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Which major nitrogenous bases are purines? Which are pyrimadines?
- purines: adenine, guanine
- pyrimadines: cytosine, thymine and uracil
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Can you tell teh structure of a purine from a pyrimidine?
Purines have 2 rings while pyrimadines have 1 ring.
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What four bases are normally found in DNA? RNA?
- DNA: adenine, thymine, cytosine, guanine
- RNA: adenine, uracil, guanine, cytosine
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What are the 3 components of a nucleotide?
nitrogenous base, sugar and a phosphate group
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Can you tell the chemical structure of a nucleotide from a nucleoside?
A nucleoside does not contain the phosphate group.
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Can you tell the chemical structure of a ribonucleotide from a deoxyribonucleotide?
A ribonucleotide contains hydroxyls which DNA does not have
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What is the modification of a normal base found in DNA that affects gene expression? What is a nucleotide that is not found in DNA or RNA that is important in energy metabolism?
The methylation od a cytosine silences the genome. ATP is important in energy metabolism.
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What is the biochemical mechanism that enable coffee-drinking students to remain wakeful for lnoger periods of cramming?
Caffeine inhibits the binding site of adenosine which is a depressant, therefore allowing for increased awake time
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What biological role do adenosine triphosphate and guanosine triphosphate have after being cyclized at their phsophates to form cAMP or cGMP?
They serve as a secondary messenger inside the cell
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What is the difference between a nucleotide and a nucleic acid?
A nucleic acis is a polymer of nucleotides.
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Why is it said that 2 strand of DNA run antiparellel?
Because one strand runs from the 5' to 3' direction while the other one is 3' to 5'.
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How many hydrogen bonds are there in between an A-T pair? How many in a G-C pair?
A-T have 2 hydrogen bonds when G-C have 3 hydrogen bonds
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What happens to DNA when it is exposed to temperatures of 94*C during a PCR procedure?
THe DNA strands separate into individual strands
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A nucloside often makes a more useful drug than a nucleotide because a nucleoside
is roughly hald the size of a nucleotide
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A patient is being given adenosine in response to life threatning cardiac arrythmia. ECG monitoring during the adenosine infusion indicate high-grade infusion does not solve the problem, which of the following should be given to reverse the effects of the adenosine?
theophylline
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