2.5: Eukaryotic Microbial Cells Flashcards
(25 cards)
What are the characteristics of eukaryotes
- genetic material housed in a nucleus
- generally larger than prokaryotes
- complex internal structure
-membrane bound organelles
-intracytoplasmic membranes used for transport
-cytoskeleton (keeps things in place and moves things where they need to be) - divide by mitosis and meiosis
how do prokaryotes and eukaryotes differ in size
- prokaryotes: 0.2 - 2 um diameter
- eukaryotes: 10-100 um diameter
how do prokaryotes and eukaryotes differ in nucleus
- prokaryotes -no nuclear membrane or nucleolus (just nucleoid space)
- eukaryotes -true nucleus with nuclear membrane and nucleolus
how do prokaryotes and eukaryotes differ in membrane-enclosed organelles
prokaryotes -absent
eukaryotes -present
how do prokaryotes and eukaryotes differ in ribosomes
- prokaryotes have smaller size (70S) ribosomes and 16S chromosomes
- eukaryotes have bigger size (80S) ribosomes and 18S chromosomes
how do prokaryotes and eukaryotes differ in chromosomal DNA
prokaryotes- singular and circular, packaged with other proteins that are not histones (usually but it was discovered that some archaea have histones)
eukaryotes -multiple linear chromosomes with histones
how do prokaryotes and eukaryotes differ in Cell divison
prokaryotes -binary fission
eukaryotes- mitosis and meiosis
describe the nucleus (remember only eukaryotes have)
- holds the genetic information
-multiple linear double stranded chromosomes
-packaged as chromatin -complex of DNA wrapped around proteins called histones - bounded by the nuclear envelope
-creating a double membrane, spanned by a nuclear pore complex which allows for movement of molecules through double membrane and into and out of the nucleus.
what do the mitochondria and chloroplasts have in common?
- Membrane bound compartments inside the cell used for energy generation
- semi-autonomous -partially dependent on the cell to replicate and grow -reproduce by divison, but division is directed by nucleus of eukaryote.
- contain their own DNA (mtDNA -mitochondria and ctDNA=chloroplast).
-no separate membrane.
-chromosome exists as a circular dsDNA.
-no histones (not in the form of chromatin).
describe the mitochondria function, size and structure
- site of respiration
- about the size of a size of a large bacterium
- inner membrane-folded to form cristae:
- outer membrane - contains porins similar to gram negative bacteria
- have their own DNA and ribosomes -70S (same as prokaryotes)
what processes of respiration occur in the inner membrane and matrix of the mitochondria
- ETC -in the membrane
- krebs cycle -in the matrix
what is streptomycin
an antibiotic that inhibits protein synthesis by 70S ribosomes (to kill bacteria), but toxic to mitochondria in high doses (bc mitochondria have 70S ribosomes too)
describe chloroplasts function and structure
- site of photosynthesis
- surrounded by two membranes
- Thylakoids -infoldings of the inner membrane
- Stroma -space surrounding thylakoids inside membranes.
- DNA and 70S ribosomes
what part of the mitochondria is equivalent to cytoplasm of prokaryote
the matrix
what part of mitochondria are equivalent to thylakoids
- equivalent to cristae of mitochondria
what part of mitochondria is equivalent to the stroma
the matrix
what is contained in the thylakoids, what process are these things for?
- contains enzymes, electron carriers, and chlorophyll involved in the light reactions -all the things needed for energy generation (through photosynthesis)
whats contained in the stroma? for what process are these things for?
- dark reaction enzymes for carbon fixation to make carbohydrates
what does the endosymbiosis hypothesis state
- that mitochondria and chloroplasts evolved from bacteria
what’s the 6 pieces of evidence for the endosymbiotic hypothesis
- semi-autonomous- mitochondria and chloroplasts reproduce by division, although directed by nucleus of eukaryote.
- Singular circular chromosome like bacteria
- lack histones like bacteria
- 70S ribosomes like bacteria
- Two membranes like some bacteria
- outer membrane has porins -like gram negative bacteria, not permeability layer
what part of envelope do mitochondria and chloroplasts have in common with gram negative bacteria? what part do they not have?
- have outer membrane with porins
- don’t have peptidoglycan, and lipid-A portion of the LPS part of the outer membrane
what genus of bacteria are mitochondria most closely related to, what phylum are they in?
Rickettsia, phylum: Proteobacteria
* which are obligate intracellular pathogens (must live inside cell and live off of it), (like mitochondria can’t live on its own)
-ex: rocky-mountain spotted fever
what genus of bacteria is most closely related to chloroplasts
- Cyanobacteria -blue-green algae that go through oxygenic photosynthesis (producing oxygen at the end of ETC, like plants)
an archaeon found from deep ocean sediment was discoved to be the prokaryote most closely related to eukaryotes, what is it called and what group does it belong to?
- called “Prometheoarchaeum syntrophicum” (unoffical not italicized)
- belongs to ‘Asgard Archaea’ super phylum
