Lecture 9 Flashcards
What does the body need to use every day regardless of diet?
A certain number of ATP’s
ATP (adenosine triphosphate) is the energy currency of the cell.
What happens when there is a surplus of carbohydrates?
The body undergoes digestion, absorption, and assimilation, with excess glucose being stored as glycogen
Glycogen is stored in the liver and skeletal muscles.
What is Glycogenesis?
The process of converting glucose into glycogen
Glycogen serves as a stored form of energy.
What is the limit of glycogen storage in the body?
About 2 lb
2 lb of glycogen can attract about 8 lb of water, totaling 10 lb of lean weight.
What happens to excess glucose after glycogen stores are full?
It is converted into fatty acids and then stored as fat
Fat is stored in Adipocytes (fat cells)
There is no limit to how much fat can be stored in the body.
How is dietary fat metabolized in the body?
Fat is either hydrolyzed into fatty acids and glycerol for ATP production or stored as is
Fat can only be metabolized aerobically.
What is the caloric density of fat?
9 kcal per gram of fat
Fat is lighter than water but provides high energy.
What happens when there is a surplus of dietary protein?
Extra amino acids are brought into the body
Amino acids are meant for building new proteins, not as fuel.
What are the main options for cells when using amino acids?
- Use amino acids to build new proteins
- Use amino acids for non-protein-building purposes (i.e. energy production/conversion to glucose)
Not used as fuel.
What is deamination?
The process of removing an amino group from an amino acid
This yields ammonia, which is converted to urea for excretion.
What hormone is primarily produced during chronic stress?
Cortisol
Cortisol has multiple effects including increasing blood glucose and suppressing immune function.
What is the overall effect of a caloric deficit on the body?
Muscle mass is broken down to produce glucose, which is then converted into fat.
To sum up, hormonally, when you are starving:
∙ your cortisol goes up and
∙ Your leptin goes down.
This counteracts the goal of fat loss during dieting.
True or False: The body stores amino acids for future use.
False
Cells do not store amino acids; they use them as needed.
What is the average protein requirement for a person?
About 1 gram of protein per kg of body weight
What happens to excessive urea production in the body?
It may cause dehydration as kidneys produce extra urine to excrete it
This can lead to kidney function issues over time.
Fill in the blank: The process of converting pyruvate into fatty acids is called _______.
Lipogenesis
This occurs after glycolysis when there is excess glucose.
What happens to excess dietary fat if it is not used for energy?
It is stored in adipocytes as is
Storing fat does not require energy expenditure.
What is the role of cortisol?
It is the number one hormone produced during chronic stress. It is a steroid hormone, normally produced in the adrenal glands, which has multiple functions:
- It increases blood glucose by inducing Gluconeogenesis
- It increases the production of insulin, which then takes the glucose out of the bloodstream and puts it into the body’s cells; and since the cells don’t need that much glucose for ATP, they end up turning all that extra glucose into fat.
Cortisol suppresses immune function and can spead up the aging process.
What is Leptin?
A hormone produced by fat cells that regulates metabolic rate and hunger.
What happens to Leptin levels when dieting?
Leptin levels decrease, slowing metabolic rate and increasing hunger.
What happens to glycogen stores during the first days of dieting?
Glycogen stores are broken down into glucose.
What is the initial weight loss composition when starting a diet?
It’s mostly water weight and glycogen loss.
What metabolic state occurs when the body runs out of glycogen?
Ketosis.
What do muscle cells use for energy when glycogen is depleted?
Fats.
