After the liver's glycogen supply runs out, several metabolic processes can occur. The correct options from your list include:
-
Certain amino acids are turned into pyruvate and then glucose. - This process is part of gluconeogenesis, where certain amino acids can be converted into glucose once glycogen stores are depleted.
-
The body metabolizes fatty acids. - Once glycogen stores are depleted, the body starts to utilize fatty acids as an alternative energy source through a process called beta-oxidation.
The incorrect option is:
- Insulin begins to break down protein to convert into glucose. - Insulin does not promote the breakdown of protein for glucose production. In fact, insulin typically helps to store nutrients and inhibit gluconeogenesis when blood glucose levels are high. In a fasting state or when glycogen is depleted, insulin levels drop, allowing for the processes of gluconeogenesis and fatty acid metabolism to occur.
So, the correct selections are the first and third options.