Chapter 23- Metabolism Flashcards
What is a calorie?
The amount of heat required to raise the temperature of one gram of water by one degree Celsius
What is metabolism?
The sum of the bodies chemical reactions
What is catabolism? What are 3 nutrients that are catabolized to generate ATP?
A series of reactions in which one substance is broken down into smaller parts
Releases energy to be used for other processes
Glucose
Fatty acids
Amino acids
What is anabolism? What are some of the larger macromolecules?
Series of reactions in which smaller molecules are combined to make larger molecules such as:
Proteins
Nucleic acids
Lipids
Carbohydrates
What is anaerobic catabolism? Where does it occur?
Process that releases only a low amount of ATP
Occurs in cytosol
What is aerobic catabolism?
Process that releases a large amount of APT
occurs in the mitochondria
What is glycolysis?
Break down of glucose to pyruvic acid
Occurs in cytosol
No O2 required
Nets 2 ATP, pyruvate and Acetyl-CoA
What is gluconeogenesis?
Synthesis of glucose from noncarbohydrate precursors such as amino acids
What is glyconeogenesis?
Formation of glycogen from glucose
What is glycogenolysis?
Break down of glycogen
What is lipolysis?
An enzyme cataloged process that liberates fatty acids and glycerol
What is ketogenesis?
A process that occurs primarily in liver cells in the mitochondrial matrix In which ketone bodies are produced through the breakdown of amino acids and fatty acids
This supplies energy during times of caloric restriction
What are ketone bodies?
Molecules produced by the liver from fatty acids during periods of low food intake or starvation When glucose is in short supply
What organ cannot metabolize ketone bodies? Which organs can?
The liver cannot metabolize them
Skeletal muscle the brain and the heart can metabolize them
Describe the absorptive state?
Time immediately following a meal when the body is absorbing nutrients
Oxidation of nutrients occurs to provide the cells with fuel, glucose and triglycerides are stored
Describe the post absorptive state
Period in which no nutrient absorption is occurring. Body relies on stored nutrients
What is the dominant hormone in the absorptive state?
Insulin
What are the dominant or major hormones in the post absorptive state?
Glucagon and glucocorticoids
How are lipids transported and distributed in the body?
They are packaged with cholesterol into Lipoproteins. Lipoproteins provide transportation in the bloodstream
What are the five classes of Lipoproteins?
Chylomicron Very low density lipoprotein Intermediate density lipoprotein Low density lipoprotein High density lipoprotein
How does the body produce energy when glucose and lipid reserves are in adequate?
Liver cells break down internal proteins and absorb additional amino acids from the blood. Amino acids are deaminated
What is deamination?
Removing an amino group and breaking down the carbon chain to provide ATP. Removes the amino group and hydrogen atom and generates an ammonium ion
What is Transamination?
Transfer of an amino group from one molecule to another.
What happens to ammonium generated from deamination?
Extra ammonium is synthesized into urea by enzymes in the liver and is then excreted in the urine
How is heat produced and eliminated from the body?
The body produces heat as a byproduct of metabolism. It is retained by water in the body and then released through radiation, convection, evaporation or conduction
How are heat loss and heat gain regulated?
Regulated by negative feedback loops in response to the increase or decrease in temperature from normal range.
Sweating/shivering
Where is the heat center?
Hypothalamus
What is the difference between thermal regulation of infants and adults?
Infants have a larger surface area and lose heat rapidly. They are much less adaptable to temperature changes than adults
Where does the citric acid cycle occur? What are its reactants and products?
Occurs in the mitochondrial matrix. Starts with acetyl CoA produced by the oxidation of pyruvate and ends with NADH, FADH2, carbon dioxide and 2 ATP
Where does oxidative phosphorylation occur? What are its reactants and products?
Occurs in the inner mitochondrial membrane. Forms ATP as electrons are transferred from reduced NADH and FADAH2 to oxygen by the ETC
Where does the electron transport chain occur what are its reactants and products?
Occurs in the mitochondrial membrane. Starts with oxygen and ends with water molecules and ATP
