Chapter 6 Proteins and Amino Acids

amino acids - building blocks of proteins. Each contains an amino group, an acid group, a hydrogen atom, and a distinctive side group, all attached to a central carbon atom.

Define Amino Acid

conditionally essential amino acid -an amino acid that is normally nonessential, but must be supplied by the diet in special circumstances when the need for it exceeds the body's ability to make it.

Define conditionally essential amino acid

nonessential amino acids - amino acids that the body can make; also called dispensable amino acids.

Define nonessential amino acids

Short term fasting burns glucose, long term burns fat.

Describe how protein metabolism is changes from a short term fast to a long term fast.

Protein supplements or amino acid supplements are not required for muscle building.

Are protein supplements or amino acid supplements required for muscle building? Can they benefit? Briefly explain.

High animal protein intake is associated with heart disease, cancer, and osteoporosis.

How are high protein diets associated with disease?

The body may need more protein as physical energy increases.

How does physical activity influence the body's need for protein? What are the three main reasons why this change occurs?

High protein diets may promote weight loss. One mechanism potential mechanism for weight loss related to high protein and lower CHO intake is to consume more vegetable protein and lower CHO, low calorie diet.

How effective are high protein diets at promoting actual weight loss? What is one potential mechanism for weight loss related to high protein and lower CHO intake?

Protein is different because it contains nitrogen

How is protein's chemistry different to CHO and fat?

Protein's chemistry similar to CHO and fat because it contains carbon, hydrogen, and oxygen.

How is protein's chemistry similar to CHO and fat?

Complementary proteins are two or more dietary proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other. Vegetarians should use this strategy in order to meet their daily protein needs.

What are complementary proteins? Who should use this strategy in order to meet their daily protein needs?

Dipeptide - Two amino acids bonded together Tripeptide - Three amino acids bonded together Polypeptide - additional amino acids join

What are the names of the different peptide chains that are different in length? How many amino acids are in each?

The two main factors that influence protein quality are digestibility and amino acid composition. High quality proteins are animal proteins and plant proteins. Low quality protein is plant proteins by themselves.

What are the two main factors that influence protein quality? What foods are considered high quality proteins? Low quality proteins?

The two states of protein energy malnutrition are Marasmus, and Kwashiorkor. • Marasmus and kwashiorkor (terms used with children) • Marasmus "dying away" - severe deprivation of food over a long time (chronic). Poor growth, dramatic weight loss, loss of body fat and muscle, apathy. • Kwashiorkor - sudden or recent deprivation of food (acute). Rapid weight loss, some muscle wasting, edema.

What are the two states of protein-energy malnutrition (PEM) and what are their clinical signs/symptoms? State which is more of a chronic malnutrition and which is more acute.

The enzyme in the stomach that is responsible for breaking down protein into smaller peptide chains is pepsin. Hydrolic acid activates the pepsin.

What enzyme in the stomach is responsible for breaking down protein into smaller peptide chains? How is this enzyme activated?

• Positive nitrogen balance is associated with anabolic metabolism seen in: • Growing infants & children • Pregnant women • People recovering from protein deficiency or illness • Body builders/athletes • Negative nitrogen balance is associated with catabolic metabolism seen with: • Starvation • Burns • Infections & Fever

What groups of people would you expect to see positive nitrogen balance? What groups of people would you expect to see negative nitrogen balance? How would you describe the metabolic state of these two groups of individuals?

Limiting amino acid is the essential amino acid found in the shortest supply relative to the amounts needed for protein synthesis in the body. Four amino acids are most likely to be limiting: • Lysine • Methionine • Threonine • Tryptophan The physiological impact of having a limiting amino acid in your diet is protein synthesis limited.

What is a limiting amino acid? What is the physiological impact of having a limiting amino acid in your diet?

Denaturation of protein is the Hydrochloric acid uncoiling that occurs in the stomach.

