Term
| During cellular respiration ____ is oxidized, and ____ is reduced. |
|
Definition
|
|
Term
| Catabolic pathways yield useable energy due to ___. |
|
Definition
|
|
Term
|
Definition
the reduced form of NAD+, which passes the electrons to the electron transport chain
|
|
|
Term
| What are the 3 metabolic stages of cellular respiration? |
|
Definition
Glycolysis (occurs in cytosol, breaks down glucose into 2 molecules of pyruvate)
The citric acid cycle (occurs in mitochondrion, completes the breakdown of glucose)
oxidative phosphorylation (occurs in mitochondrion, is driven by the electron transport chain and generates ATP) |
|
|
Term
|
Definition
the inner membrane folds of mitochondria
provide a large surface area |
|
|
Term
|
Definition
| contains hundreds of enzymes, including those required for the oxidation of pyruvate and fatty acids and for the citric acid cycle |
|
|
Term
| Where does the Krebs' Cycle occur? |
|
Definition
| in the mitochondrial matrix |
|
|
Term
| What is the net result of one turn of the citric acid cycle? |
|
Definition
3 NADH
1 GTP
1 FADH2
2 CO2 |
|
|
Term
| Cellular respiration is an ____ reaction. |
|
Definition
| exergonic meaning it produces energy |
|
|
Term
|
Definition
| Glycolysis involves the breaking down of glucose molecules from carbohydrates into molecules of pyruvate, which will continue on to the Krebs Cycle. This process occurs in the cytosol of the cell and can proceed regardless of the presence of oxygen. In the first stage of glycolysis, energy is actually used to phosphorylate the 6-carbon glucose molecule. This means that a phosphate is taken from ATP (which becomes ADP) and added to the glucose molecule. This addition of phosphate makes the molecule much more chemically reactive. The position of the glucose molecule is changed, so that it becomes its isomer, fructose. An enzyme then cuts the molecule apart, producing two 3-carbon molecules of pyruvate. Through several more steps, catalyzed by several different enzymes, the phosphate groups are removed and these pyruvate molecules are ready to enter the Krebs Cycle. The reactions of glycolysis produces a net gain of 2 ATP molecules, as well as a release of 2 water molecules and 2 NADH molecules (these are another type of energy-rich molecule) |
|
|
Term
|
Definition
| As pyruvate is being shuttled from the cytosol to the interior of the mitochondrion, a microenzyme removes one carbon and two oxygens from each molecule, producing Aceytl CoA. This two-carbon sugar that actually enters the Krebs Cycle. The Krebs Cycle is a series of steps, catalyzed by enzymes, which completely oxidize the Aceytl CoA molecule. The Krebs Cycle is an aerobic process, meaning it needs oxygen to function. One complete turn of the Krebs Cycle must occur to produce: 2 carbon dioxide molecules, 3 NADH molecules, 1 ATP molecule and 1 FADH2 molecule (yet another energy-yielding molecule). |
|
|
Term
| Explain the electron transport chain. |
|
Definition
| Very little energy has been produced during glycolysis and the Krebs Cycle. Most of the energy locked in the original glucose molecule will be released by the electron transport chain and oxidative phosphorylation. The electron transport chain is a network of electron-carrying proteins located in the inner membrane of the mitochondrion. These proteins transfer electrons from one to another, down the chain, much in the way a bucket brigade passes buckets of water. These electrons will eventually be added, along with protons, to oxygen, which is the final electron acceptor. This produces water, but does not produce any ATP. The ATP is actually produced by a proton motive force. This force is a store of potential energy created by the gradient formed when hydrogens (protons) are moved across a biological membrane. Therefore, the electron transport chain merely produces a gradient through which ATP can be made (this is known as chemiosmosis). The electron transport chain produces the remaining 32-34 ATP. |
|
|
Term
| During respiration, most energy flows in what sequence? |
|
Definition
glucose to
NADH to
electron transport chain to
proton-motive force (gradient)
to ATP |
|
|
Term
| How many ATP are produced by Cellular Respiration |
|
Definition
|
|
Term
|
Definition
| prevents a cell from wasting resources by synthesizing more product than is needed |
|
|
Term
| What is the main enzyme in cellular respiration? |
|
Definition
P-fructokinase (PFK)
[image] |
|
|
