Exam 2

Following statements apply to both micro-RNA (miRNA) and small interfering RNA (siRNA) A. Transcribed in the nucleus and exported to the cytoplasm B. Processed by Dicer C. Bind to proteins to form an RNA-induced silencing complex (RISC) D. All of the above apply to both E. A, B, C applies to microRNA and B, C applies to siRNA

E. A, B, C applies to microRNA and B, C applies to siRNA

Genes in eukaryotic cells often have intronic sequences coded for within the DNA. These sequencesare ultimately not translated into proteins. Why?

Intronic sequences are removed from RNA molecules by the spliceosome, which works in the nucleus

Genes in eukaryotic cells often have intronic sequences coded for within the DNA. These sequences are ultimately not translated into proteins. Why?

Intronic sequences are removed from RNA molecules by the spliceosome, which works in the nucleus.

Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because...

RNA is single-stranded

Cell type specific regulatory proteins ensure cell type (lineage) specific gene expression whereas simultaneously ensure that genes belonging to different lineages remain repressed. Is the statement True or false?

True

The large subunit of the ribosome is important for binding to the mRNA

false

RNA in cells differs from DNA in that...

it is single-stranded and can fold up into a variety of structures

the nucleolus is the site of...

rRNA synthesis and ribosome assembly

Which of the following molecules of RNA would you predict to be the most likely to fold into a specificstructure as a result of intramolecular base-pairing? A 5′-CCCUAAAAAAAAAAAAAAAAUUUUUUUUUUUUUUUUAGGG-3′ B 5′-UGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUG-3′ C 5′-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-3′ D 5′-GGAAAAGGAGAUGGGCAAGGGGAAAAGGAGAUGGGCAAGG-3′

A 5′-CCCUAAAAAAAAAAAAAAAAUUUUUUUUUUUUUUUUAGGG-3

Which of the following statements about RNA splicing is false? A.Conventional introns are not found in bacterial genes. B. For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene. C. Small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns. D. Splicing occurs after the 5′ cap has been added to the end of the primary transcript.

B For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene.

Which of the following statements about RNA splicing is false? A. Conventional introns are not found in bacterial genes. B. For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene. C. Small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns. D. Splicing occurs after the 5′ cap has been added to the end of the primary transcript

B. For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene.

Which of the following pairs of codons might you expect to be read by the same tRNA as a result of wobble? A. CUU and UUU B. GAU and GAA C. CCC and CAU D. AAU and AGU

B. GAU and GAA

Which of the following statements about prokaryotic mRNA molecules is false? A. A single prokaryotic mRNA molecule can be translated into several proteins. B. Ribosomes must bind to the 5′ cap before initiating translation. C. Ribosomes can start translating an mRNA molecule before transcription is complete D. None of the above

B. Ribosomes must bind to the 5′ cap before initiating translation.

Which of the following statements about the proteasome is false? A. Ubiquitin is a small protein that is covalently attached to proteins to mark them for delivery to the proteasome. B. Proteases reside in the central cylinder of a proteasome. C. Misfolded proteins are delivered to the proteasome, where they are sequestered from the cytoplasm and can attempt to refold. D The protein stoppers that surround the central cylinder of the proteasome use the energy from ATP hydrolysis to move proteins into the proteasome inner chamber

C. Misfolded proteins are delivered to the proteasome, where they are sequestered from the cytoplasm and can attempt to refold.

Which of the following statements is true? A. Ribosomes are large RNA structures composed solely of rRNA. B. Ribosomes are synthesized entirely in the cytoplasm. C. rRNA contains the catalytic activity that joins amino acids together. D. A ribosome binds one tRNA at a time.

C. rRNA contains the catalytic activity that joins amino acids together.

Which statement is true regarding the steps for mRNA being translated into protein in eukaryotes?-> A.The mRNA is transported to the cytosol after 5'-capping and polyadenylation, but RNA splicing occurs in the cytosol. B. the mRNA is translated in the nucleus and then the fully translated protein is then transported to the cytosol. C. the mRNA is transported to the cytosol after 5'-capping, polyadenylation and RNA splicing. D. The mRNA is transcribed in the cytosol and therefore, ribosomes can translate the message into protein immediately after transcription.

C. the mRNA is transported to the cytosol after 5'-capping, polyadenylation and RNA splicing

The net output of mRNAs from a gene through transcription is known as ... which is the result of multiple transcription regulators and their effect on RNA polymerase

Combinatorial Control

The number of rRNA molecules that make up a ribosome greatly exceeds the number of proteinmolecules found in the ribosome.

False

Regulatory proteins determine whether gene expression is to be increased or decreased, they exert their control of gene expression at:

Gene transcriptional level

Which of the following statements about the genetic code is correct?

The genetic code is redundant

Restriction enzymes recognize and cut DNA at specific sites only. Is this statement true or false?

True

Restriction enzymes recognize and cut DNA at specific sites only?

True

The three steps of each cycle of PCR are Denaturation, Annealing, and Amplification

True

Prominent part of many regulatory proteins contains which of the following DNA binding domains?

