Chapter 10 Quiz

Required information View the animation below, then complete the quiz to test your knowledge of the concept. Which of the following statements about RNA splicing is FALSE? a. it occurs in the nucleus b. it removes the introns c. None of these choices are false. d. it is performed by the spliceosome e. it shortens the RNA molecule

c. None of these choices are false.

During the process of transcription in a eukaryote a. DNA polymerase must first unwind the DNA duplex. b. RNA is copied into DNA by a large enzyme. c. RNA polymerase synthesizes new nucleotide chains in the 5' to 3' direction. d. genes are exported to the cytoplasm. e. ribosomes are recruited to the endoplasmic reticulum (ER).

c. RNA polymerase synthesizes new nucleotide chains in the 5' to 3' direction.

The reason that the genetic code can correctly specify the order of amino acids in a polypeptide is a. ribosomes add amino acids to the right tRNAs. b. the ribosome recognizes codons and directly attaches amino acids. c. amino acids are covalently joined to the codons in an mRNA. d. mRNAs form a shape that allows attachment of the right amino acid. e. specific tRNAs become attached to specific amino acids.

e. specific tRNAs become attached to specific amino acids

Total nucleic acids are extracted from a culture of cells and are then mixed with resin beads to which the polynucleotide 5'-TTTTTTTTTTTTTTTTTTTTTT-3' has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following molecules do you expect to be most abundant? a. pre mRNA transcript b. DNA c. tRNA d. rRNA e. mRNA

e. mRNA

In the following diagram of a ribosome, assign the correct labels. a. Messenger RNA being translated b. Small subunit c. A tRNA molecule d. A tRNA attached to a polypeptide is found in this area of the ribosome e. Growing polypeptide f. Large subunit g. 5' end of the mRNA h. A tRNA attached to a single amino acid enters here i. 3' end of the mRNA j. A tRNA that is not attached to anything exits here

From Top to Bottom Left Side: e. Growing polypeptide j. A tRNA that is not attached to anything exits here d. A tRNA attached to a polypeptide is found in this area of the ribosome b. Small subunit g. 5' end of the mRNA Right Side: f. Large subunit c. A tRNA molecule h. A tRNA attached to a single amino acid enters here a. Messenger RNA being translated i. 3' end of the mRNA

Required information View the animation below, then complete the quiz to test your knowledge of the concept. Which of the following do snRNPs bind to? a. 5' and 3' ends of the intron b. exon only c. exon and the 5' end of the intron d. 5' end of the intron only e. 3' end of the intron only

a. 5' and 3' ends of the intron

Nirenberg and Leder used synthetic 'triplets' of RNA. The purpose of these short RNA molecules was to a. take the place of part of an mRNA within the ribosome. b. function as anticodons, as if they were part of a tRNA molecule. c. covalently bond to amino acids that correspond to the codon. d. form base pairs with other triplet RNAs that the experimenters made. e. substitute for the amino acid that the codons specify.

a. take the place of part of an mRNA within the ribosome.

In eukaryotes, transcription to produce an mRNA must occur in a. the nucleus, where the chromosomal DNA is found. b. the cytoplasm, where free ribosomes are found. c. vesicles, which contain enzymes for RNA breakdown. d. either in the cytoplasm or on the endoplasmic reticulum, where ribosomes are present. e. the endoplasmic reticulum, where there are bound ribosomes.

a. the nucleus, where the chromosomal DNA is found.

Required information View the animation below, then complete the quiz to test your knowledge of the concept. Which of the following occurs as the ribosome shifts down the mRNA by a distance of three nucleotides? a. the tRNA that was in the P site moves into the E site b. the tRNA that was in the P site moves into the A site c. the tRNA that was in the E site moves into the P site d. the tRNA that was in the A site moves into the E site e. the tRNA that was in the E site moves into the A site

a. the tRNA that was in the P site moves into the E site

There is only one start codon, AUG. This means that a. the stop codons each have their own special tRNAs. b. all newly-made polypeptides have a methionine at their amino end. c. the first tRNA will have the anticodon loop 3'-AUG-5'. d. all newly-made polypeptides have a methionine at their carboxyl end. e. the 5' end of an mRNA must start with an A.

b. all newly-made polypeptides have a methionine at their amino end.

