2.2 Lab Protocol

Approximate Time: 3 hours

You will examine how the liver metabolizes carbohydrates during fasting and fed states, identifying changes in gluconeogenesis, glycogenolysis, and glycogen levels.  Indicate increase or decrease of the biochemical phenomena by drawing arrows (↑ ↓).

You will focus on protein metabolism in skeletal muscles, highlighting variations in amino acids, proteolysis, and proteogenesis during different metabolic states. Indicate increase or decrease of the biochemical phenomena by drawing arrows (↑ ↓).

You will explore lipid metabolism in adipose tissue, including lipolysis, triglycerides, fatty acids, glycerol, and lipogenesis during fasting and fed states. Indicate increase or decrease of the biochemical phenomena by drawing arrows (↑ ↓).

Activity 1 Questions:

Digestive and Absorptive Processes:

• How are proteins absorbed after enzymatic digestion? Describe the form they are in, where absorption occurs, and how they enter the body.
• In what form are lipids absorbed after enzymatic digestion, and through which structures or pathways are they transported?
• Describe how carbohydrates are absorbed following enzymatic digestion, including their final form and where this absorption takes place.
• During the absorptive state (anabolic) state, which types of molecules are synthesized, and what are these processes called for lipids, proteins, and glycogen?
• Which hormone acts on the liver to stimulate the translocation of the GLUT-4 transporter, and how does this affect glucose uptake by the tissue?
• During the post-absorptive (catabolic) state, which stored molecule is broken down to produce glucose, and what is the name of this process?

In this activity, you will observe how micelles form in the presence of soap and identify the types of molecules they can transport.

Micelles are spherical structures that form when amphipathic molecules such as soap is dissolved in water.  You will observe the formation of micelles in the presence of soap and identify the types of molecules transported by micelles. When micelles formed, the hydrophobic tails cluster together in the center, while the hydrophilic heads face outward toward the water.  This structure allows them to transport nonpolar, hydrophobic molecules such as oil in their core. In our body, micelles play a crucial role in the digestion and absorption of fats, including fat-soluble vitamins.

Activity 2 Question:

What type of molecules will these micelles transport?  Choose all that apply.

• Vitamin k
• Vitamin D
• Vitamin E
• Vitamin A
• Fatty Acids
• Small Fats
• Amino Acids
• Simple Sugars
• Simple Nucleotides

Activity 3 Question:

What factors or conditions might affect the rate of peristalsis?

In this activity, you will measure your cholesterol levels and interpret the results to understand what they may indicate about your current health status.  Cholesterol levels can provide important information about cardiovascular health, including the balance between good cholesterol and bad cholesterol.  Interpreting these results will help you connect physiological concepts to real-life health outcomes.

Because this activity involves handling body fluids, it is critical to follow proper safety protocols to protect yourself and others.  Always use gloves, properly dispose of lancets or any materials that come into contact with blood and disinfect your work area after completing the procedure.

If you need a refresher on the correct procedures for handling body fluids, do not hesitate to ask your instructor before beginning the activity.  Maintaining proper technique ensures accurate results and keeps the lab environment safe for everyone.

Total Cholesterol 

Total cholesterol is a soft, fat-like, waxy substance found in the bloodstream and in all your body’s cells. Cholesterol is an important part of a healthy body because it’s used for producing cell membranes, some hormones and serves other needed bodily functions. When there is too much cholesterol in your blood, it builds up in your arteries and can eventually increase your chances of developing heart disease.

HDL Cholesterol

HDL Cholesterol is known as the “good*” cholesterol because high levels of HDL can protect against heart disease.  Medical experts believe HDL carries LDL cholesterol away from the arteries and removes excess cholesterol from arterial plaque, slowing its buildup.  Higher HDL is desirable.  Lower HDL may increase the risk of heart disease.

Triglycerides

Triglycerides are a form of fat that the body uses to store energy.  Elevated triglycerides can be due to heredity, being overweight/obese, physical inactivity, cigarette smoking, excess alcohol consumption or a diet very high in carbohydrates.

LDL Cholesterol

LDL Cholesterol, or “bad*” cholesterol, is a thick, hard deposit, or “plaque” that can narrow the arteries and make them less flexible.  Blocked arteries in the heart can increase your risk for heart attack or stroke.

*Beware of labeling physiological processes as good and bad.  All molecules made by the body have a role in maintenance of homeostasis.

Glucose

Glucose is a type of sugar that travels through the bloodstream and is the primary source of energy for your cells.  Glucose levels that remain high over time may be indicative of diabetes which can cause damage to the eyes, kidneys, nerves, and blood vessels.