Biotech Lab#2 DNA ScissorsExtract DNA from cell

Magnify a portion of DNA & it looks like this: Double Helix

Magnify a portion of Double Helix & it looks like this:

ATCGGACGTACGGGG

TAGCCTGCATGCCCC

This is a sequence of nucleotides. How many nucleotides? 30How many bases? 30 How many base pairs? 15 This segment represents a gene.

The “Gene”• A gene is a segment of DNA with a specific sequence of

nucleotides.• A gene is associated with an organism’s trait.• A gene provides the information to make a protein that determines

what an organism can do or look like. Proteins can be one of many types.

Types of Proteins• Transport - hemoglobin• Receptor - membrane protein• Storage - albumin• Signal - insulin• Contractile - actin, myosin• Enzyme - catalase• Structural - collagen

Molecular Biologists will• Want to be able to remove the gene from the DNA• Want to take the gene and put it in another area of the DNA

or in another organism’s DNA• Let’s review DNA structure to complete this lab: DNA Scissors

DNA is antiparallel• Antiparallel means that

the two strands run in opposite direction.

• One strand runs in the 3’ to 5’ direction and opposite strand runs in the 5’ to 3’ direction.

• Diagrams to right illustrate antiparallel…look at the arrows.

Why is one end 3’ and the other 5’?• Look at the 3’ end.

Notice the black line which represents a bond. What functional group belongs here?

• Look at the 5’ end. What functional group is bonded to the 5’ carbon?

DNA Scissors

This lab is about special enzymes that will cut DNA into smaller fragments.This lab will simulate how a specific enzyme cuts the DNA.This lab shows how to prepare DNA for future use.

Restriction Enzymes• Enzymes that catalyze a reaction that will cut the DNA at a

specific location• The location on the DNA is called the restriction site• A restriction site has a specific sequence of nucleotides called

a palindrome “RACECAR”

Pieces of DNA

The picture shows the (4) strips of DNA that will be used to simulate the action of a restriction enzyme.

What kind of cuts are made?• Sticky ends

• Blunt ends

How Restriction Enzyme Works

Answer these three questions:1. What type of cut is #1? #2?

2. Identify an enzyme that can make a cut like cut#1.3. What is the palindrome sequence for cut #1?

Now do the lab……..• Read each step carefully.• Answer questions within a step on the lined paper.• Upon completion, tape DNA strips to a piece of colored paper.• Each table will submit each person’s work as a group.

What is meant by recombinant DNA?