Virus undergo replication by _________?

Question

A. duplicating its chromosomes and undergoing mitosis
B. reducing its chromosomes by half and undergoing meiosis
C. injecting its genes into a living cell
D. simple binary fission

Answer 1

C.

Viral Replication: most viruses carry the enzyme RNA replicase to make complementary RNA strands. Some viruses contain the enzyme reverse transcriptase, which produces DNA , then RNA. These are called retro viruses. HIV is an eample of a retro virus. The three basic patterns of genome replication are: DNA--->DNA, RNA---->RNA, and RNA------->DNA---->RNA. Viral components are held together by weak bond ( van der Waals forces and hydrogen bonds).
Host Specificity: Each type of virus can infect and parasitize a limited range of host cells. They are guided by external recognition areas of the host cell. This may keep a virus from infecting many different types of cells.

Lytic Cycle: Life cycle of virulent phages.

1. The phage lands on the host cell, and using 140 ATP's in its tail fibers, injects its nucleic acid core into the bacterium.

2. The host's DNA is cut up and destroyed by the enzymes produced by the host from the new DNA.

3. The now unassembled nucleotides are reassembles into phage DNA, which produces copies of the capsid.

4. The genes also produce the enzyme lysozyme, that digests the bacterial cell wall, causing the newly assembled viruses to escape.

Lysogenic Cycle: Viruses that reproduce without killing their hosts are called temperate viruses. These viruses have 2 alternate forms of reproduction. The lytic cycle or the lysogenic cycle. The process begins very similar to the lytic infection or inserting the genome into the host's genome and becoming dormant. During the lysogenic cycle one of the temperate phage's genes remains active. It codes for a repressor protein keeping the prophage genes inactive. From here on the cells reproduce regularly. Each carrying the hidden genes of the virus. Under normal circumstances harmless bacteria remain so until infected by these viruses; then they can become pathogenic. Example Botulism, diphtheria, and scarlet fever bacteria.

Answer 2

C, they don't split (meiosis and mitosis), they inject their genes into another cell and use that cell's DNA replication to make more virus, eventually overtaking the cell and causing it to burst.

Answer 3

c...lol....dey dun have chromosomes and certainly not binary fission.......