Protein Synthesis and Gene Expression Review Part 1
1. What shape does a DNA molecule have?
Double Helix
2. What is the diagram to the right called?
Nucleotide
a. What are the three parts of this structure?
Phosphate, 5-carbon sugar, nitrogenous base
3. What sugar is found in DNA?
Deoxyribose
4. DNA is copied during the s-phase of the cell cycle. What is the name of the process used to copy DNA?
DNA replication
5. Which two enzymes are involved in DNA replication and what does each one do?
a. Helicase—unwinds the double helix and breaks the hydrogen bonds (unwinds and unzips the
DNA)
b. DNA Polymerase—uses one side of the original DNA strand as template as well as base-pairing
rules to make the second side of DNA
6. Why is DNA replication considered semi-conservative?
The process saves half of the original DNA strand every time it makes a copy of the DNA
7. Genes are portions of ___DNA________ and contain instructions for assembling ___Proteins_________.
8. Describe 3 structural/chemical differences between DNA and RNA.
DNA: double stranded, has deoxyribose as the sugar, uses thymine
RNA: single stranded, has ribose as the sugar, uses uracil instead of thymine
9. What did Watson and Crick do?
Discovered the double helix shape of DNA
10. Here is a sequence of DNA:
ATCGGACCT
TAGCCTGGA
What is the complimentary strand of DNA?
11. Use the Universal Genetic Code Chart. What is the amino acid sequence formed from this mRNA?
mRNA:
AAUGGAUCUCAG
Amino Acids:
__Asn-Gly-Ser-Gln_____________________________
12. Here is a normal DNA molecule sequence
ATGGCCATG
TACCGGTAC
a. Re-write the DNA so that is has a point mutation – ACGGCCATG
TGCCGGTAC
Substitutions
b. Re- write the DNA so that is has a frame-shift mutation – insertions and deletions
ATGGCATG
TACCGTAC
13. Proteins are polymers (chains) of monomers called _____amino acids__________________.
14. How does the DNA in your intestinal cells compare to the DNA in your lung cells?
All body cells have the exact copy of DNA… the same 46 chromosomes with all the same genes
15. Why don’t stomach cells grow hair even though they contain the same genes as hair follicle cells?
Even though all cells have the same set of genes, different cells cause different genes to be expressed
16. What is recombinant DNA? Describe two reasons why scientists might want to make recombinant
DNA.
DNA that has been combined with DNA from a different organism
17. What are restriction enzymes and how are they used to make recombinant DNA?
Restriction enzymes cut DNA so that recombinant DNA can be produced
18. Describe two ways that proteins can differ from each other.
Different order of amino acids or different number of amino acids
19. Use the Universal Genetic Code Chart below. Which codons code for the amino acid glycine?
GGA, GGG, GGC, GGU
20. What is a mutation?
A change in the order of bases on DNA
21. If a codon is UUG, what is the anticodon?
AAC
22. Here is a nucleic acid sequence – GGCAAUGGAUUC – is it
DNA or RNA? How can you tell?
RNA because it has Uracil
23. Describe what happens during the following processes –
a. Replication – DNA is replicated
b. Transcription –DNA is rewritten as a
disposable copy called mRNA
Be able to use this specific chart
c. Translation –mRNA attaches to ribosomes and is used to sequence the amino acids
to make the protein
24. Explain the role of tRNA in translation.
Transfers amino acids to the ribosome during translation
25. What do ribosomes do?
Synthesize proteins
26. What happens first: transcription or translation?
Transcription
27.
7
What is an exon and an intron? Introns are portions of mRNA that are cut out. Exons are portions of the
mRNA that code for the protein
28. Name the structures listed in the diagram above:
1. tRNA
2. mRNA
3. Codons
4. Anticodons
5. polypeptide
6.amino acids
7. ribosome
29. Which step of protein synthesis is depicted in the diagram above?
Translation
30. What is “X” in the diagram to the right?
Nucleotide
31. What macromolecule is depicted in the diagram to the right? DNA
32. Who took the x-ray crystallography picture to the right?
Rosalind Franklin
33. What did this picture help to conclude about DNA?
Helped Watson and Crick discover Double Helix shape of DNA
34. Name and describe the 2 types of genetic mutations (mutations in DNA). Explain how each type of
mutation can affect the protein that is coded for by the mutated gene.
Point mutations are caused by substitutions and affects one amino acid
Frame-shift Mutations are caused by insertions and deletions and affects all amino acids after the deletion or
insertion.