Human Physiology Unit 5B:
Metabolism
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Paige Stieneke
BIOL 256
Dr. Karri Haen
April 26, 2013
Metabolism
1. Define metabolism: All chemical reactions necessary for life
2. (Catabolism, anabolism) is the synthesis of larger molecules from smaller ones, while (catabolism,
anabolism) is the breakdown or hydrolysis of complex molecules into simpler ones.
3. Absorptive is also known as the “Fed” state and is the time during and shortly after nutrient intake
4. Postabsorptive or “Fasting” is the time when the GI tract is mostly empty
5. What is the metabolic process where food is broken down to yield energy? Cellular Respiration
6. True or False: All tissues use glucose to synthesize ATP
Absorptive State
1. During the absorptive state, (catabolism, anabolism) occurs to (build, break) molecules.
2. Amino acids are converted into proteins
3. Glycerol and fatty acids are converted into triglycerides
4. Glucose is stored as glycogen
5. Excess amino acids are deaminated and are either used for energy or stored in the liver
Tissue or Organ
Muscle
Liver
Fat
Amino Acids
Protein
Keto Acids
Glucose
Glycogen
Glycogen or fat
Fat
6. What hormone controls the absorptive state? Insulin
7. Identify what stimulates this hormone’s secretion:
a. Increased blood glucose
b. Elevated blood amino acid levels
c. Gastrin, CCK and secretin
8. What does this hormone enhance? Active transport of amino acid into tissue cells, and
facilitated diffusion of glucose into tissues
9. What is the disease where glucose becomes unavailable for most body cells? Diabetes mellitus
10. Identify the two causes of diabetes:
a. Inadequate insulin production
b. Abnormal insulin receptors
Postabsorptive State
1. During the postabsorptive state, (catabolism, anabolism) occurs to (build, break) molecules.
2. Proteins are broken down into amino acids
3. Triglycerides are converted into fatty acids and glycerol
4. Glycogen is converted into glucose
Supplemental Instruction
1060 Hixson-Lied Student Success Center  294-6624  www.si.iastate.edu
5. In the muscle, protein is broken down into amino acids, and glycogen is converted into ATP and
pyruvic acid.
6. In the liver, amino acids, pyruvic acid, glycogen and fat are all converted into glucose. Fat is also
converted into keto acids to make ATP
7. What hormone controls the postabsorptive state? Glucagon by pancreatic alpha cells
8. What does that hormone enhance?
a. Glycogenolysis and gluconeogenesis
b. Fat breakdown in adipose tissue
c. Glucose sparing
Calorie Yields
For each gram of food consumed, you get:
a. Proteins: 4 kcal/g
b. Lipids: 9 kcal/g
c. Carbohydrates: 4 kcal/g
Regulation of Food Intake
Hormone
Location
Neuropeptide Y
Hypothalamus
Cholecystekinin
GI tract (intestine)
Ghrelin
GI tract (stomach)
Leptin
Adipose tissue
Function
Causes craving for carbohydrates
Promotes satiety after eating
Provides hunger signal
Released when triglyceride stores full, stops release of
Neuropeptide Y
Metabolic Rate
1. Metabolic rate is the rate of energy output equal to the total heat produced by all chemical
reactions and mechanical work in the body.
2. Basal Metabolic Rate (BMR) is the energy that the body needs to perform its functions at rest
3. Total Metabolic Rate (TMR) is the total rate of kilocalorie consumption fueling all ongoing activities
Supplemental Instruction
1060 Hixson-Lied Student Success Center  294-6624  www.si.iastate.edu