Biology Lab Test 1

Millileter (ml)

1 L

Micormeter (um)

1,000,000 th

Nanometer (nm)

1,000,000,000 th

Benedict's Solution

1. Blue color 2. Tests for sugar 3. The copper ion in the benedict's reagent reacts with part of the sugar molecule, causing a distinctive color change. The color change can range from green to red. Increasing concentrations of sugar will give a contimuum of colored products. 4. -Blue: None -Geen: Very low -Orange: High -Red: Very High

Biuret Reagent

1. Blue color. 2. Contains strong solution of sodium or potassium hydroxide and a small amount of dilulte copper sulfate solution. 3. Changes color in the presence of proteins or peptides because the peptide bonds of the protein or peptide chemically combine with the copper ions in the reagent. 4. Proteins: Purple 5. Peptides: Pinkish-purple.

What are the essential steps of the scientific method?

1. Making observations 2. Formulating hypothesis 3. Testing hypothesis 4. Coming to a conclusion 5. Developing a theory

How to Measure Volume

1. Two metric units of volume are the liter (L) and the milliliter (ml). 2. Measure L, W, and D of item. 3. Multiply L, W, and D 4. = x cm^3, one cm^3=1 ml

How to Measure Weight

1. Two metric units of weight are the gram (g) and the mmilligram (mg). 2. Use a balance scale. 3. Subtract weight of container.

How to Measure Length

1. Units of measurment for length are meters (m), centimeters (cm), millimeters (mm), micrometers (um), and nanometers (nm).

Iodine Solution

1. Yellowish-brown. 2. Reacts chemically with starch to orm a blue-black color.

Centimeter (cm)

100 th

Liter (L)

1000 ml

Millimeter (mm)

1000 th

What is a hypothesis?

A hypothesis is a tenative decision based on what one has observed. It's a prediction of what you think will happen.

A test tube contains albumin. The test for protein is positive and the test for starch is negative. Explain.

Albumin is a protein.

What do you call a sample that goes through all the steps of an experiment but does not contain the factor being tested?

Control sample.

Why is it important to test one substance at a time when doing an experiment?

If you test more than one variable at a time, you won't know which variable caused the desired change in the outcome.

Is it sufficient to do a single experiment to test a hypothesis? Why or why not?

No, because there are several variables that effect the experiment. A good scientist will run an experiment under differnt circumstances, changing one variable at a time. A well-designed experiment must be able to be replicated with the same results.

How to Make Slides of Specimens (Wet Mount)

Place a drop of liquid on a slide or, if the material is dry, place it directly on the slide and add a drop of water or stain. Cover the mount with the coverslip. Dry the bottom of the slide before placing on the stage.

Assume that you have tested an unknown sample with both biuret solution and Benedict's solution and that both tests result in a blue color. What have you learned?

That there are no sugars and no proteins in the sample.

A test tube contains starch and the enzyme amylase. After 30 minutes, the test for starch is negative and the test for sugar is positive. Explain.

The starch is broken down into sugars.

8. What results would you expect from performing the Benedicts test?

The water would turn blue and signal that there were no sugars in the water.

7. Why did you use Benedicts solution to test the diffused water?

This served as our negative control substance.

How would you test for the following substances? a. Sugars b. Fat c. Starch d. Protein

a. Benedict's Solution b. Paper c. Iodine Solution d. Biuret Solution