During the process of translation in a eukaryote a. ribosomes must be imported into the nucleus. b. mRNA interacts with ribosomes in the cytoplasm. c. transfer RNAs are joined together by a large enzyme complex. d. amino acids are synthesized by RNA polymerase. e. messenger RNA is spliced in the nucleus.

b. mRNA interacts with ribosomes in the cytoplasm.

Which type of RNA is involved in protein synthesis? a. only tRNA b. mRNA, tRNA, and rRNA c. only mRNA d. only rRNA e. The RNA involved in protein synthesis is not listed here.

b. mRNA, tRNA, and rRNA

Required information View the animation below, then complete the quiz to test your knowledge of the concept. A mutation occurred in the third codon position of a gene, but the protein still functions normally. How is this possible? a. DNA polymerase's proofreading function fixed the mistake in the nucleus. b. Proteins still function normally if only one amino acid is substituted. c. The genetic code is redundant, so that mutations in the third position of the codon often result in the same amino acid being specified. d. The ribosome recognized the mutated codon and bound the tRNA that carried the proper amino acid rather than the one specified after the mutation. e. RNA polymerase detected the mutation and transcribed the gene with the proper nucleotide.

c. The genetic code is redundant, so that mutations in the third position of the codon often result in the same amino acid being specified.

Required information View the animation below, then complete the quiz to test your knowledge of the concept. Translation is the synthesis of a. mRNA from DNA. b. proteins from tRNA. c. proteins from mRNA. d. proteins from DNA. e. mRNA from proteins.

c. proteins from mRNA.

Required information View the animation below, then complete the quiz to test your knowledge of the concept. Translation is terminated when a stop codon is presented at the ________ site. a. either A or P site b. either A or E site c. P site d. A site e. E site

d. A site

What does not occur during the processing of eukaryotic mRNA? a. several adenine (A) residues are added at the 3' end b. introns are removed by splicing c. a 5' guanosine cap is added d. a ribosome recognition sequence is added

d. a ribosome recognition sequence is added

A 5'-CUA-3' codon in an mRNA could be recognized by which of the following anticodon sequences in a tRNA? a. 5'-TAG-3' b. 3'-GAT-5' c. 5'-GAT-3' d. 3'-GUA-3' e. 3'-GAU-5'

e. 3'-GAU-5'

Required information Are both strands of DNA used in making RNA? DNA is a two-stranded molecule. Only one strand is used to transcribe mRNA. During transcription the two strands separate and RNA polymerase synthesizes mRNA based on the sequence of one the two strands. Then the two DNA strands join together again. Either strand may be used to produce mRNA. One strand does not exclusively code for mRNA while the other does not. But for any given mRNA strand only one of the DNA strands is used. The complementary nature of DNA would make it very unlikely that both strands could code simultaneously for functional proteins. Here is an analogy with language. Imagine that each letter in the alphabet had a complementary letter. For example A might match with Q, B with X, and so on. If we were to write a normal English word the complementary sequence would be determined by the letters in that word and could not be changed. It is very unlikely that the complementary sequence would be a recognizable word. View the animation below, then complete the quiz to test your knowledge of the concept. RNA polymerase is able to open the DNA double helix as it moves down the template. What type of enzymatic activity does this mean RNA polymerase must possess? a. Primase activity b. Polymerase activity c. Exonuclease activity d. Ligase activity e. Helicase activity

e. Helicase activity

Required information Are both strands of DNA used in making RNA? DNA is a two-stranded molecule. Only one strand is used to transcribe mRNA. During transcription the two strands separate and RNA polymerase synthesizes mRNA based on the sequence of one the two strands. Then the two DNA strands join together again. Either strand may be used to produce mRNA. One strand does not exclusively code for mRNA while the other does not. But for any given mRNA strand only one of the DNA strands is used. The complementary nature of DNA would make it very unlikely that both strands could code simultaneously for functional proteins. Here is an analogy with language. Imagine that each letter in the alphabet had a complementary letter. For example A might match with Q, B with X, and so on. If we were to write a normal English word the complementary sequence would be determined by the letters in that word and could not be changed. It is very unlikely that the complementary sequence would be a recognizable word. View the animation below, then complete the quiz to test your knowledge of the concept. The enzyme that accomplishes transcription is termed a. DNA ligase. b. RNA replicase. c. RNA ligase. d. DNA polymerase. e. RNA polymerase.

e. RNA polymerase.