Unit 6 BIOL 1406 LAB Review

Describe three different factors that can impact enzyme activity.

1. Temperature

2. pH

3. presence or absence of cofactors

Describe what happens to the physical structure of enzymes at suboptimal conditions using proper scientific terminology

Denaturation occurs due to the enzyme unfolding and losing its shape

Extremely high temps can disrupt the bonds and interactions between amino acids in a protein

Extremely low temps can make the enzyme more properly folded but molecules move more slowly so reaction rates are slowed

Define a colorimetric test and give an example

Any test in which a color change is used to indicate the presence of a chemical or molecule

Describe the color or Lugol’s iodine in the presence of starch

Is a blue-black color in the presence of starch

Define type of macromolecule for each of the following:

a. Starch

b. Amylase

c. Maltose

1. Starch is a polysaccharide, which is a type of carbohydrate. It is composed of long chains of glucose molecules linked together by glycosidic bonds and serves as a storage form of energy in plants.

2. Amylase is a protein, which is a type of macromolecule made up of amino acids. It functions as an enzyme that catalyzes the breakdown of starch into smaller sugar molecules, like maltose.

3. Maltose is a disaccharide, which is a type of carbohydrate. It consists of two glucose molecules linked by a glycosidic bond and is a product of starch digestion.

Explain how you can test amylase activity to determine optimal temp and pH conditions for the enzyme

1. For optimal temp, you will combine amylase w/ a starch solution in a microfuge tube then you will test for starch digestion by adding the amylase/starch mixture to Lugol’s iodine and note the color change

2. For pH conditions, you will prepare starch and iodine

Identify what color the following reactions should turn:

1. 1% starch + functional amylase + Lugol’s iodine

2. 1% starch + nonfunctional amylase + Lugol’s iodine

1. Pale yellow

2. Blue-black

For E1 and E3, explain what a black/brown tells you about amylase activity. Explain what a yellow color at the end of the exercise tells you about amylase activity

1. black/brown = amylase is not breaking the starch down effectively (low activity)

2. yellow = amylase activity is active

Explain the relationship between H+ concentration and the pH scale.

The lower the # on the pH scale, the higher the concentration of hydrogen ions in the solution

Explain what happens to the hydrogen ion concentration of a solution when acids or bases are added

1. When an acid is added, the concentration of hydrogen atoms increases. The pH also decreases

2. When a base is added, the ph increases and the concentration is decreasing.

Demonstrate the ability to determine the pH of a solution using a pH meter

Get pH meter and measure the solution

Differentiate between acids, bases, and neutral solutions

1. Acids are below 7

2. Bases are above 7

3. Neutral is 7

Define buffer and buffering capacity and give a biological example.

1. Buffering capacity is measured by how much a solution resists change in its pH when acid or base is added. It requires a weak base and acid.

2. A solution has a high buffering capacity when it resists change in pH when an acid or base is added

3. A solution has a low buffering capacity when the pH changes fairly quickly when an acid or base is added

4. An example is carbonic acid

Explain why buffers are important in biology

It’s important because it helps maintain pH

Describe how the carbonic acid buffer system works.

Carbonic acid acts as a weak acid, able to donate protons when a base is added.

When acid is added, the solution is able to absorb the protons using the conjugate base, the bicarbonate ion, reforming carbonic acid.

The effect on the pH of the solution is minimized by the presence of the weak acid and conjugate base pair

if pH goes up, the rate of the forward reaction will increase to release H+ into the solution

if pH goes down, the rate of the reverse reaction will increase to absorb H+ from the solution