HIV
T or F: Viral proteins are produced by the ribosomes of an infected host cell.
true; Viruses cannot reproduce on their own; they must infect a host cell.
_________ is not alive because they are not made of cells and require a host cell for reproduction.
viruses
Which of these sub-cellular structures is found in both eukaryotes and prokaryotes?
ribosomes
Is HIV a example of an emerging virus?
yes
Is HIV a retrovirus?
yes
symptoms of inflammatory response
"sharp": swelling, heat, redness, and pain.
AIDS
-acquired immune deficiency syndrome -the late stages of HIV infection -characterized by a reduced number of T cells -usually results in death caused by opportunistic infections.
Virus
A microscopic particle capable of infecting cells of living organisms and inserting its genetic material.
emerging viruses
A virus that has appeared suddenly or has recently come to the attention of medical scientists.
Bacteriophage
A virus that infects bacteria; also called a phage.
T or F: The widespread use of antibiotics has led to resistant strains of viruses.
False
Memory cells
remain in the body, long after the infection has passed, ready to battle future invaders
Retrovirus
An RNA virus that reproduces by means of a DNA molecule. It reverse-transcribes its RNA into DNA,
What are the two types of lymphocytes?
B cells and T cells. Both are involved primarily in the adaptive immune system
How can a virus reproduce?
By infecting living cells
Why can't we find a vaccine for HIV?
HIV evolves too quickly
Patients with advanced aids often die from infections that do little harm to healthy people. Why?
HIV infects and destroys the helper T cells of the immune system.
Which specific cells are infected by the HIV virus?
Helper T-cells
No virus poses a greater threat to the human health than the .....
Influenza virus (Flu)
How does HIV infection weaken the immune system?
It destroys helper T-cells
Does infection by HIV itself normally cause death?
No. HIV cripples the immune system, leaving a person susceptible to other deadly infections.
What determines which host cells a virus can infect?
Proteins on the outside of the virus must bind to proteins on the outside of the host cell.
The introduction of smallpox to the Americas by Europeans in the colonial era devastated populations of native Americans. Now, however, very few people are vaccinated against the smallpox virus. Why?
Smallpox virus has been eliminated from the Earth by vaccination of most of the people alive today.
Why is combination drug therapy for HIV/AIDS less likely to lead to resistance than single drug therapy?
The likelihood of one virus spontaneously mutating to be resistant to several different drugs at the same time is extremely small.
immune system
a collection of cells and organs that protect an organism's body from agents that can cause disease.
Homeostasis is a living organism's...
ability to maintain constant internal conditions even when environmental conditions change.
Nucleic Acid
all viruses have genes made up of this
Recognition Spike
allows a virus to infect a specific cell type
What is AZT?
anti-HIV/AIDS drug that interrupts transcription
nonspecific defenses
are always at the ready and are the same whether a particular infectious agent has been encountered before or not.
Which of the following is NOT a characteristic of living things? a. responding to stimuli b. creating energy c. being capable of reproduction d.exhibiting complex organization e. having DNA as a genetic code
b. creating energy
nonspecific defenses
bodily defenses that protect a person against all microorganisms, regardless of prior exposure
Cytotoxic T cells
cells bind to any cells presenting viral fragments and kill them
Helper T cells
cells coordinate immune attack (called the master immune cell)
Herpes virus
cold sores, genital herpes, chickenpox and shingles
Which of the following can be found in bacteria, but not viruses? a. proteins b. genetic material c. nucleic acids d. a cell membrane
d. a cell membrane
Which of the following is NOT part of your innate immune system? a. natural killer cells b. phagocytic cells c. stomach acid d. lymphocytes
d. lymphocytes
Adaptive immunity
describes a set of defenses that is customized to each infectious agent, providing a stronger response when an agent has been encountered before.
Phagocytosis
describes the process of engulfing and destroying a foreign particle.
HIV relies on the action of the ______ _______ ______ for reproduction.
enzyme reverse transcriptase
Tobacco Mosaic Virus
first virus discovered
Antigen
foreign substance that triggers an immune system response
Following an injury to your hand, the injured area appears red and swollen. It feels painful and warm to the touch. What is the cause of these symptoms?
inflammatory response
complement system
is a set of proteins that circulate in the blood, stimulating other defenses to help destroy an invader.
prophage
is a viral genome that has inserted itself into the genome of its host.
lysogenic cycle
is a viral life cycle in which the virus inserts its genome into the genome of its host, where it may remain dormant for long periods.
lytic cycle
is a viral life cycle that results in bursting of the host cell
Pathogen
is an agent in the environment that has the potential to cause disease.
Regulatory T cells
limits the attack
Lysogenic vs lytic cycle
lysogenic copies; lytic copies and release
Only humans can be infected by this virus
measles virus
How do vaccines convey long-term immunity to some pathogens?
memory cells
Are virus considered to be alive?
no
inflammatory response
nonspecific defense reaction to tissue damage caused by injury or infection
Is there a cure for AIDS?
nope, but progression of the disease can be slowed by anti-HIV drugs.
Capsid
protein coat surrounding a virus
specific defenses
responsible for seeking and destroying specific enemies and creating immunity
Plasma Cells
secrete free antibodies to attack the current invader
Once a bacterial cell is infected, the virus can enter one of two life cycles which are either....
the lytic cycle or the lysogenic cycle
