Deck 11: Exchange and Evolution

Question 1

Passage of genetic information from one generation to the next is known as _____ transmission

Answer 1

vertical
Explanation: Passage of genetic information from one generation to the next is known as vertical transmission.

Question 2

Which of the following statements about horizontal gene transfer are true? Please select all that apply.

A) Two gametes are donors to the zygote
B) Transfer depends on meiosis
C) Horizontal gene transfer is unidirectional
D) Horizontal gene transfer is rare in bacteria
E) Transposable elements can act as vectors of horizontal gene transfer

Answer 2

Horizontal gene transfer is unidirectional
Transposable elements can act as vectors of horizontal gene transfer

Question 3

Match the missing words in the following phrase. Most bacteria have [A] chromosomes, but a few species have [B] chromosomes. Bacteria also have [C] DNA, some of which can be passed between [D]. The most common type of these is [E], which can replicate [F] of the chromosome.

Answer 3

a. A = circular
b. B = linear
c. C = extrachromosomal
d. D = generations
e. E = plasmids
f. F = independently

Question 4

Transfer of DNA by a virus

A) Transformation
B) Conjugation
C) Transduction
D) Translation

Question 5

Not a mechanism of horizontal gene transfer

A) Transformation
B) Conjugation
C) Transduction
D) Translation

Question 6

What is the main function of proteins encoded by the genes on the F plasmid?

A) To enhance integration of transformed DNA into the recipient genome
B) To prevent destruction of virus DNA by the host
C) To create a structural bridge between the donor and recipient cell
D) To increase replication of the plasmid.

Question 7

Plasmids can be transferred between bacteria by conjugation. What structure do plasmids adopt during transfer? Please select all that apply.

A) Linear DNA
B) Single-stranded DNA
C) Circular DNA
D) Double-stranded DNA
E) Single-stranded RNA

Question 8

Which of the following statements about Agrobacterium tumefaciens are true? Please select all that apply.

A) A. tumefaciens transfers DNA to plant cells via transformation
B) A. tumefaciens transfers its own genome to plant cells
C) Plant cells containing A. tumefaciens DNA act as a source of nutrients for the bacterium
D) A. tumefaciens has an F plasmid

Question 9

Which of the following statements about viruses are false? Please select all that apply.

A) Viruses have DNA genomes
B) Viruses have RNA genomes
C) Viruses can replicate autonomously
D) Bacterial viruses also infect humans
E) Viruses have a protein coat
F) Viruses transfer their own genome to host cells

Question 10

Match the missing words in the following phrase. [A] cause their host cells to burst and release more phage. Host DNA can be packaged alongside virus DNA and transferred to the new host - this is [B]. [C] can integrate their genome into the host genome, at which point the virus is termed a [D]. When the DNA is excised from the host genome and packaged into phage, host DNA can also be packaged into the phage and transferred to the new host - this is [E]. [F] can enter cells, replicate, and exit without causing the death of the host cell.

Question 11

Which of the following characteristics are found in retroviruses? Please select all that apply.

A) Retroviruses contain RNA
B) Retroviruses contain DNA
C) The virus nucleic acid is reverse transcribed
D) The virus genome is integrated into the host genome.
E) The virus proteins are translated

Question 12

Fill in the blank. The enzyme encoded by some viruses that allows them to become incorporated into the host genome is called _____

Question 13

A functional transposable element is a discrete piece of DNA that can catalyze its own movement between genomes.

Question 14

Which of the following statements about transposable elements are true? Please select all that apply.

A) RNA elements are more abundant than DNA elements in the human genome
B) Transposable elements are usually > 10kb in size
C) Retrotransposons are DNA elements
D) Some transposable elements are derived from viruses
E) Transposase is involved in movement of DNA elements

Question 15

Fill in the blank. Most transposable elements have become mutated and have lost the capacity to move on their own. Elements that are capable of moving on their own are termed _____ elements.

Question 16

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-1

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 17

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-2

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 18

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-3

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 19

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-4

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 20

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-5

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 21

The CRISPR mechanism helps bacterial cells defend themselves against foreign DNA. Put the following CRISPR events in order, from first to last.

-6

A) Foreign DNA enters cell for first time
B) Protospacers are generated by Cas
C) Foreign DNA is incorporated into CRISPR array
D) CRISPR sequence is transcribed
E) CRISPR RNA is fragmented
F) sRNA targets foreign DNA for destruction

Question 22

The CRISPR mechanism helps bacterial cells recognize specific foreign molecules. What other defense systems does CRISPR resemble? Please select all that apply.

A) Adaptive immune system
B) Innate immune system
C) RNA interference
D) Apoptosis
E) DNA proofreading

Question 23

How do bacteria avoid destroying their own DNA with their restriction endonucleases?

A) Bacterial restriction endonucleases only affect virus and eukaryotic DNA and do not affect bacterial DNA
B) Bacteria do not have the recognition sequences for their own restriction endonucleases in their genome.
C) Restriction endonucleases cannot penetrate the bacterial nuclear membrane
D) Bacteria methylate restriction endonuclease recognition sites in their own genome

Question 24

Which of the following is a defense mechanism used by bacteria against foreign DNA?

A) Degradation of RNA-DNA hybrid
B) Repression of transcription from AT rich DNA
C) RNA interference
D) Expression of reverse transcriptases

Question 25

Which of the following natural processes are exploited in molecular biology laboratory experiments? Please select all that apply.

A) Transformation
B) CRISPR
C) Agrobacterium tumefaciens infection
D) Reverse transcription

Question 26

The core E. coli genome is about 2 Mb, which is less than half the size of the pan-genome.

Question 27

Streptococcus pneumoniae can cause pneumonia, meningitis, and blood infections. S. pneumoniae can change rapidly and evade the immune system. Which characteristics of S. pneumoniae facilitate this rapid evolution? Please select all that apply.

A) S. pneumoniae is naturally competent
B) Host immune systems cannot recognize the carbohydrate capsule that surrounds the bacterial cell
C) Capsule genes can be acquired by horizontal transfer
D) S. pneumoniae has a linear genome

Question 28

Which of the following characteristics do scientists use to identify genomic islands in bacteria? Please select all that apply.

A) Similarity to phage sequence
B) High DNA AT%
C) Presence of essential genes
D) Presence of a sliding window sequence

Question 29

Building phylogenetic trees can be challenging when horizontal transfer has occurred in bacteria. Why?

A) Trees cannot be accurately rooted when horizontal transfer has occurred
B) Virulent isolates evolve too rapidly to be captured in a phylogenetic tree
C) Lineages of bacteria from different locations are unrelated if horizontal transfer has occurred
D) Genetic differences between organisms are usually assumed to have occurred in a stepwise fashion

Question 30

A technique similar to transformation is used in the laboratory to introduce DNA into eukaryotic cells. This technique is called _____

Question 31

What is a HFR cell?

A) A cell containing non-mobile transposable elements
B) A cell containing mobile transposable elements
C) A cell containing Ti DNA
D) A cell in which F factor is integrated into the genome