Viruses and bacteria Flashcards
Definition of a Virus
A small living particle that can change cells and affect how the cells function
Definition of a Viron
A
Virus with its complete DNA or RNA core and protein coat as it exists outside the cell. Also called an “Infectious viral particle”
Definition for a Viroid
Nucleic acid without protein coat. Small infectious agent of plants
Definition of Prions
A disease - causing agent that is neither bacterial not fungal nor viral and contains no genetic materials
Do viruses contain a protein coat?
Yes They contain a protein coat ( sometimes itself enclosed by an envelope of LIPIDS, proteins and carbohydrates ) That surrounds the nucleic acids - CAPSID
What is a capsid?
It is a protein shell of a virus that encloses its genetic material
Do viruses contain RNA or DNA
Could be either
A virion is a complete, fully developed infectious particle
Composed of a nucleic acid and surrounded by a ________ ____
Protein coat
How are viruses classified?
By their protein coats
Nucleic Acid can have both DNA and RNA
T/F
F
Nucleic acid can only have either DNA or RNA
Nucleic acid can only be single stranded
T/F
False
it can be single or double stranded
Some Viruses have capsid covered by an envelope, Some envelopes are covered with spikes that are used for what?
To attach to other cells
Non enveloped viruses - capsids are not covered by what?
An envelope
What are the 4 types of viruses?
Helical
Polyhedral
Spherical
Complex
Characteristics of Helical virus/ Tobacco mosaic virus
Has a Helical capsid with the shape of a rigid rod
Does the Helical contain DNA or RNA
RNA
Polyhedral / Adenovirus is shaped like a hexagon and has a glycoprotein spike at each sphere
T/F
True
Does Polyhedral / adenovirus carry DNA or RNA?
DNA
Spherical / Influenza Virus has RNA molecules inside, how many are there
8, each wrapped in helical capsid and an outer envelope studded with glycoprotein spikes
Complex / bacteriophage contains DNA or RNA
DNA
Complex / bacteriophage has a capsid consisting of two parts. What are they
Head and tail
Viruses can grow in dead cells
T/F
False, a virus needs a living host
What is a bacteriophage?
Bacteriophages (BPs) are viruses that can infect and kill bacteria without any negative effect on human or animal cells.
For this reason, it is supposed that they can be used, alone or in combination with antibiotics, to treat bacterial infections
For a _____ to multiply, it must invade a host cell and take over the hosts metabolic machinery
Virus
For a _____ to multiply, it must invade a host cell and take over the hosts metabolic machinery
Virus
The multiplication of bacteriophages has 2 cycles, what are they?
Lytic cycle and lysogenic cycle
The Lytic is compared to a sack of baby spiders exploding
T/F
True
- Enters the host cell
- Cell is reprogrammed and begins to produce viruses
- When enough are produced, cell erupts and viruses are released
The Lysogenic cycle pinches off and forms two,
what is this process called?
Binary fission
3 Stages of the Lysogenic cycle
- Virus inserts into host cell
- Host cell divides, and each time it is copied
- At some point the Lytic cycle is triggered
5 stages of the Lytic cycle
Attachment Penetration Biosynthesis Maturation Release
What happens in the attachment phase?
Phage attaches by tail fibers to the host cell
What happens during penetration?
Phage Lysome opens cell wall, tail sheth contracts to force tail core and DNA into the cell
explain Biosynthesis
Production of phage, DNA and proteins
What happens during maturation?
Assembly of phage partciles
