Viruses variously depend on their host cell for parts of the viral replication and maturation process. Many viruses do however encode for some enzymes that facilitate certain steps or virus-specific processes for viral replication and maturation
Which cellular processes and enzymes do ALL viruses lack and must therefore ALWAYS be supplied by the host cell?
What will be an ideal response?
Answer: In general ALL currently described viruses lack (i) metabolism and (ii) translational machinery. To elaborate, all viruses lack the ability to make ATP, therefore the energy for replication and maturation of viral particles must be supplied by the host cell. Put another way, all viruses lack metabolism or metabolic enzymes capable of generating ATP or any other form of energy for anabolism. Second there are no currently described viruses that have their own ribosomal proteins, rRNA, or tRNA. All portions of the translational apparatus for synthesizing proteins are supplied by the host cell. Other enzymes, such as RNA polymerase, DNA polymerase, etc MAY be supplied by the host cell or may encoded for in the viral genome and may even be present in the viral capsid.
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From the equator to latitudes 10° north and south,
high rainfall, high humidity, and mild temperatures can support __________. Fill in the blank(s) with the appropriate word(s).
Assume that a mutation occurs in the gene responsible for the production of hexosaminidase A, such that only about 50 percent of the enzyme activity is found in the heterozygote compared with a homozygous normal individual
If heterozygotes are phenotypically normal, we would say that the mutant allele is recessive to its normal allele. Indicate whether the statement is true or false
Which of the following are the only extant animals that descended directly from dinosaurs?
A) lizards B) crocodiles C) birds D) tuataras