What is denaturation of protein and where does it occur? Why is it important to protein digestion?

Nitrogen balance is the amount of nitrogen consumed (N in) as compared with the amount of nitrogen excreted (N out) in a given period of time. The two components of nitrogen balance are nitrogen intake and nitrogen excretion. • N in > N out à Positive Nitrogen Balance • N in = N out à Nitrogen Equilibrium/Zero NB • N in < N out à Negative Nitrogen Balance

What is nitrogen balance? What are the two components of nitrogen balance? What are the three states of nitrogen balance?

Protein turnover is the degradation and synthesis of protein. The two components of protein turnover are protein synthesis.

What is protein turnover? What are the two components of protein turnover? How do these two components determine whether protein mass is added to or lost?

10 to 35 percent of daily energy intake

What is the AMDR recommendation for protein?

0.8 grams / kg of body weight / day

What is the RDA for protein?

Deamination - removal of the amino group from a compound such as an amino acid. Transamination - the transfer of an amino group from one amino acid to a keto acid, producing a new nonessential amino acid and a new keto acid.

What is the difference between deamination and transamination?

The group of enzymes that are responsible for digesting larger polypeptide chains in the small intestine are the pancreatic enzymes. The enzymes are produced and released from the pancreas.

What is the general name for the group of enzymes that are responsible for digesting larger polypeptide chains in the small intestine? Where organ are these enzymes produced and release from?

The general name given to enzymes located on the intestinal cell wall that break down small peptide chains into single amino acids are the peptidase enzymes.

What is the general name given to enzymes located on the intestinal cell wall that break down small peptide chains into single amino acids?

Peptide bond

What is the name of the bond between amino acids that link them together to form a protein?

Ammonia is the potentially harmful byproduct of amino acid deamination when protein is used for energy metabolism. The body converts ammonia to urea and excretes the urea through the blood stream which travels to the kidneys to be filtered out and excreted in the urine.

What is the potentially harmful byproduct of amino acid deamination when protein is used for energy metabolism? How does the body deal with this byproduct?

The primary role of protein in the body protein is the major structural component of all the body's cells.

What is the primary role of protein in the body? Is protein generally used to build structures, used to produce energy, or something else?

Dipeptide - 2 amino acids

What is the smallest individual component that makes up a protein?

The amino acids are transported into the blood stream.

What mechanism is used in order to absorb amino acids?

Side group

What part of every amino acid is unique to an individual amino acid?

The two processes that are required in order to build protein in any given cell is transcription and translation. Transcription is the template that is used by the cell to build the protein.

What two processes are required in order to build protein in any given cell? What is the template that is used by the cell to build the protein?

Protein is used for energy during times of starvation or insufficient protein intake. As your body breaks down glucose, a simple sugar molecule, in the first dozen steps, it produces a compound called pyruvate. When this compound enters the mitochondria, or powerhouse, of the cell, aerobic metabolism occurs in which this compound is oxidized and turned into carbon dioxide and water. In the case of anaerobic metabolism, pyruvate enters the fluid, or cytoplasm, of the cell and is turned into lactic acid via a process called glycolysis. While aerobic metabolism uses fat, protein and carbohydrates and can continue indefinitely, anaerobic metabolism uses only carbohydrates and doesn't last long.

When is protein used for ATP energy production? Briefly describe the steps for how protein can be used both aerobically and anaerobically.

Once inside the intestinal cells, amino acids may be used for energy or to synthesize needed compounds. Amino acids that are not used by the intestinal cells are transported across the cell membrane into the surrounding fluid where they enter the capillaries on their way to the liver.

Where do amino acids travel once they are released from the intestinal cells?

Lean body tissue is most often used as a source of protein when it is needed for energy or "new glucose" production

Which tissue is most often used as a source of protein when it is needed for energy or "new glucose" production?

Source of essential amino acids Practical source of nitrogen to build nonessential AA's

Why does the body need protein daily?