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

1. Introduction to Biochemistry

Nucleic Acids

Biochemistry

1. Introduction to Biochemistry

Nucleic Acids

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Multiple Choice

Which of the following best describes the difference between NAD$^+$ and NADH?

NAD$^+$ is the oxidized form, while NADH is the reduced form.

NAD$^+$ acts as an electron donor, while NADH acts as an electron acceptor.

NAD$^+$ is found only in DNA, while NADH is found only in RNA.

NAD$^+$ contains two phosphate groups, whereas NADH contains only one.

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Verified step by step guidance

Step 1: Begin by understanding the role of NAD$^+$ and NADH in biochemical reactions. NAD$^+$ (nicotinamide adenine dinucleotide) is a coenzyme involved in redox reactions, where it alternates between oxidized (NAD$^+$) and reduced (NADH) forms.

Step 2: Clarify the oxidation and reduction states. NAD$^+$ is the oxidized form, meaning it can accept electrons during a reaction. NADH is the reduced form, meaning it has already gained electrons and can donate them in subsequent reactions.

Step 3: Examine the statement about electron donor and acceptor roles. NAD$^+$ acts as an electron acceptor because it gains electrons to become NADH. Conversely, NADH acts as an electron donor because it can transfer electrons to other molecules.

Step 4: Address the incorrect statements. NAD$^+$ and NADH are not exclusive to DNA or RNA; they are coenzymes involved in metabolic pathways. Additionally, both NAD$^+$ and NADH contain two phosphate groups, so the statement about differing phosphate numbers is incorrect.

Step 5: Conclude by identifying the correct description: NAD$^+$ is the oxidized form, while NADH is the reduced form. This distinction is fundamental to understanding their roles in cellular metabolism and energy transfer.