L11B BACTERIA & ARCHAEA Flashcards
What type of cells are bacteria & archaea?
Prokaryotes.
List the defining features of prokaryotes. (6)
- Most are unicellular and small 0.5-10um
- They lack a nucleus
- They have a simple genome and one circular chromosome
- Most have a cell wall
- They have a ribosome structure different than eukaryotes
- They reproduce asexually through binary fission.
TRUE OR FALSE: Prokaryotes are only found in moist environments.
FALSE: Prokaryotes are everywhere and are the most abundant organism on earth.
think of bacteria when you think of prokaryote!!
What are the two main variations in metabolic diversity of prokaryotes? What are the two sub-types of each?
Sources of energy (CHEMOtroph: energy from chemical bonds or PHOTOtroph: energy from sunlight.)
Sources of carbon (AUTOtroph: inorganic CO2 or HETEROtroph: organic compounds like sugar, fat, carb, AA, protein.)
Fill in the blanks.
- Photoautotroph
- Photoheterotroph
- Chemoautotroph
- Chemoheterotroph
Name the two types of -trophs that only prokaryotes use.
Photoheterotrophism and Chemoautotrophism.
Plants and some protists are photoautotrophic (photosynthesis), and all Animals & Fungi and many protists are chemoheterotrophic.
Describe the different types of anaerobes found in prokaryotes.
- Obligate aerobes: need O2 for cellular respiration
- Obligate anaerobes: poisoned by O2.
- Facultative anaerobes: can use O2 if present but is not necessary
What is binary fission?
Process whereby prokaryotic cells reproduce. The DNA replicates and the cell grows, then it divides and each daughter cell receives identical copy of parental DNA.
If bacteria reproduce asexually, how is there so much genetic diversity among them? (4)
4 different ways:
1. Mutation ie. horizontal gene transfer
2. Transduction ie. virus
3. Transformation ie. picking up DNA bits from environment
4. Conjugation ie. genetic material transfer thru sex pilus
How do archaea siffer from bacteria? (3)
- They lack peptidoglycan in their cell walls.
- Their cell membranes have unique membrane lipids
- Their DNA & RNA structures differ from bacteria.
Name the three groupings within Archaea.
- Methonogens live under anaerobic environments (ie herbivore gut) where they produce methane.
- Halophiles live under high salt concentrations (ie great salt lake)
- Thermoacidophiles live in hot acidic environments (ie hydrothermal vent)
What is an extremophile?
Archaebacteria that lives in extreme environments.
What is the relation between the circular DNA and the plasmid in prokaryotes?
The DNA in the nucleiod region holds the information necessary for the existence of the bacteria, and plasmids are smaller fragments of DNA that usually don’t carry genes essential for survival.
What is transduction?
Transduction is a virus aka phage injecting its DNA into recipient cell’s chromosome.
What is conjugation?
Transfer of genetic material (DNA and plasmids) between two bacteria via sex pilus.