Chapter 2: Microbial Cell Structure and Function Flashcards
What can you conclude if you Gram stain an archaeal cell and it turns pink (the color of safranin)?
The primary stain was washed out, but the cell does not have a gram-positive or gram-negative cell wall.
As you add solute and measure the rate at which a charged solute enter a cell, you notice that the rate of solute entry continues to rise and does not follow the expected curves for high-affinity transporters, low-affinity transporters, or simple diffusion. Why is this happening?
Both high- and low-affinity transporters can transport the solute.
Modern endosymbiotic theory proposes that eukaryotic cells arose from ______________
a bacterial cell taking up residence within an archaeal cell
How are photosynthetic cyanobacteria able to function?
They must have the necessary enzymes and membranes for the reactions of photosynthesis to take place.
Which of the following is true about bacterial, archaeal, and eukaryl flagella?
These flagella are all different.
You are handed a slide and see pale ovals surrounding darkly colored bacterial cells. What are these structures?
Capsules
Why is LPS often injected into animals to stimulate an immune response to study the immune system?
LPS is a virulence factor and mimics a bacterial infection, causing an immune response.
Why are infections caused by “Streptococcus pneumoniae” bacteria with capsules often more severe than those cause by “S. Pneumoniae” without capsules?
The capsule covers the bacterial cell wall and protects it from recognition by the immune system.
At which stage of endospore formation does the bacterium sense that the environment is becoming inhospitable?
The cell leaves the vegetative cycle and undergoes an asymmetric cell division.
If a researcher examining cell components finds evidence of dipicolinic acid in a bacterial cell, what can be concluded?
The cell is experiencing harsh conditions.
If you find a bacterial cell that lacks pili, what can you deduce about it?
It is gram-positive.
The hydrophobic portion of a bacterial plasma membrane consists of______________.
fatty acid tails
Why do charged molecules and ions have difficulty crossing the plasma membrane?
They are stopped by the hydrophobic region.
What type of flagella extend in a tuft from one side of a bacterial cell?
Polar and lophotrichous
Transport proteins generally _____________________
transport a specific substrate
