prokaryotes and eukaroytes (L2) Flashcards
definition of a prokaryote
‘An organism lacking a nucleus and other membrane-bound organelles and usually having its DNA in a single circular molecule.’
Why are we interested in the structure and contents of a bacterium?
further our understanding of biology
aid in the diagnosis of infectious disease
aid in drug discovery
give me some structures in a prokaryotic structure
nuceloid
pillio
plasmids
what are some Structures common to all bacteria
Complex outer envelope protects from environmental stresses
Compact genome maximise the production of cells from limited resources
Tightly coordinated cell functions coordinate action enables high reproduction rate
give me the model of the bacterial cell
Cytoplasm – gel like network
Cell membrane
Cell wall
Outer membrane
Single chromosome
Ribosomes
what are pilli
Are Protein Fibers Extending from the Surface of Many Prokaryotes
what do pilli help with
-attach cells to surfaces
-to form biofilms and microcolonies
-Some bacterial species have conjugation pili, used to transfer genetic material between cells
what do Prokaryotic flagella contain
a helical filament, a hook, and a basal body
what does bactiera exhibit
exhibit chemotaxis, moving up the concentration gradient of a chemical attractant
what is the glycocalyx
Is an Outer Layer External to the Cell Wall
describe the glycocalyx
The glycocalyx is located external to the cell wall.
Composed of polysaccharides and sometimes small proteins.
A thick glycocalyx adhered to the cell forms a capsule.
A capsule serves as a protective layer
.
A thinner layer of polysaccharides is known as a slime layer.
It facilitates cell attachment to surfaces.
Overall, it offers protection and adhesion capabilities to cells.
what does the glycolax protect from
It protects cells from the environment and allows them to attach to surfaces
what is the fuction of the membrane
Holds the cytoplasm in
Carry proteins with specific functions (ATP synthesis)
what do eujaroytes use to strengthen the membrane
cholesterol
what do prokaryotes use to strengthen the membrane
terpenes (hopanoids, hopanes)
describe the cell wall
It is made of peptidoglycan
It is highly porous to ions and small organic molecules
Single molecule
describe peptidglyocan structure
Parallel polymers of disaccharides (glycans)
These are cross-linked with peptides
describe gram + bactiera
Thick cell wall
- Multiple layers of peptidoglycan
- Teichoic acids
decribe gram - bactiera
- Thin cell wall (single layer of peptidoglycan)
- Outer membrane - LPS
describe the genome
Single chromosome
Single chromosome
Haploid
what is the purpose of the plasmid
Transfer genetic traits between bacteria
May give bacteria a selective advantage in an environment
describe fungi
Molds have hyphae
Hyphae intertwine to make visible masses known as mycelia
Cell walls made of chitin
Fungi cause disease through three major mechanisms
Allergic responses to fungi
Mycotoxins (e.g., aflatoxins;)
Infections (mycoses
describe malaria
A protist disease caused by Plasmodium spp.
Generally found in tropical and subtropical regions
give me summary of prokaryotes
The cell wall is a conserved structure called peptidoglycan
Peptidoglycan is made of two repeating sugar subunits
Gram positive and Gram negative bacteria have different cell envelopes
summarise eukaroytes
Can be difficult to treat
Many are opportunistic
Some are killers
