Quiz 14 Review Flashcards
How are ATP formed?
Electron transport system –> phosphorylated ADP (doesn’t have to be in electron transport so mainly just phosphorylation of ADP)
From which part of the mitochondria do NAD and FAD get pumped from and where are they pumped to?
During electron transport, H+ are taken up and accumulate in the intermembrane. Once the concentration of H+ is greater than the mitochondria matrix the are pumped from the intermembrane to the mitochondrial matrix.
What is the purpose of the TCA cycle as defined in class?
a. The oxidation of Acetyl-CoA
De novo synthesis of fatty acids in the fat cell starts with acetyl-CoA. Contrast the steer and market hog above in how the fat cell gets the acetyl-CoA.
-
Ruminants (cow)
- ferment dietary glucose to VFA, principally acetate
- derived acetate is converted to acetyl-CoA in cytosol of fat cells which can directly enter fatty acid biosynthesis
- ferment dietary glucose to VFA, principally acetate
-
pig-
- absorb their glucose
- glycolysis produces pyruvate in cytosol; the acetyl-CoA is generated in the mitochondrea
- acetyl Co-A in mitochondria then shuttled out to form citrate
The TCA cycle occurs in the cytosol. True or False? If false, what cellular compartment should it be?
a. In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion
In which cellular organelle does the electron transport system function?
Mitochondria
Now that the fat acids from the diet and from de novo synthesis are stored in the fat cells as TAG, they are available for the animal to use in the event of feed restriction and fasting. Moving the fatty acids out of the fat cell is referred to as “mobilization of fatty acids” and involves more lipases. What are the three lipases involved in this process that occurs in the fat cell?
- Mobilization of FA lipases:
- Adipose Triglyceride Lipase
- Hormone-Sensitive Lipase
- MAG Lipase
How does diabetes affect metabolism in liver cell
Insulin decreases.
Nutrient availability is high, but cells cannot respond without insulin.
Liver cell:
- Gluconeogenesis increases: blood glucose increases.
- B-oxidation increases.
- Ketone production increases (50-100 fold).
- Blood pH decreases: ketoacidosis occurs.
What is the purpose of the TCA cycle?
Oxidation of Acetyl- CoA
Define its purpose -what is produced by each cycle?
- fatty acid oxidation
To produce acetyl CoA, NADH, and FADH2
What is pyruvate converted to that starts the TCA cycle?
a. The first reaction occurs from condensation of acetyl-CoA with oxaloacetate to form citrate
What is produced for a Fatty acid with a given number of C-atoms:
10 C/2=5 C, and 5 Acetyl- CoA
5-1=4
4 NADH
4 FADH2
Wha is the purpose, as stated in class on the slides used to illustrate this process, of this reaction sequence? Also, in what part of the cell will this reaction sequence take place?
- purpose of b-oxidation:
- produce acetyl-CoA
- NADH
- FADH2
The fatty acids in #16 will be transported through the blood as free fatty acids and will be taken up by cells, such as muscle cells, cardiac muscle cells, and other, for use as a substrate for ATP generation. What is the first reaction that occurs involving fatty acids (carboxylic acids) that is commonly referred to as “fatty acid activation”?
- converts the carboxyl to the CoA-thioester
- Defined:
- The addition of CoA to the fatty acid that prepares the fatty acid for further metabolism.
What else is produced as part of this process that will be used later in ATP production?
NADH
How many ATP can be produced by the interaction of one FADH2 with the electron transport system?
2 ATP are possible
Even though one NADH is produced during glycolysis, this NADH is not going to result in production of the same number of ATP that NADH that occurs from the TCA cycle will. Why is this?
Because NADH does not freely move from the cytosol to the mitochondria
In a fasted animal how is metabolism characterized in fat cells
Insulin decreases.
Catecholamine effectiveness increases.
Fat cell:
- Catecholamines increase: cAMP increases: Protein kinase increases: HSL activity increases: fatty acid hydrolysis increases.
- Glycerolipid biosynthesis decreases.
- ACC activity decreases: fatty acid synthesis decreases.
- LPL activity decreases = Fatty acid release from cells increases.
- Glycerol release increases: transported to liver for gluconeogenesis.
For a fatty acid that contains 6 carbons, what and how many of what is produced (that will be used in the overall process for ATP production will occur when this fatty acid is completely oxidized? (Know how to solve, as there will be different C # given)
- Split C# in 1/2= # of Acetyl-CoA–> subtract 1 from this number to get FADH2 and NADH #’s
-
Produces 3 Acetyl-CoA and 2 FADH2 and 2 NADH
- acetyl CoA# x10
- for each FADH2, two ATP are produced
- for each NADH, three ATP are produced
- SO multiply it out.
- (3x10)+(2x2)+(2x3)= 40ATP
How much ATP from the complete oxidation of a single glucose molecule is possible?
