Lesson 2 & 3 Flashcards
How do bacteriophages insert their genetic material into a host cell?
The bacteriophage lands on the cell and inserts it’s genetic material by penetrating the membrane.
How do most viruses insert their genetic material into the host cell?
The virus and the cell makes contact with membranes and merge. The nucleic acid (DNA or RNA) will enter the inside of the cell.
What are the three steps of a viral infection?
- Attachment (virus attaches itself to the target cell)
- Penetration (the virus enters the cell)
- Uncoating and replication (virus releases viral RNA into the cell)
What is and how do dormant viruses differ from other viruses?
They are not reproducing or causing symptoms in your body. Dormant viruses can cause cancer if they spend enough time in the cell.
Compare the lytic and lysogenic cycles.
“In the lytic cycle, viruses quickly take over the host cell, make many copies, break the cell, and infect other cells. In the lysogenic cycle, viruses sneak into the host’s DNA, stay hidden, and wait. Later, they become active, make copies, and infect other cells.”
What is a RNA viruses?
A RNA virus is a virus that has ribonucleic acid (RNA) as its genetic material.
What do RNA viruses have to do different than DNA viruses? Why must they do this?
Replicate in the cytoplasm.
What is the risk of RNA and reverse transcription into DNA?
Can potentially be cancer causing.
What is the difference between bacteria and viruses? Which can you use antibiotics to fight?
Bacteria:
single cells that can survive on their own, inside or outside the body.
Viruses:
cause infections by entering and multiplying inside the host’s healthy cells.
Antibiotics ONLY work for BACTERIAL infections.
How are viruses transmitted from one organism to another?
-Bodily fluids
-Airborne
-Insect vectors
-Direct contact (e.g. via an infected surface)
What is the viral barrier for plants?
The cell wall.
What is the viral barrier for humans?
Skin.
What is the first line of defense?
Physical and Chemical Barriers (Innate Immunity).
E.g. “The closed surface of the skin and of all mucous membranes already forms a physical barrier against germs, which protects them from entering. Additionally, chemical substances like acid, enzymes or mucus prevent bacteria and viruses from gaining a foothold.”
What is the second line of defense?
Nonspecific Resistance (Innate Immunity).
E.g. “Pathogens that successfully cross the physical barriers are next encountered by the second line of defense. This innate immune response mostly involves immune cells and proteins to nonspecifically recognize and eliminate any pathogen that enters the body.”
What is the third line of defense?
Specific Resistance (Acquired Immunity).
“The third line of defense is immune cells that target specific antigens. The immune cells that play a role in the third line of defense are B-cells and T-cells, both are white blood cells. The B-cells produce antibodies. The T-cells help identify pathogenic cells and destroy targeted cells.”
