Diversity of life & Prokaryotes Flashcards
What are 3 ways to measure biodiversity?
- Genetic variation
- Species composition
- Function
How many species have been named?
~ 1.5 million
What is a problem with new species being discovered/named?
A lot of them are duplicates
What are 2 factors that majorly affect species diversity, and how do they?
- Area: the more area, the more species (not a 1:1 ratio -> ‘2x area = 10-25% more species’)
- Climate: Warm + wet = more
What group of species is the most diverse?
Arthropods (includes insects, spiders, crustaceans, and beetles)
What do eukarya have that bacteria & archaea DEFINITELY don’t have?
A nuclear envelope.
Out of bacteria, archaea, and eukarya, which group always has organelles?
eukarya.
Discuss the lipids (how they are bonded to glycerol) in plasma membranes of the three main groups?
In bacteria & eukarya, glycerol is bound to straight-chain fatty acids. The cell membrane is made of a double layer of lipids (tail to tail)
In archaea, glycerol is bound to branched fatty acids via an ETHER linkage, and the cell membrane is a layer of single cells with a lipid middle and glycerol on either end.
How many chromosomes do archaea and bacteria often have?
Just one, that is a circle.
What are plasmids?
Bits of DNA outside the chromosome that are easily exchanged during sex.
What is the difference between cells that are gram-positive and gram-negative?
Gram-positive have a thick cell wall with only one plasma membrane (the stain gets thru to the inside)
Gram-negative have TWO plasma membranes on either side of the cell wall (stain can’t get thru).
Reproduction and exchange of genetic material are done at the same time in eukaryotes. Explain how they’re done separately in bacteria.
- Genetic material is exchanged between bacteria by Conjugation, Transformation, or Transduction.
- Bacteria reproduce quickly by binary fission.
What is the difference between genetic conjugation, transformation, and transduction?
Conjugation is when genes on plasmids are transferred.
Transformation is when free genetic material is taken up.
Transduction is when bacteriophages infect bacteria and bring in new genetic material.
What are endospores?
Structures produced by bacteria during harsh, unfavorable conditions that are highly resistant.
Aside from endospores, how do bacteria deal with harsh environmental conditions?
They produce biofilm which traps debris and other cells. (plaque, stromatolites, etc.)
How do bacteria respond to chemical signals? Give a technical term and explain.
The can move towards or away (chemotaxis) by using their flagella, gliding, rolling, etc.
True or false: Prokaryotes are autotrophs.
False:
Trick question, they can be autotrophs OR heterotrophs, they are highly diverse in their feeding.
What is the difference between facultative and aerotolerant anaerobes?
Facultative WILL use O2 if available, whereas aerotolerant can survive around O2, but don’t use it.
What is the most common type of energy transformation (feeding style)?
chemoheterotrophs.
Can plants fix nitrogen into ammonia to be consumed?
No, they live in symbiosis with bacteria that do it for them.
What is the difference between exotoxin and an endotoxin-style bacteria?
Exotoxins are proteins secreted by bacteria, they’re very toxic. Endotoxins are when it’s just something about the bacterial membrane that is toxic - not as toxic.
Why are alpha-proteobacteria so important?
They are slightly related to us because they gave rise to the protomitochondrion which were taken up by eukaryotes and became the mitochondria.
How did scientists used to classify prokaryote vs how do they do it now?
Used to use morphology and gram-staining, now they use DNA sequencing.
What group shows the most genetic diversity?
Prokaryotes
What group shows the most functional diversity?
Prokaryotes
What is the consequence of prokaryotes being the first living things?
It meant that they were always present to take advantage of new niches, so they’re everywhere.
