ch. 17 & 18 quiz (exam 4)

. Which of the following is an effect of methylation in a cell's DNA? a. Those genes will not be expressed b. The rate of transcription will increase c. Methylated genes are expressed d. Methylating genes is not a reversible process

a

At which site of the large ribosomal subunit do all subsequent tRNAs bind? a. A site b. P site c. E site

a

DNA is the genetic material of all living organisms. Which of the following describes a difference between prokaryotic DNA and eukaryotic DNA? a. Eukaryotic DNA is antiparallel while prokaryotic is not b. Prokaryotic DNA uses uracil while eukaryotic DNA uses thymine c. Prokaryotic DNA is haploid while eukaryotic DNA is diploid d. Prokaryotic DNA is circular while eukaryotic DNA is linear

a

DNA polymerase and RNA polymerase have similar functions. Which statement is an incorrect description of these enzymes? a. Both enzymes require a primer. b. DNA polymerase is used in replication while RNA polymerase is used in transcription c. Both enzymes add nucleotides to the 3' end of a chain d. The binding of RNA polymerase is preceded by the binding of transcription factors

a

If a sequence initially reading Met-Lys-Phe-Stop is mutated, and you are left with Met-Stop, what kind of mutation can you assume has occurred? a. Nonsense b. Missense c. Silent d. Frameshift mutation

a

In which direction are codons on the mRNA strand read during translation? a. 5'----> 3' b. 3'----> 5' c. It does not matter which way it is read

a

Transcription is _______. a. The synthesis of RNA from a DNA template b. The synthesis of proteins from information on a mRNA c. The synthesis of polydiester linkages from an exon d. The synthesis of brain cells by neurokinetic means

a

Where does the small ribosomal subunit specifically bind on the mRNA strand? a. The 5' untranslated region (5' cap) b. The AUG sequence c. At the 3' polyA tail end of the mRNA strand d. None of the above

a

Where does transcription take place? a. In the nucleus of the cell b. In the cytoplasm of the cell c. It would depend on whether or not mRNA processing will take place d. It occurs partially in the nucleus and partially in the cytoplasm

a

Why was it decided that a 3 nucleotide codon sequence was more viable than a 2 nucleotide codon sequence? a. Having two nucleotides in a codon would only account for 16 possible amino acids, rather than the required 20 b. Having two nucleotides per codon would account for over 64 different possible amino acids, which was too many c. Having two nucleotides per codon would actually work theoretically, but did not happen experimentally. d. None of the above

a

A section of mRNA reads as follows: 3'-GGUUAAGUA- 5'. How would this be translated? a. Gly-Stop-Val b. Met-Asn-Trp c. Start-Asn-Stop d. Ill-Asn-Stop

b

A section of mRNA reads as follows: 5' - AUGGUGACGUUUUAG - 3'. How many amino acids does this code? a. 3 b. 4 c. 5 d. 6

b

At which site of the large ribosomal subunit does the first tRNA bind? a. A site b. P site c. E site

b

Codons are triplet nucleotide sequences that play an essential role in translation. Where are the codons located? a. tRNA b. mRNA c. DNA template strand d. rRNA

b

During gene expression, an error creates a mutation in the codon GUU. Which of the following is not an example of what could have replaced GUU in order to create a silent mutation? a. GUC b. UGA c. GUA d. GUG

b

T or F. Adding 3 nucleotide bases to an mRNA will cause a frameshift mutation. a. True b. False

b

T or F. All cells in an organism are being expressed simultaneously. a. True b. False

b

T or F. The polyA tails and 5' end cap regions on eukaryotic DNA are translated during the translation step of gene encoding. a. True b. False

b

T or F. Tightly packaged DNA, in the form of heterochromatin, is more accessible for transcription, and that gene will more likely be expressed. a. True b. False

b

The _____ is found in eukaryotes, but not prokaryotes regarding the initiation phase of transcription. a. RNA polymerase b. TATA box c. a promoter region d. all of the above are in eukaryotes, and not prokaryotes

b

Which enzyme is essential for transcription and has functions such as unwinding the double helix and synthesizing mRNA? a. DNA polymerase b. RNA polymerase c. Primase d. Transcription Factor

b

Which of the following is not a way to increase the rate of transcription? a. Acetylation b. Polyadenylation c. Methylation d. All of the above are ways to increase the rate of transcription

b

Which of the following is not one of the three steps of transcription? a. Initiation b. Replication c. Termination d. Elongation

b

Which of the following refers to the complex of the small ribosomal subunit, large ribosomal subunit, mRNA, and first tRNA at the P site? a. Transcription Initiation Complex b. Translation Initiation Complex c. mRNA Binding Complex d. Start Codon Complex

b

. Which of the following is true of the start codon for eukaryotes and prokaryotes? a. The codon is AAA, and codes for Methionine b. The codon is AAA, and codes for Arginine c. The codon is AUG, and codes for Methionine d. The codon is AUG, and it codes for Arginine

c

The codon chart shows that there is redundancy but not ambiguity in the genetic code. How can this statement be explained? a. One codon can code for several amino acids. b. Any mistakes are corrected during the proofreading process. c. Individual amino acids can have more than one codon, but each codon only translates one amino acid d. The same 20 amino acids are used repeatedly. but in different combinations, to create different proteins, accounting for the necessary genetic diversity of life

c

What type of bond is catalyzed between the building amino acid chain and the new amino acid brought in by the tRNA (now on the A site). a. Phosphodiester bond b. Glycosidic Linkage c. Peptide Bond d. None of the above

c

Which of the following increases mRNA stability and prevents degradation of the mRNA after it exits the nucleus? a. the poly(A) tail on the 3' end of the mRNA b. the 5' end cap on the 5' end of the mRNA strand c. both A and B d. none of the above

c

Which of the following is not a stop codon? a. UAA b. UAG c. UCG d. UGA

c

Which of the following is used to transcribe DNA to mRNA? a. Both DNA strands can be used simultaneously b. Only the leading strand of DNA can be used c. Either strand of DNA can be used depending on the gene, but only one may be used at a time d. None of the above

c

A cell builds its proteins from the instructions encoded in its ______? a. Cytoplasm b. Cell membrane c. Amino Acid d. Genome

d

In Eukaryotes ​we make pre-mRNA that must be edited before being released into the cytoplasm. How is the pre-mRNA prepared? a. A polyadenylation (AAUAAA) tail is added to one end b. Splicing occurs and introns are removed from the mRNA strand, leaving exons behind c. A 5' end cap is added d. All of the above e. Only two of the above answers are correct

d

Translation involves the coordination of several different molecules. Which of the following pairs is incorrectly matched in terms of function? a. small rRNA subunit - binds to mRNA b. tRNA - brings the nucleotides to be added to the polypeptide c. "A" site on rRNA - houses the next nucleotide to be added d. mRNA - contains the anticodons to be translated

d

What are anti-codons? a. Nucleotide triplets that are carried on tRNA with an amino acid on the opposite side b. A codon sequence that has been reversed due to mutation c. A codon that is antiparallel to that of the mRNA strand d. Both a and c

d

Which of the following does not correctly pair a process with the location where that process occurs in eukaryotes? a. Replication- nucleus b. Translation- cytosol c. Transcription- nucleus d. mRNA processing- cytosol

d

Which of the following is not a nucleotide monomer found in ribose? a. Cytosine b. Guanine c. Adenosine d. Thymine

d

Which of the following is one of the two major steps of protein synthesis? a. Transcription b. Elongation c. Translation d. A and C e. B and C

d