Do Now:

Answer the pre-lab questions on the front page of your handout.

Learning Objectives: DNA ExtractionBy the end of this class, you will be able to:1. Make predictions about the appearance of

DNA2. Discover and explain how we are able to

remove DNA from cells and see it even though DNA is very small and can usually only be seen with a powerful microscope

3. Predict traits that could be given to strawberries using biotechnology

4. Determine that the leafy green part of strawberries appears so different from the red fleshy part of the strawberry due expression of different genes and not due to different genes existing in different parts of the plant

Vocabulary Review

1. Solution:a liquid mixture in which one substance is dissolved in another substance

Vocabulary Review

2. Soluble:able to dissolve in something.

Example: Sugar is soluble in water

Vocabulary Review

3. Precipitate (noun):A solid substance that is not dissolved in a solution

Precipitate (Verb):To cause a solid substance to separate from a solution

Vocabulary Review

3. Extract (noun):a solution obtained by steeping or soaking a solid in a liquid

Extract (Verb):To remove or take out something

Vocabulary Review

4. Filter (noun):something that separatessolids from liquids

Filter (verb): to remove solids from a liquid

Vocabulary Review

6. Histone Protein:

A protein that DNA winds around

Vocabulary Review

7. Phospholipid membrane:A cell membrane that is made up of two layersof phospholipids.Phospholipids have a polar (water-loving) head and a non-polarfatty tail.

Vocabulary Review

8. Biotechnology:Taking DNA from one organism and puttingit into another organism

Vocabulary Review

9. Gene Expression:The conversion of the information encoded in a gene first into messenger RNA and then to a protein.

Are all genes being expressed in an organism at all times?

Vocabulary Review

10. Knead:To mix and work into a uniform mass, as by folding, pressing, and stretching with the hands

Vocabulary Review

11. Analogy:a comparison between two things, usually on the basis of their structure and for the purpose of explanation or clarification

Background Information

• The long strands of DNA store the genetic information of living things. DNA is present in every cell of plants, animals, and other living things, with one exception.

• What cells have no nucleus and therefore

have no DNA?

Background Information

• The DNA found in strawberry cells can be extracted using common materials. We will use a DNA extraction buffer. This extraction buffer will help us remove the DNA from the strawberry cells. It contains salt and soap.

Background Information

• The salt breaks up the histone proteins that the DNA is wrapped around.

• Why would we need to break up these proteins before extracting the DNA from cells?

Background Information

• The soap dissolves the phospholipid part of the strawberry cell and nuclear membranes.

Why do we need to dissolve the cell and nuclear membranes before extracting the DNA?

Laboratory Safety

• None of the chemicals or materials we will be using in this lab are particularly dangerous. However, you must be careful and follow a few basic rules:

Laboratory Safety Rules• 1. DO NOT EAT ANYTHING. I know the strawberries look

delicious. Do not eat them. Today, they are not food, they are laboratory materials.

• 2. BE CAREFUL WITH THE SCISSORS. Mrs. Campbell will demonstrate the correct way to hand somebody a pair of scissors.

• 3. WASH YOUR HANDS after you have finished the lab activity.• 4. POUR LIQUIDS CAREFULLY. Do not splash any liquids on

purpose. If you spill something, wipe it up with a wet paper towel, then wipe the surface again with a dry paper towel.

MaterialsCheck your lab station to make sure you have these items:

• Plastic zip-top bag• 1 strawberry• DNA extraction buffer• graduated cylinder• cheesecloth• funnel• test tube• test tube rack• wooden skewer• ice cold isopropyl alcohol• scissors

Breaking Laboratory Safety RulesBreaking the rules will cause you to lose your lab privileges. You will have to sit in a chair in the back of the room and watch everybody else do the lab. Continued disruptive behavior will earn you a referral.

Modeling the Lab Procedure

Watch Mrs. Campbell as she goes through all of the steps of the lab.

Clean Up

After you have finished the lab:-throw away the zip-top bag and the cheesecloth-dump the liquid from the test tube in the bucket that is next to the sink-place test tubes, funnels, and sticks in the appropriate bins by the sink-wipe down your table and wash your hands-start working on the Conclusions and Analysis questions-if you finish the Conclusions and Analysis questions, you may start your homework (the genetic engineering article and questions)