DNA Lab
Do Now: Decode the message by matching the letter according to the following
pattern
PLEASE USE CAPITAL LETTERS
A-T
C-G
A T G C
T
A
C
G T C
A A A C
T G T C
A T T C
G
G
1. How are DNA, chromosomes and genes linked?
Your chromosomes are composed of DNA. DNA contains all the information
for your growth and function. It stores the information using a genetic code. The
genetic code only has four letters (A, T, C, G). This code can be millions or
billions of “letters” long. Imagine the code as an instructions book with all the
instructions on how to make and operate every cell of your body. This book is
divided into 46 chapters, or chromosomes. Each chromosome (or chapter) is
further subdivided into sections or genes. These genes provide instructions for
each type of cell and determine our characteristics such as your height, sex, skin
color, etc.
1. What are chromosomes made from?
2. What information does DNA contain?Explain how your Chromosomes can be
compared to a book.
DNA Replication Steps
1. When DNA is ready to replicate, an enzyme (Helicase) signals it to unzip or
split in half. The chemical bonds that hold the nitrogen bases together
break apart.
2. Then, new bases are carried to each separated side and they bond according
to the pattern. Remember, if an adenine is on the original strand, a thymine
base will bond to it.
3. Then, on the other strand where the original base was bonded, a
complementary (matching) base will bond. For example, if a thymine was on
one strand, an adenine will bond to it.
4. By following the original pattern and by matching up nitrogen bases, each
new DNA molecule will have the same pattern as the original strand.
Questions:
1.
What happens in the first step of DNA Replication?
2. What is happening in the second step of DNA Replication?
3. What is happening in the final two steps of DNA
Replication?
DNA Replication Example
Follow the directions to Replicate a Section of DNA.
1. Here is an example of a section of DNA.
A
C
C
C
G
T
T
G
C
G
G
A
A
T
C
A
G
C
C
T
T
G
G
G
C
A
A
C
G
C
C
T
T
A
G
T
C
G
G
A
C
T
2. Next, the DNA Helicase unzipped the two strands of DNA.
3. Below is a copy of the top half of the DNA strand, complete the pattern by
matching the A with T and the G with C.
A
C
C
C
G
T
T
G
C
G
G
A
A
T
C
A
G
C
4. Below is a copy of the bottom half of the DNA strand, complete the pattern by
matching the A with T and the G with C.
T
G
G
G
C
A
A
C
G
C
C
T
T
A
G
T
C
G
G
A
5. Compare the strand created in step 3 with the strand in step 1?
6. Compare the strand created in step 4 with the strand in step 1?
7. Compare the strand created in step 3 with the strand in step 4?