Topic 2 Flashcards
Difference between prokaryotes and eukaryotes (2)
- Prokaryotes are smaller in size (bacteria cell size roughly equivalent to Mitochondria)
- Eukaryotes have membrane bound organelles that compartmentalize cells. Prokaryotes have cell wall/cell membrane –> compartmentalization is closed off.
Most bacteria cell are _______ micro-metres in length.
0.5 to 10
(Largest Prokaryote: Epulopiscium fishelsoni
Smallest Prokaryote: Mycoplasma pneumonia)
Why does surface area to volume ratio matter in terms of cell size and cell growth?
SA/V ratio affects how quickly cells exchange nutrients and waste into their environment. Small cells can grow/reproduce more quickly–> use less time/energy to replicate cells.
Shape of prokaryotes are determined by what factors? (4)
In no particular order:
- cell wall structure
- cell growth
- division mechanisms
- cell differentiation
Know your morphology vocab kidzz! (6 important terms)
- Coccus (sphere)
- Rod
- Spirillium (worm-like)
- Spirochete (S-shape/wavy hair shape)
- Stalk and Hypha (look like ladles)
- Filamentous
Name three types of Cocci: spheres and examples!!
- Staphylococci: cluster of cocci –> ex: Staphyloccus aureus, in human microbiota and opportunistic pathogen
- Dippococci: pairs of cocci –> ex: Neisseria gonorrhoeae, STD gonorrhea
- Streptococcus: chains of cocci –> ex: Streptococcus pyogenes, strep throat
Note: You can also have a single free-floating sphere —> ‘coccus’
Name Bacilli rod example:
Salmonella enterica –> food positioning and can cause typhoid fever
Example of Vibrio: Comma shaped:
hint: Neha’s pun ;)
Vibrio cholerae; human pathogen that can cause diarrhea and hydration
Name example of Helical shape:
Spring shaped
Helicobacter pylori; human stomach, cause of stomach ulcers, stomach cancers
Example of Spirochetes (Long spirals):
Borrelia burgdorferi; bacteria pathogen causing Lyme diseases by ticks
Example of Appendaged/Budding:
Caulobacter crescentus; study bacterial cell cycle, asymmetric cell division
Example of Filamentous Shape:
Noodles shaped!
Chloroflexus aurantiacus; photosynthetic bacteria don’t produce oxygen
How can cell shape affect aspects of day to day life? (5)
o Nutrient access/uptake (surface:volume ratio)
o Motility
o Attachment to surfaces
o Formation of biofilms
o Interactions with other microbes and/or eukaryotic host cells
Monomorphic vs Pleomorphic:
hint: mono means single; p stands for pleural
Monomorphic: adopt one shape; observed in most pure cultures of bacteria
Pleomorphic: multiple different morphologies for same bacterium, adopt multiple morphologies
What causes different morphologies/changes of morphology? (3)
o Differentiation into different cell types or spore formation –> cell program change
o Altered morphology in response to environmental stress
o Altered morphology due to mutation
What’s special about Arthobacter crystallopoietes?
Its pleomorphic!
Rod shapes during fast/logarthmic growth
Coccus during slow/ no growth
Major structures of the Cell Envelope: (4)
- Cytoplasmic membrane
- cell wall
- outer membrane
- S-layers
Roles of the Cell Envelope: (4 main ones)
o Maintains barrier with environment
o Protects cell from stress
o Allows transport of nutrients into cell and waste out of cell
o Energy conservation/production
Difference between Gram-negative and Gram-positive cell envelope?
Gram positive:
thick cell wall, no outer membrane, different/smaller periplasmic space
Gram negative: (think of a sandwich - has 2 membranes)
thin cell wall, outer membrane, has another cell membrane, periplasmic space b/w the two membrances
Explain the three functions of cytoplasmic membrane:
- Permeability barrier: prevents and functions as a gateway for transport of nutrients, waste in/out of cell
- Protein anchor: site of proteins that participate in transport, chemotaxis, bioenergetics
- Energy conservation: Site of generation and dissipation of proton motive force ( this basically saying that it helps pump photons against the energy/photon gradient)
Hydrophilic vs Hydrophobic:
Hydrophilic: “water loving” molecules; Ionic
and/or polar.
Hydrophobic: “water fearing” molecules; nonpolar.
Which parts of the cytoplasmic membrane are hydrophilic and hydrophobic?
Hydrophilic: Backbone –> glycerol and phosphate (is conserved in both euk. and prok.)
Hydrophobic: Fatty Acid Tails –> E.g. unsaturated
fatty acids (contain double bonds = kinks) increase fluidity (decrease rigidity) of membrane.
What are the three proteins found in the cytoplasmic membrane?
- Peripheral membrane proteins –> only on one side of the membrane
- Integral membrane proteins (embedded in membrane)
- Transmembrane proteins (are
integral membrane proteins that pass all the way through membrane) –> runs from one side to another
Why does it mean when the Cytoplasmic membrane have “two faces”?
One side of cytoplasmic membrane faces the cytoplasm and the other faces outward (
periplasmic face).
Specific Topolgies!
2 faces of the cytoplasmic membrane are identical in respect to the phospholipids, but not identical cause the proteins in different direction make domains face different from one another.