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i need this very a science projection so if you know plzzzzzzzz tell cuz im totally confused and i have no clue thxsssssssss

2007-03-08 10:52:14 · 3 answers · asked by 2hot4u 2 in Science & Mathematics Chemistry

3 answers

Viruses
All viruses have a capsid or head region that contains its genetic material. The capsid is made of proteins and glycoproteins. Capsid contruction varies greatly among viruses, with most being specialized for a particular virus's host organism. Some viruses, mostly of the type infecting animals, have a membranous envelope surrounding their capsid. This allows viruses to penetrate host cells through membrane fusion. The virus's genetical material rests inside the capsid; that material can be either DNA, RNA, or even in some cases a limited number of enzymes. The type of genetic material a virus contains is used in classification, and is discussed in Virus Classification.
In addition to the head region, some viruses, mostly those that infect bacteria, have a tail region. The tail is an often elaborate protein structure. It aids in binding to the surface of the host cell and in the introduction of virus genetic material to the host cell.
Virus "Life" Cycles
Figure1.2: Generalized Replication of Viruses
Though the details of virus infection and replication vary greatly with host type, all viruses share 6 basic steps in their replication cycles. These are: 1) attachment; 2) penetration; 3) uncoating; 4) replication; 5) assembly; 6)release. As shown in Figure 1.2, the virus must first attach itself to the host cell. This is usually accomplished through special glycoprotiens on the exterior of the capsid, envelope or tail. Next, penetration occurs, either of the whole virus or just the contents of the capsid. If the entire capsid enters, the genetic material must be uncoated to make it available to the cell's replication machinery. Replication of genetic material takes place, as well as the production of capsid and tail proteins. Once all of the necessary parts have been replicated, individual virus particles are assembled and released. Release often takes place in a destructive manner, bursting and killing the host cell.
Some viruses have a slightly more complicated replication cycle involving lytic and lysogenic phases. The lytic phase is similar to that described above, with virus particles infecting and being replicated. In the lysogenic phase, however, viral genetic material that has entered the host cell becomes incorportated in the cell and lies dormant. It is passed on to the progeny of the infected cells. Eventually, the lytic phase will start again, and cells that were never infected themselves, but carry the viral genetic material will begin to produce new virus particles.


Living things
# Living things are made of cells.
# Living things obtain and use energy.
# Living things grow and develop.
# Living things reproduce.
# Living things respond to their environment.
# Living things adapt to their environment.

Quick Question... you in the 6th grade??? if you are that stuff should be in the first few chapters of your life science text book. i mean heck im in 7th and i remember this.

2007-03-08 10:56:57 · answer #1 · answered by mikey b 2 · 0 0

A virus is a microscopic particle (ranging in size from 20 - 300 nm) that can infect the cells of a biological organism. Viruses can replicate themselves only by infecting a host cell.

An organism is a living complex adaptive system of organs that influence each other in such a way that they function in some way as a stable whole.

2007-03-08 10:58:11 · answer #2 · answered by Anonymous · 0 1

For a virus..........

They are not living
They punch holes into cells and inject their dna
They have a protein coat called a capsid
Once DNA is in the host cell where the dna was injected, parts are created and assembled to make more viruses
The cell will either then burst (lytic cycle) or not burst and divide (lysogenic cycle)

For living organisms, we are alive unlike viruses.
They are made of cells
They influence each other

2007-03-08 11:00:06 · answer #3 · answered by Mathman90 2 · 0 1

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