Metabolism Flashcards
Energy Intake/Absorptive Efficiency
oxidation of carbon and hydrogen in dietary molecule; carbohydrates, protein, and fat
Energy out is used for
membrane transport, mechanical work, and chemical work; synthesis of short-term energy storage (ATP) and long term storage (glycogen)
Fed State
following a meal, when the products of digestion are being absorbed, used, and stored
is the fed state anabolic or catabolic
anabolic; synthesis of complex molecules from smaller molecules
What occurs in glucose metabolism
most plasma is used for immediate energy production, some is stored as glycogen
What is liver glycogen used for?
regulating blood glucose
What is muscle glycogen used for?
to power muscle contraction
Where is glycogen stored?
in the liver and muscles
Excess glucose turns into lipids through what process
lipogenesis
What will happen if you eat excess protein?
the amino acid will go through gluconeogenesis and turn into glucose
Where is lipoprotein lipase found?
In the capillary beds surround adipose tissue
What kind of lipid is used for immediate energy production?
free fatty acids
What is the fasted state?
once all nutrients from a meal have been diegsted, absorbed, and distributed to various cells; plasma glucose begins to fall
is the fasted state anabolic or catabolic?
in a net catabolic state; breakdown of complex molecules into smaller molecules
What is the first to occur in the fasted state?
liver glycogen becomes glucose
what happens second in the fasted state
adipose lipids become free fatty acids and glycerol that enter blood
What happens third in the fasted state?
muscle glycogen can be used for energy, muscles use fatty acids and break down their proteins to amino acids that enter the blood
What is the last thing to happen in a fasted state
the brain uses glucose and ketones for energy
What does the muscle lack that the liver has that helps the liver make glucose?
glucose-6-phosphatase
What does glucose-6-phosphatase do?
it removes a phosphate group from glucose-6-phosphate which creates glucose
Does the muscle make glucose?
Not directly, the muscle goes through glycolysis and makes pyruvate and lactate which goes to the liver to be made into glucose (gluconeogenesis)
What happens during the fasted state, when the fat storage is being targeted?
perilipin gets phosphorylated so that the fat can be accessed, hormone-sensitive lipase gets activated by the phosphorylation as well and digested the fat into free fatty acids and glycerol
What signal activates perilipin and hormone-sensitive lipase to begin to break down the fats?
a high catecholamine to low insulin ratio
What are 3 ways that skeletal muscle contributes to glucose homeostasis during a fasted state?
glucose sparing, Cori cycle, breaking down proteins and then turning those into glucose (glucogenesis)
What occurs during glucose sparing
the skeletal muscle is dependent on fatty acids for an energy source (instead of glucose)
What occurs during the Cori cycle
glycogen is converted to pyruvate and lactate through glycolysis and goes to the liver to be converted to glucose (can be brought back to the muscle so it is considered a cycle)
How does skeletal muscle break down proteins and turn it into glucose?
gluconeogenesis
What does the brain use as energy molecules
glucose and ketones
insulin
hormone of energy usage and storage
glucagon
hormone of energy release
alpha cells secrete
glucagon
beta cells secrete
insulin
metabolism is controlled primarily by
the insulin-glucagon ratio
What signals stimulate insulin secretion?
high levels of plasma glucose, and high level of plasma amino acids
What signals stimulate glucagon secretion
low level of plasma glucose, high level of plasma amino acids (you break down amino acids when you are in a fasted state for long enough to go through gluconeogenesis, or if you eat a lot of protein you still see glucagon release because you will want to turn it into glucose by gluconeogenesis)
What dominates in a fed state
insulin
What dominates in a fasted state
glucagon
Insulin stimulates what
glucose oxidation, glycogen synthesis, fat synthesis, and protein synthesis
Glucogon stimulates
glycogenolysis (glycogen to glucose), gluconeogenesis, and ketogenesis
