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Topic 3.5 Review Book
Transcription & Translation
Name: ___________________
Topic 3 The Chemistry of Life
Topic 3.5: Transcription and Translation (Textbook Pages 69-74)
Key facts
1. RNA contains the 5C sugar ribose, is single stranded and contains the bases adenine, uracil, cytosine,
and guanine. Notice thymine is missing in RNA. RNA is a chain of RNA nucleotides connected by a
covalent bond between the phosphate of one nucleotide and the 3C of the next nucleotide.
2. DNA transcription involves the copying of the genetic code from DNA onto a strand of RNA.
3. This RNA strand is complementary to the DNA template strand.
4. The genetic code is actually composed of triplets of bases called codons. The codons are present on
the RNA formed during translation. Therefore, codons do not contain thymine.
5. The RNA formed during transcription is called messenger or mRNA. This mRNA carries the genetic
code out of the nucleus to the ribosomes in the cytoplasm.
6. It is at the ribosomes where the process of translation occurs. Translation is the process that leads
to the formation of polypeptides, proteins.
7. In the cytoplasm tRNA molecules contain anticodons. The tRNA anticodons pair with the mRNA
codons through base pairing. Because each tRNA with a particular anticodon carries a specific amino
acid, the codon – anticodon match allows a very specific protein or polypeptide to be produced.
8. A particular sequence on a DNA molecule that codes for a specific protein is called a gene. This gene
will always code for the formation of the same protein during the process of its transcription and
translation.
9. There is a third type of RNA called ribosomal RNA (rRNA). This rRNA composes a significant part of
the ribosome which is the structure at which protein synthesis occurs via the process of translation.
10. The term translation is appropriate as during the process there is a change from the language of
DNA (nitrogenous base sequence) to the language of proteins (amino acid sequence).
Complete the following.
1. List three differences between RNA and DNA.
RNA
DNA
1________________________________
1______________________________
2________________________________
2______________________________
3________________________________
3______________________________
2. In general, what happens in DNA transcription?
3. What type of RNA is produced by transcription?
Name ______________________________
Section _____________
4. Why must helicase be involved in transcription?
5. In general, how are replication and transcription similar?
6. In general, how are replication and transcription different?
7. On what molecule would one find a codon?__________________
8. What is a codon?
9. What is the function of RNA polymerase?
10. What organelle does mRNA deliver the genetic code to?__________________
11. Name the process that results in protein synthesis.____________________
12. What is the function of tRNA in protein synthesis?
13. What part of the tRNA binds with the codon of the mRNA at the ribosome?
14. What does tRNA transport to the ribosomal-mRNA complex?___________________
15. The genetic code is said to be universal. What does this mean?
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Name ______________________________
Section _____________
16. The genetic code is said to be degenerate. What does this mean?
17. How many different amino acids are there that make up proteins (polypeptides)?____
18. What type of bond allows the connection between the anti-codon of the tRNA and the codon of the
mRNA at the ribosome?_____________________
19. How many subunits does a ribosome have?____________
20. Are there differences between prokaryotic and eukaryotic cell ribosomes?_______ Explain.
21. What is a third type of RNA involved in translation?________ What does it do?
22. What does the one gene/one polypeptide hypothesis state?
23. Follow the genetic code through protein synthesis.
a. DNA TTACGGCTA
b. mRNA-
_____________
c. tRNA anticodons-
_____________
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