phrase and draw yourself a picture, labeling symbols to be the different types of structures and using arrows to show how they relate to each other.
The paragraph deals with the role of enzymes in the part known as mitochondria. It talks about the different functions of enzymes that there are and the different ways in which they work as part of the process and how they help it to occur. You might benefit from looking up the meaning of key words such as mitochondria to help you in understanding this passage.