Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

2. Water

Properties of Water

Biochemistry

2. Water

Properties of Water

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Multiple Choice

A major cause of rancidity of lipids in foods is exposure to:

carbon dioxide

oxygen

hydrogen

nitrogen

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Verified step by step guidance

Understand the concept of lipid rancidity: Lipid rancidity occurs when fats and oils degrade, leading to unpleasant odors and flavors. This process is often caused by chemical reactions such as oxidation.

Identify the key chemical reaction: Oxidative rancidity is the most common type of rancidity in lipids. It involves the reaction of unsaturated fatty acids with oxygen, forming peroxides and other degradation products.

Analyze the options provided: Carbon dioxide, hydrogen, and nitrogen are relatively inert gases and do not readily react with lipids to cause rancidity. Oxygen, however, is highly reactive and can initiate lipid oxidation.

Relate oxygen to lipid oxidation: Oxygen interacts with unsaturated fatty acids in lipids, especially in the presence of catalysts like light, heat, or metal ions, leading to the formation of free radicals and subsequent degradation.

Conclude the reasoning: Based on the chemical properties and the process of oxidative rancidity, oxygen is the major cause of lipid rancidity in foods.