Name_______________________Period______ Date __________Score______
BIOLOGY I LAB – DNA, RNA, & Protein Synthesis 12-11 NOVAK
Prelab
Most of the following introduction questions can be found in chapter 9&10, a dictionary and using Google.
Match the following vocabulary words in bold all capitals and prefixes to the definition below by putting the capitalize vocabulary word into its blank below. Each term is used just once.
AMINO ACID, BASE-PARING, CODON, ANTICODON, DEOXYRIBOSE, DNA, GENE, HYDROGEN, MESSENGER RNA (mRNA), NITROGENOUS BASE, NUCLEOTIDE, PEPTIDE, PROTEIN, REPLICATION, RIBOSE, RIBOSOME, TRANSCRIPTION, TRANSFER RNA (tRNA), TRANSLATION, URACIL
1________________________ The molecule in which genetic code is located within the nucleus
2________________________ A cellular organic compound that is made of one or more chains of amino acids and that is a principle component of all cells
3________________________ One of twenty different organic molecules that combine to form proteins
4________________________ A type of chemical bond holding amino acids together
5________________________ A section of DNA coding for one protein
6________________________ A basic unit of DNA composed of three subunits
7________________________ A type of chemical bond holding bases together in the center of the DNA double helix
8________________________ A subunit of a nucleotide containing either adenine, thymine, guanine, or cytosine"
9________________________ The DNA rule in which adenine always connects with thymine and cytosine always connects with guanine
10________________________ The type of sugar in a DNA nucleotide
11________________________ The process of making a copy of DNA
12________________________ The process by which DNA is copied onto RNA
13________________________ The molecule onto which the DNA code is copied during transcription
14________________________ The type of sugar in RNA
15________________________ The nitrogenous base of RNA that pairs with adenine"
16________________________ A three nucleotide base sequence that encodes for one amino acid
17________________________ The portion of protein synthesis that takes place in the cytoplasm and that uses the codons in mRNA molecules to specify the sequence of amino acids
18________________________ The site in the cytoplasm of protein synthesis
19________________________ During protein synthesis, a type of RNA molecule that transfers amino acids to the growing end of the polypeptide chain in the ribosome
20________________________ The triplet code on the transfer RNA that pairs with the codon on the messenger RNA during protein synthesis
21. Put the following terms related to protein synthesis in the correct order:
ribosomes, amino acids, protein, DNA, mRNA, transcription, tRNA, translation
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In the following amino acids, give all possible codons in the mRNA (use the chart on page 211):
23. Glycine ________________________________________________
24. Trytophan ________________________________________________
25. Leucine ________________________________________________
26. Valine ________________________________________________
27. Serine ________________________________________________
28. Asparagine ________________________________________________
29. Tyrosine ________________________________________________
30. Aspartic Acid ________________________________________________
31. Glutamic Acid ________________________________________________
32. Arginine ________________________________________________
33. Cysteine ________________________________________________
34. Pheylalanine ________________________________________________
35. Proline ________________________________________________
36. Name a start codon ________________________________________________
37. Name the stop codons ________________________________________________
Materials: push pins (five colors), small paper clips, scissors, striped soda straws, solid color soda straws, “amino acid” cards, scotch tape, piece of notebook paper
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PART I - A MODEL FOR DNA
In this part of the lab you will construct a DNA molecule using push pins and soda straws. The straws and paper clips will represent the sugar phosphate “backbone” on each side of the molecule (make sure the straws are the same LENGTH). The push pins will represent the nitrogenous bases of the nucleotides. Blue push pins will represent thymine, green push pins will represent adenine, yellow push pins will represent cytosine, and red push pins will represent guanine. BE CAREFUL WITH THE PUSH PINS, THEY ARE VERY SHARP. According to your teachers directions construct one side or strand of the DNA molecule in this exact base sequence (be sure to place the push pins in the center of each straw’s length):
T A C A C A A T G A A G C T T T T A A C A G G G G C A C C A A T T
Lay this strand on the lab desktop which represents the nucleus of the cell. This above sequence of letters represents the DNA base sequence of one gene. The sequences of bases in DNA eventually code for the sequences of amino acids in a protein. How many bases are in this sequence? 1-1________________ How many codons are in this DNA sequence or gene? 1-2________________ How many amino acids do you guess this sequence will assemble? 1-3________________ Which base is used the most in this DNA sequence or gene? 1-4________________ Which base is used the least in this DNA sequence or gene? 1-5________________ Where would this DNA sequence be located within the cell? 1-6________________ Show you teacher the assembled DNA strand you have just constructed.
