Term
| What is the function of DNA in the cell? |
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Definition
| To store genetic information. |
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Term
| Compare the structure of the nitrogen bases. How do purines and pyrimidines differ? |
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Definition
| Purines (A/G) have a double ring and pyrimidines (C/T) have a single ring. |
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Term
Write the complementary sequence to the following:
5' AGGTCACGTCTAGCTAGCTAGA 3' |
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Definition
| 5' TCTAGCTAGCTAGACGTGACCT 3' |
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Term
| Which of the ribose carbons participate in the phosphodiester bond? |
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Definition
| The 5' ribose carbon carries the phosphate group that forms a phosphodiester bond with the hydroxyl group on the 3' ribose carbon of the next nucleotide in the chain. |
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Term
| Which of the ribose carbons carries the nitrogen base? |
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Definition
| The 1' ribose carbon carries the nitrogen base. |
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Term
| Why does DNA polymerase require primase activity? |
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Definition
| DNA polymerase cannot begin synthesis without a 3' OH group. |
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Term
| What is the covalent bond between nucleotides catalyzed by DNA polymerase? |
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Definition
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Term
| Is DNA replication conservative or semi-conservative? |
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Definition
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Term
| What is the lagging strand in DNA synthesis? |
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Definition
| The 5' to 3' strand, which must be copied in a discontinuous manner, in repeated 3' to 5' chunks. |
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Term
| Short pieces of DNA involved in DNA synthesis in replicating cells are called _______ fragments. |
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Definition
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Term
| Name the function of polymerase. |
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Definition
| It catalyzes formation of a phosphodiester bond between nucleotides. |
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Term
| Name the function of helicase. |
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Definition
| Helicase unzips two complementary strands of DNA so replication can take place. |
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Term
| Name the function of primase. |
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Definition
| Primase adds an RNA primer where replication should begin, to provide a 3' OH group for DNA polymerase. |
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Term
| Name the function of exonuclease. |
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Definition
| Exonuclease digests phosphodiester bonds from the ends of nucleic acid molecules. |
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Term
| Name the function of endonuclease. |
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Definition
| Endonuclease digests phosphodiester bonds within the polymer chains, breaking the sugar-phosphate backbone of DNA. |
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Term
| A plasmid was disgested with the enzyme HpaII. On agarose gel electrophoresis, you observe three bands: 100, 230, and 500 bp. How many HpaII sites are present in this plasmid? What are the distances between each site, and what is the total size of the plasmid? |
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Definition
| Three HpaII sites are present, and the distances between them are the same as the length of the base pair fragments. The plasmid is 830 bp. |
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Term
| Using the same plasmid from the previous question and cutting it with BamH1 instead yields two pieces, 80 and X bp. How many BamH1 sites are in the plasmid, and what is X in base pairs? |
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Definition
| There are two BamH1 sites, and X is 750 bp. |
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Term
| Same plasmid as previous cards - How would you determine where the BamH1 sites are in relation to the HpaII sites? |
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Definition
| Cut the plasmid with both of them and see how long your fragments are. |
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Term
| The plasmid has one EcoR1 site into which you want to clone a blunt-ended fragment. What type of enzyme could turn an EcoR1 sticky end into a blunt end? |
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Definition
| A single-strand exonuclease can digest the EcoR1 overhang, forming a blunt end. Alternatively, a polymerase could fill in the overhang to make a blunt end. |
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Term
| Compare how DNA moves from cell to cell by a) conjugation, b) transduction, and c) transformation. |
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Definition
a) conjugation involves direct cell-to-cell contact
b) transduction is DNA transmission by viruses
c) transformation is the uptake of DNA from destroyed cells |
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Term
| Bacteria with phenotype A+ are mixed with bacteria with phenotype A- in culture. Some of the A- bacteria become A+. When A+ bacteria are removed and A- bacteria only are grown in the A+ cell culture medium, they all remain A-. What type of transfer occurred in the mixed culture? |
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Definition
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Term
| What was the rationale for labelling bacteriophage with 35S and 32P in the Hershey and Chase "blender" experiment? |
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Definition
| It showed that viral protein remained outside the cell while viral DNA entered the cell. |
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Term
| A plasmid that carries genes for its own transfer and propagation is called __________. |
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Definition
| Self-transmissible. Usually large plasmids contain these genes and small plasmids do not. |
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Term
| What enzymes can convert a supercoiled plasmid to a relaxed circle? |
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Definition
| Helicases (topoisomerases) |
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