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24 Cards in this Set
- Front
- Back
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1. What is the central dogma of molecular biology?
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DNA is transcribed into RNA
RNA is translated into protein |
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2. What does transcribed mean?
What does translated mean? |
A strand of messenger RNA is constructed by a chemical messenger that moves along the unwound portion of DNA, using it as a template
Molecular process that converts the information in a strand of messenger RNA into a corresponding sequence of amino acids |
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3. What are the three major macromolecules?
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DNA
RNA Proteins |
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4. What is the role of each macromolecule?
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DNA
-stores genetic information -contains plans to build organism and regulate its operation RNA -disposable copies of DNA (not maintained) Proteins -enzymatic machinery -info on RNA is translated into protein |
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5. What is the structure of DNA?
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Four deoxynucleotides
Nucleotides of DNA contain -deoxyribose sugar -nitrogenous bases -a phosphate |
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6. What is a nucleotide?
What is a nucleoside? |
Nitrogenous base, sugar, and a phosphate
Nitrogenous base and deoxyribose sugar |
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7. Which type of phosphate is used as a precursor for DNA synthesis?
Which type is incorporated into DNA? |
Triphosphates
Monophosphates |
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8. How does the sugar of DNA differ from the sugar of RNA?
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Deoxyribose sugar
-H on 2' C -OH on 3' C Ribose sugar -OH on both 2' and 3' C |
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9. What are the two types of nitrogenous bases and how do they differ?
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1. Purines - double ring structure
2. Pyrimidines - single ring structure |
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10. Which nitrogen bases are purines?
Which nitrogen bases are pyrimidines? |
Adenine and Guanine
Cytosine, Thymine, and Uracil |
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11. What are the bases in DNA and RNA?
How do the bases pair? |
DNA: A, G, C, T
RNA: A, G, C, U A : T (DNA) A : U (RNA) G : C (both) |
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12. How is DNA structured?
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1. Double Helix
2. Two antiparallel strands -one goes 3' -> 5' -complimentary partner goes 5' -> 3' |
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13. How do the monophosphates connect to one another in DNA?
How do the two strands connect to one another? |
Phosphodiester bonds (not symmetrical)
H-bonds between base pairs A : T/U by 2 H-bonds G : C by 3 H-bonds |
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14. What is chromatin?
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DNA in eukaryotic cells
DNA complexed with histones |
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15. What are histones?
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Small basic proteins
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16. What are nucleosomes?
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DNA histone complexes
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17. How does DNA synthesis proceed?
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Semiconservative
-each daugther DNA receives one original DNA strand from parent Discontinous -leading and lagging strand |
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18. What is a replisome?
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Assembly of enzymes responsible for DNA replication
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19. What is one of the most important enzymes in the replication of DNA?
What are four common features that all of this type of enzyme share? |
DNA polymerase
1. Synthesis 5' to 3' -add onto 3' OH end 2. Require a template -read and copy a strand of DNA 3. Require a primer 4. Use deoxynucleoside triphosphates as precursor for DNA synthesis |
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20. What is the leading strand in DNA synthesis?
What is the lagging strand in DNA synthesis? |
Strand copied continuously
Strand copied discontinuously |
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21. What are Okazaki fragments?
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Short pieces of synthesized DNA on the lagging strand
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22. How are Okazaki fragments synthesized?
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1. Synthesized in 5' to 3' direction
2. Primed by a short primer made of RNA |
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23. What synthesizes the RNA primer?
What happens to the Okazaki fragment once it is completed? |
Primase
1. RNA primer is removed by a 5' to 3' exonuclease (RNAse H) 2. Gap caused by removal of primer is filled in by another DNA polymerase 3. Nicks between fragments are sealed by ligase (enzyme) |
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24. What events occur at the replication fork?
Seven steps |
1. Helicase unwinds double helix
2. Leading strand is replicated in straight forward manner in 5' to 3' 3. RNA primers are synthesized on lagging strand by primase 4. Primers are elongated by DNA polymerase in 5' to 3' direction resulting in Okazaki fragments 5. RNA is removed from fragments by 5' to 3' exonuclease 6. Gap caused by removal of primer is filled in by DNA synthesis carried out by another DNA polymerase 7. Nick between adjacent fragments is sealed by DNA ligase` |
