6.6.2 The Role of Transfer RNA: Charging a tRNA Molecule Flashcards Preview

AP Biology > 6.6.2 The Role of Transfer RNA: Charging a tRNA Molecule > Flashcards

Flashcards in 6.6.2 The Role of Transfer RNA: Charging a tRNA Molecule Deck (7)
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1
Q

note

A
  • During translation, transfer RNA (tRNA) molecules perform an important role in providing the correct amino acid for a growing polypeptide strand. A tRNA anticodon binds to an mRNA codon, specifying for a particular amino acid. A mistake could lead to a defective protein meaning problems in cell function.
    • The process of charging a tRNA molecule involves bonding a tRNA molecule with a specific amino acid. The process occurs with the help of an enzyme, aminoacyl-tRNA synthetase. The process is endergonic and requires an expenditure of ATP.
  • The structure of tRNA enables the molecule to translate the two languages of cellular activity: nucleotides and proteins. The structure enables a tRNA to recognize a correct mRNA codon specifying for a particular amino acid.
  • Illustration (a) is a two-dimensional representation of tRNA. A specific amino acid attaches at the 3’ end of the molecule. The anticodon contains complementary sequences to three bases on the mRNA strand. The simplified representation of tRNA, as shown in illustration (a), is often used to diagram the events of translation
2
Q

the process by which amino- acyl-tRNA synthetase joins a specific amino acid to a tRNA molecule:

A
  1. The active site of the enzyme binds the amino acid and an ATP molecule.
  2. The ATP loses two phosphate groups and attaches to the amino acid as adenosine monophosphate (AMP).
  3. A specific tRNA binds to the amino acid and the AMP drops off.
  4. The enzyme releases the aminoacyl tRNA complex or charged amino acid.
3
Q

How does an amino acid get bound to the proper tRNA?

A
  • There are 20 different enzymes each responsible for bringing a specific amino acid to tRNA
4
Q

__________ take the energy of an ATP molecule and harness it to provide energy for an endergonic reaction, such as activating a tRNA.

A
  • phosphorylated intermediates
5
Q

With regard to tRNA charging, how many high-energy phosphate bonds must be hydrolyzed to provide the energy required to activate one tRNA molecule?

A
  • two
6
Q

In the “charging” of a tRNA with its amino acid, the phosphorylated intermediate specifically involves a phosphate bond with

A
  • an amino acid molecule
7
Q

The function of tRNA during protein synthesis is to

A
  • bring the appropriate amino acid to the growing polypeptide strand

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