Lab 8 - Cell Motility Flashcards
What is Brownian Movement?
An oscillating motion caused by the molecules in the surrounding liquid media hitting the organism
What is “True Motility”?
Directed movement by an organism
Define Chemotaxis, Phototaxis, and Aerotaxis?
Movement that occurs in response to a chemical or light stimulant or [O2]
What is the purpose of the cytoskeleton?
Gives cells, internal organization, shape, and capacity to move.
What are 5 main descriptors of microtubules?
- long and hollow
- Cylindrical
- The largest type of cytoskeleton filament
- Rigid compared to other 2
- Made up of tubulin subunits
When do microtubules usually form?
During cell division as a part of the mitotic spindle
What are 4 descriptors for Microfilaments/Actin filaments?
- Made of Actin monomers
- the smallest of the cytoskeleton filaments
- helical
- flexible
Where are Microfilaments/Actin filaments found?
Everywhere! But especially cortex under the plasma membrane»_space; This means that it’s key to cell motility in pseudo pods
What are 2 main descriptors for Intermediate filaments?
- Rope like
- Most stable
Where are intermediate filaments found?
- inner nuclear membrane
- extends across the cytoplasm
How does the cytoskeleton play a role in the lung disease?
People with lung disease have neutrophils that are unable to change in shape and squeeze through capillaries; this is due to changes in the actin filament/microfilament that causes ruffling
What is cytoplasmic streaming?
The circular flow of cytoplasm within a cell; speeds up the distribution of materials and movement of organelles
What is difference between ectoplasm and endoplasm?
Ectoplasm: viscous & peripheral
Endoplasm: fluid & internal
How do pseudopods extend and contract?
Through the assembly or disassembly of actin subunits into actin filaments/ microfilaments, and microfilaments into networks that convert from soluble like endoplasm to gel like ectoplasm.
What are the 3 colour states of Congo Red?
- Orange-red: pH greater than 5»_space; Basic
- Purple: pH between 3-5
- Blue: pH lower than 3»_space; Acidic
Describe the colour changes the yeast cells goes through as it’s digested by the paramecium
Yeast enters oral groove (orange-red), formation of food vacuole occurs (orange-red), Cytoplasmic streaming moves food vacuole and lysosome toward each other (orange-red), Food vacuole and lysosome fuse and digestion occurs (blue), the digestion vacuole fuses with the anal pore to excrete waste (blue)
Provide an explanation for the colour changes that you see in paramecium digesting yeast that has been treated with Congo Red.
Initially the yeast cell is basic, as indicated by the orange-red of the pH indicator. It’s not until the yeast cell within a food vacuole fuses with a lysosome that the yeast cell turns from orange-red to blue. This indicates that the pH within the lysosome is lower than 3. This is because the lysosome is full of acid hydrolases that are necessary for digestion and happen to be acidic. When the yeast cell turns blue, digestion must be occurring.
What is a power-stroke?
When the stalk is rigid but bending at the base causes movement
What is an axoneme?
The 9+2 array of microtubules
Define the Sliding Microtubule Model?
Explains how energized motor proteins make the 9+2 doublets slide in sequence, and because there are restrictions and spokes linking them, this motion of unified sliding is converted into a bending motion.
Tldr; energized motor proteins make 9+2 microtubules slide in sequence, bc of restrictions the unified sliding causes a bending motion and then relaxes = movement
Describe the parts that make up bacterial flagella, starting from the plasma membrane
Plasma membrane, Basal body: S-ring, rod, P-ring, Outer membrane, L-ring, Hook, Filament
What are the 4 arrangements of Flagella?
The kid has a Balloon (Polar/Monotrichous) that flies away, kid gets Candy (Amphitrichous), kid Unwraps candy (Lophotrichous), kid Drops candy (Petritrichous)
How does redox potential indicator demonstrate movement of a microorganism through a medium?
As bacteria grow in the media, they take up the dye and reduce it with dehydrogenase enzymes, turning the colourless redox potential indicator red and insoluble. therefore red will only be present where the bacteria is present and since it’s water insoluble it creates a sort of trail that we can follow of the bacterias movement.
Is E coli or Staph motile?
E coli is.
How do microfilaments aid ameboid movement?
- microfilaments interact with myosin at the cells trailing end
- this action pushes the endoplasm up into the pseudopod moving the cell forward
