translation of rna to protein


The mRNA, which is transcribed from the DNA in the nucleus, carries the directions for the protein-making process. mRNA tells the ribosome ( Figure 1.1) how to create a specific protein. Ribosomes translate RNA into a protein with a specific amino acid sequence. The tRNA binds and brings to the ribosome the amino acid encoded by the mRNA. The process of reading the mRNA code in the ribosome to make a protein is called translation ( Figure 1.2): the mRNA is translated from the language of nucleic acids (nucleotides) to the language of proteins (amino acids). Sets of three bases, called codons, are read in the ribosome, the organelle responsible for making proteins. This summary of how genes are ex- pressed shows that DNA is transcribed into RNA, which is translated, in turn, to protein. The one letter code represents amino acids. The following are the steps involved in translation: mRNA travels to the ribosome from the nucleus. The following steps occur in the ribosome: The base code in the mRNA determines the order of the amino acids in the protein. The genetic code in mRNA is read in words of three letters (triplets), called codons. Each codon codes for an amino acid. There are 20 amino acids used to make proteins, and different codons code for different amino acids. For example, GGU codes for the amino acid glycine, while GUC codes for valine. tRNA reads the mRNA code and brings a specific amino acid to attach to the growing chain of amino acids. The anticodon on the tRNA binds to the codon on the mRNA. Each tRNA carries only one type of amino acid and only recognizes one specific codon. For example, a GGC anticodon will bind to a CCG codon, and a CGA anticodon will bind to a GCU codon. tRNA is released from the amino acid. Three codons, UGA, UAA, and UAG, indicate that the protein should stop adding amino acids. They are called stop codons and do not code for an amino acid. Once tRNA comes to a stop codon, the protein is set free from the ribosome. The following chart ( Figure 1.3) is used to determine which amino acids correspond to which codons.




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ribosomes are the organelles where proteins are made.

-->  a. true

b. false

translation translates from one language to another.

-->  a. true

b. false

during translation, the mrna is translated from _ into _.

a) nucleic acid, amino acids

b) nucleotides, protein

-->  c) nucleotides, amino acids

d) nucleic acid, protein

what is the role of the trna molecules?

a) the trna determines the order of the amino acids in the protein.

-->  b) the trna reads the mrna code and brings a specific amino acid to the

c) the trna brings the genetic message to the ribosome from the nucleus.

d) all of the above

what is the sequence of the anticodon that binds to a cua codon?

-->  a) gau

b) gat

c) cua

d) cta

which of the following statements concerning codons is true?

a) codons are read in the ribosome.

b) codons are found in the mrna sequence.

c) codons consist of three rna bases.

-->  d) all of the above statements are true.

ggg codes for glycine and ccc codes for proline. if the sequence within a gene is ggggggcccgggccc, what is the amino acid sequence of the corresponding protein?

a) gly-gly-pro-gly-pro

-->  b) pro-pro-gly-pro-gly

c) gly-gly-pro-pro-gly

d) pro-pro-gly-gly-pro

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