Human Physiology (Biol 236)
Exam Outline

It is to be understood that you will have read the corresponding sections of the textbook for lecture topics that we have covered!

Chapter 2, part 1 Outline (Metabolic Physiology) Updated on 9/9/22

Cell Metabolism
• Know the basic molecules that can be metabolized [carbohydrates, lipids, proteins (amino acids), and lactic acid]
• What order does our body tend to metabolize amino acids, lipids, and carbohydrates to meet energy demands? [ Remember that our body routinely, every day, metabolizes lactic acid from skeletal muscle activity and also amino acids from digestion or from normal wear and tear of muscles.]
• Know the vocabulary of metabolism shown lecture notes (glycolysis, glycogenesis, glycogenolysis, gluconeogenesis, lipogenesis, lipolysis).

Glycogen metabolism (see blank and key flow diagrams on online syllabus)
• Know the terms glycogenesis and glycogenolysis.
• How do pancreatic hormones insulin and glucagon affect glycogenesis and glycogenolysis?
• Know the enzyme needed for glycogenesis (glycogen synthase), and the enzymes needed for glycogenolysis (glycogen phosphorylase & glucose 6 phosphatase)

Glucose metabolism (see blank and key flow diagrams on online syllabus)
• Know what enters glycolysis (glucose does), and what is the main product of glycolysis (2 pyruvate are).
• Know what enters the anaerobic respiration pathway (2 pyruvate does) and what the products of fermentation are (2 ATP and lactic acid).
• Know what enters pyruvate conversion (2 pyruvate does), and what the main products are (2 Acetyl CoA are).
• Know what enters the Kreb's cycle (2 Acetyl CoA are), and what are the main products (the hydrogen ions from the NADH2 and FADH2)
• Know all the main product from the electron transport chain (30 - 32 ATP, 10 NAD, 2 FAD, 12 H2O)
• Know THIS image!



• Where within a cell (the cytoplasm versus the mitochondria) can glycolysis and fermentation occur versus aerobic respiration (pyruvate conversion, kreb's cycle and electron transport chain)?
• What is the effect of ischemia on heart muscle when blocked blood flow leads to fermentation and lactic acid buildup? (Angina pectoris Clinical App)
• Why do we need to breathe oxygen (what is its role in the electron transport chain)?
• Why is cyanide so deadly? Clinical Application

Lactic acid metabolism (see blank and key flow diagrams on online syllabus)
• What is the risk of a buildup of lactic acid in the bloodstream from anaerobic respiration in skeletal muscles?
• What is the Cori Cycle? What organ is involved? Reviewing the Cori Cycle slide is a great way to review the enzymes are involved in glycogenesis, or glycogenolysis in the liver. Also see practice flow diagram and key on glycogen metabolism to review this. . Know that making glucose from lactic acid is an example of gluconeogenesis.


Lipid metabolism (see blank and key flow diagrams on online syllabus)
• Know the terms lipogenesis and lipolysis.
What are the steps of lipogenesis in adipose and the liver? (see practice flow diagram and key)
1. extra glucose converted to pyruvate (1 glucose goes through glycolysis to make 2 pyruvate)
2. 2 pyruvate converted to 2 acetyl CoA by pyruvate conversion
3. 2 acetyl CoA is then converted in the liver into: cholesterol, ketones, and fatty acids
4. fatty acids converted into triglycerides (white fat) and stored.
What are the steps to lipolysis, when the body needs energy, in adipose and the liver?
1. triglycerides broken into ketones.
- ketones being used for energy by cells is called ketosis. See Clinical App on ketosis
- high levels of ketones in the blood can drop blood pH, which is called ketoacidosis.

2. triglycerides also broken into fatty acids, which can enter blood stream for cells to use for energy, but can cause metabolic acidosis.
- IF NEEDED, fatty acids can be converted into acetyl CoA, which enters kreb's cycle and eventually leads to ATP production. Acetyl CoA can be converted back into pyruvate (by going backward through pyruvate conversion). Then pyruvate can be converted back into glucose (by going backwards through glycolysis). Making glucose from a non-carbohydrate, such as lipids, is called gluconeogenesis.

Amino acid metabolism
How are proteins (amino acids) metabolized by the liver and then excreted by the kidneys? (see practice flow diagram and key)
• excee a.a. converted into pyruvate.
• Pyruvate can be converted into glucose (by going backwards through glycolysis). This is another example of gluconeogenesis.
• Pyruvate and then go through pyruvate converstion to make acetyl CoA, which can enter Kreb's cycle and eventually make ATP.
• Acetyl CoA can be converted to fatty acids, which can be turned into triglycerides.

What happens to the excess a.a. that can't be metabolized by the above pathways?
• liver converts a.a. to urea, and urea excreted by kidneys.
• What is the significance of measuring BUN in a blood panel? What is "azotemia"?

• What is phenylketonuria (PKU)? Clinical App

• Metabolism of what kinds of molecules can lead to metabolic acidosis (hint: they probably have the word acid in them!)

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