Bio 189 lab quiz 3

Question 1

what is a disaccharide?

Answer 1

two molecules

Question 2

How could a polysaccharide be broken down into individual monosaccharides?

Answer 2

An enzyme can break a glyosidic linkage via a hydrolysis reaction.

Question 3

Would you expect a large amount of the following molecule to be in a liquid form or solid form at room temperature?

Answer 3

Because of an absence of carbon/carbon double bonds, I would expect the sample to be in a solid form.

Question 4

Look at the molecule shown below. Which statement about this molecule is correct?

Answer 4

This molecule is an unsaturated fatty acid.

Question 5

If a test tube contained a clear solution of starch, what would you predict would be the result of a Benedict’s test on this sample?

Answer 5

The sample would change color to blue, indicating a negative result.

Question 6

If a test tube contained a clear solution of glucose (monomers), what would you predict would be the result of an Iodine test on this sample?

Answer 6

The sample would change color to yellow indicating a negative result.

Question 7

Look at the molecule shown below. Which statement about the R side chain of this molecule is correct?

Answer 7

This region determines how the amino acid interacts with other molecules.

Question 8

What type of reaction would produce the results shown below?

Answer 8

A hydrolysis reaction breaking a peptide bond.

Question 9

Which of the following nitrogenous bases would not be used in the construction of a DNA polymer?

Answer 9

Uracil

Question 10

What part of the nucleotide should you look at if you are trying to determine if you are looking at a purine or a pyrimidine?

Answer 10

Examine the nitrogenous base

Question 11

What does the intensity of a positive Sudan test indicate?

Answer 11

Concentration of lipids

Question 12

Imagine you are testing two samples, A & B, that have been placed on paper to absorb (in a drawn circle).

After you perform the Sudan test:

the circle containing sample A is blue
the circle containing sample B is orange
What is the correct interpretation of these results?

Answer 12

The orange color indicates a positive test for lipids, so Sample B contains lipids.

Question 13

If a test tube contained a clear solution of individual amino acids (monomers), what would you predict would be the result of a Biuret test on this sample?

Answer 13

The sample would change color to blue-green, indicating a negative result.

Question 14

What does the color intensity of a positive Biuret test indicate?

Answer 14

Concentration of peptide bonds

Question 15

What does the color intensity of a positive Dische diphenylamine test indicate?

Answer 15

Concentration of deoxyribose

Question 16

If a test tube contained an RNA solution, what would you predict would be the result of a Dische diphenylamine test on this sample?

Answer 16

The sample would remain clear, indicating a negative result.