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NAME______________________________
1. The three parts of any nucleotide are ________________, _________________, and _____________________.
2. List the missing differences between DNA and RNA:
DNA
RNA
a. Double stranded
a. _________________________
b. _________________________
b. Ribose
c. _________________________
c. May leave nucleus
d. Thymine
d. __________________________
3. What are the 3 types of RNA and what are their functions in making proteins?
a. ________________ _________________________________________________________________
b. ________________ _________________________________________________________________
c. ________________ _________________________________________________________________
4. Why are proteins important? (look in your protein reading)
5. What is a gene? ___________________________________________________________________________
6. Where are genes located? ______________________________________
Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the
sentence or statement true.
____
7. If a nucleic acid contains uracil, it is DNA. _________________________
____
8. A codon consists of four nucleotides. _________________________
____
9. The anticodon AGA is complementary to the mRNA codon TCT. _________________________
Completion
10. Figure 12.1 is _________ and is found in the _____________ of a cell.
Figure 12-1
11. The structure labeled X in Figure 12-1 is a(an) ____________________.
12. In Figure 12-3 below, A, B, and C are three types of ____________________.
Figure 12-3
13. What type of RNA is A? ______________________
14. What type of RNA is B? ______________________
15. What type of RNA is C? ______________________
16. Protein Synthesis takes place in two stages. _______________________ happens first and then
_________________________ takes place.
17. During transcription, a working copy of DNA is produced since DNA cannot leave the ___________________.
18. The order of nitrogenous bases in DNA determines the order of ____________________ in proteins.
19. Comparing DNA and RNA: Place an “X” in the DNA, RNA or both columns where appropriate.
DNA
RNA
Nucleotides
Deoxyribose
Ribose
Single-stranded
Double-stranded
Nitrogenous base
Thymine
Uracil
Template for the synthesis
of nucleic acids
DNA
Double helix
Replication
Translation
Transcription
Messenger
More than one form
Found in nucleus
May leave nucleus
Does not leave nucleus
20. Determine the amino acid sequence from the DNA strand below.
DNA
TAC TTA AAA CTT CGA CTA TTT ATT
mRNA
amino acid
21. Determine the anticodon from the mRNA sequence.
mRNA
CCC ACU UGG CAU CCU GGU CGU
anticodon
22. What information is on the outside of the wheel? ______________________
23. What information is needed to use the wheel? __________________
RNA
Mechanism of Protein Synthesis
Once the structure of DNA became known, scientists could reconstruct the events by which the cell makes proteins.
DNA carries the genetic code, the cell's "master plan" for protein synthesis. RNA copies this code and brings together
the amino acids that form the proteins.
Word Bank
DNA
Nitrogenous Bases
Codon
mRNA
Transcription
Nucleus
mRNA
Ribosome
Cytoplasm
Translation
tRNA
Protein
Anti-codon
Amino Acid
• Study the diagrams below, which represent the process of protein synthesis. Using the letters as guides, complete the following
paragraphs.
24. Step 1: ________________________________
25. Step 2: ____________________________________
26. What does each letter in the diagram above represent?
A. __________________________
E. __________________________
B. __________________________
F. __________________________
C. __________________________
G. __________________________
D. __________________________
27. Protein synthesis begins in the figure on the right, when a strand of (A) __________________unravels. The code for
producing a protein is carried in the sequence of the (B) ________________ in the DNA. Each group of three (B's)
forms a(n) _____________________, which represents a particular amino acid. One of the unwound strands of DNA
forms a complementary strand called (C) ______________________. This process is called
_________________________. It takes place in the _________________ of all cells.
In the figure on the right, (C) has moved into the ________________________, where it attaches to a (D)
____________________. A phase of protein synthesis called ______________________ then begins. A t-shaped
molecule of (E) ________________________ approaches the (D) ribosome. At one end of this molecule are three
nitrogenous bases known as an (F) _______________________. At the (D)ribosome, each (F) anti-codon aligns with
its complementary base pair on the (C). This occurs according to the base pairing rule. At the other end of (E), an (G)
_______________________is attached. As the (D) moves along the strand of (C), new (E's) are attached. This brings
the (G's) close to each other. The (G's) are joined by bonds, and the resulting strand is a
__________________________.
Mutations:
28. Which type of mutation involves a whole extra chromosome? __________________________
29. What do we call a mutation that only affects the formation of one protein? _____________________
The following is the base sequence on the template strand of a DNA molecule:
1 2 3
4
5 6
7 8 9 10 11 12 13 14 15 16 17 18
TACGCCAGTGGT TCGCAC
30. Give the base sequence of the strand of mRNA read from the original template DNA strand.
A U G CGG
31. What protein would this mRNA code for? (Use the mRNA to figure out the amino acids)
32. If the sixth nucleotide in the original DNA strand were changed from C to T, the DNA strand would be:
1 2 3
4
5 6
7 8 9 10 11 12 13 14 15 16 17 18
TACGCCAGTGGT TCGCAC
T
33. What would the mRNA become?
34. What is the resulting protein (amino acid sequence)?
KEY CONCEPTS: Answer the following question in complete sentences. You may draw diagrams to help you.
What is the structure of RNA?
How are proteins made?
Why does the body make proteins?
How can mutations affect the DNA, the RNA, and the protein?