What’s Up With Cell Bio Exam 4

44 Questions | By Jaffryf | Last updated: Mar 22, 2022 | Total Attempts: 161

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What’s up with cell biology? Hello and welcome to another wonderful quiz on the scientific study of biology, where we’ve been focusing our full attention on cells, what is contained within them and how they operate. Think you know all there is to know about cells? Find out in this quiz!

Questions and Answers

1.

If two DNA strands of identical length were analyzed, which of the following statements would be true of their T(..?) or melting temperature?
- A.
  
  The DNA with the greater number of repetitive sequences will melt more slowly (lower T.)
- B.
  
  DNA with high GC content must have a lower T
- C.
  
  All DNA strands of equal length have equal T
- D.
  
  DNA with a low AT content would melt more slowly
2.

Which DNA polymerase is mainly responsible for genome replication in E. coli?
- A.
  
  DNA polymerase III
- B.
  
  DNA polymerase (alpha)
- C.
  
  DNA polymerase I
- D.
  
  DNA polymerase II
3.

The precentage of GC in a DNA sequence affects the Tm of the sequence because
- A.
  
  The higher the amount of GC, the lower the Tm
- B.
  
  The higher the amount of GC, the higher the Tm
- C.
  
  GC rich sequences will haev a higher Tm because they have less hydrogen bonds
- D.
  
  GC rich sequences will have a lower Tm because they have more hydrogen bonds
- E.
  
  B and c
4.

Which one of the following proteins and enzymes do not function at the origin of replication in E. coli?
- A.
  
  DNA ligase
- B.
  
  SSBs
- C.
  
  Helicase
- D.
  
  DnaA, dnaB and Dna C proteins
5.

Which enzyme in E. Coli is responsible for reliving the tension ahead of the fork that results when the DNA is unwould to form the replication bubble or eye?
- A.
  
  Replicase
- B.
  
  Helicase
- C.
  
  DNase
- D.
  
  Gyrase
6.

_________ bonds are responsible for the polymer backbone of DNA, while _____ bonds primarely account for complementary base pairing in DNA.
- A.
  
  Ionic; hydrogen
- B.
  
  Covalent; hydrogen
- C.
  
  Hydrogen, covalent
- D.
  
  Covalent, ionic
- E.
  
  None of the above
7.

Which subunit of RNA polymerase establishes template binding to a promoter in prokaryotes?
- A.
  
  Beta prime
- B.
  
  Alpha
- C.
  
  Sigma
- D.
  
  Beta
8.

Which RNA polymerase transcribes protein-coding genes into mRNA in eukaryotes?
- A.
  
  RNA polymerase IV
- B.
  
  RNA polymerase III
- C.
  
  RNA polymerase I
- D.
  
  RNA polymerase II
9.

What are the two main types of post-transcriptional modications that take place int he mRNA of eukaryotes?
- A.
  
  The addition of a poly-T sequence at the 5' end of the gene and the addiction of a poly-U tail at the 3' end.
- B.
  
  The addition of a 7-mG cap at the 5' end of the transcript and the addition of a poly-A sequence at the 3' end of the message.
- C.
  
  The addition of a poly-A sequence at the 5' end and the addition of a 7-mG cap at the 3' end of the RNA transcript.
- D.
  
  The excision of the introns and the addition of a 7-mG cap to the 3 end.
10.

An intron is a section of
- A.
  
  Protein that is clipped out postranslationally
- B.
  
  RNA that is removed during RNA processing.
- C.
  
  DNA that is removed during DNA processing
- D.
  
  Transfer RNA that binds to the anticodon
- E.
  
  Carbohydrate that serves as a signal for RNA trasnsport
11.

Introns are known to contain temrination codons (Uaa, UGA, or UAG) yet these codons do not interrupt the coding of a particular protein. why?
- A.
  
  UAA, UGA, and UAG are initiator codons, not termination codons.
- B.
  
  Exons are spliced out of mRNA before translation.
- C.
  
  These triplets cause frameshift mutations, but not termination.
- D.
  
  More than one termination codon is needed to stop translation
- E.
  
  Introns are removed from mRNA before translation
12.

DNA polymerases always synthesize new DNA by adding nucleotides on to the 5' phosphate.
- A.
  
  True
- B.
  
  False
13.

Meselson and Stahl alowed baclene raise in 13N medium to replicate in 14N medium. at the end of two rounds of DNA replication, they observed ___ band(s) in their centrifugation tubes which was/were composed of _____..
- A.
  
  1; single strands of 15N DNA base-paired to single strands of 14N DNA
- B.
  
  1; doublestrands of DNA, each strand made up of a mixture of 14N and 15N DNA.
- C.
  