Next, assemble the complementary side of the above DNA sequence. Match the push pins of the first sequence above to the push pins on the complementary side by matching the colors. The blue with the green and the yellow with the red. These matching or pairing bases in the DNA are matched together according to the 1-7________________ ________________ rule. In DNA, what always matches or joins with adenine? 1-8________________ In DNA, what always matches or joins with cytosine? 1-9________________ How many rungs do you now have in this DNA “ladder”? 1-10________________ Show your teacher the assembled DNA molecule you have constructed.
PART II – A MODEL FOR MESSENGER RNA
DNA never leaves the nucleus. Instead it makes a copy of the code of the gene and sends it out of the nucleus to the 2-1________________. This process of copying the DNA to mRNA is called 2-2________________. This copy of the DNA code is a molecule called 2-3________________. This molecule acts as a template on which the protein molecule will be synthesized. Remove the second (complementary) strand of DNA you constructed so that the original strand can be “read” to make mRNA in this nucleus. Since RNA has a different sugar along the sugar phosphate sides use the solid color straws to assemble the mRNA strand. As you assemble the mRNA strand remember that RNA substitutes thymine found in DNA for a base called 2-4________________. For the base uracil use white push pins. How many uracils will the mRNA have? 2-5________________. How many bases does the mRNA strand have altogether in this gene? 2-6________________ How many codons does the mRNA strand have? 2-7________________ How many amino acids do you guess this strand of mRNA will code for? 2-8________________ Cut a piece of notebook paper into a large circle and label the circle the ribosome. Lay the mRNA strand onto the ribosome. As soon as you have finished, show your teacher your mRNA strand on the ribosome. What happens at this ribosome? 2-9___________________________
PART III – A MODEL FOR PROTEIN SYNTHESIS
When the mRNA reaches the ribosome, it is ready to be used as a template for protein synthesis. The assembling of the protein at the ribosome using the mRNA as a template is called 3-1________________ The mRNA attaches to the ribosome and the codons are matched with the anticodons of the tRNA as the tRNA brings amino acids to the mRNA. After the match, the tRNA releases the mRNA and leaves the amino acid at the ribosome to be joined with the next amino acid brought in by the next tRNA. What type of bond joins amino acids? 3-2________________ obtain a sheet of amino acid cards and cut them along the lines provided. According to your teachers directions make tRNA molecules with anticodons attached to the amino acid cards. Use the chart on page 211 in your book to help determine the amino acids anticodons. Then bring the anticodons with their amino acid to the mRNA. With each new tRNA attach the amino acid to the previous amino acid using scotch tape. Continue until all the codons on the mRNA have been read. Keep in mind, the first and the last codons on the mRNA do NOT code for an amino acid. What do they do? 3-3________________________________________________ How many amino acids are in the chain? 3-4________________ Which of the amino acids are repeated? 3-5________________ In the following blank, give the sequence of the amino acids (in order). 3-6 ________________________________________________________________________________
This chain of amino acids represents the 3-7________________ ADH. ADH is a hormone in human plasma that controls the fluid level of your blood. Show your protein molecule of ADH you made to your teacher.
Now go back to the original DNA strand. Replace only one base. Replace the fourth base adenine with cytosine. How does this change of only one base change the eventual amino acid sequence in the protein molecule of ADH? 3-8________________________________________________ This is an example of a mutation which is a change is a 3-9_______________. Like a broken key that will not unlock its door, the substitution of only one amino acid changes the 3-10________________ of the protein molecule preventing it from working properly.
POST LAB – (REVIEW & APPLICATION)
On a piece of notebook paper number and answer the following (you do not have to write the questions):
R1. What makes up the “backbone” of DNA?
R2. What is the most important part of a nucleotide and why?
R3. Explain the DNA base pair rule.
R4. Name two ways RNA differs from DNA
R5. Explain the difference between transcription and translation in protein synthesis.
R6. In the following DNA sequence, give its complementary bases pairing. A A T C G A T G G C T T
R7. In the previous question, give the mRNA sequence that would form from it.
R8. In the previous question, give the amino acid sequence that would form from it.
R9. If a mRNA codon was UGC, what anticodon would be on tRNA?
R10.What is the function of a start and stop codon.
R11. Give an example of a Start codon.
R12. Give an example of a Stop codon
R13. What is the role of tRNA in protein synthesis?
R14. With what kind of chemical bond are amino acids joined?
R15. During protein synthesis, where in the cell does mRNA first form?
R16. During protein synthesis, where is mRNA located in the cytoplasm?
R17. Before protein synthesis, where is tRNA located
R18. What is ADH and what is its function?
R19. Shape is the most important quality of a protein. What gives any protein its correct shape?
R20. What is a mutation?
R21. How does a mutation affect protein?
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Bio I Lab DNA, RNA, Protein Synthesis 12-11 Novak