Unit 4 FRQ (Blood Sugar Homeostasis) Answers

AP Bio Free Response Question: Protein Powders

👋 Welcome to the AP Bio Unit 1 FRQ on Protein Powders. These questions are a bit longer, so get ready with some paper and a pencil, or open up a blank page on your computer. Once you’re finished, you can compare your responses with the Unit 1 FRQ (Protein Powders) Answers to see how you did.

🤔 Need a refresher on the unit? Take a look at the Unit 1 Overview for a quick recap.
😩 Getting stuck halfway? Check out all the available Unit 1 Resources to help you through it.
⏱ Remember, the AP Biology exam has 6 free-response questions and you’ll have 90 minutes for the entire FRQ section. That means you should allow ~15 minutes per FRQ.

Setup

High-quality proteins are essential for optimal health. In the healthcare and fitness industries, protein powders are widely used to meet nutritional needs and maximize muscle growth. Protein powders can be made from both dairy and vegetable sources, including whey, casein, soy, and pea protein. There are also blended powders that contain a mix of these protein sources. Table 1 (not provided here) includes details of five different types of protein powders, including a blend of all four.

Questions

(a) A nutritionist is working with a patient who is training for a marathon. In addition to protein, identify which macromolecule will be most essential to their training and explain why.

In addition to protein, the most essential macromolecule for marathon training is carbohydrates. Carbohydrates serve as the body’s primary source of energy, particularly during prolonged exercise like running a marathon. They are broken down into glucose, which is stored as glycogen in the muscles and liver. During physical activity, glycogen is converted back into glucose to fuel muscle contractions, helping the runner maintain energy levels and endurance throughout the marathon.

(b) Describe how the structure of amino acids relates to the function of the protein as a whole.

The structure of amino acids directly influences the function of a protein. Each amino acid contains a central carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and a unique R group (side chain). The sequence of amino acids, or primary structure, determines how the protein will fold into its secondary, tertiary, and possibly quaternary structure. These folding patterns are stabilized by interactions among R groups, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges. The final three-dimensional shape of the protein determines its function—whether it acts as an enzyme, structural protein, transporter, or hormone. Any changes in the sequence of amino acids can alter the protein’s shape and potentially affect its function.

(c) Using the template provided, construct a graph of the availability of methionine across all five protein options.

To create a graph showing the availability of methionine across the five protein powders:

1. Label the x-axis with the five protein options: whey, casein, soy, pea, and blend.
2. Label the y-axis with the availability of methionine (in grams or as a percentage).
3. Plot the values from Table 1 for each protein type.
4. Connect the points if applicable, and ensure the units are included.

This graph will help visualize the differences in methionine content between each protein source, which can be useful for determining which protein powder best meets specific dietary needs.

(d) Collagen peptides are a popular powder to mix into foods and drinks. These peptides contain collagen proteins, which support hair, skin, and nail health. However, nutritionists advise against relying on collagen as a source of protein because it does not contain the amino acid tryptophan, and therefore it is not a complete protein. Explain why the absence of tryptophan makes collagen peptides incomplete and inadequate as a primary source of protein.

The absence of tryptophan makes collagen peptides an incomplete protein because tryptophan is one of the nine essential amino acids that the human body cannot synthesize on its own. A complete protein contains all of the essential amino acids in adequate proportions, which is crucial for proper protein synthesis and maintaining body functions. Without tryptophan, the body cannot build certain proteins effectively, which makes collagen an inadequate choice for meeting daily protein needs, especially for muscle growth, immune function, and other critical physiological processes. While collagen is beneficial for skin, hair, and nails, it should be complemented with other protein sources that provide a full amino acid profile to ensure overall health and wellness.