Exam 2 Study Guide
1. Describe how proteins differ from carbohydrates and lipids.
∙ Differ because of their chemical composition ∙ Presence of Nitrogen makes them unique
2. Identify the structure of an amino acid molecule including its five essential components.
∙ Chain of amino acids contained by a peptide bond with a side chain
∙ Contains a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.
5 Essential Components:
1.A central carbon atom
2. A hydrogen atom
3. An amino group - consisting of a nitrogen atom and two hydrogen atoms
4. A carboxyl group - consisting of a carbon atom, two oxygen atoms, and one hydrogen atom
5. An R-group or side chain - consisting of varying atoms
3. Differentiate among essential amino acids, nonessential amino acids, and conditionally essential amino acids.
∙ Essential amino acid: must be supplied by diet as it CANNOT be made by the body
***MEMORIZE 9 ESSENTIAL AMINO ACIDS
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7. Histidine (only essential for
∙ Nonessential Amino Acids: Can be made in the body (do not need to know the 11 kinds)
∙ You don't need to worry about getting
enough of these amino acids since your body
will compensate for any gaps in your diet
∙ Conditionally Essential Amino Acids: lacks an essential amino acid precursor but can become essential under certain conditions
∙ 8 out of 11 nonessential AA
∙ When you’re sick or under significant stress, your body may not be able to produce
enough of these amino acids to meet your
4. Discuss the factors used to evaluate protein quality.
∙ Digestibility: If you can’t completely digest and absorb a protein source, you won’t get the benefits of all the amino acids the food contains We also discuss several other topics like Who is responsible for the first accurate
measurement of the circumference of the
∙ Essential Amino Acid Composition: highest quality sources of protein are those that contain all of the essential amino acids. Such proteins are called “complete” proteins
5. Explain how proteins are made and the relationship between protein shape and function.
∙ The synthesis of RNA from DNA is called
transcription which the mRNAs are then translated into a protein; 1 amino acid is added to the protein strand for every 3 bases in the RNA
∙ FUNCTION is dependent upon SHAPE
***Once protein structure is denatured, we shift its function
6. Discuss how proteins are digested and absorbed by the body.
∙ Before your body can use protein to build and repair tissues, the large molecules of protein must be digested by enzymes into amino acids. D We also discuss several other topics like What does isotonic mean?
1. Digestion of protein begins in your stomach with the aid of gastric juices. Pepsin from the
intestinal lining and the pancreas breaks the
peptide bonds that hold the protein molecule
together and digestion continues in the small
2. From there, amino acids are absorbed into the bloodstream and transported throughout your body.
7. Describe deamination, where it occurs in the body, the products produced, and the fate of these products.
∙ An oxidative reaction that occurs under aerobic conditions in all tissues but especially the liver
∙ Amino acids are separated as an amino group is removed if there is an abundance of protein We also discuss several other topics like What process is the repulsion of one electron by another electron, shields electron from full effects of nucleus?
1. The breakdown of amino acids releases
nitrogen-containing amine groups (NH2) which can be toxic to cells.
2. The liver removes these amine groups via the process of deamination and converts them into
harmless products keto acid and ammonia
(which is converted into urea and excreted in
8. Explain how the catabolism of proteins differs from the catabolism of carbohydrates and lipids.
∙ Carbohydrates, fats, and proteins are broken down into their individual monomer units: carbohydrates into simple sugars, fats into fatty acids and glycerol, and proteins into amino acids
1. After deamination, the carbon skeletons of amino acids can be oxidized for energy.
2. The carbon skeletons of glucogenic amino acids are converted into pyruvate, whereas those of We also discuss several other topics like Social value includes the private value of the good.
ketogenic amino acids are converted into acetyl CoA
3. The end products of protein catabolism are carbon dioxide, water, ATP, and urea (which lipids and carbohydrates don’t produce)
9. Explain nitrogen balance
∙ measure of nitrogen input minus nitrogen output ***Nitrogen Balance = Nitrogen intake - Nitrogen loss.
