In: Biology
1.Even when the activation energy is lowered, endergonic reactions are not spontaneous. What else can enzymes do that causes endergonic reactions to go forward?
2.It is usually very important for eukaryotic cells to obtain oxygen and remove carbon dioxide. However, no transport proteins for these molecules exist in the membrane. Why?
3.How does the glucose cotransporter force glucose to move up its concentration gradient and into the cell?
through diffusion of glucose |
|
through diffusion of sodium ions |
|
through hydrolysis of ATP |
|
through osmosis |
1. The activation energy of a chemical reaction is related to its rate. If activation energy is high, the chemical reaction will be slow. This is because molecules can only complete the reaction once they have reached the top of the activation energy barrier. Molecules that catalyze biochemical reactions are called enzymes. They lower the activation energy of reaction inside cell. Reactions with a positive ∆G , on the other hand, require an input of energy and are called endergonic rns . In this case, the products, or final state, have more free energy than the reactants, or initial state.An endergonic reaction will not take place on its own without transferring energy into the reaction or increase of entropy somewhere else.endergonic reactions are coupled to exergonic reactions, making the combination energetically favorable.
2. In eukaryotic cells the enzymes that catalyze the steps involved in respiration and energy conservation are located in rod-shaped compartments called mitochondria.
3. Through diffusion of Na+ ions
The Na+/glucose cotransporter ,found in the apical membrane of epithelial cells of the small intestine and renal proximal tubules, utilizes the Na+ electrochemical gradient to drive the uphill transport of glucose into the cell.