NUSC 1165 Exam 3 Questions with Correct Answers 100% Verified By Experts| 2025/2026
Latest Update
Sources of Dietary Protein ■Animal
-Meats: 3 oz. = 20 g protein
-Poultry
-Fish
-Eggs: 1 egg = 7 g Protein
-Dairy Products: 1 cup Milk = 8 g protein
■Plant
-Legumes: 6-10 g protein/half cup serving
-Nuts & Seeds: 5-10 g protein/quarter cup serving
-Grains: 2-3 g/slice or half cup serving
Protein-rich foods also provide important nutrients ■Animal Sources
-B Vitamins
-Minerals - Iron, zinc, calcium
■Plant Sources
-B Vitamins
-Minerals - Iron, zinc, calcium
-Fiber
-Phytochemicals
-Unsaturated Fats
Dietary sources of protein corn oil, olive oil, sunflower seeds, peanut butter, tofu, kidney
beans, eggs, salmon, beef, chicken breast, 1% milk, cheddar cheese, cottage cheese, yogurt,
orange, kiwi, banana, avocado, broccoli, corn, potato, oatmeal, spaghetti, whole-wheat bread
Amino acid structure ■Amino Acids: Building blocks of proteins.
,■Central carbon atom
-Hydrogen atom
-Amino Group
-Acid Group
-Side Chain
Essential amino acids histidine, isoleucine, leucine, lysine, methionine, phenylalanine,
threonine, tryptophan, valine
Nonessential amino acids alanine, arginine*, asparagine, aspartic acid, cysteine*, glutamic
acid, glutamine, glycine*, proline*, serine, tyrosine*
*considered conditionally essential
Transamination ■Transfer of amino group to a carbon compound to generate a new amino
acid.
alanine + alpha-ketoglutarate <--> pyruvate + glutamate
alanine --> pyruvate (NH2 lost from alanine)
alpha-ketoglutarate --> glutamate
Conditionally essential amino acids ■Amino acids that are essential in the diet under
specific conditions or at specific times of life.
■Examples:
-Phenylalanine --> Tyrosine
-Methionine --> Cysteine
,Protein Structure ■Peptide bonds hold amino acids together.
■Multiple amino acids joined together by a peptide bond form polypeptide chains.
The shape of the protein determines its function ■Collagen & alpha-keratin
-Provides strength to fingernails and ligaments.
■Hemoglobin (Red Blood Cells)
-Spherical shape
-Alteration in Amino Acids --> Hemoglobin loses its shape
■Sickle-Cell Anemia
■Denaturation
-Alteration of a protein's 3-D Structure
-Due to change in temperature or heat
Protein Digestion - Mouth: Mechanical processing of protein due to chewing.
- Stomach:
Pepsinogen --> Pepsin (Activated by hydrocholoric acid)
- Pancreas: Produces enzymes (trypsin, chymotrypsin, and carboxypeptidase)
Small Intestine:
Transport proteins move the protein digestion products into the intestinal mucosa.
a). Amino acids that share the same transport protein compete with each other for absorption
b). Dipeptides and tripeptides enter the mucosal cell and then broken down into amino acids.
- Amino acids pass from the mucosal cell and travel to the liver via the hepatic portal vein.
***Little dietary protein lost in the feces
, Amino acid absorption ■Di- and tripeptides enter the mucosal cells of the small intestine
using one of several energy-requiring active transport systems.
■Amino acids sharing the same transport system will compete for absorption.
- Example: Branched Chain Amino Acids: Leucine, isoleucine, and valine
- If leucine is in excess- What happens to isoleucine and valine?
Protein Digestion and Food Allergies ■Occur when a dietary protein is absorbed without
being completely digested.
■Common sources:
-Milk, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish.
■Reaction of the Immune System:
-1st Time: Stimulation of the immune system
-2nd time: Immune system identifies protein as a foreign, harmful substance.
- Attacks Protein --> Allergic Reaction occurs
■Symptoms:
-Vomiting, diarrhea, rash, hives, drop in blood pressure, decreased breathing.
-Anaphalaxis: Most severe reaction - breathing difficulties, rapid drop in blood pressure.
Amino Acid Pool ■Amino acids in the body's tissues and fluids, available for use.
