Chapter 15.6: The Structure of tRNA and Ribosomes Flashcards

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1
Q

Define o Aminoacyl-tRNA Synthetases

A

any of a group of enzymes that attach specific amino acids to the correct tRNA during the tRNA-charging reaction. Each of the 20 amino acids has a corresponding enzyme

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2
Q

What is any of a group of enzymes that attach specific amino acids to the correct tRNA during the tRNA-charging reaction. Each of the 20 amino acids has a corresponding enzyme?

A

o Aminoacyl-tRNA Synthetases

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3
Q

What are the two parts of tRNA molecule?

A

acceptor stem and anticodon loop

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4
Q

Define acceptor stem

A

the 3’ end of a tRNA molecule; the portion that amino acids become attached to during the tRNA charging reaction

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5
Q

What is the 3’ end of a tRNA molecule; the portion that amino acids become attached to during the tRNA charging reaction?

A

acceptor stem

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6
Q

What is the function of the anticodon loop?

A

o Bottom loop of the cloverleaf, and it can base-pair with codons in mRNA

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7
Q

Define charging reaction

A

the reaction by which an aminoacyl-tRNA synthetase attaches a specific amino acid to the correct tRNA using energy from ATP

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8
Q

What is the reaction by which an aminoacyl-tRNA synthetase attaches a specific amino acid to the correct tRNA using energy from ATP?

A

charging reaction

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9
Q

Is the charging reaction endergonic or exergonic?

A

endergonic

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10
Q

What is the first step of the charging reaction?

A

In the first step of the reaction, the amino acid is activated. The amino acids react with ATP to produce an intermediate with the carboxyl end of the amino acid attached to AMP. The two terminal phosphates (pyrophosphates) are cleaved from ATP in this reaction.

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11
Q

After In the first step of the reaction, the amino acid is activated. The amino acids react with ATP to produce an intermediate with the carboxyl end of the amino acid attached to AMP. The two terminal phosphates (pyrophosphates) are cleaved from ATP in this reaction, what is the next step of the charging reaction?

A

The amino acid-AMP complex remains bound to the enzyme. The tRNA next binds to the enzyme.

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12
Q

After The amino acid-AMP complex remains bound to the enzyme. The tRNA next binds to the enzyme., what is the last step of the charging reaction?

A

The last step of the reaction transfers the amino acid from AMP to the tRNA, producing a charged tRNA and AMP. The charged tRNA consists of a specific amino acid attached to the 3’ acceptor stem of the its RNA

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13
Q

Define P site

A

in a ribosome, the peptidyl site that binds to the tRNA attached to the growing polypeptide chain

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14
Q

What is in a ribosome, the peptidyl site that binds to the tRNA attached to the growing polypeptide chain?

A

P site

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15
Q

Define A site

A

in a ribosome, the aminoacyl site, which binds to the tRNA carrying the next amino acid to be added to a polypeptide chain

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16
Q

What is in a ribosome, the aminoacyl site, which binds to the tRNA carrying the next amino acid to be added to a polypeptide chain?

A

A site

17
Q

Define E site

A

in a ribosome, the exit site that binds to the tRNA that carried the previous amino acid added to the polypeptide chain

18
Q

How are the sites in ribosomes organized?

A

o Relative to the mRNA, the sites are arranged 5’ to 3’ in the order E, P, and A

19
Q

What is the order that tRNA goes through the ribosome?

A

o The incoming charged tRNAs enter the ribosome at the A site, transit through the P site, and then leave via the E site

20
Q

What are the two functions of the ribosome?

A

o The two functions of the ribosome involve decoding the transcribed message and forming peptide bonds

21
Q

Define peptidyl transferase

A

in translation, the enzyme responsible for catalyzing the formation of a peptide bond between each new amino acid and the previous amino acid in a growing polypeptide chain

22
Q

What is in translation, the enzyme responsible for catalyzing the formation of a peptide bond between each new amino acid and the previous amino acid in a growing polypeptide chain?

A

peptidyl transferase