Q: The study materials mention 'Rf' values in chromatography. What is the formula for calculating the Rf value?

$Rf = \frac{\text{Distance traveled by solute}}{\text{Distance traveled by solvent front}}$

Q: Which of the following equations correctly represents the conversion of glucose to fructose in the body?

$\text{Glucose} \xrightarrow{\text{isomerase}} \text{Fructose}$

Question 1

Which technique is primarily used to separate proteins based on their size and charge, as indicated in the study materials?

Accepted Answer

Chromatography: paper type

Question 2

In paper chromatography, what is the main factor that determines how far a molecule travels up the paper?

Accepted Answer

Its solubility in the mobile phase

Question 3

Given the chromatogram shown in the study materials, which spot would represent the molecule with the highest affinity for the stationary phase?

Accepted Answer

The spot closest to the origin

Question 4

Which of the following is NOT a common application of paper chromatography in biochemistry?

Accepted Answer

Amplifying DNA sequences

Question 5

The study materials mention 'Rf' values in chromatography. What is the formula for calculating the Rf value?

Accepted Answer

$Rf = \frac{	ext{Distance traveled by solute}}{	ext{Distance traveled by solvent front}}$

Question 6

If a pigment in a chromatography experiment has an Rf value of 0.8, and the solvent front moved 10 cm, how far did the pigment travel?

Accepted Answer

$8\ 	ext{cm}$

Question 7

Which of the following is a critical step in preparing a paper chromatography experiment to ensure accurate results?

Accepted Answer

Marking the origin line with pencil

Question 8

The study materials show two molecular structures labeled 'Fructose' and 'Glucose.' Which of the following statements is correct regarding their structural difference?

Accepted Answer

Fructose is a ketose, while glucose is an aldose.

Question 9

Which carbon atom in glucose is the carbonyl carbon, as shown in the structure in the study materials?

Accepted Answer

Carbon 1

Question 10

In the context of carbohydrate separation, which property is most important for distinguishing between glucose and fructose using paper chromatography?

Accepted Answer

Polarity

Question 11

A student runs a paper chromatography experiment and observes that two spots have identical Rf values. What is the most likely explanation?

Accepted Answer

The two compounds are likely the same or have very similar properties.

Question 12

Which of the following best describes the role of the stationary phase in paper chromatography?

Accepted Answer

It interacts with the sample to slow down movement based on affinity.

Question 13

If a mixture contains glucose, fructose, and sucrose, which would you expect to have the lowest Rf value in a polar solvent system?

Accepted Answer

Glucose

Question 14

Which of the following is a reason why pencil is used instead of ink to mark the origin in paper chromatography?

Accepted Answer

Pencil does not dissolve in the solvent and interfere with results.

Question 15

A chromatogram shows four distinct spots after separation. What does this indicate about the original sample?

Accepted Answer

The sample contained at least four different compounds.

Question 16

Which of the following equations correctly represents the conversion of glucose to fructose in the body?

Accepted Answer

$	ext{Glucose} \xrightarrow{	ext{isomerase}} 	ext{Fructose}$

Question 17

In a chromatography experiment, what would be the effect of using a more polar solvent?

Accepted Answer

Non-polar compounds would travel less, polar compounds would travel more.

Question 18

Which of the following is a limitation of paper chromatography for separating complex mixtures?

Accepted Answer

It may not resolve compounds with very similar polarities.

Question 19

If a student wants to identify an unknown sugar using paper chromatography, which step is essential for comparison?

Accepted Answer

Running known standards alongside the unknown sample.

Question 20

Which of the following best explains why fructose and glucose can be separated by paper chromatography?

Accepted Answer

They have different chemical structures and polarities.

Carbohydrates: Properties, Classification, and Epimers

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