Bio Lab Chemistry Quiz

Biuret reagent contains ________ ions which react with peptide bonds under the alkaline conditions of the reagent and produce the color change associated with the presence of protein.

Copper

How can you determine the optimum pH of an enzyme?

Test the enzyme at different pH levels.

Imagine that you are observing an enzyme-catalyzed reaction in lab. Every time you add more enzyme, the reaction rate increases proportionally until the reaction rate suddenly levels off. No other chemicals were added, and no modifications were made in the experimental setting. Why do you think the reaction rate stopped increasing?

The molecules of substrate were all bound to enzyme.

Imagine that you are observing an enzyme-catalyzed reaction in lab. Every time you add more enzyme, the reaction rate increases proportionally until the reaction rate suddenly levels off. No other chemicals were added, and no modifications were made in the experimental setting. Why do you think the reaction rate stopped increasing?

The molecules of substrate were all bound to enzyme. (saturation)

The formation of a green color after heating with Benedict's reagent indicates that a sample contains simple sugars.

True

The specificity of catalase only to hydrogen peroxide can be shown by comparing

a mixture of hydrogen peroxide and catalase

reagent can be used to detect the presence of sugars.

benedicts

Which of the following reagents is best suited for the detection of protein?

biuret

Which of the following tests is best suited for the detection of fat and oils?

brown paper

Enzyme activity can be determined in the following ways:

by measuring how much of the enzyme is consumed

When Benedict reagent is added to a solution containing simple sugars, the solution turns green, orange, or red. In the absence of simple sugars, the solution is blue. Benedict reagent was added to solutions that may or may not contain simple sugars. The data can be seen in the table below. The color change that occurs is considered the

dependent variable

Which substance in a reaction will not change in concentration as the reaction proceeds?

enzyme

Which of the following are functions of adipose tissue? (Select all that apply)

insulation gamete production storage of fat glucose storage (glycogen) cushioning of organs

can be used to detect the presence of starch.

iodine

The image shows a Biuret test to determine the presences of protein. Is it positive or negative?

light blue = negative

Which group of molecules are insoluble in water?

lipids

Which of the following is completely insoluble in water?

lipids

Match each test with the substance it is intended to detect.

lipids: brown paper test protein: biuret test Benedict's: simple sugar iodine: starch

How often can a catalase molecule be used to hydrolyze hydrogen peroxide?

many times

What are the building blocks of complex carbohydrates?

monosaccharides

At higher temperatures molecules move _____ rapidly. (one word answer)

more

An unknown liquid sample is tested for chemical composition. You receive the following results: iodine test = yellow; biuret test = purple; Benedict's test = red; and paper lipid test = clear. Which of the following are present in this sample? (Select all that apply)

protein and sugar

Based on your procedure from the pH enzyme lab, how can you accurately measure how pH alone affects an enzyme's ability to function?

same amounts of enzymes and different pH values

Which of the following is the action on an enzyme?

speed up reactions

Select each substance that is necessary to have a reaction.

water

When enzyme activity rate has reached stability, an increase in the enzyme concentration will

will not make any difference in the enzyme rate.

What is the minimal drying time for the paper lipid test?

15 minutes

At room temperature, Biuret reagent should react with protein within

30 seconds

Enzymes increase the reaction rate of a specific reaction.

true