Science Chpt. 7 Sect.1
What is a virus?
a tiney nonliving particle that invades and then multiplies inside a living cell.
Are viruses cells?
Viruses are not cells
What is the one characteristic that viruses share with organisms?
they can multiply
Where can viruses only multiply in?
when they are inside a living cell
Are any organisms safe from viruses?
no organisms are safe from viruses
What is the organism call where a virus can multiply in call?
What is a host?
a living thing that provides a source of energy for a virus.
What do viruses act like?
Whta is a parasite?
an organism that live on or in a host and cause it harm
What do almost all viruses do to host cells?
they destroy the host cells
Are viruses smaller than host cells?
yes, viruses are smaller than host cells
What is the robot-like virus that infects bacteria called?
What is a Bacteriophage?
A virus that infects bacteria
What are the two basic parts of a virus?
A protien coat and genectic material
What does a virus's genectic material contain?
the instructions for making new viruses
What is the function of the protein coat?
an outer coat to protect the virus
What does the shape of the surface proteins allow the virus to do?
the shape of the surface protien allows it to attach "lock" itself on to certain cells in a host
What are the viruses protieins like?
like "keys" that fit only into certain "locks" or proteins, on the surface of a host's cells
Because the lock-and-key action of a virus is specific
a certain virus can attach only to one or a few types of cells
Most cold viruses infect cells where?
only in the nose and throat of humans
When can a virus attach itself to a cell?
only if the virus' surface proteins can fit those on the cell
What information does a virus' genectic material contain?
instructions for making new viruses
What does the Virus's outer membrane proteins lock onto?
the host cells surface proteins
Some viruses are also surrounded by and additional out membrane called what?
After a virus attaches to a host cell what does it do?
it enters the host cell
Once a virus is inside a host cell what happens?
a virus's genetic material takes over many of the cell's funtions.
When a virus's genetic material takes over a cell's function what does it do?
It instructs the cell to produce the virus's proteins and genectic material.
What do the proteins and genetic materials assemble into once made inside a host cell?
What are the two types of viruses that can attack a cell?
Active Viruses and Hidden Viruses
What is an Active Virus?
it immediately goes into action
Once the virus goes into the host cell where does it go?
into its genetic material
What does the virus's genetic material do to the host cell?
it takes over the cells functions and starts to produce the virus's proteins and genectic material?
What does the invade cell start doing when the virus invades it?
it acts like a "photcopy machine" and makes copy after copy of the new virus
When the host cell if full of the new virus what happens to it?
the host cell bursts open releasing hundreds of new viruses and dies
What is a Hidden Virus?
Viruses that do not immediately become active in a host cell
What do the Hidden Virus do in the new cell?
Where do the Hidden Viurses hide?
in the host cells genectic material
After the Hidden Virus invades the host cell what does it do?
it become part of the host cell's genetic material
In a Hidden Virus what happens to it when the host cell divides?
the virus's genetic material is copies along with the host's genetic material
When a Hidden Virus becomes active what does it act like?
an Active Virus
What is an example of a Hidden Virus?
a cold sore
What activates the Hidden Virus of a cold sore?
sunlight or stress
Where in a host cell does a hidden virus "hide" while it is inactive?
in the genetic material of the cell
What can viruses cause?
Can plants and animals get viruses?
What are the four way Viral Diseases can spread?
Contact with a contaminated object, bite of an infected animal, moisture droplets from sneezes and coughs, and contact with body fluids, like blood from an infected person
Are there any cures for viral diseases?
What is the best treatment for viral infections?
What are the three best things one must do to treat a viral infection?
bed rest, drink plenty of fluids, and eating a well-balanced meal
When you have a virus we can only do what?
treat the symptoms with over-the counter medications like advil
How do you prevent the spread of Viral Diseases?
by getting a vaccine
What is a Vaccine?
a substance introduced into the body to stimulate the production of chemicals that destroy specific disease-causing viruses and organisms
Why don't vaccines cause disease themselves?
the vaccines are weakened or altered viruses
What do vaccines contain?
an altered or weakened virus
What does a vaccine do?
tirgger the body's natural defenses and puts the body on "alert"
What are some examples of Viral Diseases?
polio, measles, and chichen pox
What are some ways to protect ourselves from getting a viral disease?
keeping a healthy body (rest, fluids, exercise), and by washing hands often and not sharing eating or drinking utensils
How are viruses simliar to organisms?
they can multiply
What basic structures do all viruses share?
protein coat and an inner core with genectic material
What role do the proteins in a virus's outer coat play in the invasion of a host cell?
it allows the virus to attach itself to the host cell like a key on the outer protein coat which locks onto the hosts cells surface protein cell
What are the additional steps that occur when a hidden virus multiplies?
it first hides in the genectic material and is copied when the cell divides and becomes unhidden when it is triggered to do so
How are vaccines important in preventing viral diseases?
helps prevent the spread
Baceriophages are viruses that attack and destroy what?
Which part of a virus determines which host cells it can infect?
Most bacteria are surrounded by a figid protective structure calles what
What is a virus called when it enters a cell and immediately begins to multiply?
What will most likely happen after the virus attaches to the bacterial cell?
the virus will inject its genetic material into the bacterial cell