Modified Review for Lecture 15.
What you need to know:
3 differences between RNA and DNA
Transcription:
What is the end product or end result of transcription?
What are the steps involved in initiation? Elongation? Termination?
What is the name of the sequence that induces termination? What happens
to the newly synthesized RNA? What happens to the RNA
polymerase?
What three modifications of RNA occur before the RNA exits the
nucleus?
What is the purpose of each modification?
Translation:
Draw a basic figure of a tRNA – where does the amino acid bind?
What is the anticodon? What is its function?
If given the anticodon sequence, can you determine the RNA sequence to
which it binds?
What enzyme is responsible for adding amino acids to tRNA molecules?
Be prepared to be given a DNA sequence and be asked for the resulting
mRNA and protein sequence.
Steps in translation – Initiation, Elongation and Termination
Outline the steps for each.
What are 3 possible outcomes of single base pair mutations.
Questions.
1. Transcription is initiated when RNA polymerase binds to
A) a promoter
B) an initiator
C) a transcriptor
D) a codon
2. Name two ways that pre-mRNA transcripts are modified after synthesis. In what
subcellular compartment do these modifications take place?
3. Eukaryotic mRNA transcripts are modified in order to
A) prevent degradation of the mRNA
B) help the mRNA be transported to the cytoplasm
C) help the mRNA attach to ribosomes
D) all of the above
4. In eukaryotes, the "start" codon also specifies the amino acid,
A) phenylalanine
B) valine
C) aspartate
D) methionine
E) methionine
5. Together with proteins, rRNA
A) provides a site for polypeptide synthesis
B) transports amino acids to the ribosome
C) travels to the ribosome to direct the assembly of polypeptides
D) transcribes DNA
E) translates DNA
6. In transcription, the nucleotide sequence CAT in DNA would specify
_______________ in mRNA.
A) TAC
B) GAU
C) CAT
D) GTU
E) GUA
7. The genetic code consists of groups of three nucleotides called
A) codons
B) introns
C) anticodons
D) reading frames
E) triplets
8. The function of tRNA is to
A) provide a site for polypeptide synthesis
B) transport amino acids to the ribosome
C) travel to the ribosome to direct the assembly of polypeptides
D) transcribe DNA
E) translate DNA
9. During the formation of the initiation complex in translation, a _______________ is
positioned first.
A) met-tRNA
B) ser-tRNA
C) tyr-rRNA
D) mval-tRNA
E) cyst-tRNA
10. Enzymes called amino acyl-tRNA synthetases
A) synthesizes tRNA
B) attaches amino acids to tRNA
C) strips tRNA from its amino acid in the process of translation
D) destroys excess tRNA molecules
E) helps tRNA synthesize amino acids
11. The function of mRNA is to
A) provide a site for polypeptide synthesis
B) transport amino acids to the ribosome
C) travel to the ribosome to direct the assembly of polypeptides
D) transcribe DNA
E) translate DNA
12. The process of _______________ cuts introns from the primary transcript and the
final "processed" mRNA is produced.
A) RNA cleaving
B) RNA translocation
C) RNA elongation
D) RNA splicing
E) RNA releasing
13. In mRNA, the series of nucleotides CCC specifies
A) serine
B) proline
C) alanine
D) arginine
E) stop
14. A molecule of tRNA with the anticodon AAA will transport the amino acid
A) phenylalanine
B) lysine
C) proline
D) glycine
E) arginine
15. In messenger RNA, the nucleotide series UAG specifies
A) arginine
B) serine
C) stop
D) proline
E) aspartate
16. Which enzyme is incorrectly matched to its function?
A) RNA polymerase -- transcription
B) aminoacyl-tRNA synthetase -- attaches an amino acid to a tRNA
C) peptidyl transferase -- translation
D) DNA ligase -- joins Okazaki fragments
E) All of the above are paired correctly.
17. Identify the polypeptide that would be produced as a result of transcribing and
translating the following DNA sequence.
DNA: ...3' A C C A A G T C T 5'...
A) arg - phe - trp
B) arg - leu - gly
C) thr - lys - ser
D) trp - phe - arg
E) gly - leu - arg
18. The strand of DNA used in the previous problem undergoes a mutation, such that the
second C from the 3' end is changed to a T. The mutant DNA is shown below. What
would change in the polypeptide?
Mutant DNA: ...3' A C T A A G T C T 5'...
A) no change
B) polypeptide would be 1 amino acid shorter
C) polypeptide would be 1 amino acid longer
D) 1 amino acid would substitute for another
E) translation would terminate within this stretch
19. The direct result of transcription is:
A) a duplicate DNA molecule
B) nRNA
C) a protein
D) mRNA
E) none of the above
20. The direct result of translation is:
A) a duplicate DNA molecule
B) nRNA
C) a protein
D) mRNA
E) all of the above
21. Which one of the following is not associated with transcription?
A) tRNA
B) mRNA
C) RNA polymerase
D) DNA
E) a promoter
22. Which one of the following is not associated with translation?
A) rRNA
B) mRNA
C) tRNA
D) anticodon
E) All are involved with translation.
23. Genes are composed of segments of "extra," nonessential materials called exons.
A) True
B) False
24. Name three differences between RNA and DNA
25. How do sequence-specific transcription factors induce transcription of a gene?
26. What enzyme is responsible for synthesis of RNA during transcription? What is the
direction of synthesis?
27. Draw a basic diagram of a tRNA molecule – make sure to label the amino acid
attachment site and the anti-codon. Describe how the anti-codon functions during
translation.
28. What are the three tRNA binding sites in the ribosome?
29. What causes the synthesis of a protein to be terminated?
30. Describe 3 ways that a base-pair substitution in DNA would affect the resulting
protein?