Erstellt von J yadonknow
vor fast 7 Jahre
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Frage | Antworten |
What is the size range of prokaryotes? | 0.2um to >700um |
What is the size range of eukaryotic cells? | 10um to >200um |
What are the advantages of being small? | Large SA:V Faster nutrient exchange per unit cell volume Grow faster Can support a large population Faster evolution more cellular divisions = higher rate of mutations within a population Allows rapid adaptation to changing environments |
What are the limitations to being small? | Must fit all essential organelles and materials inside 0.15um diameter to fit all organelles Anything less than 0.1um is unlikely to be a cell |
Describe briefly the process of gram staining | CV Iodine Ludol's reagant saffranin |
What are endospores? | Highly differential cells that are resistant to heat/harsh chemicals/radiation Survival structures |
Describe the process of sporulation | Essential nutrient is exhausted Vegetative cell stops growing Endospore develops within the vegetative cell and is released as a mature endospore Germinates when conditions are favourable to form a vegetative cell |
What names relate to the differing stages of endospore development within a vegetative cell? | Terminal Sub-terminal central |
What is the structure of an endospore? (5) | Many layers = protection Exosporium - thin protein covering Spore coat - layers of spore specific proteins Cortex - loose cross-linked murein Core - everything else |
Function of fimbriae (2) | Let cells adhere to surfaces and each other Assist in disease process |
Function of pili (2) | Conjugation Adhesion of pathogen to specific host tissues |
How to visualise pili | E microscope coated in virus particles |
What is polar flagellation? | Flagella attached to one or both ends of an MO |
What is tuft flagellation? | Group of flagella attached to one end type of polar |
What is peritrichous flagellation? | Multiple locations |
Describe flagella | Helical filaments composed of many flagellin copies, wavelengths are characteristic of species |
What is the motor? | The central rod embedded in the cell membrane that passes through a series of rings, with Mot proteins acting as stators |
Where does the energy for rotation come from? | Movement of H+ across membrane through mot complex |
MOA (3) | H+ flow -> channel Exert ES<3 on helically arranged charges of ring <3 btw. charges causes rotation |
Describe the movement control of peritrichous cells | CCW rotation Tumbles when switching to CW, flagella push apart Flagella bundle and rotate CCW |
Methods of polar movement (2) | Reversible flagella rotation Unidirectional rotation |
Describe gliding | PS slime used to connect cell surf w/ solid surf. As slime adheres to surface cell pulled along |
Which pili facilitate this type of movement? | Type IV twitching motility pili |
What is the life cycle of myxobacteria? (5) | Sporangioles Myxospores Aggregation of veg cells Mound Fruiting body |
MOA (6) | 1. Sporangioles release myxospores 2. Myxospores germinate to veg cells 3. Veg cells swarm, pick up each other's slime trails to form aggregates 4. Agg. heap to form mound 5. Mounds of MXB diff. into mature fruiting body 6. Myxospores produced w/in sporangioles |
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