Zinc finger domain

The CAP activator protein and the Lac repressor both control the Lac operon. You create cells that are mutant in the gene coding for the Lac repressor so that these cells lack the Lac repressor under all conditions. For these mutant cells, state whether the Lac operon will be switched on or off in the following situations:

in the absence of glucose and the presence of lactose

Once an mRNA is produced, its message can be decoded on ribosomes. The ribosome is composed of two subunits: the __ subunit, which catalyzes the formation of the peptide bonds that link the amino acids together into a polypeptide chain, and the __ subunit, which matches the tRNAs to the codons of them RNA

large, small

Transcription is similar to DNA replication in that...

nucleotide polymerization occurs only in the 5′-to-3′ direction

You have a segment of DNA that contains the following sequence: 5′-GGACTAGACAATAGGGACCTAGAGATTCCGAAA-3′ 3′-CCTGATCTGTTATCCCTGGATCTCTAAGGCTTT-5′ You know that the RNA transcribed from this segment contains the following sequence: 5′-GGACUAGACAAUAGGGACCUAGAGAUUCCGAAA-3′ Which of the following choices best describes how transcription occurs?

the bottom strand is the template strand; RNA polymerase moves along this strand from 3′ to 5′

Which of the following choices best describes how transcription occurs? 5′-GGACTAGACAATAGGGACCTAGAGATTCCGAAA-3′ 3′-CCTGATCTGTTATCCCTGGATCTCTAAGGCTTT-5′

the bottom strand is the template strand; RNA polymerase moves along this strand from3′ to 5′

An incoming aminoacyl-tRNA carrying the next amino acid in the chain will bind to the __ site by forming base pairs with the exposed codon in the mRNA

A

Which of the following is true about Eukaryotic mature mRNA transcript after it emerges from the RNA polymerase: A. Mature mRNA contain 5' 7-methylguanosine cap. B. Mature mRNA contain poly (A) tail. C. Mature mRNA does not contain introns. D. All of the above.

D. All of the above

In eukaryotic organisms the regulatory DNA sequences may be spread out over 1000s of base pairs.Usually, more than one regulatory factor binds to their respective regulatory DNA sequences of a gene and exerts a combinatorial control on the gene expression. Which of the following statement is correct with respect to regulatory proteins and general transcription factors: A. The general transcription factors that assemble at the promoter are the same for all genes transcribed by RNA polymerase, B. the transcription regulators and the locations of their DNA binding sites relative to the promoters are different for different genes. C. the transcription regulators along with mediators recruit chromatin modifying proteins, are assembled at the promoter. D. All of the above is correct.

D. All of the above is correct.

Which of the following is true about cDNA and genomic DNA libraries: A. cDNA libraries are made from RNA transcripts. B. DNA libraries are made from genome segments. C. A cDNA library chip may contain all the genes expressed in a cell D. All of the above is true.

D. All of the above is true

Which of the following is true about cDNA and DNA libraries: A. cDNA libraries are made from RNA transcripts. B. DNA libraries are made from genome segments. C. A cDNA library "ChIP" may contain all the genes expressed in a cell D. All of the above is true.

D. All of the above is true.

The activator and repressor protein that regulate the Lac operon is expected to have following DNA binding domains: A. Helix-turn-helix B. Helix-loop-helix C. Bacterial activators or repressor are not regulatory factors D. Both A and B are correct

D. Both A and B are correct

Which of the following is true about splicing: A. In splicing exons are excised but introns are retained. B. In splicing introns are excised but exons are retained. C. 5' UTR and 3' UTR which are non-protein coding exons are retained. D. Both B and C are correct.

D. Both B and C are correct.

Which of the following methods is not used by cells to regulate the amount of a protein in the cell? A. Genes can be transcribed into mRNA with different efficiencies. B. Many ribosomes can bind to a single mRNA molecule. C. Proteins can be tagged with ubiquitin, marking them for degradation. D. Nuclear pore complexes can regulate the speed at which newly synthesized proteins are exported from the nucleus into the cytoplasm.

D. Nuclear pore complexes can regulate the speed at which newly synthesized proteins are exported from the nucleus into the cytoplasm

Which of the following statements is false? A. A new RNA molecule can begin to be synthesized from a gene before the previous RNA molecule's synthesis is completed. B. If two genes are to be expressed in a cell, these two genes can be transcribed with different efficiencies. C. RNA polymerase is responsible for both unwinding the DNA helix and catalyzing the formation of the phosphodiester bonds between nucleotides. D. Unlike DNA, RNA uses a uracil base and a deoxyribose sugar.

D. Unlike DNA, RNA uses a uracil base and a deoxyribose sugar

The two things that are absolutely essential for PCR to occur are the DNA polymerase and the ____________

DNA primer

central dogma

The principle that genetic information flows from DNA to RNA to Protein

Imagine that an RNA polymerase is transcribing a segment of DNA that contains the following sequence: 5′-AGTCTAGGCACTGA-3′ 3′-TCAGATCCGTGACT-5′ If the polymerase is transcribing from this segment of DNA from left to right, which strand (top or bottom)is the template?

bottom

You have a segment of DNA that contains the following sequence:5′-GGACTAGACAATAGGGACCTAGAGATTCCGAAA-3′ 3′-CCTGATCTGTTATCCCTGGATCTCTAAGGCTTT-5′ You know that the RNA transcribed from this segment contains the following sequence: 5′-GGACUAGACAAUAGGGACCUAGAGAUUCCGAAA-3′ Is the transcribed RNA sequence shown:

correctly

The sigma subunit of bacterial RNA polymerase...

recognizes promoter sites in the DNA

A neuron and a white blood cell have very different functions. For example, a neuron can receive and respond to electrical signals while a white blood cell defends the body against infection. This is because ______

the neuron expresses some mRNAs that the white blood cell does not