Question 1

Which of the following ions is most important for nerve impulse transmission in humans?

Accepted Answer

Na$$^{+}$$

Question 2

A student performs Benedict's test on four solutions: glucose, sucrose, maltose, and starch. Which solution is LEAST likely to show a positive result (color change)?

Accepted Answer

Sucrose

Question 3

Which of the following best explains why Sudan Black stains lipids intensely?

Accepted Answer

Sudan Black is non-polar and partitions into the non-polar regions of lipids.

Question 4

Which of the following is a correct chemical formula for a monosaccharide commonly found in living systems?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$}$$

Question 5

During Benedict's test, which chemical change indicates the presence of a reducing sugar?

Accepted Answer

$$\mathrm{Cu$$^{2+}$$} is $$reduced to $$\mathrm{Cu^+}$$

Question 6

Which of the following best describes the difference between triglycerides and phospholipids?

Accepted Answer

Triglycerides have three fatty acid chains, while phospholipids have two and a phosphate group.

Question 7

Which of the following ions is essential for blood coagulation and nerve impulse transmission?

Accepted Answer

Calcium (Ca$$^{2+})$$

Question 8

A student adds IKI reagent to a solution and observes a blue-black color. What does this indicate?

Accepted Answer

Presence of helical polysaccharides such as starch

Question 9

Which of the following best explains why not all sugars are reducing sugars?

Accepted Answer

Only sugars with a free carbonyl group (aldehyde or ketone) can act as reducing agents.

Question 10

Which of the following is a function of iodine (I) in the human body?

Accepted Answer

Thyroid gland function

Question 11

Which of the following best describes the structure of amylose (starch)?

Accepted Answer

A linear polymer of glucose units linked by $$\alpha-1$$,4 glycosidic bonds

Question 12

Which of the following is a major anion in extracellular fluids?

Accepted Answer

Chloride (Cl$$^{-})$$

Question 13

A patient is found to have low potassium (K$$^{+}) $$levels. Which of the following symptoms is most likely?

Accepted Answer

Impaired nerve impulse transmission

Question 14

Which of the following is a correct description of a reducing agent in Benedict's test?

Accepted Answer

A molecule that donates electrons to another molecule

Question 15

Which of the following best explains why phospholipids are suitable for forming cell membranes?

Accepted Answer

They have both hydrophilic and hydrophobic regions, allowing them to form bilayers.

Question 16

Which of the following is a correct formula for the reaction of a reducing sugar with Benedict's reagent?

Accepted Answer

$$\mathrm{Cu$$^{2+}$$ + e^- \rightarrow Cu^+}$$

Question 17

Which of the following is a function of magnesium (Mg$$^{2+}) in $$the human body?

Accepted Answer

Component of enzymes, electron carrier molecules, transport of DNA

Question 18

Which of the following best describes the difference between amylose and amylopectin?

Accepted Answer

Amylose is a linear polymer, while amylopectin is branched.

Question 19

Which of the following is a correct description of the role of chloride (Cl$$^{-}) in $$the human body?

Accepted Answer

Major anion in extracellular fluids

Question 20

Which of the following best explains why lipids do not dissolve in water?

Accepted Answer

Lipids are non-polar and water is polar, so they do not mix.

Biological Molecules: Lab 3

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