Question

15 multiple choice 2 points
which of the following is not true about hemoglobin?
erythrocytes do not contain hemoglobin
a molecule consists of globin and four heme groups
there are >250 million hemoglobin molecules per red blood cell
it greatly increases o2 transport

16 multiple choice 2 points
which of the following is true about enzymes?
they are usually specific for a single type of reaction
they are proteins and catalysts
they bring reactants together in precise orientations
all of the above
none of the above

17 multiple choice 2 points
which of the following is not a main nutrient class?
proteins
lipids
enzymes
carbohydrates

Explanation:

Analyze hemoglobin characteristics

• Erythrocytes (red blood cells) are packed with hemoglobin, which is essential for oxygen transport. The statement "Erythrocytes do not contain hemoglobin" is false.
• Hemoglobin consists of globin proteins and four iron-containing heme groups.
• Each red blood cell contains approximately 250–280 million hemoglobin molecules.
• Hemoglobin greatly increases the blood's oxygen-carrying capacity.

Analyze enzyme characteristics

• Enzymes are highly specific catalysts, typically accelerating a single type of chemical reaction.
• Most enzymes are proteins that act as biological catalysts.
• Enzymes bind substrates at their active sites, bringing reactants together in precise orientations to facilitate the reaction.
• Since all individual statements are true, "all of the above" is the correct choice.

Identify main nutrient classes

• The six major classes of nutrients required by the body are carbohydrates, lipids, proteins, water, vitamins, and minerals.
• Enzymes are biological catalysts (proteins) produced by the body to speed up chemical reactions, but they are not classified as a dietary nutrient class.

Answer:

Question 15

• (A) Erythrocytes do not contain hemoglobin (Correct answer)
• (B) A molecule consists of globin and four heme groups
• (C) There are >250 million hemoglobin molecules per red blood cell
• (D) It greatly increases O2 transport

Question 16

• (A) They are usually specific for a single type of reaction
• (B) They are proteins and catalysts
• (C) They bring reactants together in precise orientations
• (D) all of the above (Correct answer)
• (E) none of the above

Question 17

• (A) proteins
• (B) lipids
• (C) enzymes (Correct answer)
• (D) carbohydrates