∙ Sources of nitrogen intake include meat, dairy, eggs, nuts and legumes, and grains and cereals
∙ Examples of nitrogen losses include urine, feces, sweat, hair, and skin.
10. Describe at least four functions of proteins in the body.
1. Anabolism: Source of nitrogen & EAA
2. Structural and Mechanical Functions
3. Transport: Carriers and membrane pumps
4. Enzymes: Catalyze metabolic reactions
5. Hormones: Regulate body processes
6. Immunity: Antibodies are proteins
7. Fluid Balance: Vascular proteins attract water 8. Acid-Base Balance: Buffer
∙ Source of Glucose
∙ Source of Energy: 4 kcals
11. Calculate your Recommended Dietary Allowance for protein.
To estimate RDA Protein intake:
1. Take weight in lbs (ex. 150) and divide by 2.2 to convert to kg (ex. 150/2.2=68.2 kg) If you want to learn more check out What are the various types of intracellular junctions?
2. Multiple kg weight (68.2kg) by 0.8g to get grams of protein recommendation
3. (ex. 68.2kg x 0.8g = 54.56g protein/day)
12. Identify the potential health risks associated with high-protein diets.
∙ Some high-protein diets include foods such as red meat and full-fat dairy products, which may
increase your risk of heart disease and contribute to high cholesterol
∙ A high-protein diet may worsen kidney function in people with kidney disease because your body may have trouble eliminating all the waste products of protein metabolism
13. List six foods that are good sources of protein, including at least three non-meat sources.
3. Meat/ Poultry
4. Greek Yogurt
14. Describe two disorders related to inadequate protein intake or genetic abnormalities.
1. Kwashiorkor: protein efficiency
∙ Immune system and hormones are impaired ∙ Low blood albumin
∙ Edema (tissue swelling): water is leaking into stomach and cause inflation
2. Marasmus: general starvation
∙ Muscle and fat wasting
∙ Slowed metabolism
∙ Impaired brain development
15. Define the types of vegetarian diet, health risks and health benefits
1.Lacto Vegetarian: Lacto-vegetarians do not eat red or white meat, fish, fowl or eggs.
However, lacto-vegetarians do consume dairy
products such as cheese, milk and yogurt.
2. Ovo Vegetarian: Ovo-vegetarians do not eat red or white meat, fish, fowl or dairy products. However, ovo-vegetarians do consume egg
3. Lacto-ovo vegetarian: Lacto-ovo vegetarians do not consume red meat, white meat, fish or
fowl. However, lacto-ovo vegetarians do
consume dairy products and egg products. This is the most common type of vegetarian.
Benefits: May reduce heart disease, cancer, and type 2 diabetes
Risks: Lack of protein, Vitamin B, Iron, and Omeg-3 Fatty Acid intake
1. Describe the types and structure of lipids in the diet.
1.Saturated Fatty Acid:
1. Structure is straight
2. Saturated with hydrogen
3. ONLY Single Bonds NO double bonds
2.Monounsaturated Fatty Acid:
1. Double bond allows susceptibility for oxidation 2. Loose hydrogen
3. MUFA (olive oil has a lot)
3.Polyunsaturated Fatty Acid:
1. 3 double bonds
2. Understand how structure of lipids dictate digestibility and function.
∙ Those with longer fatty acid associated with it (triglyceride) are stacked and become more easily solid
∙ High in saturated fats may liquidly if the length of the fatty acid is shorter
∙ Shorter fatty acid chains (like in coconut oil) can move around more and thus melt
3. List the functions of specific lipids in the body.
∙ Storage form of energy
∙ Supply essential fatty acids
∙ Carrier of fat-soluble compounds
∙ Part of cell membrane and lipoprotein
∙ Emulsifier in foods (keeps water and fat