Chapter 11

Using the codon table, what conclusions can be drawn about the genetic code? -Each codon includes all four of the bases U, C, A, and G. -The 64 codons are roughly evenly distributed between amino acid codons and stop codons. -Many amino acids are encoded by multiple codons. -There are three codons that specify the end of translation.

-Many amino acids are encoded by multiple codons. -There are three codons that specify the end of translation.

The anticodon on a tRNA that carries the amino acid valine to a growing polypeptide is 3' - CAU- 5'. What was the triplet in DNA that specified placement of valine here? A. 3' - CAT - 5' B. 3' - GTA - 5' C. 3' - GAU - 5' D. 3' - CAU - 5'

A. 3' - CAT - 5'

If the DNA sequence shown below goes through transcription and translation, how many amino acids will result from this sequence? 3'- TACGGCACCTAT -5' A. 4 B. 3 C. 2 D. 1

A. 4

Degeneracy in the genetic code seems wasteful. Of what possible value could degeneracy be, when it allows for more than one possible codon for most amino acids A. Degeneracy provides protection against some single nucleotide mutations B. Degeneracy helps prevent abnormal behavior of organisms C. Degeneracy is important because some codons do not code for any amino acid D. All codons for a particular amino acid are the same because of degeneracy

A. Degeneracy provides protection against some single nucleotide mutations

During bacterial translation, initiation occurs in three steps. Which step is last? A. The large ribosomal subunit binds to the mRNA. B. The small ribosomal subunit binds to the mRNA. C. The ribosome finds the start codon on a piece of mRNA. D. The initiator tRNA binds to the start codon. E. The large and small ribosomal subunits bind to each other.

A. The large ribosomal subunit binds to the mRNA.

The part of the tRNA molecule that hydrogen bonds to the codon on an mRNA in a ribosome is called the A. anticodon. B. decoder. C. attachment site. D. codon binding site. E. reverse codon.

A. anticodon.

The progress of a tRNA through a ribosome in the course of elongation can be summarized as: (Note: ignore the initiator tRNA) A. cytoplasm --> A site --> P site --> E site --> cytoplasm B. cytoplasm --> P site --> A site --> E site --> cytoplasm C. cytoplasm --> A site --> E site --> P site --> cytoplasm

A. cytoplasm --> A site --> P site --> E site --> cytoplasm

In a codon chart that shows the genetic code, amino acids are specified by nucleotide triplets of what specific nucleic acid? A. mRNA B. tRNA C. DNA D. All of these answer choices are true

A. mRNA

What type of molecule possess the anticodon and caries amino acids to the site of protein synthesis? A. tRNA B. rRNA C. mRNA D. Codon

A. tRNA

The codon table identifies the amino acid sequence that can be translated from a human mRNA sequence. This chart can also be used to identify amino acid sequences for other organisms. Select all of the organisms that use the codon assignments shown in the codon table. -whale shark -Staphylococcus aureus -mouse -lizard -rose bush

ALL! -whale shark -Staphylococcus aureus -mouse -lizard -rose bush

Which statement about bacterial translation is true? A. Amino acids are added to the growing polypeptide chain by a phosphodiester linkage. B. Amino acids are added to the amino group at the end of a growing polypeptide chain. C. None of the statements are true of bacterial translation. D. Amino acids are added to a growing mRNA molecule. E. Amino acids are added to the 3'‑hydroxyl of the growing polypeptide chain.

C. None of the statements are true of bacterial translation.

Which part is responsible for the unique properties of each amino acid? A. carboxyl group B. α‑carbon atom C. R group D. amino group

C. R group

TRUE or FALSE? Organisms use a triplet code opposed to longer codes because longer codes might provide more opportunities for errors during copying and take longer to translate, which is not that efficient compared to the triplet code.

True

TRUE or FALSE? Organisms use a triplet code opposed to shorter codes because a codon with only one or two nucleotide(s) per codon would produce only four or sixteen different codons respectively, which is not enough to specify all 20 amino acids.

True

TRUE or FALSE? The initiator tRNA that carries formyl-methionine (in bacteria) or methionine (in eukaryotes) can only bind to the P site of the ribosome and never occupies the A site.

True