26. Prokaryotes

Using the figure below, describe the stages that may have led to the origin of life.

Unlike plant cell walls that contain cellulose, bacterial cell walls are composed of          .

Which of the following correctly describe the fermentation pathway? Select True or False for each statement. T/F It includes a reaction that oxidizes NADH to NAD+. T/F It synthesizes ATP by substrate-level phosphorylation. T/F It includes a reaction that reduces NAD+ to NADH. T/F It synthesizes electron acceptors, so that cellular respiration can continue.

Researchers examined the relationship between gut microbiomes and depression. To do so, they collected fecal samples from people with depression and also a control group of individuals with no signs of depression. They then performed a fecal microbiota transfer (FMT) by adding the samples to rats that had no gut microbiota and examined behaviors associated with depression and anxiety as well as species of bacteria that ended up growing in the rats’ guts. The results are presented below. Graph (a) shows the rats’ interest in a pleasurable experience (drinking sugar water). Graph (b) shows the amount of time rats spent out in the open versus along the edge of an area (a sign of anxiety). Graph (c) shows the number of species observed in rats after FMT.

Patients from the depression group had relatively high levels of bacteria in the genus Paraprevotella (a Gram-negative bacterium) relative to the control group of patients. Which of the following is a structural difference between Paraprevotella and methicillin-resistant Staphylococcus aureus (MRSA), a Gram-positive bacterium?

a. Paraprevotella contains a thick layer of peptidoglycan in its cell wall and MRSA lacks peptidoglycan.

b. The plasma membrane of Paraprevotella is surrounded by a cell wall that contains a relatively thin layer of peptidoglycan and an outer membrane and MRSA cells are surrounded by cell walls with a relatively thick layer of peptidoglycan,

c. Paraprevotella produces endospores but MRSA does not.

d. Paraprevotella lacks a plasma membrane but MRSA cells are surrounded by two plasma membranes.

Which is (are) true concerning the cell wall of prokaryotes?

The peptidoglycan molecule is responsible for the:

The Gram stain works because of differences in the ________ of bacteria.

What is the function of the glycocalyx in bacterial cells?

__________ is the slime-like layer of polysaccharides on the outer surface of bacterial cells.

___________ are an organized layer of polysaccharides tightly anchored to the cell wall.

Which of the following is not a function of slime layers and capsules:

Which of these are true about pili?

The presence of fimbriae on a bacterial cell is most likely to have a critical role in

Endospores are:

Formation of endospores _________.

What 2 bacterial genera produce endospores?