  Double strands of 14N DNA at the top and double strands of 14N DNA at the bottom.
- D.
  
  2; double strands of 14N DNA at the top and strands of 15N DNA based-paired to strands of 14N DNA in the middle
- E.
  
  2; strands of 15N DNA base-paired to strands of 14N DNA in the middle and double strands of 15N DNA at the bottom.
14.

Why is an RNA primer considered essential for DNA synthesis by DNA polymerase III?
- A.
  
  There is no particular reason; that is simply what has been observed.
- B.
  
  The enzyme requires a free 3'-OH group
- C.
  
  The enzyme requires a free 3'-PO4 group
- D.
  
  The enzyme requires a free 5-PO4 group
15.

Which of the following statements best describes Okazaku fragments?
- A.
  
  They are formed int he leading strand
- B.
  
  They add nucleotides to the elongating DNA
- C.
  
  They are formed int he lagging strand
- D.
  
  They are synthesized by primase
16.

Which of the following clusters of terms accurately describes DNA as it is generaly viewed to exist in prokaryotes and eukaryotes?
- A.
  
  Double-stranded, parallel, (A+T)/(C+G)=variable, (A+G)/(C+T)=1.0
- B.
  
  Double-stranded, antiparallel, (A+T)/(C+G)=variable, (A+G)/(C+T)=1.0
- C.
  
  Single-stranded, antiparallel, (A+T)/(C+G)=1.0, (A+G)/(C+T)=1.0
- D.
  
  Double-stranded, parallel, (A+T)/(C+G)=1.0, (A+G)/(C+T)=1.0
17.

If 15% of the nitrogenous bases is a sample of DNA from a particular organism is thymine, what percentage should be cytosine?
- A.
  
  14%
- B.
  
  30%
- C.
  
  70%
- D.
  
  35%
- E.
  
  40%
18.

If Avery, MacLead, and McCarty had determined that the transforming molecule was a protein, what experimental results would not have been observed?
- A.
  
  Heat-killed cultures treated with RNase would transform the R cells.
- B.
  
  Heat-killed cultures treated with protease would transform the R cells
- C.
  
  Heat-killed cultures treated with DNase would transform the R cells
- D.
  
  Heat killed-cultures treated with protease would not transform the R cells
19.

Which enzyme makes DNA from an RNA template?
- A.
  
  RNA polymerase
- B.
  
  Replicase
- C.
  
  DNA polymerase
- D.
  
  Reverse transcriptase
20.

Which of the following statements best describes the structure of a DNA molecule?
- A.
  
  DNA is composed of a oxynucleoside inphosphate with a base attached to it.
- B.
  
  DNA is composed of a sugar-phosphate backbone with bases projecting towards the inside of the back bone.
- C.
  
  DNA is composed of a sugar-phosphate backbone with bases projecting towards the outside of the backbone.
- D.
  
  DNA is composed of a sugar-phosphate backbone with bases projecting towards the outside of the backbone.
- E.
  
  DNA is composed of a sugar-phosphate backbone made up of bases hyrdogen-bonded to each other.
21.

Transcribed regions present in the mature mRNA would arise from a ______ while transcribed reigions NOT present in the mature mRNA would arise from a _____
- A.
  
  Stop codon; initiation codon
- B.
  
  Anticodon; codon
- C.
  
  Intron; exon
- D.
  
  Exon; intron
- E.
  
  Initiation codon; stop codon
22.

Which of the following options has the events of prokaryotic transcription in order
- A.
  
  Elongation, termination, promoter binding, rho binding, transcription bubble
- B.
  
  Promoter binding, elongation, termination, rho binding, transcription bubble
- C.
  
  Rho binding, promoter binding, elongation, termination, transcription bubble
- D.
  
  Promoter binding, transcription bubble, elongation, rho binding, termination
- E.
  
  Transcription bubble, promoter binding, elongation, termination, rho binding
23.

In addition to highly repetitive and unique DNA sequences, a third category of DNA sequences exists. What is it called and what types of elements are involved?
- A.
  
  Composite DNA, lelomeres (?_ and heterochromatin
- B.
  
  Dominant DNA, euchromatin and heterochromatin
- C.
  
  Multiple gene family DNA, hemoglobin and 5. OS RNA
- D.
  
  Moderately repetitive DNA, SINEs, LINEs, and VNTRs
- E.
  
  Permissive DNA, centromeres and heterchromatin
24.

Which of the following can account for multiple proteins from a primary transcript?
- A.
  
  Replication
- B.
  
  Alternative splicing
- C.
  
  Alternative editing
- D.
  
  5' methylation
25.

Telomerase is an enzyme involved in the replication of the ends of eukaryotic chromosomes
- A.
  
  True
- B.
  
  False