Eukaryotes vs Prokaryotes Flashcards
What are the 7 different characteristics in judging if a cell is a prokaryote or eukaryote?
What is the size of a eukaryotic cell?
Prokaryotic cell?
- cell size
- packaging of DNA genome
- genome complexity
- organelles
- ribosomes
- flagella
- cell wall
10 micrometres
1-2 micrometres
How is DNA packed in eukaryotes?
What else does this enable? Does this occur in prokaryotes too?
What are the 2 ways DNA is organised in prokaryotes?
What are the 2 differences in proteins associated with DNA?
What do prokaryotes not have?
If some archaea have histones instead, what does that make them?
DNA associated with histones & packed into chromosomes in double-membrane nucleus
Microtubules to attach to chromosomes for mitosis/meiosis. No- undergo binary fission
1 chromosome = aggregate of circular DNA organised around NAPs nucleoid associated proteins (prokaryote genome)
Plasmid = smaller circular DNA for survival
Eukaryotes = histones Prokaryotes = NAPs
Nucleus (nucleolus, nucleoplasm)
Higher order organism
How would you describe the prokaryotic genome? 3 ways
How would you describe the eukaryotic genome? 3 ways
Small & circular
Not complex- 2-13Mbp
1,000-5,000 protein coding genes
Larger & linear with lots variety
Complex- 10-10kMbp
6,000-40,000 protein coding genes
What kind of organelles do eukaryotes contain?
What organelles do prokaryotes contain?
What type of eukaryotes have mitochondria? What about anaerobic eukaryotes & prokaryotes?
What do chloroplasts do? Are they present in prokaryotes?
How did chloroplasts and mitochondria come about in eukaryotes?
Membrane bound organelles: ER, golgi, centrioles, mitochondria etc. Some contain plastids (like chloroplasts)
Internal membrane systems- ancestors of eukaryotic organelles
Aerobic ones
Anaerobic = mitosomes
Prokaryotes don’t have mitochondria- respirate in plasma membrane
Fix carbon dioxide- no
a-proteobacterium engulfed by archaea led to formation of mitochondria. cyanobacterium formed chloroplast.
both have thylakoid membranes which were sites for photosynthesis & respiration & so evolved from there
What are the ribosomes associated with in eukaryotes?
Prokaryotes?
Where are they generally found in all organisms?
What type of ribosomes do prokaryotes have?
What type of ribosomes do eukaryotes have?
What do ribosomes contain? What does it do?
How can different antibiotics affect different organisms?
What does S stand for?
ERs or free floating
free floating (no ER as membrane bound)
Areas where translation occurs/where a specific protein is required (like near a cell wall)
70s (30s + 50s subunits) but not additive
80s (40s + 60s) and also 70s in eukaryotes originating from bacteria
proteins & RNA (rRNA)- site of protein synthesis
ribosomes have different sensitivities- e.g can inhibit 70s but not 80s
Svedberg- measure of size & density but it is not an additive property (intensive)
What is LUCA in a phylogenetic tree? Where is it found?
Why is 16S rRNA useful for classification? What has it been used for?
What is distinct about the eukarya branch?
What else could you use for classification? What did this discover?
What is next gen sequencing? Why is it better?
Last universal common ancestor- root of the tree
Highly conserved but also has variable regions- so can compare & classify species into different relationships. Used to define 3 domains (bacteria, archaea & eukarya)
where eukarya = smallest section of tree
ribosomal proteins- eukarya more closely related to archaea
Whole genome sequencing rather than small sections- cheap, easy, quick
What are the flagella in eukaryotes made of?
What are its characteristics?
What are the flagella in prokaryotes made of?
What are its characteristics?
Microtubule bundles (which prokaryotes don’t have) surrounded in a membrane sheath
complex structure & single motion
single filament from flagellin
simpler structure, rotary motor to rotate flagellum in a spiral
What is a cell wall? What is it for?
What is the eukaryotic cell wall made of?
Prokaryotes?
How can you characterise bacteria with its cell wall?
What eukaryote has transparent cell walls?
Rigid polymer layer outside of cell membrane.
Rigidity, shape, protection & prevents amoeboid movement & phagocytosis
Cellulose in plants & algae
Chitin in fungi
Peptidoglycan in bacteria & some archaea
Gram staining:
Gram positive = retain stain as has thick peptidoglycan wall
Gram negative/actinomycetes = thin layer so won’t retain gram staining
Diatoms- opaline silica
What did Leeuvenhoek observe?
Louis Pasteur?
Robert Koch?
What were Koch’s 4 postulates? (showing link between microbes & disease)
What are some exceptions?
Microbes as “animalcules”
Showed that cells arose from cells and did not just spontaneously arise
Discovery of making bacterial culture from blood from a diseased animal and transferring it into a healthy animal
- Microbe must be found in abundance in the organism suffering with disease but not found in the healthy one
- microbe must be isolated from diseased organism & grown in culture
- cultured microbe should cause disease when inoculated into healthy organism
- microbe must be re-isolated after inoculated in host & identified as original causative agent
Some bacteria can’t be grown on pure culture in a lab. Some pathogens that don’t infect animal models
Isolating bacteria——-
What was the dilution method of Lister in 1878?
What was wrong with it?
What was Koch’s solid medium for spatial separation of individual cells?
How has this evolved?
What 3 ways could you maintain your colonies/strains?
What is the problem with sub culturing?
Dilute bacterial culture to only 1 organism & incubate
Could dilute to 0 on accident
Spread bacteria culture onto boiled potato slice & incubate & pick 1 colony
Use agar plate & gelling agent & incubate & pick 1 colony
- Regular sub culture into fresh medium
- freeze storage
- freeze dry
growing continuously for many generations can produce different strains of bacteria
In classifying bacteria, what are the 3?
What are the 2 methods of classification for bacteria?
What DNA sequence similarity is deemed to be suitable for two organisms to be in the same species?
1st = Genus (capitalised & in italics)
2nd = species (italics & lower case)
3. specific strain (not italicised)
Classical approach = identify features so size, shape, growth requirements, metabolism, host range etc
Molecular taxonomy = evolutionary relationships from DNA/RNA/protein sequencing
> 70%
