Cellular Characteristics + Prokaryotes Flashcards
Cellular characteristics can be classified as ______ or _______
Prokaryotes & eukaryotes
All cellular characteristis include plasma membrane, cytoplam, ______, ______
Nucleic acid, ribosomes
Maintain cell shape
Allows substance in/out
Plasma membrane function
Phospholipid
Proteins
Plasma membrane consits
One head
- hydrophillic
- polar
Phospholpid head
Two fatty acid tails
- hydrophobic
- non-polar
Phospholipid tails
2 layers of phospholipids (bilayer)
Heads on edges
Tails face inwards
Phospholipids in plamsa membrane
Plasma membrane has permeability (selective)
Size
-small molecules pass more easily
Hydrophobic molecules pass more easily
Lipid solubility
Uncharged molecules pass more easily
Charge permeability
At surface of membrane not inserted into hydrophobic tails
Peripheral proteins
Integrated into membrane interested into hydrophobic tails
Intergal protein
Postionting:
- can extend only part way into membrane
- can extend across entire membrane
Intergal protein
High concentration -> low concentration
No energy input required
Passive proccess
Low concentration -> high concentration
Energy input required
Active process
Simple diff. Facilitated diff. Osmosis are ______ process
Passive
High concentration -> low concentration
Directly through membrane
-doesnt involve integral membrane proteins
Simple diffusion
High concentration -> low concentration through intergal membrane proteins (transporter proteins)
Facilitated diffusion
Form channels
Non-specific
Channel protein
Bind molecule->change shape
Specific
Carrier proteins
- Movement of water across membrane from high concentration of water -> low concentration water
- water moves to high concentration of solutes
- water can cross directly or use aquaporins
Osmosis
Channels that allow water to quickly cross membrane
Aquaporins
Ability of a solution to make water move into or out of a cell via osmosis
Tonicity
Solute concentration is the same inside and
outside cell
-Water moves equally into and out of cell
Isotonic solution
Solute concentration is greater outside the cell
-Water moves out of cell -> plasmolysis (shriveling of cytoplasm)
Hypertonic solution
-Solute concentration is less outside the cell -Water moves into cell -> lysis (cell bursts)
Hypotonic solution
Low to high concentration
-Require energy (ATP)
Active process
Molecule isn’t altered
-In prokaryotes and eukaryotes
Group translocation
Molecule is altered
-In prokaryotes only
Group translocation
Inside plasma membrane
-Mostly water
Cytoplasm
Include DNA and RNA
Differs in prokaryotes and eukaryotes
Nucleic acid
Site of protein synthesis
- Composed of proteins + ribosomal RNA (rRNA)
- Differs in prokaryotes and eukaryotes
Ribosomes
Before
Pro
Karyo
Nucleus
- Before nucleus developed
- Include bacteria and archaea
Prokaryotes
Flagella/Archaella
- Fimbriae/pili
- Axial filaments
- Glycocalyx
Prokaryotic cell wall
Long appendages that propel some bacteria
Bacterial flagella
Function: motility
Bacterial flagella
Self-directed movement of an organism
Motility
One flagellum
Monotirchous
Multiple flagella at one end
Lophotrichous
Flagella at both ends
Amphitrichous
Flagella surround entire cell
Peritrichous
No flagella
Atrichous
Filament of bacterial flagellum
Outermost region
Filament composed od
Flagellin, hollow inside
Bacterial flagellum hook
Links filament to basal body
Basal body of bacterial flagellum
Anchors flaguellum to cell wall and plamsa membrane
Results from rotation of basal body
Rings of basal body rotate -> filament spins
Movement of Bacterial flagella
Bacteria swim in stright line
Flagella rotate counter-clockwise
Motility is Run
Bacteria turn in random manner
Flagella rotate clockwise
Tumble
Movement toward/away from a substance
Taxis
movement toward a substance (attractant)
-Many runs, few tumbles
Positive taxis
movement away from a substance (repellent)
-Frequency of tumbles increases
Negative taxis
Movement toward/away from chemicals
Chemotaxis
On motile Function: motility Rotate like flagella Differences from bacterial flagella: \_\_\_\_\_\_ are thinner Consist of archaellins Solid
Archaella
Short, thin, proteinaceous appendages
Many per cell
Function: mediate attachment to surfaces
Fimbriae
Usually longer than fimbriae
1 or 2 per cell
Functions: motility and DNA transfer
Pili
Found in spirochetes
-Spirochete: type of spiral bacteria
-Contain outer sheath (outside cell wall)
Located between outer sheath and cell wall
Function: motility
Axial filaments
Sticky, gelatinous substance outside cell wall
Composed of polysaccharides, proteins, or both
Glycocalyx
organized and firmly attached to the cell wall
-Composed of uncharged polysaccharides
Glycocalyx capsule
unorganized and easily removed from the cell
wall
Slime layer
helps cells in a biofilm attach to a surface/each other
Glycocalyx extracellular polymeric substance
Degree of oathogenicity
Virulence
-Prevent desiccation
-Adhere to surfaces -> attach and cause
infection
-Resist phagocytosis
-Nutritional reserve
The capsules increase bacterial virulence
- Surrounds plasma membrane
- Composed of peptidoglycan
- Basis for differentiating Gram-positive from Gram- negative bacteria
Bacterial cell wall
Space between plamsa membrane and cell wall
Gram positive bacteria
Space between plasma membrane and outer membrane
Gram -negative bacteria
No cell wall
No defined shape
Mycoplasma
Cell wall contains mycolic acid
Mycolic acid prevent:
Desiccation
Digestion after phagocytosis
Acid fast bacteria
Atypical cell wall include ______ species
Mycobacterium and nocardia
Composition of primary phospholipids & proteins
Prokaryote plasma membrane
Nucleoid, ribosome, inclusions
Prokaryotic cytoplasm
Where bacterial DNA is stored
-not surrouunded by a nuclear membrane
Nucleoid
Single circular chromsome
Bacterial DNa structure
Function: protein synthesis -70S -Composed of 2 subunits 50S subunit 30S subunit
Prokaryotic ribosomes
glycogen and starch storage
Polysaccharide granules
Lipid storage
Lipid inclusions
Sulfur storage
Sulfur granules
Formed by some bacteria (Bacillus and Clostridium)
-Actively metabolizing cells: vegetative cells -______: dormant state—not actively metabolizing -Highly durable
-Coat composed of keratin and calcium diplocholinate
Formed via sporogenesis
Triggered by harsh conditions
Endospores
- When environment improves, endospore will
_____ back into vegetative body - Layers surrounding endospore are broken down,water enters, metabolism resumes
- One endospore germinates back into one vegetative body
- Doesn’t increase the number of cells
Emdospore Germination