16 Questions
What type of molecules can move freely across the cytoplasmic membrane of bacterial cells?
Small uncharged, non-polar molecules
What is the net movement of a chemical down its concentration gradient called?
Diffusion
Which type of transport requires energy for molecules to enter the bacterial cell?
Active transport
What type of molecules is the cytoplasmic membrane essentially impermeable to?
Large/charged molecules
What is the main source of potential energy for diffusion?
Concentration gradient
What represents the diffusion of water through a selectively permeable membrane along its concentration gradient?
Osmosis
Which type of transport allows the diffusion of molecules across the membrane via a membrane protein that acts as a channel?
Facilitated diffusion
What provides the energy for transporting a molecule against its concentration gradient in active transport?
Stored chemical energy or dissipation of another concentration gradient
What type of transport uses the energy stored in chemical gradients, often the proton motive force, to power the transport of a different molecule against its gradient?
Symport
What is the main function of a sodium-proton antiporter?
pH and Na+ homeostasis
What is the purpose of the Lac permease symporter?
To drive the uptake of lactose and some related disaccharides into the cell
What happens to the transported substance in group translocation?
It is bound by a transporter and chemically modified during transport
What powers the transport of substances across the cytoplasmic membrane in ATP binding cassette (ABC) transporters?
ATP
Where are prokaryotic ABC transporters best studied?
Gram-negative bacteria
What type of protein binds vitamin B12 with high affinity and transports it across the outer membrane using energy from the TonB complex?
OM barrel protein BtuB
What is the classic example of group translocation?
Glucose uptake using the phosphotransferase system
Test your knowledge of transport mechanisms in bacterial cells with this quiz. Explore how nutrients and molecules enter bacterial cells through the cytoplasmic membrane and gain a deeper understanding of the gatekeeping role it plays in cellular processes.
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