Midterm 2 Chee 370

35 Questions | By Sboo | Updated: Mar 22, 2022 | Attempts: 469

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1.

What term would be applied to a regulatory condition that occurs when protein is associated with a particular section of DNA and greatly reduces transcription?
- A.
  
  Induction
- B.
  
  Activation
- C.
  
  Negative control
- D.
  
  Positive control
- E.
  
  Stimulation
2.

Secondary metabolites appear during which of the following stages?
- A.
  
  At, near, or in the lag phase
- B.
  
  At, near, or in the stationary phase
- C.
  
  At, near, or in the exponential phase
- D.
  
  At, near, or in the death phase
3.

DNA moves within an electric field because it
- A.
  
  Is positively charged
- B.
  
  Is negatively charged
- C.
  
  Makes up chromosomes, which are slightly electromagnetic
- D.
  
  Can possess different charges (positive or negative) depending on its base sequence
4.

Which of the following is NOT a means of regulating gene expression?
- A.
  
  Modifying proteins after they are synthesized
- B.
  
  Varying the rate at which messenger RNAs are transcribed
- C.
  
  Varying the rate at which messenger RNAs are translated
- D.
  
  Deleting genes from cells in which they are not needed
- E.
  
  Regulating the life span of a protein
5.

Dideoxyribonucleotides (ddNTPs) used for DNA sequencing lack oxygen atoms at
- A.
  
  The 1' carbon of the pentose sugar
- B.
  
  The 3' and 5' carbons of the pentose sugar
- C.
  
  The 2' and 3' carbons of the pentose sugar
- D.
  
  The 1' and 2' carbons of the pentose sugar
- E.
  
  The 5' carbon of the pentose sugar
6.

Which of the following best describes siRNA?
- A.
  
  A double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
- B.
  
  A molecule, known as Dicer, that can degrade other mRNA sequences
- C.
  
  A portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
- D.
  
  A short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
- E.
  
  A single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns
7.

The reason for using Taq polymerase for PCR is that
- A.
  
  Only minute amounts are needed for each cycle of PCR
- B.
  
  It has regions that are complementary to primers
- C.
  
  It is heat stable and can withstand the temperature changes of the cycler
- D.
  
  It binds more readily than other polymerases to primer
- E.
  
  All of these are correct
8.

Yeast artificial chromosomes contain which of the following elements?
- A.
  
  Origin of replication only
- B.
  
  Centromeres and telomeres only
- C.
  
  Centromeres, telomeres, and an origin of replication
- D.
  
  Telomeres only
9.

Some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region. What term is given to this advantageous arrangement of restriction sites?
- A.
  
  Palindrome
- B.
  
  Complementation
- C.
  
  Consensus sequence
- D.
  
  Polylinker
- E.
  
  B-galatosidase
10.

A metabolite excreted by a microorganism during exponential growth is called
- A.
  
  Primary metabolite
- B.
  
  Immobilized enzyme
- C.
  
  Secondary metabolite
- D.
  
  Exoenzyme
11.

Which pair of enzymes is necessary to make recombinant DNA?
- A.
  
  Ligase and restriction enzyme
- B.
  
  DNA polymerase and RNA polymerase
- C.
  
  DNA polymerase and ligase
- D.
  
  Restriction enzyme and DNA polymerase
12.

Type II restriction endonucleases
- A.
  
  Natively function to methylate specific nucleotides and prevent foreign DNA from being incorporated into the genome
- B.
  
  Recognize nucleotide sequences that are palindromic
- C.
  
  Are heterodimers
- D.
  
  Require ATP energy to cleave dsDNA
13.

The promoters of positively controlled operons require activator proteins, because
- A.
  
  RNA polymerase easily recognizes the consensus sequence
- B.
  
  They are needed to bind to the allosteric site of RNA polymerase
- C.
  
  They are required to inactivate the repressor proteins
- D.
  
  The promoters have nucleotide sequences that bind RNA polymerase weakly, which are not close matches to the consensus sequence
14.

Suppose ENZ-1 and ENZ-2 are two different restriction enzymes. If various pieces of DNA from different species are cut with these enzymes (as follows), which would most easily form recombinant molecules?
- A.
  
