Ch 12-Brooker Biology-Gene Expression at the Molecular Level

True or False: mRNA must be processed in the nucleus prior to transcription of a protein in eukaryotes. A) True B) False

A) True

True or False: Ribosomes are composed of protein subunits and ribosomal RNA? A) True B) False

A) True Feedback: Refer to table 12.2

True or False: Structural genes result in polypeptides of a specific sequence that carry out a specific function for the organisms in addition to RNA molecules with specific functions. A) True B) False

A) True Refer to page 243

True or False: Synthesis of an mRNA strand begins at the promoter in a 5' to 3' direction while the template strand of DNA is read in the 3' to 5' direction. A) True B) False

A) True Refer to page 245

True or False: The attachment of amino acids to tRNA molecules is catalyzed by Aminoacyl-tRNA synthetase. A) True B) False

A) True Refer to page 253

True or False: The tRNA that is complementary base paired to the initial start codon is required for full ribosome assemble of the small and large subunits. A) True B) False

A) True Refer to page 257

An organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in the formation of a biologically functional product is most accurately referred to as a(n) A) gene. B) chromosome. C) enzyme. D) genome. E) snRNP.

A) gene. refer to page 243

Which of the following best represents the central dogma of gene expression? A) During transcription, DNA codes for polypeptides. B) During transcription, DNA codes for mRNA, which codes for polypeptides during translation. C) During translation, DNA codes for mRNA, which codes for polypeptides during transcription. D) none of the above.

B) During transcription, DNA codes for mRNA, which codes for polypeptides during translation.

Which of the following does not play a role in transcription in prokaryotes? A) Sigma factor B) Pre-mRNA processing C) Formation of open complex D) Termination sequence E) Regulatory sequence

B) Pre-mRNA processing Refer to page 244

The synthesis of a polypeptide occurs during which stage of translation? A) initiation B) elongation C) termination D) splicing

B) elongation

During eukaryotic RNA processing, the nontranslated sequences that are removed are called A) exons. B) introns. C) promoters. D) codons. E) ribozymes.

B) introns.

The relationship between the bases in a messenger RNA molecule and the sequence of amino acids in a polypeptide is specified by A) a ribosome. B) the genetic code. C) codons. D) RNA polymerases. E) DNA polymerases.

B) the genetic code. Refer to page 248

Which one of the following rRNA molecules would not be found in a cytosolic eukaryotic ribosome? A) 60S B) 5S C) 16S D) 18S E) 28S

C) 16S Refer to page 254

Which of the following is/are not modifications to Beadle and Tatum's one gene one enzyme hypothesis? A) Proteins that are not biological catalysts are also coded for by genes. B) Genes encode individual polypeptide chains, but some functional proteins are composed of more than one polypeptide chain. C) Some enzymes are lipid molecules, which are not coded for by genes. D) Some genes encode RNA molecules E) None of these choices are modifications to the one gene, one enzyme hypothesis.

C) Some enzymes are lipid molecules, which are not coded for by genes. Refer to page 242

The __________ is the site where the translation process takes place. A) mitochondria. B) nucleus. C) ribosome. D) lysosome. E) ribozyme.

C) ribosome.

During the initiation step of translation, the first codon, _______ will enter the _________ and associate with the initiator tRNA. A) UAG, A site B) AUG, A site C) UAG, P site D) AUG, P site E) AUG, E site

D) AUG, P site

The last amino acid added in a polypeptide chain is said to be at the ________ of the protein. A) 5' end B) 3' end C) N terminus D) C terminus E) 60S side

D) C terminus Refer to page 249

Choose the correct sequence of events during the termination stage of a polypeptide? I. Peptidyl transfer reaction in P site II. Disassociation of ribosome, mRNA and release factor III. Release factor binds to A site complementary to stop codon IV. tRNA enters A site complementary to mRNA sequence V. tRNA released through exit site VI. Polypeptide released from ribosome A) III IV V B) I II IV C) VI III II D) III VI II E) IV VI I

D) III VI II Refer to page 258

Which of the following applies to both transcription and translation? A) Promoter and terminator B) Initiation complex and open complex C) Activation, regulation and termination D) Initiation, elongations and termination E) Activation, processing and termination

D) Initiation, elongations and termination Refer to pages 244 and 256

Which of the following codons does not specify Leucine (Leu)? A) UUG B) CUA C) CUG D) UUC E) CUC

D) UUC Refer to Table 12.1

The functional product of a structural gene is A) tRNA. B) mRNA. C) rRNA. D) a polypeptide. E) a,b, and c.

