Topic 2 Molecular Genetics: Protein Synthesis Flashcards
1
Q
- DNA replication doesn’t just stop at replicating an identical strand of DNA - if we need to synthesize a protein, we follow some additional steps. First, though, let’s review the different types of RNA which will be key players in protein synthesis
A
Note
2
Q
- A single stranded template; since there are 64 possible ways that four nucleotides can be arranged in triplet combinations (4 x 4 x 4), there are 64 possible codons. 61 of these codons code for amino acids, while the remaining 3 are stop codons. mRNA is also the least abundant RNA molecule due to its high turnover rate
A
- mRNA
3
Q
- he three stop codons are UAA, UAG, and UGA which do not code for any amino acids
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Note
4
Q
- A clover shaped transporter of anticodons; the C-C-A-3’ end of tRNA attaches to the amino acid being transported, and the other portion is the anticodon which base pairs with the codon in mRNA.
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tRNA
5
Q
- The exact base pair of the third nucleotide in the codon is often not required, allowing 45 different tRNA’s to base-pair with 61 codons that code for amino acids
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Wobbles
6
Q
- tRNA’s clover shape is held together by hydrogen bonds (via intramolecular base pairing)
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Note
7
Q
- tRNA is also the smallest of the RNA molecule
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Note
8
Q
- The nucleolus is an assemblage of DNA actively being transcribed into rRNA, which come together to form ribosomes. A ribosome has four total binding sites: one for mRNA, and three for tRNA (P, A, and E). The P site is for the tRNA that carries the growing polypeptide chain, the A site is for the 2nd tRNA that delivers the next amino acid, and the E site is for the empty tRNA before leaving the ribosome.
- The ribosome is assembled in nucleolus but the large and small subunits are exported separately to the cytoplasm.
A
- rRNA
9
Q
- rRNA is the most abundant RNA molecule - think r for ‘rich’, t for ‘tiny’ (tRNA), and m for ‘meager’ (mRNA)
A
Note
