Biology › Understanding Translation Processes
During protein elongation, what site in the ribosome do tRNA molecules enter?
The A site
The P site
The E site
The R site
As amino acids are added to a polypeptide during translation, tRNA molecules will enter the A site of the ribosome. The tRNA is then transferred to the P site, where a peptide bond is formed between the amino acid residue and the amino acid chain. Finally, the tRNA moves to the E site to release its tRNA and exit the ribosome.
Which of the following statements about the genetic code is true?
A codon will only code for one amino acid
An amino acid can only have one codon that codes for it
The genetic code has different rules between different species
The codon found on mRNA is an exact match for the anticodon found on the tRNA
The genetic code is considered both degenerative and unambiguous. A codon will only code for one amino acid, making the code unambiguous. In contrast, multiple codons can code for the same amino acid, making it degenerative. For example, UGU will always code for cysteine, but UGC also codes for cysteine.
Nearly every living organism uses the same genetic code. tRNA anticodons are complementary to mRNA codons; they are not the same code.
Which of the following accurately illustrates the central dogma of biochemistry?
DNA is transcribed into RNA, which is translated into protein
DNA is translated into RNA, which is transcribed into protein
Protein is transcribed into RNA, which is translated into DNA
RNA is translated into DNA, which is transcribed into protein
Protein is translated into RNA, which is transcribed into DNA
DNA contains genetic information that is transcribed into mRNA. This process is known as transcription, and occurs in the nucleus. After modification in the nucleus, mRNA exits the nucleus and enters the cell cytoplasm. In a process called translation, mRNA (in conjuction with tRNA and a ribosome) is used as a template to join amino acids to form specific polypeptides.
In summary, DNA is transcribed into RNA, which is translated into protein.
How many sites are there on the ribosome to house tRNA?
Three
Two
One
Four
Five
The ribosome contains three sites: the A, P, and E sites.
The A site is where activation occurs, starting translation. This is where a tRNA molecule enters the ribosome and matches its anticodon to the mRNA codon.
The tRNA then shifts over to the P site to attach the amino acid. The ribosome facilitates the formation of a peptide bond, adding the amino acid to the chain.
At the E site, the empty tRNA exits the ribosome and dissociates from mRNA.
What is the composition of ribosomes?
rRNA and protein
rRNA only
protein only
mRNA only
DNA only
Ribosomes are made up of rRNA and proteins. rRNA synthesis, and ribosome assembly takes place in the nucleolus.
The process of creating a protein from mRNA is known as __________.
translation
transcription
extraction
modification
Translation refers to the processing of an mRNA script into a protein. This process utilizes ribosomes and tRNA. In translation, messenger RNA (which is produced by transcription from DNA) is decoded by a ribosome to produce a specific amino acid chain, or polypeptide. The polypeptide is later folded into an active protein.
Which of the following is not a phase of translation?
Modification
Termination
Elongation
Initiation
Translation is the process of creating protein from an mRNA template, and consists of initiation, elongation, and termination. Modification of protein strands may occur after translation, but the three defined steps of translation are initiation, elongation, and termination. Many types of transcribed RNA, such as tRNA, rRNA (ribosomal), and small nuclear RNA, do not undergo translation in order to become functional proteins.
Which of the following best describes the process of translation?
mRNA to protein
DNA to mRNA
DNA to protein
DNA to rRNA
Protein synthesis starts in the nucleus with transcription. Transcription is the process where DNA is transcribed into mRNA. Translation occurs in the cytoplasm within ribosomes where mRNA is translated and becomes a protein with the help of rRNA and tRNA.
What is the purpose of tRNA in translation?
It carries an amino acid to the ribosome in order to be added to the growing polypeptide
It transfers the mRNA to the ribosome for translation
It adds to proteins in order to form the ribosomes
It carries the newly formed protein to the Golgi apparatus in order to be modified
tRNA is responsible for bringing individual amino acids to the ribosome in order to be incorporated into the protein. It has an anticodon that attaches to a specific codon found on the mRNA. Once the tRNA and mRNA are bound, a peptide bond if formed between the amino acid residue from the tRNA and the amino acid chain on the ribosome. This is how amino acids are added to the growing protein.
Anticodons pair with mRNA codons during which stage of protein synthesis?
Translation
Transcription
Transformation
Transfusion
Transfection
During translation, the ribosome binds to mRNA and to the appropriate tRNAs. On the ribosome, the mRNA condons are translated into the amino acid sequence of a protein with the help of the tRNA anticodons.
Transcription refers to the synthesis of an RNA molecule from a DNA template. Transformation occurs when a bacterium is able to absorb and incorporate genetic material from the extracellular environment. Transfusion is the transfer of blood from a donor to a recipient. Transfection is the infection of bacteria by phage DNA.