D) a polypeptide.

Transcription of a gene begins at a site on DNA called ___________ and ends at a site on DNA known as ___________. A) an initiation codon, the termination codon. B) a promoter, the termination codon. C) an initiation codon, the terminator. D) a promoter, the terminator. E) an initiator, the terminator.

D) a promoter, the terminator.

The movement of the polypeptide from the tRNA in the P site to tRNA in the A site is referred to as A) peptide bonding. B) aminoacyl binding. C) translation. D) peptidyl transfer reaction E) elongation

D) peptidyl transfer reaction

An RNA molecule that has catalytic activity is most accurately referred to as a(n) A) RNase. B) enzyme. C) spliceosome. D) ribozyme. E) ribosome.

D) ribozyme. Refer to page 246

The addition of an amino acid to a tRNA molecule is catalyzed by a(n) ________, and is driven by ________. A) peptidyl transferase; ATP B) aminoacyl tRNA synthetase; GTP aminoacyl C) peptidyl transferase; GTP D) tRNA synthetase; ATP E) aminoacyl tRNA synthetase; hydrolysis of the amino acid from a polypeptide chain.

D) tRNA synthetase; ATP Refer to page 253

The region of the tRNA that is complementary to a codon in mRNA is A) the acceptor stem. B) the codon. C) the peptidyl site. D) the anticodon. E) the adaptor loop.

D) the anticodon.

The genetic code is both ________ and ________. A) conservative; dispersive B) ambiguous; degenerate C) degenerate; quadruplicate D) universal; degenerate E) universal; ambiguous

D) universal; degenerate Refer to page 248

Which one of the following events is not part of the maturation of a eukaryotic mRNA? A) Poly-A tail addition B) 5' cap addition C) Intron removal and splicing of exons D) Binding of snRNP subunits E) Attachment to ribosome

E) Attachment to ribosome Refer to pages 246 and 247

Which of the following molecules is not directly involved in the synthesis of a polypeptide chain? A) mRNA B) ribosomal proteins C) tRNA D) rRNA E) DNA

E) DNA Refer to Table 12.2

Which of the following accurately represents the Central Dogma of molecular biology? A) DNA is translated into protein, which is then transcribed into RNA. B) RNA is transcribed into DNA, which is then translated into protein. C) DNA is translated directly into protein. D) RNA is translated into protein, which is then transcribed into DNA. E) DNA is transcribed into RNA, which is then translated into protein.

E) DNA is transcribed into RNA, which is then translated into protein. Refer to page 242

Match the type of RNA on the left with the specific function on the right. I tRNA A. Carries polypeptide sequence according to genetic code II mRNA B. Essential component in ribosome construction and function III rRNA C. Carries amino acids to growing polypeptide according to genetic code A) i = b; ii = c; iii = a B) i = a; ii = b; iii = c C) i = c; ii = b; iii = a D) i = b; ii = a; iii = c E) i = c; ii = a; iii = b

E) i = c; ii = a; iii = b Refer to page 252

The small subunit of a ribosome is composed of A) a protein. B) an rRNA molecule. C) many proteins. D) many rRNA molecules. E) many proteins and one rRNA molecule.

E) many proteins and one rRNA molecule.

In bacteria, proteins called ________ recognize the sequence of bases in a promoter; in eukaryotes, proteins called ________ serve this function. A) transcription factors; sigma factors B) initiation factors; elongation factors C) transcription factors; initiation factors D) sigma factors; snRNPs E) sigma factors; transcription factors

E) sigma factors; transcription factors Refer to pages 244 and 245