Monday, quiz and pineapple wrap up

Today you had your quiz and then we wrapped up the pineapple lab. Make sure you can answer the following questions about enzymes.

1. What are enzymes?
2.What is an active site?
3. What things in the enzyme's environment can denature it?
4. What is the molecule an enzyme acts on?
5. How does the environment affect an enzyme's function?
6. What happens to the collagen in gelatin when you dissolve it in hot water and then refridgerate it?


We then went over the basics of bacterial growth (which is by binary fission).Here is a great site on bacterial growth and the stages.

From the cellsalive site:

LAG PHASE: Growth is slow at first, while the "bugs" acclimate to the food and nutrients in their new habitat.

LOG PHASE: Once the metabolic machinery is running, they start multiplying exponentially, doubling in number every few minutes.

STATIONARY PHASE: As more and more bugs are competing for dwindling food and nutrients, booming growth stops and the number of bacteria stabilizes.

DEATH PHASE: Toxic waste products build up, food is depleted and the bugs begin to die.

Homework for Thursday: Read and take notes on the 13.5 handout and then read the lab for thursday.

Monday -Design lab

Today we reviewed your pineapple enzyme design labs and chose 2 possible ideas.

1. Independent Variable - juice type (orange, peach, grape, lemon).


2. Independent Variable - temperature (85, 60, 37, 24)

Part of your homework again tonight is to write up the PROCEDURE. You must have it written out when you arrive tomorrow.

Remember to use your original lab as a guide. You need to have a list of all the materials you need and then the steps (i.e. how to make the jello, how much to add to each tube, how many tubes does each group need). AND then a list of the IV, DEP, etc.

example from your original lab

1.      Label test tubes as “pineapple – hot,” “pineapple – RT,” “apple juice – hot,” “apple juice – RT,” and “water.”  Apply the tape at the top of the test tube with a “tail” as shown at right, so steam from the water bath does not remove the labels.

2.      Prepare gelatin in an appropriate beaker.

a.    Dissolve the contents of a gelatin packet in ¼ cup cold water.

b.    Add ¾ cup boiling water to the mixture and stir until completely dissolved.

3.      Pipette 3ml of juice or water into each test tube according to the labels, using transfer pipettes.  Do not cross-contaminate juices by using a pipette in different types of juice.

4.      Place your “hot” tubes in a beaker of water.  Heat the beaker on the hotplate until a thermometer in the water of the beaker reads 85°C.  Carefully remove the tubes from the heat.  Allow contents to come to room temperature (RT).

5.      Add 10 ml ROOM TEMPERATURE gelatin mixture to each test tube.  Use the big pipette for this and do not let the gelatin drip into the green pipetter.  Shake tubes well to ensure mixing of contents

6.      Refrigerate test tubes overnight.

We also reviewed the sickle cell gel electrophoresis handout. If asked could you answer the following questions..
1. What is the phenotype if someone is Aa? Explain
2. What is a recessive allele?
3. How do we use restriction enzymes to determine genotype of sickle cell?

The last part of your homework is the handout below

7 text homework 5 from lvilleDrFox

Thursday - More on Enzymes

Thursday we worked on the lab involving how proteolytic enzymes and/or heat affect proteins such as collagen. Collagen is a structural protein involved in skin, connective tissue and bones of animals. Below are a couple of images of collagen and how it is organized.

Enzymes have specific 'substrates' or targets on which they work. Some enzymes 'digest' or 'break down' their substrate, while others put 2 targets together. Which type is our 'proteolytic' enzyme from fruit? What is the enzyme's substrate in our lab? Will that enzyme break down another substrate?

Proteins (which is what enzymes are!) can be denatured by heat and some chemicals. This is the process of denaturation.

In our lab, we are looking how 2 variables affect