little explanation with each answer please (5-7 Phix174 is a +ssDNA bacteriophag
ID: 133636 • Letter: L
Question
little explanation with each answer please
(5-7 Phix174 is a +ssDNA bacteriophage. Which is the made first during replication? a. +SSDNA b. -RNA c. +mRNA d. -sSRNA e. dsDNA (S-7: A 8. Rhinoviruses are +ssRNA viruses that cause colds. During genome replication, which polynucleotide is made first? a. +ssDNA b. SSRNA c. dsRNA d. -sSDNA e. dsDNA 15-6, U) 9 What would happen if a bacterial cell's modification enzymes were not functional? They would be unable to a. produce interferon. b. ferment. c protect themselves from their own restriction endonucleases d. protect themselves from viral restriction endonucleases e destroy viral DNA.Explanation / Answer
7. Phix174 is a +ssDNA bacteriophage. Which is the made first during replication?
ANSWER IS:
e. dsDNA
EXPLANATION:
First ?X174 attaches to its host then its ssDNA molecule is inserted into the cell. Then this DNA strand (+) serves as template for the synthesis of a complementary (?) strand.
The single-stranded DNA is converted into a covalently closed, double-stranded, circular replicative form of DNA.
These two strands form a double helix which then replicates itself several times.
The (?) strand of these DNA molecules then act as templates for the synthesis of mRNA molecules.
8. Rhinoviruses are +ssRNA viruses that cause colds. During genome replication, which polynucleotide is made first?
ANSWER IS:
b. -SSRNA
EXPLANATION:
During genome replication of rhinoviruses, -SSRNA is made first. Replication begins when replication proteins copy the (+) ss RNA make (-) ss RNA strand. Then this negative strand is replicated to further form (+) strands.
9. What would happen if a bacterial cell's modification enzymes were not functional? They would be unable to
ANSWER IS:
c protect themselves from their own restriction endonucleases
EXPLANATION:
Bacteria have restriction enzymes that cleave double stranded DNA at specific points. This helps in preventing infection by destroying the foreign DNA.
Bacteria possess restriction modification system to protect themselves from restriction enzymes, so that restriction enzymes only destroy foreign DNA.
Bacteria has restriction modification system that methylases and protects the host DNA by methylation in the restriction enzymes sequence, so that restriction enzymes not able to cleave methylated DNA.
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