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39 Cards in this Set
- Front
- Back
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What are the bond types in DNA? |
Hydrophobic Hydrogen bonds Base Stacking Electrostatic interactions |
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What is Chargaff's rule? |
A+G = C + T |
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How many hydrogen bonds are between C and G? |
3 bonds |
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What conformation is in the nucleotide in? |
Anti confromation |
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What are the major and minor grooves on DNA? |
DNA Binding proteins can contact the bases through the major groove - DNA Binding proteins such as transcription factors |
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B DNA |
Typical DNA Right helix and hydrated |
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Why can DNA assume different configurations? |
1) Deoxyribose is not a rigid molecule - inherent flexibility 2) C1- N glycosidic bond can rotate |
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Z - DNA |
left handed helix Alternating C and G bases Found in active genes - helps with regulation of transcription |
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A DNA |
Dehydrated form of DNA Usually found in test tubes |
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Eukaryotic DNA is linear - how is it still able to supercoil? |
Matrix Associated Regions (MARs) Loops of DNA off of the nuclear matrix |
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What is an example of DNA Supercoiling? |
Movement of RNA Polymerase through double helix will leave a negative supercoil behind it and a positive supercoil ahead of it. |
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What do you need to complete PCR? |
1) DNA template 2) Nucleotides 3) Primers (10 to 12 nucs) 4) Taq Polymerase ( heat stable enzyme) |
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What are the steps of PCR? |
1) Denaturation (94) 2) Annealing (54) 3) Extensions (72) |
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What are some examples of DNA templates for PCR? |
Dried blood semen Vaginal swabs single hair Fingernail clippings Toothbrush * FORENSICS |
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Is RNA double stranded? |
RNA is single stranded |
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Does Chargaff rule apply for RNA? |
No |
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How do we get mRNA? |
Comes from hnRNA that is spliced by snRNA to make mRNA |
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What is tRNA? |
Transfer RNA Transfers amino acids to grow a peptide |
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What is rRNA ? |
Ribosomal RNA and is a part of ribosomes Provides site for and contributes to translation |
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Why does RNA form unique and complex 3-D structures? |
- ss - so can easily coil back on itself - Can form complimentary base pairs - Base stacking helps stabilize the shapes |
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How does the sugar of RNA Contribute to the 3-D shape of RNA? |
Carbon 2 has a hydroxyl group and can form hydrogen bonds and stabilize the 3d structure This cannot occur in DNA |
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How is hnRNA modified? |
7-methyl-guanosine cap to 5' end Addition of poly A tail to 3' end Splicing |
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Why is the 7-methyl-guanosine cap important? |
Protects from nucleases Promotes translation |
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Why is the poly A tail important on hnRNA? |
Protects against loss of codon Promotes export of mRNA into cytoplasm for translation |
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What is a sn RNP? |
small nuclear ribonucleoprotein particles snRNAs that are complexed with several proteins |
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What is a spliceosome? |
Slurps and pre-mRNA - functions to remove introns |
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Why do we have introns? |
So we can do alternative gene replication and splicing Make different combinations of genes to increase the number of protein possibilities |
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How does the cell know which protein to make via alternative splicing? |
Specific cells/tissues will make specific proteins Cell can receive external signals Cell may make on protein at one stage of differentiation and another protein at another stage |
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How do eukaryotic and prokaryotic mRNA differ? |
Prokaryotic mRNA is translated immediately ( no caping, poly A or splicing)
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What are cistrons? |
DNA sequence that contains coding information for a polypeptide and signals needed for ribosome function |
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Monocistronic vs polycistronic |
Eukaryotes are monocistronic - single peptide Prokaryotes are polycistronic - code for more than one |
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What ends are important in tRNA? |
3' terminus covalently bonds to specific aa Anticodon regions binds to complimentary region on mRNA |
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How much of our RNA is rRNA? |
80% |
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What are ribosomes? |
rRNA and proteins |
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What is the role of rRNA in a ribosome? |
Enzymatic functions - including peptide bond formation |
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What is the name of prokaryotic ribosome? |
70s (50s or 30s) |
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What is the name of eukaryotic ribosome? |
80s (60s and 40s) |
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What is the s in 80s? |
svedberg units |
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Central dogma |
Gene to mRNA ( via snRNP and hnRNA) to protein ( via tRNA and ribosomes) |
