Lecture Set 2 : Part 5 Flashcards
what are the features of eukaryotic cells?
-genetic material housed in a nucleus
-generally larger than prokaryotes
-complex internal structure
-divide by mitosis and meiosis
what is included within a eukaryotes complex internal structure?
-membrane bound organelles / intracytoplasmic membranes (transport)
-cytoskeleton (some prokaryotes have, but it is different)
what are examples of intracytoplasmic membranes?
-endoplasmic reticulum
-golgi complex
-mitochondria
-chloroplasts
is the flagella of a eukaryote the same as that of a prokaryote?
-NO
-it is structurally + functionally different
what is specifically contained within the nucleus?
-multiple linear double stranded DNA chromosomes
-can also take chromatin form (complex of DNA and histone proteins)
how do histone proteins and DNA interact? how do they do so?
-form tight-packing of DNA for better organization
-DNA is negatively charged and histones are positively charged to do so
-DNA + histones = nucleosomes
how is the nucleus bound?
-by a double membrane
-has a spanned nuclear pore complex to allow for the transport of molecules in and out of the nucleus (does so with transport proteins)
what are the mitochondria and chloroplasts?
-membrane bound compartments inside the cell (double membrane bound)
-used for energy generation
-both semi-autonomous (reproduce independently of the nucleus in terms of DNA)
-contain their own DNA (mtDNA + cpDNA)
-no separate membrane containing this genetic material
how does the genetic material within mitochondria and chloroplasts arrange itself?
-as a circular double stranded DNA chromosome
-no histones
-similar to bacterial arrangement
what are the features of the mitochondria?
-site of cellular respiration
-size of a large bacterium
-bound by 2 membranes (inner and outer)
-contains its own 70S ribosomes (similar to a prokaryote)
-contains mtDNA
what are the features of the inner membrane of the mitochondria?
-folded to form cristae
-electron transport chain is located within the membrane
-Krebs cycle takes place within the matrix (on the inside of the inner membrane)
-less permeable than the outer membrane
what is a feature of the outer membrane of the mitochondria and chloroplasts?
-contains porins (proteins that form channel-like pores)
-allows the passage of small molecules
what is an antibiotic toxic to mitochondria? why is this?
-streptomycin (aminoglycide)
-inhibits protein synthesis of the 70S ribosomes which is within the mitochondria
-why peptidoglycan is usually a better target
what are the features of the chloroplasts?
-site of photosynthesis
-bound by 2 membranes (less permeable inner and more permeable outer)
-contains its own 70S ribosomes (similar to a prokaryote)
-contains cpDNA
what are thylakoids in the chloroplast?
-infoldings of the inner membrane (disc structure)
-enzymes, electron carriers, and chlorophyll inside (used for light reactions/energy generation)
what is the stroma within the chloroplast?
-space surrounded by the inner membrane
-contains dark reaction enzymes for carbohydrate synthesis (calvin cycle)
-also contains the DNA and 70S ribosomes
what dark reaction enzyme is found within the stroma?
-RuBisCO
what is the endosymbiotic hypothesis?
-mitochondria and chloroplasts evolved from bacteria
what evidence is there to support the endosymbiotic hypothesis?
-semi-autonomous
-circular chromosomes lacking histones
-70S ribosomes
-2 membranes (outer membrane with porins)
what can be seen when comparing the 16S rRNA gene sequences in terms of mitochondria?
-most closely related to the genus Rickettsia (phylum = proteobacteria)
-these bacteria are obligated to be intracellular pathogens (cannot live without a host)
what is a disease caused the the Rickettsia genus?
-rocky-mountain spotted fever
what can be seen when comparing the 16S rRNA gene sequences in terms of chloroplasts?
-most closely related to cyanobacteria (like blue-green algae)
-can perform oxygenic photosynthesis
what prokaryote has been found to be the most closely related to a eukaryote?
-archaea from deep ocean sediment
-belongs to the asgard archaea
-has similar genomic features to eukaryotes (DNA around histones)
-took a long time to isolate (needs a buddy to grow)
-named promeheoarchaeaum synthrophicum
what were researchers able to find within a marine algae?
-nitrogen fixing organelle
-nitrogen fixation is only known to be done by prokaryotes
-semi-autonomous and has its own DNA
-also requires proteins from genes encoded in the nucleus of the algae
-called the nitroplast
-evolutionarily related to cyanobacteria
