Chapter 17 Flashcards
Study Guide
What is a Prion
A proteinaceous infectious particle
Misshaped protein changes normal protein into misshaped protein.
Seen in CWD, Mad Cow, and Creutzfeld Jakob Disease
What is a Viroid?
Naked strands of RNA that take over cells to make more viroids
Seen in plants
What components make up a virus
Outer Capsid- Composed of protein subunits
Inner Core- Viral genome with DNA & RNA
What are the 5 Stages of the viral Cycle?
Attachment Penetration Biosynthesis Maturation Release
What happens in Attachment
Capsid combines with a receptor in the bacterial cell wall
What happens in Penetration
A viral enzyme digests away part of the cell wall and viral DNA is injected into the bacteria cell
What happens during Biosynthesis
Viral components begins after the virus inactivates host genes. Machinery of the host cell then carries out viral DNA replication
What happens during Maturation
Viral DNA and capsids assemble to produce several hundred viral particles
What happens during Release
Release of the phage particles. Bacteria Cell Dies
What happens in Lytic Vs Lysogenic Viral Cycles
Lytic is Attachment, Penetration, Biosynthesis, Maturation, Release.
Lysogenic phase a affected bacterial cell doesnt immediately produce phages, but might later. Following penetration, integration occurs. Viral DNA becomes incorporated into bacterial cell DNA with no destruction of host. Can re-enter lytic stage at any time.
Why dont antibiotics work on viruses?
Because they specifically target the bacterias machinery, which they cannot find after it has been taken over by a virus
What is a Retrovirus
Viruses that use RNA as their genetic material
How does the cell cycle work in a retrovirus
Enters the cell, reverse transcript converts retroviral RNA into DNA. Viral DNA then goes to nucleus and becomes intergrated into host genome. Can exit cell and infect another. (HIV)
Structure of a prokaryotic cell
No nucleus or other membrane bound organellles
2 domains with prokaryotic cells
Archaea
Bacteria
What are the major shapes of Bacteria?
Rods
Spheres
Spirals
How do scientists think cells originated?
In rocks 3.5 million years ago. All from prokaryotic cells
Function of Nucleoid in bacteria cell
Location of the bacterial chromosome
Function of Plasma Membrane in bacteria cell
Sheet that surrounds cytoplasm and regulates entrance and exit of molecules
Function of Cell Wall in bacteria cell
Structure that provides support and shapes the cell
Function of capsule in a bacteria cell
gel-like coating outside the cell wall that enhances ability to cause disease
Function of Ribosome in a bacteria cell
Protein synthesis
Function of Flagellum in bacteria cell
Locomotion
Function of Fimbriae in bactera cell
Hairlike bristles that all adhesion to surfaces
Function of Pilus is bacteria cell
Hollow appendage used to transfer DNA to other cells
What is meant by the term bianary fission
Bacteria Reproduction (Asexually)
Define Photoautotroph
Something that can create food by themselves from the sun
Define Chemoheterotroph
Organisms that have to obtain energy by ingesting building blocks (Humans)
Define Symbiosis
An interaction between 2 different organisms living in close physical association. Usually mutually beneficial
Define Commensalism
One partner benefits, the other doesnt benefit but isnt harmed either
Define Mutualism
Both partners benefit
Define Parasitic
One partner benefits and the other is harmed
2 Differences between Archaea and Bacteria
Archaea have more complex RNA polymerase
Archaea are very metabolically diverse
Where are Archaea typically found?
In “ancient” environments. Places other things can not live.
What is the endosymbiotic theory?
Mitochondria and Chloroplasts were once prokaryotic cells on their own. They both contain DNA.
