Question

1. the number of new virions released from each bacterium host cell represent the _______.

2. "phage" attacks and multiple in __________.

Answer 1

Answer:1

Virusescan reproduce only within a host cell. The parental virus (virion) gives rise to numerous progeny, usually genetically and structurally identical to the parent virus. Viruses proliferate in natural environments by infecting cells and hijacking their replication and protein synthesis machinery. After new viral proteins are synthesized and assembled, bursts of viruses are released from the infected (and usually soon to be dead) cells to repeat the process all over again.Number of new virions or viruses released from each infected cell or bacterium host cell is referred to as the viral burst size. The emission of new viruses from an infected cell hence occurs as a burst with characteristic numbers of viruses and with time scales lasting from minutes to days depending upon the kind of virus and host. Burst sizes for different viruses have a large range corresponding in turn with the range of different sizes of the host cells. The impact of a viral infection on the host metabolism is determined by thinking about the volume taken up by the newly synthesized viruses in comparison with the size of the host cell that is fraction of the host cell volume is occupied by all the viruses make up a viral or virion burst.Example,in the case of bacteria and the viruses that infect them, a T-phage with ?50 nm diameter shows burst sizes of ?200 in an E. coli cell, representing ?2% of the volume. This may reflect limits to how much biomass viruses can extract from infected cells.

Answer:2

The viruses that infect bacteria are called bacteriophage.

The two different cycles that bacteriophages may use to infect their bacterial hosts:

• The lytic cycle: The phage infects a bacterium, hijacks the bacterium to make lots of phages, and then kills the cell by making it explode (lyse).

• The lysogenic cycle: The phage infects a bacterium and inserts its DNA into the bacterial chromosome, allowing the phage DNA (now called a prophage) to be copied and passed on along with the cell's own DNA.

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