ICC Biology Lab Module 3

Why isn't there a color change to purplish-black when iodine is added to milk?

Starch is not present.

Which of the observed test tubes represent the following reaction? Oil & vinegar dressing + Sudan IV --> Red stain dispersed in oil only

Test tube # 3

What is the role of the iodine solution that was added to test tube # 1?

The iodine serves as an indicator of starch.

In the presence of glucose, Biuret's reagent changes from blue to purple in color.

False

In the presence of protein, iodine changes to a purple color.

False

In the presence of starch, Benedict's solution changes from blue to orange or brick red in color.

False

When mixed with a lipid, Sudan IV evenly stains the lipid.

True

Cellular respiration is _________.

both a and b (a catabolic reaction that produces energy from food!)

The term that describes the affect that high temperatures have on enzymes is _______.

denatures

Which of the following biological macromolecules (molecules of life) was omitted from this lab?

nucleic acids

Plants store glucose in the form of

starch

Is Sudan IV soluble in water?

No

Is a lipid soluble in water?

No

Which of the following explains the absence of a color change in test tube #2 that contains 15 drops of glucose solution and 3 drops of iodine?

All of the above are true. (Iodine does not test (indicate) for glucose, Starch was not present, and Glucose does not contain starch.)

Amylase is ________.

All of these (found in saliva, necessary for the break down of starch in the mouth, and an enzyme.)

What is the role of the Benedict's solution in test tube # 4?

All of these are correct (Benedict's solution shows that starch breaks down into glucose in the presence of amylase, The Benedict's solution shows that starch breaks down into glucose, and The Benedict's solution indicates the presence of glucose.)

Which of the following indicates for simple sugars (glucose)?

Benedict's Solution

Which of the following indicates for proteins?

Biuret's Reagent

Which of the following indicates for lipids?

Both C and D are true (Sudan IV and Greasy Spot Test.)

Proteins are present in ______.

Both plant and animal cells

Which of the following indicates for simple starch?

Iodine

What is the purpose of test tube # 3 (containing starch, amylase, iodine and placed in a warm water bath)?

It shows that starch breaks down into glucose in the presence of amylase.

Is Sudan IV soluble in oil?

Yes

If one adds iodine to milk, how long must one wait for a purplish black color change to occur?

forever

Organisms are said to be ___________ if they cannot make their own food.

heterotrophic