Transcription

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? A) Complementary B) Covalently bound C) Permanently base-paired D) Identical

A) Complementary

What happens to RNA polymerase II after it has completed transcription of a gene? A) It is free to bind to another promoter and begin transcription. B) It is degraded. C) It begins transcribing the next gene on the chromosome. D) It joins with another RNA polymerase to carry out transcription.

A) It is free to bind to another promoter and begin transcription.

The direction of synthesis of an RNA transcript is _____. A) 1' —> 5' B) 5' —> 3' C) 1' —> 3' D) 3' —> 5' E) 2' —> 4'

B) 5' —> 3'

Where does RNA polymerase begin transcribing a gene into mRNA? A) The ribosome directs it to the correct portion of the DNA molecule. B) It starts after a certain nucleotide sequence called a promoter. C) It looks for the AUG start codon. D) It starts at one end of the chromosome. E) Transfer RNA acts to translate the message to RNA polymerase.

B) It starts after a certain nucleotide sequence called a promoter.

The flow of information in a cell proceeds in what sequence? A) from RNA to DNA to protein B) from protein to RNA to DNA C) from DNA to RNA to protein D) from RNA to protein to DNA E) from DNA to protein to RNA

C) from DNA to RNA to protein

___________ are composed of amino acid monomers.

Proteins/Polypeptides

_________ edits the RNA transcript that has been assembled along a DNA template.

RNA processing

__________ is the process by which a DNA template is used for the manufacture of several different types of RNA

Transcription

RNA processing converts the RNA transcript into _____

mRNA

Suppose that a portion of double-stranded DNA in the middle of a large gene is being transcribed by an RNA polymerase. As the polymerase moves through the sequence of six bases shown in the diagram below, what is the corresponding sequence of bases in the RNA that is produced? Diagram of DNA showing a coding strand and a template strand. Coding strand from 3' to 5' reads C C G A G T. Template strand from 5' to 3' reads G G C T C A. Enter the sequence of bases as capital letters with no spaces and no punctuation. Begin with the first base added to the growing RNA strand, and end with the last base added.

-UGAGCC There are three principles to keep in mind when predicting the sequence of the mRNA produced by transcription of a particular DNA sequence. The RNA polymerase reads the sequence of DNA bases from only one of the two strands of DNA: the template strand. The RNA polymerase reads the code from the template strand in the 3' to 5' direction and thus produces the mRNA strand in the 5' to 3' direction. In RNA, the base uracil (U) replaces the DNA base thymine (T). Thus the base-pairing rules in transcription are A→U, T→A, C→G, and G→C, where the first base is the coding base in the template strand of the DNA and the second base is the base that is added to the growing mRNA strand.

After transcription begins, several steps must be completed before the fully processed mRNA is ready to be used as a template for protein synthesis on the ribosomes. Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus? Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus? A) A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA. B) A translation stop codon is added at the 3' end of the pre-mRNA. C) Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. D) Coding sequences called exons are spliced out by ribosomes. E) A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.

A) A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA. C) Noncoding sequences called introns are spliced out by molecular complexes called spliceosomes. E) A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.

Which of the following is a function of a poly-A signal sequence? A) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away. B) It is a sequence that codes for the hydrolysis of the RNA polymerase. C) It allows the 3' end of the mRNA to attach to the ribosome. D) It adds the poly-A tail to the 3' end of the mRNA. E) It adds a 7-methylguanosine cap to the 3' end of the mRNA.

A) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10-35 nucleotides away.

RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such variability in RNA polymerase? A) It might allow the polymerase to recognize different promoters under certain environmental conditions. B) It could allow ribosomal subunits to assemble at faster rates. C) It could allow the polymerase to react differently to each stop codon. D) It could alter the rate of translation and of exon splicing. E) It might allow the translation process to vary from one cell to another.

A) It might allow the polymerase to recognize different promoters under certain environmental conditions.

A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that A) many noncoding stretches of nucleotides are present in mRNA. B) there are termination exons near the beginning of mRNA. C) there is redundancy and ambiguity in the genetic code. D) many nucleotides are needed to code for each amino acid. E) nucleotides break off and are lost during the transcription process.

A) many noncoding stretches of nucleotides are present in mRNA.

What determines which base is to be added to an RNA strand during transcription? What determines which base is to be added to an RNA strand during transcription? A) The order of the chemical groups in the backbone of the RNA molecule B) Base pairing between the DNA template strand and the RNA nucleotides C) The previous base D) Base pairing between the two DNA strands

B) Base pairing between the DNA template strand and the RNA nucleotides

Which of these correctly illustrates the pairing of DNA and RNA nucleotides? A) GTTACG CAATCG B) GTTACG CAAUGC C) GTTACG GTTACG D) GTTACG ACCGTA E) GTTACG UAACAU

B) GTTACG CAAUGC

In which of the following actions does RNA polymerase differ from DNA polymerase? A) RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to double-stranded DNA. B) RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis. C) RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template. D) RNA polymerase is much more accurate than DNA polymerase. E) RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA.

B) RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

After an RNA molecule is transcribed from a eukaryotic gene, what are removed and what are spliced together to produce an mRNA molecule with a continuous coding sequence? A) silencers ... enhancers B) introns ... exons C) promoters ... operators D) operators ... promoters E) exons ... introns

B) introns ... exons

If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media? A) minimal medium B) minimal medium supplemented with nutrient B only C) minimal medium supplemented with nutrient C only D) minimal medium supplemented with nutrient A only E) minimal medium supplemented with nutrients A and C

B) minimal medium supplemented with nutrient B only

Transcription begins at a promoter. What is a promoter? Transcription begins at a promoter. What is a promoter? A) A site found on the RNA polymerase B) Part of the RNA molecule itself C) A site in DNA that recruits the RNA Polymerase D) A nontranscribed sequence on the DNA E) A site where many different proteins will bind

C) A site in DNA that recruits the RNA Polymerase

What is the process called that converts the genetic information stored in DNA to an RNA copy? What is the process called that converts the genetic information stored in DNA to an RNA copy? A) Replication B) Translocation C) Transcription D) Translation

C) Transcription

The following question refers to a simple metabolic pathway: A--> B-->C A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation? A) an accumulation of A and B and no production of C B) an accumulation of B and C and no production of A C) an accumulation of A and no production of B and C D) an accumulation of B and no production of A and C E) an accumulation of C and no production of A and B

C) an accumulation of A and no production of B and C

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following? A) the sequence of the intron that immediately precedes each exon B) the number of polypeptides making up the functional protein C) the various domains of the polypeptide product D) the number of start sites for transcription E) the number of restriction enzyme cutting sites

C) the various domains of the polypeptide product

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is A) 5' TCA 3'. B) 3' UGA 5'. C) 3' ACU 5'. D) 3' UCA 5'. E) either UCA or TCA, depending on wobble in the first base.

D) 3' UCA 5'.

Use the following model of a eukaryotic transcript to answer the question. 5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' Which components of the previous molecule will also be found in mRNA in the cytosol? A) 5' UTR I1 I2 I3 UTR 3' B) 5' I1 I2 I3 3' C) 5' E1 E2 E3 E4 3' D) 5' UTR E1 E2 E3 E4 UTR 3' E) 5' E1 I1 E2 I2 E3 I3 E4 3'

D) 5' UTR E1 E2 E3 E4 UTR 3'

What is the function of RNA polymerase? A) It adds nucleotides to the 5' end of the growing mRNA molecule. B) It relies on other enzymes to unwind the double helix. C) It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. D) It unwinds the double helix and adds nucleotides to a growing strand of RNA. E) All of the above.

D) It unwinds the double helix and adds nucleotides to a growing strand of RNA.

DNA does not store the information to synthesize which of the following? DNA does not store the information to synthesize which of the following? A) Proteins B) DNA C) Messenger RNA D) Organelles

D) Organelles

Which of the following statements best describes the promoter of a protein-coding gene? Which of the following statements best describes the promoter of a protein-coding gene? A) The promoter is a site at which only RNA polymerase will bind. B) The promoter is a site found on RNA polymerase. C) The promoter is part of the RNA molecule itself. D) The promoter is a nontranscribed region of a gene.

D) The promoter is a nontranscribed region of a gene.

What is a ribozyme? A) a mutated ribosome B) an enzyme that holds open the DNA double helix while RNA polymerase adds nucleotides C) a biological catalyst consisting of DNA D) a biological catalyst made of RNA E) a DNA sequence near the promoter that assists in the binding of RNA polymerase

D) a biological catalyst made of RNA

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because A) enzymes are made of DNA, and affected individuals lack DNA polymerase. B) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies. C) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors. D) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. E) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA.

D) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A) aminoacyl synthetase B) ribosomes and tRNA C) the protein product of the promoter D) several transcription factors (TFs) E) start and stop codons

D) several transcription factors (TFs)

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. For any given gene, what ultimately determines which DNA strand serves as the template strand? For any given gene, what ultimately determines which DNA strand serves as the template strand? A) the location along the chromosome where the double-stranded DNA unwinds B) which of the two strands of DNA carries the RNA primer C) the location of specific proteins (transcription factors) that bind to the DNA D) the base sequence of the gene's promoter

D) the base sequence of the gene's promoter

RNA polymerase moves in which direction along the DNA? A) 3' → 5' along the coding (sense) strand B) 5' → 3' along the template strand C) 3' → 5' along the coding strand D) 5' → 3' along the double-stranded DNA E) 3' → 5' along the template strand

E) 3' → 5' along the template strand

In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene? A) eukaryotic tRNAs B) eukaryotic ribosomal subunits C) eukaryotic polymerases D) the introns E) a bacterial promoter sequence

E) a bacterial promoter sequence

DNA template strand 5'_________3' DNA complementary strand 3'__________5' In the transcription event of the previous DNA, where would the promoter be located? A) at the 3' end of the newly made RNA B) to the right of the non-template strand C) to the left of the template strand D) to the left of the non-template strand E) to the right of the template strand

E) to the right of the template strand

Life as we know it depends on the genetic code: a set of codons, each made up of three bases in a DNA sequence and corresponding mRNA sequence, that specifies which of the 20 amino acids will be added to the protein during translation. Imagine that a prokaryote-like organism has been discovered in the polar ice on Mars. Interestingly, these Martian organisms use the same DNA → RNA → protein system as life on Earth, except that there are only 2 bases (A and T) in the Martian DNA, and there are only 17 amino acids found in Martian proteins

In the most general case of x bases and y bases per codon, the total number of possible codons is equal to xy . In the case of the hypothetical Martian life-forms, is the minimum codon length needed to specify 17 amino acids is 5 (25 = 32), with some redundancy (meaning that more than one codon could code for the same amino acid). For life on Earth, x = 4 and y = 3; thus the number of codons is 43, or 64. Because there are only 20 amino acids, there is a lot of redundancy in the code (there are several codons for each amino acid).

This type of RNA first plays a role in... -pre mRNA -mRNA -snRNA

Transcription/RNA Processing

This type of RNA first plays a role in... -tRNA -rRNA

Translation

__________ is the process by which information encoded in RNA is used to manufacture a polypeptide.

Translation