Nutrition Test 2 Review: Proteins Composition

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Questions and Answers

What is the role of hydrochloric acid in protein digestion?

Denatures protein and opens up folded structure (correct)

Breaks proteins into single amino acids

Converts pepsin to pepsinogen

Controls the production of hydrochloric acid

Which enzyme is responsible for breaking tripeptides and dipeptides into single amino acids?

Peptidases (correct)

Gastrin

Proteases

Pepsin

What is the function of pepsin in protein digestion?

Converts pepsinogen to pepsin

Breaks proteins into single amino acids (correct)

Controls the production of hydrochloric acid

Denatures protein

In protein digestion, where do amino acids go after being absorbed by enterocytes of the intestine?

Transported to the liver by the portal vein Signup and view all the answers

What is the impact of consuming too much protein on kidney health?

Could increase the risk of kidney disease Signup and view all the answers

What is the primary function of gastrin in the stomach?

Controls production of hydrochloric acid Signup and view all the answers

What is one potential consequence of a vegetarian diet according to the text?

Increased risk for kidney stones Signup and view all the answers

Which of the following statements about the composition of proteins is correct?

Proteins are composed of macromolecules that are long chains of amino acids, and the specific arrangement of amino acids determines the structure and function of the protein. Signup and view all the answers

How many different amino acids are typically used to make proteins in the human body?

20 amino acids Signup and view all the answers

Which of the following amino acids is classified as an essential amino acid?

Threonine Signup and view all the answers

What is the term used to describe the process of combining two incomplete protein sources to create a complete protein?

Mutual supplementation Signup and view all the answers

Which of the following is an example of complementary proteins mentioned in the text?

Beans and rice Signup and view all the answers

In which organ does the digestion of proteins primarily occur?

Both the stomach and small intestine Signup and view all the answers

Which of the following amino acids is classified as a dispensable amino acid?

Tyrosine Signup and view all the answers

What is the term used to describe amino acids that the body cannot produce or produces in low quantities, and must be obtained from food?

Indispensable amino acids Signup and view all the answers

Which of the following statements about complete proteins is true?

A complete protein is a combination of two incomplete proteins that together provide all 9 essential amino acids. Signup and view all the answers

According to the information provided, which of the following statements is correct about the digestion of proteins?

Proteins are digested in the stomach, liver, and small intestine. Signup and view all the answers

Which of the following statements about kwashiorkor is true?

It is characterized by edema and wasting, typically seen in children aged 1-3 years who no longer receive breast milk and have a low protein intake. Signup and view all the answers

What is the recommended daily intake of sodium for adult males according to the given information?

1500 mg/day Signup and view all the answers

Which of the following statements about vitamin E is incorrect?

Vitamin E deficiency is common and can lead to anemia and impaired immune function. Signup and view all the answers

Which of the following electrolytes is essential for the transmission of nerve impulses and muscle contractions?

Potassium (K) Signup and view all the answers

What is the primary function of vitamin D in the body?

Regulating calcium and phosphorus absorption, and blood calcium levels Signup and view all the answers

Which of the following statements about beta-carotene is true?

Beta-carotene is a precursor of retinol, an active form of vitamin A. Signup and view all the answers

Which of the following minerals is essential for the remodeling of bones and assisting in the production of osteocalcin?

Vitamin K Signup and view all the answers

What is the primary cause of hyponatremia (low blood sodium concentration)?

Disorders that cause the kidneys to retain too much water, diluting blood sodium Signup and view all the answers

Which of the following statements about magnesium is incorrect?

Magnesium is not involved in the metabolism of vitamin D. Signup and view all the answers

Which of the following conditions is characterized by low bone mass and deterioration of bone tissue, leading to an increased risk of fractures?