36 ATP
How many ATP can be produced by the interaction of one NADH with the electron transport system?
3 ATP are possible
What molecule serves as the terminal electron acceptor of the electron transport system?
Oxygen
In addition to the NADH that occurs from glycolysis, what general reactions or cycles will result in production of the remaining NADH associated with the complete oxidation of glucose?
TCA (Tri Carboxylic Acid) Cycle
How many ATP possible in fatty acid oxidation?
Depends on the number of H in each fatty acid
What molecule that occurs in de novo synthesis of fatty acids in the fat cell will regulate fatty acid oxidation when this molecule is produced in the muscle cell? Will it activate or inhibit? How?
malonyl-CoA by blocking the uptake of fatty acids into the mitochondria
How many ATP can be produced by the complete oxidation of one glucose molecule?
Total 36 ATP per glucose molecule
What else is produced as well as lost during this process?
Produced=NADH
Lost= CO2
This TAG transport lipoprotein you identified above will be transported through the blood stream to sites such as fat cells, muscle cells, and other cells. In fat cells an enzyme is synthesized and secreted to the outside of the cell where it is anchored to the cell. This enzyme catalyze hydrolysis of TAG from circulation so that the fatty acids can be transported into the cell. Which enzyme is this?
-
Lipoprotein lipase:
- made by the particular cell, and secreted where it anchors itself just outside the cell.
- When chylomicrons, or other circulating triaglycerols arrive at the cell, lipoprotein lipase catalyzes hydrolysis of fatty acids, which are taken up by the cell
What is fatty acid activation?
Arrive at the cell and enter the cytosol to form fatty acid CoA <- yes! To get there converts carboxyl to thioester which is the bond of the fatty acid to Co-ASH
Based on what powers ATP production in the electron transport system, what will the fatty acid have more than glucose that makes it a better storage form of potential energy than glucose?
more H+ ions
What characterizes the “energy charge” of the cell?
Cellular level of ATP and NADH indicate the energy level
High ATP:ADP and NADH:NAD decreases activity of glycolysis and TCA Cycle
Fatty acid biosynthesis:
Define it
Producing new fatty acids
Acetyl-CoA–>Malonyl-CoA–>anchored to fatty acid synthase
In which complex of the electron transport system does NADH interact?
NADH transfers its electrons and H+ through each complex (I,II,III)
How does is start when pyruvate enters
Pyruvate converts to Acetyl-CoA then: Condensation of Acetyl- CoA with oxalosuccinate to form citrate
Now that you have looked up the purpose of the TCA cycle and what pyruvate is converted to in this process, you (hopefully) recalled Acetyl-CoA. What does Acetyl-CoA condense with to produce that specific TCA from three questions ago?
a. Acetyl-CoA condenses with Oxalosuccinate to form citrate
What is the largest fatty synthesized by fatty acid biosynthesis?
Palmitic acid
Each time NADH, FADH2, and oxygen interact with the electron transport system, what gets “pumped” from one part of the mitochondria to another part of the mitochondria?
Hydrogen Ions (H+)
How can lactation in over-finished dairy cows result in similar conditions to diabetes?
Lactation hormone cause reduced fat deposition in fat tissue
Increased fatty acid mobilization from fat cells -> Stimulate lipolysis so much more fatty acid released compared to good body condition cow, hits liver and liver can’t deal with that level of fatty acids = continued oxidation and accumulation causes ketoacidosis
Nutrient and body energy stored support the mammary gland need for milk production (fatty acids)
Over-condition (fat) dairy cows have problems
What general reaction do lipases catalyze?
Hydrolysis of carboxyl ester (I’m pretty sure that’s right, but in general they catalyze the hydrolysis of fatty acids)
Which enzyme catalyzes the reaction above? (de novo fatty acid synthesis involves carboxylation of acetyl-CoA–> malonyl-CoA)
acetyl- CoA carboxylase
How can multiple fetuses in ovine ewes cause a form of pregnancy toxemia?
Ketone production can become excessive if lactation or pregnancy places too many demands on the available glucose -> fatty acid oxidation synthesis increases in response = ketone production increases
Huge draw of blood glucose from ewe when they reach a certain size
The draw maternal glucose blood glucose just drops dramatically, and insulin secretion is stimulated by blood glucose levels = insulin secretion drops
For triacylglycerols (TAG) consumed by all animals, where in the animal will digestion begin?
- Non- ruminants: stomach
- Ruminant: Rumen
Hopefully by now you have recognized a pattern regarding getting TAG from a feed source to TAG as a stored source of fatty acids by the animals: Diet TAG -> intestinal FA’s -> intestinal cell TAG -> blood circulation TAG -> cell surface TAG -> cell surface FA’s -> intracellular FA’s -> stored TAG in fat cell. For the non-ruminant, there are four lipases involved in the above process. What are they (again)?
- lingual lipases
- Gastric Lipases
- Pancreatic lipases
- colipase Lipase