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41 Cards in this Set
- Front
- Back
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Approximately how many genes are there in a human? |
20-25 thousand |
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How was bacterial DNA transformation first proven? |
Mice were injected with a nonlethal R strain and a lethal, but dead S strain, and the R strain took on traits from the S strain and killed the mouse |
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What bases are purines? How do they look? |
2 carbon rings. Adenine and Guanine |
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What bases as pyrimidines? How do they look? |
1 carbon ring. Cytosine, Thymine, Uracil |
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Which bases pair up? |
A matches with T (and U in RNA) C matches with G |
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Who discovered DNA was shaped like a double helix? |
Watson and Crick |
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What type of bond connects complementary bases? |
Phosphodiester Bond or hydrogen bond |
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What does it mean that strands are antiparallel in nature? |
The 5 end of one strand is matched up with the 3 end of its complementary strand |
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What makes one end the 5’ and the other the 3’ |
5 end has a phosphate 3 end has an OH (is a sugar) |
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Where is DNA located in Eukaryotes? In Prokaryotes? |
Nucleus Nucleoid |
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What does DNA wrap around to create a nucleosome? |
histone protein |
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What creates the bead on a string model? |
Small sections of DNA called linker DNA attached one nucleosome to the next nucleosome |
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Where is heterochromatin located and how is it unique? |
The very ends of sister chromatids and the centromere. The genes are not expressed in any traits |
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What is Euchromatin and where is it located? |
In between the ends and the centromere. Where your traits that are expressed are located. ex: hair, eye color. |
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Conservative |
Old DNA stays together, New DNA stays together |
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Semi-conservative |
One of the old strand pairs with a new strand |
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Dispersive |
Every strand had both new and old parts |
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Which model is correct? |
semi-conservative |
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What enzyme unwinds DNA so it can replicate? |
Topoisomerase |
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What does helicase do? |
Separates the two strands by breaking the bonds |
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What is the purpose of single stranded binding proteins and where are the located? |
At the Y shaped replication forks They keep the DNA from winding back up |
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What enzyme adds bases? |
DNA polymerase |
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Which strand of parental DNA does the leading strand replicate from? What direction will it replicate in? |
The parents strand is the 3 end. From 5 to 3 |
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Which parental strand of DNA does the lagging strand replicate from? WHat direction will it replicate in? |
Start with the 5 end of parent DNA Work its way to the 3 end in small sections by replicating |
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What are the piece of the lagging strand called? |
Okazaki fragments |
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What enzyme binds them together? |
Ligase |
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Where are telomeres and what sequences are they made of? |
Both ends of a strand of DNA TTAGGG |
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What enzyme creates telomeres? |
Telomerase |
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What is the function of telomeres? |
To protect the euchromatin |
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What cells typically have telemorase? |
Stem cells, injured sex cells |
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What does the lack of the enzyme cause? |
aging |
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How does proofreading correct errors in replication? |
Checks the bases as it adds them to make sure it adds up |
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How is mismatch repair different? |
It happens after the new DNA strand has been made |
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What does Nucleotide excision repair? What is caused is these mistakes aren’t corrected? |
Thymine dimers (bond between two T’s side by side) Xeroderma pigmentosa |
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What is the difference between induced and spontaneous mutations? |
Spontaneous means mutations happen randomly Induced mutation is caused by exposure to something |
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What causes the most common point mutation? |
Substitutions (wrong letter) |
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Silent |
No effect |
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Missense |
Causes amino acid that is made to change, some effect |
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Nonsense |
Substitutes a stop codon for an amino acid |
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How are transverse substitutions different than transition substitutions? |
Transition are when purines are replaced by another purine(A&G) Transverse is when pyrimidine and purine get switched |
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What causes frameshift mutations? |
Insertions, deletions, and translocations |
