When a new tRNA enters the ribosome it is in which site?
Incoming aminoacy- tRNAs (a tRNA with an amino acid covalently attached is called an aminoacyl- tRNA ) enter the ribosome at the A site . The peptidyl- tRNA carrying the growing polypeptide chain is held in the P site . The E site holds empty tRNAs just before they exit the ribosome .
Which of the following processes takes place in a 3 → 5 direction?
During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3 ‘ →5 ‘ direction . However, for any given gene, either strand of the double-stranded DNA may function as the template strand.
Where does the tRNA carrying the initial amino acid bind on the ribosome?
At the beginning of translation, the ribosome and a tRNA attach to the mRNA. The tRNA is located in the ribosome’s first docking site. This tRNA’s anticodon is complementary to the mRNA’s initiation codon, where translation starts. The tRNA carries the amino acid that corresponds to that codon.
What happens to the tRNA at the E site?
The tRNA in the A site (with the polypeptide chain) will shift to the P site , and the empty tRNA previously in the P site will shift to the E site (where it will exit the ribosome). A new tRNA (in this case, one bearing Phe) will bind to the newly exposed codon in the A site , and the process can then repeat.
What are the 7 steps of translation?
Terms in this set ( 7 ) mRNA binds to the small subunit of the ribosome. tRNA with anticodon complementary to the first codon to be translated on the mRNA binds to the ribosome. a second tRNA with an anticodon complementary to the second codon on the mRNA then binds.
What are the 4 steps of translation?
Translation happens in four stages: activation (make ready), initiation (start), elongation (make longer) and termination (stop). These terms describe the growth of the amino acid chain (polypeptide). Amino acids are brought to ribosomes and assembled into proteins.
What occurs during translation?
Translation occurs in a structure called the ribosome, which is a factory for the synthesis of proteins. The ribosome has a small and a large subunit and is a complex molecule composed of several ribosomal RNA molecules and a number of proteins.
Where does DNA replication take place?
Explanation: In humans, DNA is found in the nucleus of cell. The process of replication (which copies DNA ) must take place in the nucleus since this is where the DNA is found.
What is produced during transcription?
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). The newly formed mRNA copies of the gene then serve as blueprints for protein synthesis during the process of translation.
In what two places in the cell can translation occur?
In eukaryotes, transcription and translation take place in different cellular compartments: transcription takes place in the membrane-bounded nucleus, whereas translation takes place outside the nucleus in the cytoplasm. In prokaryotes, the two processes are closely coupled (Figure 28.15).
What are the 5 steps of transcription?
Transcription is the name given to the process in which DNA is copied to make a complementary strand of RNA. RNA then undergoes translation to make proteins. The major steps of transcription are initiation , promoter clearance, elongation , and termination .
What happens at the E site of a ribosome?
The A site accepts an incoming tRNA bound to an amino acid. The P site holds a tRNA that carries a growing polypeptide (the first amino acid added is methionine (Met)). The E site is where a tRNA goes after it is empty, meaning that it has transferred its polypeptide to another tRNA (which now occupies the P site ).
What are the A P and E sites on the ribosome?
The P – site (for peptidyl) is the second binding site for tRNA in the ribosome . The other two sites are the A- site (aminoacyl), which is the first binding site in the ribosome , and the E – site (exit), the third. During protein translation, the P – site holds the tRNA which is linked to the growing polypeptide chain.
What are the 3 binding sites for tRNA?
The ribosome has three binding sites for tRNA molecules that span the space between the two ribosomal subunits: the A (aminoacyl), P (peptidyl), and E (exit) sites . In addition, the ribosome has two other sites for tRNA binding that are used during mRNA decoding or during the initiation of protein synthesis.
How is tRNA charged?
Before an amino acid can be incorporated into a growing polypeptide, it must first be attached to a molecule called transfer RNA , or tRNA , in a process known as tRNA charging . The charged tRNA will then carry the activated amino acid to the ribosome.