Term
| How many start codons exist? |
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Definition
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Term
| How many stop codons exist? |
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Definition
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Term
| What is the Wobble-Hypothesis? |
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Definition
| The Wobble Hypothesis is that, in many cases, the third codon is unecessary or "wobbly" |
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Term
| How many codons for amino acids? |
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Definition
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Term
| What does it mean to say that the genetic code has no commas? |
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Definition
| no breaks in the code, continues letters. This has important implication when you consider the reading frame; an insertion can shift the entire frame |
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Term
| What is gene translocation? |
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Definition
| When a piece of genetic code breaks from one chromosome and is added to another |
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Term
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Definition
| loss of a segment of a chromosome |
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Term
| What is a point mutation? |
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Definition
| Small change (a few nucleotides) to a sequence of DNA |
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Term
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Definition
| Typically happen with DNA transposons, inversion is the act of flipping a sequence of DNA |
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Term
| What is a dominant-negative mutation? |
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Definition
| This is a mutation that codes for a protein that inhibits some function |
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Term
| What is a conditional mutation? |
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Definition
| A mutation that only has expression during specific conditions |
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Term
| What is a gain-of-function mutation? |
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Definition
| Mutation that causes more expression of protein than typical |
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Term
| What is a loss-of-function mutation? |
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Definition
| Mutation that causes less expression of protein then typical |
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Term
| What is a lethal mutation? |
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Definition
| mutation that leads to a death in the organism |
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Term
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Definition
| Mutation that causes the protein to no longer work |
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Term
| What are the two types of point mutations? |
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Definition
Transition and Transversion
Transition: exchange like for like (purine for purine or pyrimidine for pyrimidine)
Transversion: swaps nucleotide type |
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Term
| What is a silent point mutation? |
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Definition
| Point mutation that has no bearing on expression |
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Term
| What is a frame-shift mutation? |
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Definition
| A mutation that moves the entire reading frame (typically through addition or deletion of a nucleotide) |
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Term
| What enzyme attaches amino acids to their particular tRNAs? |
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Definition
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Term
| Where does amino acid attachement occur on the tRNA? |
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Definition
| on the 3' end, uses a CCA end for attachment |
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Term
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Definition
| code on the tRNA that is complementary to the codon on the mRNA it matches too |
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Term
| What drives the process of amino acid attachment to tRNA via synthetases? |
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Definition
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Term
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Definition
| Open Reading Frame: The space on the mRNA that gets "read" by the tRNA's |
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Term
| What is cap-binding complex, and of what is it composed? |
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Definition
| Cap-binding complex is composed of EIF4G and EIF4E (among others). This is the complex that aids in translation |
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Term
| What are the steps of translation? |
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Definition
1. Cap-binding complex joins the mRNA
2. Cap-binding complex is joined by EIF4B
3. 43S rRNA subunit is recruited
4. 60s and 43s join at the start codon
5. Protein synthesis begins (multiple 60s/40s complexes will attach at the start codon and continue coding |
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Term
| What are the two sites for elongation of protein synthesis? How do they function? |
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Definition
A and P sites.
The A site recruits the incoming aminoacyl-tRNA.
The P site has the growing protein |
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Term
| What enzyme catalyzes peptide-bond formation? |
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Definition
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Term
| What promotes release of the protein from the ribosome? |
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Definition
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Term
| What is the action of Aminoglycosides such as Streptomycin? |
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Definition
Bind the bacterial 30s subunit and cause misreading of the the genetic code.
At high doses the aminoglycosides also inhibit initiation |
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Term
| What is the action of tetracyclines? |
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Definition
| Tetracyclines block the A spot so that new amino acids cannot be joined to the existing chain |
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Term
| What is the action of Chloramphenicol? |
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Definition
Chloramphenical inhibits the formation of peptide bonds among amino acids by binding to the 50s Ribosomal subunit.
High levels of Chloramphenicol can disrupt mitochondrial translation |
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Term
| What is the action of Erythromycin? |
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Definition
| Erythromycin blocks peptide bond formation between amino acids by inhibiting the action of transferase |
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