Osteoporosis Signup and view all the answers

Study Notes

Enzymes and Protein Digestion

Enzymes break down proteins into peptides and amino acids in the stomach and small intestine
- Hydrochloric acid denatures proteins, allowing access for digestion
- Pepsin breaks apart proteins into single amino acids and shorter polypeptides
- Gastrin regulates the production of hydrochloric acid and pepsin release in the stomach
- Enzymes in the small intestine break down polypeptides into single amino acids
- The pancreas and small intestine secrete enzymes called proteases that break proteins into peptides and single amino acids

Vegetarian Diets

2.3% of Canadians identify as vegan
Vegetarian diets:
- Reduce intake of fat and total energy, reducing the risk of obesity and type 2 diabetes
- Lower blood pressure
- Reduce the risk of heart disease
- Reduce the risk of certain cancers (colorectal)
- Reduce the risk of kidney stones and gallstones
However, vegetarian diets may lack certain vitamins and minerals and may require supplementation

Protein-Energy Malnutrition

Kwashiorkor: a form of protein-energy malnutrition characterized by wasting and edema, typically seen in children 1-3 years old who no longer receive breast milk and have a low protein intake
Marasmus: a disease caused by inadequate energy intake, especially protein, most common in children 6-18 months old in impoverished conditions

Fluids and Electrolytes

Water intake recommendations:
- Men (19-50): 3.7 L of total water/day (3.0 L from beverages, 0.7 L from food)
- Women (19-50): 2.7 L of total water/day (2.0 L from beverages, 0.7 L from food)
Athletes and people working in hot environments may require more water
Fluid and electrolyte balance is crucial to maintain proper bodily functions

Electrolytes

Sodium (Na):
- Intakes: Females → 1500 mg/d, Males → 1500 mg/d
- Functions: fluid and electrolyte balance, blood pressure regulation, nerve impulse transmission, muscle contraction
- High sodium intake can lead to hypertension
Chloride (Cl):
- Intakes: Females → 2300 mg/d, Males → 2300 mg/d
- Functions: fluid and electrolyte balance
Potassium (K):
- Lab range: 3.5-5.0 mmol/L
- Intakes: Females → 2600 mg/d, Males → 3400 mg/d
- Functions: fluid and electrolyte balance, transmission of nerve impulses, muscle contractions
- High-potassium diets can lower blood pressure
Phosphorus (H0P4):
- Intakes: Females → 700 mg/d, Males → 700 mg/d
- Functions: fluid balance, bone formation, enzyme activation, DNA and RNA synthesis
- High phosphorus levels can occur in people with kidney disease, vitamin D excess, and phosphorus-containing antacids

Antioxidants

Oxidation: a chemical reaction where atoms lose electrons
Antioxidants: molecules that donate electrons to free radicals
Vitamin E:
- Functions: antioxidant, cell membrane protection, nerve and muscle function
- RDA: 15 mg alpha-tocopherol
- Deficiency: erythrocyte hemolysis, loss of muscle coordination, poor immune function
Vitamin C:
- Functions: antioxidant, collagen synthesis, hormone synthesis, immune function
- Functions: antioxidant, enhance immune function, protect against LDL oxidation
Beta-Carotene:
- Functions: antioxidant, immune function, skin and eye protection
- 12 units of beta-carotene = 1 unit of vitamin A
Selenium:
- Functions: antioxidant, thyroid hormone production, immune function
- Deficiency: Keshan disease

Bone Health

Calcium:
- RDA: 19-50: 1000mg/day, Women 51+: 1200mg/day, Men 51-70: 1000mg/day, 70+: 1200mg/day
- Functions: bone formation and maintenance, acid-base balance, muscle contraction, nerve function
- Deficiency: osteoporosis, increased fracture risk
Vitamin D:
- Functions: calcium regulation, bone health
- Deficiency: osteomalacia (soft bones)
Vitamin K:
- Functions: bone remodeling, blood clotting
- Deficiency: inability of blood to clot
Phosphorus:
- Functions: critical for bone mineral composition, enzyme activation, ATP production
- Deficiency: rare but can occur in people with kidney disease, chronic diarrhea, and malnourished elderly adults
Magnesium:
- Functions: bone health, hydroxyapatite formation, ATP production, heart health
- Deficiency: secondary to kidney disease, chronic diarrhea, alcohol abuse

Diseases of the Bone

Osteoporosis:
- Low bone mass and deterioration of bone tissue, leading to increased fracture risk
- Influences on osteoporosis risk: aging, hormonal changes, smoking, low body weight, low calcium intake, low sun exposure, alcohol abuse, history of amenorrhea, estrogen deficiency, testosterone deficiency, repeated falls, sedentary lifestyle, long-time use of glucocorticoids
Osteomalacia:
- Softening of bones in adults due to vitamin D deficiency

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Description

Prepare for your nutrition test with a review on proteins composition. Learn about the structure of proteins, the breakdown of amino acids, and the difference between essential and non-essential amino acids.