Download Once a virus has entered the host cell, it varies in the mode and

Biology
Viruses
Name ___________________________
Date ______________ Class ________
Welcome to Mysterious Invaders
In this site we will explore:
 The common characteristics associated with viruses
 The structure of viruses and their life cycles
 The relationship between the body and the immune system
Did you know?
1. Viruses are considered the __________________________________ to exist on earth.
2. Viruses remain inactive (______________) until they encounter a living
______________l.
3. Viruses exist in many different _________________________ and ___________.
4. Evidence shows viruses existed over _________________ of years ago.
5. Viruses contain _________________________ that can be altered according to the host.
6. Viruses are considered _____________ and can __________ any living cell of almost
every species.
7. Plant viruses only infect ___________ and animal viruses only infect _____________.
8. Viruses may be classified as _______________ or ________________.
9. Viruses are too _____________ to be seen with a light microscope.
10. Your body contains a ______________ right now!
Viral Vocabulary
Acute- characterized by______________________________________________.
Antibodies- any of a large number of ______________of high molecular weight
that are produced normally by ____________________ after stimulation by an ___________.
Antigen- usually _______________________________substance (as a toxin or enzyme)
capable of stimulating an_________________________.
Chronic- marked by ____________________ or frequent _________________: not acute
DNA- a type of ____________________that is the molecular basis of _______________,
located especially in cell _______________, and are constructed of a _______________
held together by ______________________.
Dormant- having ____________________________ suspended.
Host Cell - a cell which has been ________________________________________.
Immune System - the bodily system that ______________________________________.
Infection - _____________________________________________________________.
Naked virus - viral agent not containing _______________________________________.
Parasites - an organism living __________________________ another organism.
Protein - any of numerous naturally occurring extremely complex substances that consist of
_______________________residues joined by ______________________.
Retrovirus- ______ viruses (HIV) that produce reverse transcriptase by means of which
_____ is produced using their RNA as a _________________.
RNA - a _______________ that contains ________ and ________ as structural components.
Vaccine- a preparation of__________________________, living attenuated organisms, or
living fully _____________ organism that is administered to produce or artificially increase
_________________ to a particular disease.
Living or Not?
The Characteristics of a Virus
Viruses, even smaller than the smallest ______________, have a large impact on the
_________
population. Viruses are considered the smallest _________________-causing agent of all
time.
The true mystery lies within the characteristics attained by them, in order to be considered
living according to conventional biology an organism must satisfy certain criteria. Living
things:

Have _______________ organization

Have the ability to adapt and respond to
_____________________ stimulus

Maintain _________________

Are able to ______ and _____________
viable offspring
Carry out normal _______________
processes on their own.

Label the bacteriophage on the right.
Viruses tread the thin line between the ___________ and the ________________ because
they lack life-sustaining characteristics to classify them as living.
Viruses are considered _________________ because they depend solely on a
____________ to initiate and sustain their course. Without a host, a virus remains
___________or ____________ until the desired medium is readily available.
A _____________ is a cell in which a virus uses genetic information to ________________
and carry out normal viral functioning. Viruses are known to be notorious and very picky
when it comes to cell selection.
Most viruses identify with certain receptor sites located on the outer __________________ of
the cell. Scientific research shows that ________________ only infect plants and
______________ only infect animals. However, indirectly the effects of plant viruses may
have a direct relationship with animals and the bioavailability of _________________.
The Lytic Way or the Lyso Road?
Depending on the shape of the virus, the mode of entry could become quite unique.
Most viruses are surrounded by a ________________ known as a capsid and use “legs” to
insert
the ______________ material into the host cell, somewhat resembling a needle and syringe.
Many others simply fuse their way into the cell's ______________________. Viruses may
contain _________________ as the harmful genetic material that contributes to the
development of various diseases.
Once a virus has entered the host cell, it varies in the mode and mechanism of action
according to the type of virus. Viruses tend to take on a lytic or lysogenic lifecycle once the
DNA and/or RNA replication has taken place.
Lytic lifecycle
Viruses that undergo the lytic cycle can be characterized as the viruses that are on a mission
seek out & _________________ their host cell.
This process is also known as _____________ because the
newly replicated ____________ leave the cell through the
________________, leaving the membrane non-functional.
Penetration of the membrane occurs and the DNA is altered
and the host cell acts as a _______________________ site
until the cell eventually _____________ to release the viral by-products into the body.
Lysogenic lifecycle
Some viruses may choose an alternate cycle to undergo once ______________ the cell.
Well, have you ever wondered why certain viruses are seemingly _____________, yet
treatable, exist in our inner matrix and tend to cause annoying things like _______________
and cold sores? You know those things that just reoccur and never go away permanently?
In a lysogenic lifecycle, the virus _________ the host cell, but
instead of changing the entire _______________________, it
alters it by modifying the original __________of the host cell.
This cycle is slightly different from the ________ cycle in that
the virus tends to ______________ the cellular infrastructure
instead of just destroying the host cell at once.
Me, the Virus, and My Body...
The body system mostly associated with viruses would be none other than the
__________________. This system of the body takes the role of _______________ our
vital organs, tissues, and fluids from invasion by pathogens.
Our ___________ system plays an intricate role as our body's first line of ____________.
The immune system _______________ and prepares for battle as ________________
invade our bodies and begin to attack. As a result, the _________________ are formed to
counter attack these foreigners to rid the body of them and prevent reoccurrences. Moreover,
scientific studies continue to educate us on the viruses that affect our bodies and tend to
shed some light on the MYSTERY of VIRUSES.