Prokaryote Cells Flashcards
Cell Theory
- All living organisms are composed of one or more cells and their products
- Cells are the monomer for any organism
- New cells arise from pre-existing, living cells
Prokaryote vs. Eukaryote
P do not contain a nucleus or membrane bound organelles
Prokaryotes include three classes:
Bacteria, arched and blue-green algae
Taxonomy
Classification of living organisms
Largest taxonomic division is the
Domain
Three domains:
Archea, eukaryotes and bacteria
Each domain can be further divided into
Kingdoms
The three eurkayotic kingdoms are
Anamilia, plantae and fungi
Protists
Single-celled eukaryotes
Prokaryotic genome is a
Single double-stranded circular DNA chromosome
In bacteria, transcription and translation occur
Translation occurs via
Simultaneously in the cytoplasm
Multiple ribosomes translate the RNA simultaneously before it is done being transcribed
Are E and P ribosomes the same?
No
Plasmid
Circular piece of double-stranded DNA which is much smaller than the genome
Plasmid are extrachromosomal genetic elements meaning they
Encode gene product which confer advantage upon a bacterium carrying the plasmic
ex: antibiotic resistant genes
Plasmids are capable of autonomous replication meaning
Single plasmid molecule within a bacterial cell may cause itself to be replicated into many copies
Conjugation
Plasmids also orchestrate bacterial exchange of genetic information
Many cocci / one coccus
Round bacteria
Many bacilli / one bacillus
Rod-shaped bacteria
Many spirochetes or spirilla / one spirochete or spirillum
Spiral-shaped bacteria
Bacterial cell wall is composed of
Peptidoglycan which is cross-linked chains made of sugars and AA including D-alanine (not found in animal cells)
Protoplast
Osmotically fragile structure created by the lysozyme tearing the bacterial cell wall
Gram staining
Method of classification based on which bacteria turn color
Two groupings in gram staining:
Gram positive, stain a strong dark purple
Gram negative, stain a weak light pink color
Gram positive bacteria have a
Thick peptidoglycan layer (cell wall) outside the cell membrane and no layer beyond this
Gram negative bacteria have a
Thinner peptidoglycan layer (cell wall) but have an additional outer layer containing lipopolysaccharide
Periplasmic space
Intermediate layer between the cell membrane and cell wall in gram negative bacteria
Found here are enzymes that degrade antibiotics
Increased protection from environment is cause for weak staining
Capsule / glycocalyx
Sticky layer of polysaccharide “goo” surrounding the cell and often an entire colony of bacteria
Makes it harder for the immune system to eradicate bacteria and enables bacteria to stick to smooth surfaces
Flagella
Bacteria mobility, only meaning of locomotion
Motile
Bacteria with one or more flagella
Monotrichous
Flagella are only on one end
Amphitrichous
Flagella located on both ends
Peritrichous
Multiple flagella
Three components of flagella
Filament, hook and basal structure
Basal structure of flagella function
Anchor flagella and rotate the rod/flagellum
Most important thing to remember about the prokaryotic flagella is that its structure is
different from the eukaryotic one
Pili
Long projections on the bacterial surface involved in attaching to different surfaces
Sex pilus
Attaching F+ (male) and F- (Female) bacteria which facilitated formation of conjugated bridges
Fimbriae
Smaller structures not involved in locomotion or conjugation but involved in adhering to surfaces