Cell Morphology Flashcards
What are the two most common shapes of bacterial cells?
Bacillus (rod) or coccus (round)
Why is cell shape not a good indicator of species?
Most bacteria are one of two shapes. Less common shapes are better species indicators
How can a cell be cube shaped?
Found in cells that live in extremely high salt concentrations. The salt interacts with the membrane to make a cube
What dictates the shape of a cell?
The cell wall
Why is it hard for a cell to change shape?
The cell wall is too rigid to allow the flexibility needed for shape changing
How small are bacteria compared to eukaryotic cells?
10-100X smaller
Why are bacterial cells so small?
Have a higher surface area to volume ratio
Why is having high surface area a good thing?
Allows efficient exchange of materials with the environment
What is the problem with having a larger volume?
Harder to transport stuff around inside the cell, diffusion doesn’t work well
Why do small cells grow faster than large cells?
They have a higher surface area and have more efficient nutrient exchange, so they reach the size where they divide faster than large cells
Why do small cells evolve faster than large cells?
They divide more often, so they have more DNA replication errors and random mutations
How are Epulopiscium cells able to get so big?
They live in the guts of sturgeonfish, which is a relatively steady environment. To solve the problem of protein diffusion, they have 40 000 copies of their chromosome arranged around the outside of the cell. They also have a highly folded membrane to increase surface area
