Bacteria and Viruses (help) Flashcards
What are prokaryotes?
Unicellular organisms that lack a nucleus.
Do prokaryotes have DNA?
Yes, but it floats freely around the cell
What are the 2 kingdoms of prokaryotes?
Bacteria and Archaea
Are archaea and bacteria prokaryotes?
No, they are eukaryotes
Which is larger: bacteria or archaebacteria?
Bacteria
TRUE OR FALSE: Bacteria includes a wide variety of organisms
true
T or F: Bacteria only lives in human beings
False: Bacteria lives almost everywhere, including humans
What is a bacteria usually surrounded by?
Usually surround by a cell wall that protects the cell from injury and determines its shape
What do bacteria cells contain?
They contain peptidoglycan
What is peptidoglycan?
Its a polymer of sugars and amino acids that surrounds the cell membrane. Peptidoglycan wall makes the cell especially resistant to damage
How do bacteria move around?
They move around either using a flagella, cilia, or secreting liquid
Do archaea have peptidoglycan?
No
T or F: Archaea live in extremely harsh environments
True
What are the 3 shapes that a bacteria can have? List the describe.
- Bacilli (rod-shaped)
- Cocci (spherical shape)
- Spirilla (spiral/corkscrew shape)
Do prokaryotes need a supply of chemical energy?
Yes
What are the different ways prokaryotes obtain energy? List and describe
- Heterotroph - Take in organic molecules from environment or other organisms to use as both energy and carbon supply
- Photohetetroph - Like basic heterotrophs, but also use light energy
- Photoautroph - Use light energy to convert CO2 into carbon compounds
- Chemoautotroph - use energy released by chemical reactions involving ammonia, etc.
What is binary fission?
This is how prokaryotes reproduce. It’s an asexual process which produces genetically identical.
What is endospore?
A thick internal wall that encloses the DNA and a portion of the cytoplasm. An endospore forms when growth conditions are unfavorable. Endospores can remain dormant for years.
What does endospore do for the cell?
It makes it possible for some prokaryotes to survive very hard conditions
What are the 2 ways prokaryotic populations can evolve?
- mutation
- conjugation
Describe the mutation process for a prokaryote
In prokaryotes, mutations are inherited by daughter cells produced by binary fission. But first a random change occurs in the DNA.
Describe the conjugation process for prokaryotes
Conjugation is a way for prokaryotes to exchange genetic info. Two cells build a small bridge and plasmids carry pieces of genetic information between the cells. This creates some genetic diversity.
Why are prokaryotes important to life?
Prokaryotes are essential in maintaining every aspect of the ecological balance of the living world. Some species also have specific uses in the human industry.
Describe prokaryotes in decomposition
Prokaryotes assist in the breakdown of dead organisms. This supplies raw materials to other organisms that need them to survive. It also maintains equilibrium in the environment.
Describe prokaryotes as producers:
Photosynthetic prokaryotes are among the most important producers on the planet. This species produces A LOT of stuff.
How are prokaryotes important to food chains?
Food chains are dependent on prokaryotes as producers of food and biomass.
What organism does nitrogen fixation?
Prokaryotes
What is nitrogen fixation?
Converting nitrogen gas into ammonia. Ammonia can then be converted to nitrates that plants use.
All organisms need nitrogen to make proteins and molecules!
How do humans use proteins?
Prokaryotes are used in the production of foods and commerical products (for example: yogurt, synthesizing drugs). Some bacteria are also used to remove petroleum and remove human waste or poison from water.
What is a virus?
A nonliving particle made of proteins, nucleic acids, and sometimes lipids.
What are viruses made of?
Proteins, nucleic acids, and sometimes lipids
Are viruses particles or cells?
Particles
Are viruses alive?
No
Are viruses cells?
No
What is the structure of viruses?
- Very small!!
- Have capsids
- Have proteins on their surface membrane (this is alternative to capsid)
- DNA or RNA
What is a capsid?
A protein coat surrounding a virus. Used to trick the host cell into taking in the virus, or in letting it inject its DNA into the host cell
Why do viruses infect very specific types of cells? Can viruses infect any organism?
While viruses can infect lots of organisms, they are very selective because because the virus must bind precisely to proteins on the host cell surface and not every cell will match that