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1. Science of Nutrition(0)

What is Nutrition
(0)

Nutrients
(0)

Macronutrients
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Micronutrients
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Fiber and Phytochemicals
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Energy in Food
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Nutrition as a Science
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Finding Credible Nutrition Information
(0)

2. Tools for Healthful Eating(0)

Healthful Eating
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Three Guides to a Healthful Diet
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Dietary Guidelines for Americans
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Dietary Reference Intakes
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Food Labels
(0)

3. The Human Body & Digestion(0)

Hunger, Satiety, and Hormones
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Overview of the Digestive System
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Organs of the Gastrointestinal Tract
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Accessory Organs
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Nutrient Absorption and Transport
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The Gut Microbiome
(0)

Disorders of the Digestive System
(0)

4. Carbohydrates(0)

Intro to Carbohydrates
(0)

Simple vs Complex Carbohydrates
(0)

Why Do We Need Carbohydrates?
(0)

Fiber
(0)

Carbohydrate Digestion
(0)

Dietary Guidelines for Carbohydrates
(0)

Alternative Sweeteners
(0)

Blood Glucose Regulation
(0)

Diabetes
(0)

5. Lipids(0)

Introduction to Lipids
(0)

Why Do We Need Lipids?
(0)

Fatty Acids
(0)

Digestion of Fats
(0)

Dietary Guidelines for Lipids
(0)

Cardiovascular Disease
(0)

6. Proteins(0)

Introduction to Proteins
(0)

Protein Structure
(0)

Protein Synthesis
(0)

Why Do We Need Protein?
(0)

Protein Digestion
(0)

Dietary Guidelines for Proteins
(0)

Protein-Related Disorders
(0)

7. Vitamins(0)

Introduction to Vitamins
(0)

Fat-Soluble Vitamins
(0)

Water-Soluble Vitamins
(0)

Dietary Guidelines for Vitamins
(0)

Other Vitamin-Like Nutrients
(0)

8. Water and Minerals(0)

Water
(0)

Introduction to Minerals
(0)

Major Mineral: Sodium and Potassium
(0)

Hypertension and Minerals
(0)

Major Mineral: Calcium and Phosphorus
(0)

Osteoporosis: Minerals and Bone Health
(0)

Major Mineral: Chloride, Magnesium, & Sulfur
(0)

Trace Minerals: Iron and Copper
(0)

Trace Minerals: Fluoride and Iodine
(0)

Other Trace Minerals
(0)

9. Alcohol(0)

Alcohol Consumption
(0)

Alcohol Metabolism
(0)

Short-Term Effects of Alcohol
(0)

Long-Term Effects of Alcohol
(0)

10. Energy Balance: Body Weight, Obesity, & Eating Disorders(0)

Healthy Weight
(0)

Energy Balance
(0)

Assessing Weight Related Health Risk
(0)

Factors That Influence Weight
(0)

Weight Loss
(0)

Maintaining Weight
(0)

Gaining Weight
(0)

Eating Disorders
(0)

11. Nutrition & Fitness(0)

Introduction to Physical Fitness
(0)

Exercise
(0)

Using Energy to Fuel Exercise
(0)

Nutrition & Physical Activity
(0)

Ergogenic Aids
(0)

12. Food Safety & Regulation(0)

Food Safety
(0)

Foodborne Pathogens
(0)

Foodborne Toxins
(0)

Food Preservation & Additives
(0)

U.S. Food Safety Systems
(0)

Natural, Organic, & Bioengineered Foods
(0)

13. Food Insecurity in the US and the World(0)

Food Insecurity
(0)

Global Food Insecurity
(0)

14. Nutrition: Pregnancy Through Infancy (0)

Preconception Nutrition
(0)

Nutrition During Gestation
(0)

Potential Complications During Pregnancy
(0)

Breastfeeding
(0)

Nutritional Needs for Infants
(0)

15. Nutrition: Toddlers to Late Adulthood(0)

Nutrition For Young Children (Ages 1-5)
(0)

Nutrition For School-Age Children (Ages 6-11)
(0)

Nutrition During Adolescence (Ages 12-19)
(0)

Nutrition For Older Adults (Ages 50+)
(0)

6. Proteins

Protein Structure

6. Proteins

Protein Structure: Videos & Practice Problems

Video Lessons Practice Worksheet

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5 of 0

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Problem 5Multiple Choice

Which description correctly explains how peptide bonds form between amino acids and why the amine and carboxyl groups of interior residues appear chemically different from free amine or carboxyl groups?

Peptide bonds are ionic interactions between R groups; the backbone amine and carboxyl groups remain entirely unmodified, which is why they always appear as free —NH2 and —COOH in polypeptides.

Peptide bonds result from spontaneous formation of disulfide bridges between backbone sulfurs and do not involve dehydration, so backbone amine/carboxyl chemistry is unchanged.

Peptide bonds form by a condensation (dehydration) reaction linking the carboxyl carbon of one amino acid to the amine nitrogen of the next, producing an amide linkage; interior residues lack free —NH2 and —COOH because those groups are tied up in peptide bonds.

Peptide bonds form through phosphorylation of the carboxyl group and ester formation with neighboring hydroxyls, causing backbone amine groups to become permanently positively charged while carboxyls become neutral esters.

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