Biology Questions and Answers
injects its DNA molecules into the host
cell.
Within the host cell the viral DNA is
transcripteproduced. Virald and thus messen mRNA then is translateger RNA isd (^)
and viral proteins are made.
Viral polypeptides made within thcell are cut by enzymes called proteasese host (^)
and then copies oassembled with the f the virus arenewly formed (^)
proteins. When the assemblage of new
viruses is completed the cell mbreaks and the viruses are released toembrane
the outside. Oproduce hundreds of viruses.ne sole infected cell can
- What are retroviruses? How
do they reproduce and what is
the role of the enzyme reverse
transcriptase?
Retroviruses are viruses whose genetic
material is RNA.SARS (severe acute HIV and the virus orespiratory f
syndrome) are examples of retrovirus.
These viruses inoculate their RNA into
the host cell and within thRNA is reversely transcripted e cell thinto DNA.e viral
DNA made from the viral RNA then
commanproteins fds the synthesis ofor the assemblage of new viral (^)
viruses and the breaking of the host cell
to liberate them outside.
The enzyme reverse transcriptase is the
catalystRNA into DNA. T of the reverse transcription he enzyme is part ofof
the virus and it is also inoculated into
the host cell.
- What is the basic structure
of the HIV virus? What is the
function of the glycoproteins
of its envelope?
HIV is an RNA virus. In its core thereare two strands of RNA and reverse
transcriptase molcovered by a capsid, a ecules. Tlayer ohe core isf proteins. (^)
The capsid then is covered by an
envelope havinlipids. g glycoproteins and
The glycoprare located oteins oon the outer surface f the HIV envelopeof the (^)
virus and they are responsible for the
recognition of(the HIV host cell is the CD4 the cells to be infected
lymphocyte) and for the adhesion of the
virus to receptor the cell membrane. (CD4 is aglycoprotein of the outer
membrane of some lymphocytes).
- What are bacteriophages?
Bacteriopin parasitismhages are viruses specialize of bacteria. They are usedd (^)
in genetic engineering as molecular
cloning vehicles to iDNA into bacteria. Tnsert recomhey were also usbinanted (^)
in the former Soviet Union to treat
bacterial infections.
Bacteriophages have a polyhedron-like
capsid “head” of and DNA as gethe virus is connected netic material. Tto a tailhe
that ends in small fibers that help the
virus to and to inject its genetic material intoattach to the bacterial cell wall
the host.
http://www.biology-questions-and-answers.com