  Human DNA cut with ENZ-1 and gorilla DNA cut with ENZ-2
- B.
  
  Human DNA cut with ENZ-1 and human DNA cut with ENZ-2
- C.
  
  Bacterial DNA cut with ENZ-1 and gorilla DNA cut with ENZ-2
- D.
  
  Human DNA cut with ENZ-2 and bacterial DNA cut with ENZ-2
15.

In biotechnology research, DNA fragments created by restriction enzyme action are separated from one another via
- A.
  
  Centrifugation
- B.
  
  Crossing over
- C.
  
  The polymerase chain reaction
- D.
  
  Gel electrophoresis
- E.
  
  Filtering
16.

Genomic imprinting, DNA methylation, and histone acetylation are all examples of
- A.
  
  Karyotypes
- B.
  
  Chromosomal rearrangements
- C.
  
  Epigenetic phenomena
- D.
  
  Genetic mutation
- E.
  
  Translocation
17.

Which of the following is the correct sequence of the polymerase chain reaction?
- A.
  
  Heat to 90 celsius (to bind primers and enzymes), then cool to 50 celsius (to separate DNA), then reheat to 70 celsius (to synthesize DNA)
- B.
  
  Heat to 70 celsius (to bind primers and enzymes), then cool to 50 celsius (to synthesize DNA), then reheat to 90 celsius (to separate DNA)
- C.
  
  Heat to 90 celsius (to separate DNA), then cool to 50 celsius (to bind primers and enzymes), then reheat to 70 celsius (to synthesize DNA)
- D.
  
  Heat to 70 celsius (to separate DNA), then cool to 50 celsius (to bind primers and enzymes), then reheat to 90 celsius (to synthesize DNA)
18.

A ______ consists of cloned DNA fragments for all expressed genes in a particular tissue.
- A.
  
  PCR library
- B.
  
  Shotgun library
- C.
  
  Guggenheim library
- D.
  
  Genomic DNA library
- E.
  
  CDNA library
19.

A _______ is a single-stranded DNA molecule attached to a radioactive or fluorescent compound that is complementary to a specific sequence of DNA. Such pieces of DNA are used to identify and study cloned genes in hybridization experiments.
- A.
  
  Probe
- B.
  
  Vector
- C.
  
  Promoter
- D.
  
  Polypeptide
- E.
  
  Plasmid
20.

Which of the following does not apply to eukaryotic gene regulation?
- A.
  
  Regulation as a result of compartmentalization
- B.
  
  Protein degradation (turnover)
- C.
  
  Gene regulation by attenuation
- D.
  
  Protein folding
- E.
  
  MRNA degradation (turnover)
21.

A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate?
- A.
  
  A large polypeptide
- B.
  
  A plant virus
- C.
  
  A plasmid
- D.
  
  A typical bacteriophage
- E.
  
  A BAC
22.

When making a complementary DNA (cDNA) library, which enzyme is used to copy mRNA into DNA?
- A.
  
  RNA polymerase
- B.
  
  Primase
- C.
  
  Reverse transcriptase
- D.
  
  DNA polymerase
- E.
  
  DNA ligase
23.

A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in
- A.
  
  Continuous translation of the mRNA because of alteration of its structure
- B.
  
  Irreversible binding of the repressor to the operator
- C.
  
  Continuous transcription of the structural gene controlled by that regulator
- D.
  
  Complete inhibition of transcription of the structural gene controlled by that regulator
- E.
  
  Inactivation of RNA polymerase by alteration of its active site
24.

During DNA replication,
- A.
  
  Methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the nucleus
- B.
  
  Methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template
- C.
  
  DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied
- D.
  
  All methylation of the DNA is lost at the first round of replication
- E.
  
  Methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication
25.

Attenuation occurs in the biosynthetic pathway for phenylalanine in E. coli. Therefore, the leader sequence for this pathway will be rich in which of the following?
- A.
  
  Threonine
- B.
  
  Phenylalanine
- C.
  
  Histidine
- D.
  
  Isoleucine