Term
| During times of low levels of glucose, glucose can be synthesized from what 3 sources? |
|
Definition
1. the end products of glycolysis
2. amino acid carbon skeletons (after deamination)and
3. Citric Acid Cycle intermediates |
|
|
Term
| Can lipids be used to synthesize glucose directly? |
|
Definition
| no, lipids are broken down to Acetyl-CoA and fed through the citric acid cycle to provide engergy or needed intermediates |
|
|
Term
| The gluconegenic pathway typically starts with what substrate? |
|
Definition
|
|
Term
| What is the function of Pyruvate Carboxylase in the gluconeogenic pathway? |
|
Definition
| It condenses pyruvate and bicarbonate to form oxaloacetate |
|
|
Term
| What two pathways both use Pyruvate Carboxylase? |
|
Definition
| Glycolytic and gluconeogenesis pathways |
|
|
Term
| What energy source is used for the enzyme action of Pyruvate Carboxylase? |
|
Definition
| Pyruvate Carboxylase hydrolises ATP --> ADP + Pi |
|
|
Term
| What is the function of biotin in gluconeogenesis? |
|
Definition
| It is a CO2 carrying cofactor |
|
|
Term
| Where does gluconeogenesis occur? |
|
Definition
| Steps 1&2 occur in the mitochondria and Steps 3&4 occur in the cytoplasm |
|
|
Term
| How many enzymes are involved in gluconeogenesis? |
|
Definition
| 4 - Pyruvate Carboxylase, Phosphoenolpyruvate Carboxykinase, Fructose-1,6-Biosphosphatase, & Glucose-6-Phosphatase |
|
|
Term
| Which steps in glucneogensis liberate energy? |
|
Definition
|
|
Term
| What is the function of Phosphoeolpyruvate Carboxylkinase? |
|
Definition
| It transfers a phosphate group to oxaloacetate via hydrolysis of GTP resulting in Phosphenolpyruvate and GDP+Pi |
|
|
Term
| How is Posphoenolpyruvate transported to the cytoplasm? |
|
Definition
| It is transported via the Phosphoenolpyruvate Transporter |
|
|
Term
| If Phosphoenolpyruvate carboxykinase is in the cytoplams, how is it useful? |
|
Definition
| It can still function if the Malate Shunt or the Aspartate Shunt transport oxaloacetate from the mitochondria to the cytoplasm |
|
|
Term
| What is the function of Fructose-1,6-Bisphosphatase in gluconeogenesis? |
|
Definition
| It converts Fructose-1,6-Bisphosphatase into Glucose-6-Phosphate and releases Pi |
|
|
Term
| What is the function of Glucose-6-Phosphatase? |
|
Definition
| It converts Glucose-6-Phosphate into Glucose and releases Pi |
|
|
Term
| When is propionate a major starting point for gluconegenesis? |
|
Definition
|
|
Term
| How is plant material converted to propionate? |
|
Definition
| Celluse (Plant carbohydrates) are digested/broken down by microbes in hte rumen of mammals (chewing their cud) |
|
|
Term
| How is propionate useful in gluconeogenesis? |
|
Definition
| When absorbed, it is ran through the TAC cycle (Succinyl-CoA->TAC) and gluconeogenesis to provide glucose |
|
|
Term
| Where is propionatre found in humans? |
|
Definition
| it is also a byproduct of odd-fatty acids in humans (it can then be converted into glucose) |
|
|
Term
| What is the "control" molecule for gluconeogensis? |
|
Definition
|
|
Term
| How is a futile cycle prevented in gluconeogenesis? |
|
Definition
| fructose-2,6-phosphate allosterically binds to turns on and off the pathways of glycolysis and gluconeogenesis |
|
|
Term
| With high levels of fructose-2,6-phosphate, how does it bind in the cell? |
|
Definition
| it binds to allosterically ACTIVATE phosphofructokinse (starting glycolysis) and allosterically INHIBITS fructose-1,6-bisphosphatase (inhibits gluconeogenesis) |
|
|
Term
| List an advantage to aerobic and anaerobic respiration in cells. |
|
Definition
Aerobic - gives more energy
Anaerobic - works faster |
|
|
Term
| When would muscles typically run anaerobically? |
|
Definition
| When there is a great energy need |
|
|
