Flashcards in ATP production Deck (19):
True or False: Lipids consumed in the diet can be used as an immediate source of energy.
True, they can also be stored in adipose tissue for future use.
True or False: Triglycerides are continuously stored and broken down depending on the immediate energy needs of the body.
True. When the energy in the diet equals the body's energy requirements the net amount of stored triglycerides does not change.
What is the first step of the process to produce ATP from triglycerides?
Beta-oxidation, the carbon chain of fatty acids is broken into 2-carbon units that form acetyl-CoA and release high-energy electrons.
What is oxaloacetate?
A 4-carbon molecule derived from carbohydrates.
What must the acetyl-CoA combine with to enter the citric acid cycle?
An oxaloacetate to form a 6-carbon molecule called citric acid.
Where are the high-energy electrons released in beta-oxidation and the citric acid cycle shuttled to?
The last stage of cellular respiration - the electron transport chain.
What does the electron transport chain do?
Molecules in the chain accept electrons and pass them down the chain until they combine with oxygen to form water. The energy in the electrons is used to generate ATP.
What does the reactions of the citric acid cycle produce?
Carbon dioxide (one carbon at a time).
What happens when there is insufficient oxaloacetate?
Fatty acids cannot enter the citric acid cycle and ketone bodies form.The glycerol from triglyceride breakdown can be used to produce ATP or glucose through gluconeogenesis.
True or False: Glycerol makes up a large portion of the carbon in a triglyceride molecule, so lots of glucose comes from triglyceride breakdowns.
False. Glycerol makes up a small portion and the amount of glucose produced is small.
What happens when carbohydrate is available for triglyceride metabolism?
Acetyl-CoA can enter the citric acid cycle, producing energy and carbon dioxide. The cycle can continue for as long as there is carbohydrates.
What happens when carbohydrate is unavailable for triglyceride metabolism?
Ketones are produced which can be used for energy, excreted in urine, or accumulated in blood.
Where does excess energy consumed as carbohydrates or protein first go?
To the liver where it can be inefficiently synthesized into fatty acids and transported to adipose tissue.
How much can fat cells increase in weight by?
50 times increase.
What happens when fat cells reach their maximum weight?
New fat cells can be synthesized.
What can use ketones as an energy source?
Muscles and adipose tissue.
How much of the body's energy needs can be provided through ketones after days of starvation?
50%, the other half must be from glucose.
What does the body break down to convert to glucose for energy for the brain?