Specific Amino Acid To T Rna example essay topic

6.4 Translation 6.4. 1 Explain how the structure of t RNA allows recognition by a t RNA-activating enzyme that binds a specific amino acid to t RNA, using ATP for energy. Each amino acid has a specific t RNA activating enzyme that helps t RNA to combine with its complementary m RNA codon. The enzyme has a 3 part active site that recognizes three things: . A specific amino acid. ATP, .

A specific t RNA. The enzyme attaches the amino acid to the 3' end of the t RNA. The amino acid attachment site is always the base CCA. 6.4. 2 Outline the structure of ribosomes including protein and RNA composition, large and small subunits, two t RNA binding sites and m RNA binding sites... Two subunits, large and small.

Proteins and ribosomal RNA molecules form part of structure... Binding sites for t RNA on ribosome surface, two t RNA molecules can bind to the ribosome... There is a binding site for m RNA on the ribosome surface. 6.4. 3 State that translation consists of initiation, elongation, and termination. 6.4. 4 State that translation occurs in a 5' to 3' direction. Translation occurs in a 5' to 3' direction.

The ribosome moves along the m RNA toward the 3' end. The start codon is nearer to the 5' end than the stop codon. 6.4. 5 Explain the process of translation including ribosomes, , start codons, and stop codons. Initiation. When RNA reaches the cytoplasm, it attaches its 5' end to the small subunit of the ribosome.

AUG is called the start codon because it initiates the translation process... The anti codon on one end of a t RNA molecule is complementary to a specific codon on the m RNA. The codon AUG bonds with a t RNA molecule holding the amino acid methionine (the initiator t RNA)... The large ribosomal subunit has two t RNA binding sites: the P site and the A site. t RNA molecules in these sites attaches to the m RNA. t RNA molecules move from the A site to the P site so when initiation is done the initiator t RNA is in the P site.

Elongation. One of the binding sites for t RNA is vacant. The small subunit of the ribosome makes sure that a t RNA with complementary anti codons bind together... The large subunits advances over the small and detaches the polypeptide. This is then attached to a peptide linkage to the single amino acid... The small subunit then slides across the large one.

At the same time it moves 3 nucleotides along the m RNA in a 5 to 3 directions... Lastly the t RNA is displaced from the binding site so it detaches from the ribosome. It can be used again in translation after a t RNA activating enzyme has added another amino acid. Termination. The stop codon (UGA) is one that does not code for an amino acid and terminates the process... The polypeptide is released and the m RNA fragments return to the nucleus.

These nucleotides are recycled and used for RNA and DNA synthesis... t RNA also is returned to its free state and attaches to its specific amino acid so as to be ready for the translation process when needed. 6.4. 6 State that free ribosomes synthesize proteins for use primarily within the cell and that bound ribosomes synthesize proteins primarily for secretion or for lysosomes..