week 1 (unit 1) Flashcards
(52 cards)
2 types of organisms
cellular and acellular
4 groups of cellular organisms
bacteria, archaea, fungi, protists
4 groups of acellular organisms
viruses, viroids, prions, satellites
Woese discovered that archaea are more closely related to…
eukarya
bacteria characteristics
single-celled, cell wall with peptidoglycan, lack membrane-bound nucleus, extreme environments, does and does not cause disease
archaea characteristics
unique rRNA sequences, unique membrane lipids, unusual metabolic characteristics, extreme environment, does not cause disease (to humans bc we don’t live in the same environment)
eukarya characteristics
membrane-enclosed, larger, more complex,
- protists: unicellular, larger
~protozoa: animal-like
metabolism
~algae: photosynthetic
- fungi: ~unicellular (ex: yeast)
~multicellular (ex: mold,
mushrooms)
Virus charcteristics
when was life first identified on Earth?
3.5-3.8 bya
how can life be traced that far back?
through carbon dating, fossils, and molecular fossils (hopanes), prokaryotes
stromatolites
they are photosynthesizers, abt 3.5 byo, mineralized layers of cyanobacteria
when did the Oxygen Revolution happen?
abt 2.5 bya
what was the Oxygen Revolution?
early earth lacked O2 and so when O2 began rising it led to the extinction of many prok, but some did survive and they had adapted to an anaerobic environment (meaning they dont NEED O2 to survive). Some used cellular respiration to harvest energy
What is endosymbiosis?
when an org lives in another org
Endosymbiotic Theory
origin of mitochondria, chloroplasts, and hydrogenosomes,
~our mitochondrial DNA may be
more similar to bacteria than to the
DNA in our other cells
LUCA (last universal common ancestor)
the 3 domains of life originated from, archaea and euk diverged from a common ancestor and bacteria evolved independently
how do b,a, and e reproduce?
a and b - horizontal gene transfer
e - sexual reproduction (aka vertical gene transfer)
microbial taxonomy
phylum
class
order
family
genus
species
strain
~ fgspecies- 16s rRNA sequencing
~strain- shotgun metagenomic sequencing
Why use 16s rRNA sequencing?
It is highly conserved in a and b and that sequence is present in all strains
what evolved from prokaryotes?
ribosomes, cytoplasm, cell membrane, and metabolic pathways
Lucretius
he said there are good and bad things
fracastoro
he came up with “spores” and believed there were little things that were causing disease
Hooke
-coined the term “cell”
- made the best compound microscope and illumination system
- book: Micrographia
Anton
- 1st to observe single-celled organisms (animalcules - little animals)