-Energy: 4 kcal/g
Dietary proteins --> digestion --> amino acid pool --> protein synthesis --> body proteins
Body proteins --> protein breakdown --> amino acid pool --> energy, synthesis of glucose or
fatty acids, synthesis of nonprotein molecules that contain nitrogen
Latest Update
Sources of Dietary Protein ■Animal
-Meats: 3 oz. = 20 g protein
-Poultry
-Fish
-Eggs: 1 egg = 7 g Protein
-Dairy Products: 1 cup Milk = 8 g protein
■Plant
-Legumes: 6-10 g protein/half cup serving
-Nuts & Seeds: 5-10 g protein/quarter cup serving
-Grains: 2-3 g/slice or half cup serving
Protein-rich foods also provide important nutrients ■Animal Sources
-B Vitamins
-Minerals - Iron, zinc, calcium
■Plant Sources
-B Vitamins
-Minerals - Iron, zinc, calcium
-Fiber
-Phytochemicals
-Unsaturated Fats
Dietary sources of protein corn oil, olive oil, sunflower seeds, peanut butter, tofu, kidney
beans, eggs, salmon, beef, chicken breast, 1% milk, cheddar cheese, cottage cheese, yogurt,
orange, kiwi, banana, avocado, broccoli, corn, potato, oatmeal, spaghetti, whole-wheat bread
Amino acid structure ■Amino Acids: Building blocks of proteins.
,■Central carbon atom
-Hydrogen atom
-Amino Group
-Acid Group
-Side Chain
Essential amino acids histidine, isoleucine, leucine, lysine, methionine, phenylalanine,
threonine, tryptophan, valine
Nonessential amino acids alanine, arginine*, asparagine, aspartic acid, cysteine*, glutamic
acid, glutamine, glycine*, proline*, serine, tyrosine*
*considered conditionally essential
Transamination ■Transfer of amino group to a carbon compound to generate a new amino
acid.
alanine + alpha-ketoglutarate <--> pyruvate + glutamate
alanine --> pyruvate (NH2 lost from alanine)
alpha-ketoglutarate --> glutamate
Conditionally essential amino acids ■Amino acids that are essential in the diet under
specific conditions or at specific times of life.
■Examples:
-Phenylalanine --> Tyrosine
-Methionine --> Cysteine
,Protein Structure ■Peptide bonds hold amino acids together.
■Multiple amino acids joined together by a peptide bond form polypeptide chains.
The shape of the protein determines its function ■Collagen & alpha-keratin
-Provides strength to fingernails and ligaments.
■Hemoglobin (Red Blood Cells)
-Spherical shape
-Alteration in Amino Acids --> Hemoglobin loses its shape
■Sickle-Cell Anemia
■Denaturation
-Alteration of a protein's 3-D Structure
-Due to change in temperature or heat
Protein Digestion - Mouth: Mechanical processing of protein due to chewing.
- Stomach:
Pepsinogen --> Pepsin (Activated by hydrocholoric acid)
- Pancreas: Produces enzymes (trypsin, chymotrypsin, and carboxypeptidase)
Small Intestine:
Transport proteins move the protein digestion products into the intestinal mucosa.
a). Amino acids that share the same transport protein compete with each other for absorption
b). Dipeptides and tripeptides enter the mucosal cell and then broken down into amino acids.
- Amino acids pass from the mucosal cell and travel to the liver via the hepatic portal vein.
***Little dietary protein lost in the feces
, Amino acid absorption ■Di- and tripeptides enter the mucosal cells of the small intestine
using one of several energy-requiring active transport systems.
■Amino acids sharing the same transport system will compete for absorption.
- Example: Branched Chain Amino Acids: Leucine, isoleucine, and valine
- If leucine is in excess- What happens to isoleucine and valine?
Protein Digestion and Food Allergies ■Occur when a dietary protein is absorbed without
being completely digested.
■Common sources:
-Milk, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish.
■Reaction of the Immune System:
-1st Time: Stimulation of the immune system
-2nd time: Immune system identifies protein as a foreign, harmful substance.
- Attacks Protein --> Allergic Reaction occurs
■Symptoms:
-Vomiting, diarrhea, rash, hives, drop in blood pressure, decreased breathing.
-Anaphalaxis: Most severe reaction - breathing difficulties, rapid drop in blood pressure.
Amino Acid Pool ■Amino acids in the body's tissues and fluids, available for use.
-Energy: 4 kcal/g
Dietary proteins --> digestion --> amino acid pool --> protein synthesis --> body proteins
Body proteins --> protein breakdown --> amino acid pool --> energy, synthesis of glucose or
fatty acids, synthesis of nonprotein molecules that contain nitrogen
