DNA Protein Synthesis exer

Lab Report

Name: ________________________
Section: ______________________

DNA & Protein Synthesis
Exercise 1 – Modeling DNA
Observations from Procedures:
1. What are the three components of a DNA molecule nucleotide?

2. What is the sugar found in DNA molecules?

3. List the four bases which are unique to DNA.

4. Fit any six nucleotides together to form a row, then list the six nucleotides in the order you
used them. (Hint: The PO4 will be connected to the sugar, where as the nucleotide will
bonded to the sugar. D-P-D-P-D-P This creates the “backbone” of the DNA molecule
allowing the nucleotide bases to interact with each other.)

5. Work with your model pieces and try fitting the bases together to make a double strand as
shown in the illustration above. Write in the names of the bases that could pair with each to
make the complimentary pairs.
cytosine

_______________

thymine

_______________

adenine

_______________

guanine

_______________

6. After determining the pairing pattern of the nitrogenous bases, add the missing bases to this
hypothetical strand of DNA. (A=adenine, C=cytosine, G=guanine, T=thymine)
3’

5’

A

C

G

G
T

C

T

A

C
C

5’

T
G
3’

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Exercise 2 – The Globin Gene
Observations from Procedures:
1. Use the DNA coding strand below to complete the DNA molecule by creating a
complimentary strand. To do this, remember that the nucleotide base pair association
between DNA is A -T and G –C. Write the DNA complimentary strand for this portion of
the hemoglobin ?-subunit.
Coding Strand:

CGT CTC TTC GGA CAC

Complimentary Strand:

_______ ______ ______ _______ _______

2. Write the mRNA sequence that will be created in the process of transcription. Remember
that the coding strand of the DNA is the strand that has the information for the gene, so you
must transcribe the coding strand. To go through the process of transcription the DNA –
RNA pairing relationship is A – U, T – A, C – G and G – C.
Coding Strand:

CGT CTC TTC GGA CAC

mRNA Strand:

_______ ______ ______ _______ _______
codon #1

codon #2 codon #3

codon #4

codon #5

3. Translate the mRNA into amino acids. Use Table 1 for the correct amino acids or this link:
http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/gencode.html
Write your amino acid sequence starting with codon #1.
First
amino acid

+

Second
amino acid

+

Third
amino acid

+

Fourth
amino acid

+

_____________
_

+

_______________
_

+

______________
_

+

_______________
_

+

Questions:
4. What would happen if one of the DNA nucleotides was deleted?
5. What if the first T was substituted for an A?

6.

Would a substitution always result in a change why or why not?

Lab Report

Name: ________________________
Section: ______________________

7. How many nucleotides would it take to construct the coding strand of the entire 146 amino
acid globin molecule?

8. How many nucleotides would it take to model this part of the double stranded DNA
molecule?

9. Do you think this is a complete DNA molecule (chromosome) or part of one? Explain.

10. What molecule of all that you have worked with in this exercise has ultimate control over
protein synthesis? Explain you answer.

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