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24 Cards in this Set
- Front
- Back
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Name four properties of the genetic code |
Directional, redundant, universal, nonoverlapping |
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Three different possible reading frames. What is the one being used called |
Open Reading Frame (ORF) |
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What is a missense mutation |
a change in a nucleotide that leads to the replacement of an amino acid with another amino acid |
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Nonsense mutation |
Change that converts a codon specifying an amino acid into a termination codon |
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Silent (synonymous) mutation |
Change that does not lead to any change in amino acid sequence |
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Frameshift mutation |
Insertion or deletion of a multiple of one or two nucleotides. This causes the reading frame to be shifted |
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What kind of mutation causes sickle cell anemia? What is the change in the genetic code? and What amino acid change results? |
Missense mutation. GAG to GUG Glutamic acid to valine |
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What kind of mutation causes B-thalassemia? What results? |
Nonsense mutation May inactivate B-globin |
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What causes alpha-thalassemia |
Framshift mutation which results in loss of function of alpha-globin |
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Which end of the tRNA has the amino acid, and what does the amino acid bind to? |
The 3' end. It binds to a terminal adenosine |
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What is significant about the third position of the anticodon region? |
It is the wobble position. Since it does not need to be complementary, a single anticodon sequence can bind multiple codons |
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What do you call a tRNA that has its amino acid attached? |
a charged or aminoacylated tRNA |
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What attaches the appropriate amino acid to the tRNA? |
Aminoacyl-tRNA Synthetases |
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What ensures that this process is carried out with high fidelity? |
1) The synthetase captures the correct tRNA by recognizing the anticodon or other nucleotides in the tRNA 2) Synthetase has high affinity for matching amino acids and lower affinity to others 3) Synthetase has proof reading activity that edits out mismatches |
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What is responsible for the catalytic functions of the ribosome? |
the rRNA |
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What is the function of ribosomal proteins? |
Structural role |
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What is the size of the eukaryotic ribosome and its two subunits? |
80S 40S and 60S |
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What are used for sources of energy? |
ATP and GTP |
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What steps require energy? |
Binding of amino acid to tRNA Binding of charged tRNA to A site Translocation of the ribosome Initiation and termination |
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Initiation is composed of what three steps? |
Association of preinitiation complex with 5' cap Scanning for initiator AUG codon Formation of the initiation complex |
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What composes the preinitiation complex |
Initiator Met-tRNA eIF2 bound to GTP Smaller ribosomal subunit |
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What facilitates the movement of the complex in scanning for the initiation codon? |
Helicase |
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What is the name of the initiation sequence? |
Kozak sequence |
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What happens once the AUG is identified? |
eIF2 hydrolyzes its GTP causing its release and causing the complex to join with the 60S subunit to form the initiation complex |
