Control of Energy Flashcards
(15 cards)
What are the primary sources of energy for the body?
Carbohydrates provide glucose, which is the primary fuel for the body.
Fats provide fatty acids and ketone bodies.
Proteins provide amino acids.
Why is glucose the first choice fuel for all organs?
Glucose is the primary fuel for the body as it can be easily metabolized by various organs for energy. Red blood cells rely solely on glucose for energy, and they require a constant supply to function properly.
What role does the liver play in metabolic regulation?
The liver is a focal point for metabolic regulation. It is enzymatically rich and plays a key role in breaking down or synthesizing carbohydrates, lipids, and amino acids. It also stores glycogen for energy.
What is the primary energy store in adipose tissue?
Adipose tissue primarily stores energy in the form of triglycerides, which can be broken down into fatty acids and glycerol when needed.
Which tissue has a high energy demand and relies heavily on glucose?
Neural tissue has a high energy demand, primarily relying on glucose. It does not store energy, so low glucose levels can result in unconsciousness.
What is the difference between the absorptive and post-absorptive states?
Absorptive state: This occurs immediately following a meal, during which nutrients are absorbed and stored as energy. Insulin is the primary hormone.
Post-absorptive state: This occurs when nutrients are no longer being absorbed, and the body relies on internal energy reserves. Glucagon is the primary hormone during this state.
What is the role of insulin during the absorptive state?
Insulin plays a key role in promoting energy storage during the absorptive state. It encourages the storage of glucose as glycogen in the liver, the storage of fat in adipose tissue, and the uptake of glucose into cells.
How does the insulin receptor function?
The insulin receptor is a tyrosine kinase receptor that detects insulin in the body. It stimulates the translocation of GLUT vesicles to the membrane, facilitating glucose uptake. GLUT 2 vesicles are found in the liver and pancreatic beta cells, while GLUT 4 vesicles are found in adipose tissue and muscle.
What happens when the glucagon receptor is activated?
When the glucagon receptor (GCGR) is activated in the post-absorptive state, it triggers an enzyme cascade that results in the conversion of glycogen to glucose, thereby raising blood glucose levels.
What process breaks down glucose into pyruvate, and where does this occur?
The process of glycolysis breaks down glucose into two molecules of pyruvate. This occurs in the cytoplasm of the cell.
What are the two pathways that pyruvate can take after glycolysis?
Aerobic metabolism: Pyruvate is converted to acetyl CoA and enters the mitochondria for further energy production.
Anaerobic metabolism: In the absence of oxygen, pyruvate is fermented into lactate, which is then transported to the liver for gluconeogenesis.
What happens to glucose when it is used up?
When glucose is used up, the body initiates processes like glycogenolysis (breaking down glycogen to release glucose) and glycogenesis (creating glycogen from glucose to store it) to maintain blood glucose levels.
What is lipolysis, and when does it occur?
Lipolysis is the breakdown of stored triglycerides into glycerol and fatty acids. It occurs when glucose reserves are depleted, and the body switches to fat stores for energy.
What happens to the fatty acids released during lipolysis?
he fatty acids undergo beta-oxidation in the mitochondria to form acetyl CoA, which then enters the Krebs cycle for energy production. If necessary, ketogenesis occurs, producing ketone bodies that can be used as an alternative energy source.
How does the body store excess energy after ATP production?
After sufficient ATP is produced, the body stores excess energy through lipogenesis, where acetyl CoA is converted into fats such as cholesterol, steroids, and phospholipids.
