Exam 2: Microbial Cell Structure and Function

Explain why prokaryotes tend to survive and adapt more rapidly to extreme and dynamic environmental conditions than eukaryotes.

Elaborate on why discovering endospores was important to microbiology.

Photoreceptors are analogous to chemoreceptors in that they are both proteinaceous sensors.

Mitochondria and hydrogenosomes are similar in that they both

You are studying swimming motility in a pathogenic bacillus. You create mutations in random genes and then test which mutations effect swimming motility by looking at the mutant cells under the microscope. One of the mutant bacteria cannot swim anymore, but still rotates around in one spot when you watch them. Using electron microscopy you discover that some parts of the flagella are still present in the cell wall, but no long flagella are visible. Which gene do you think is mutated (i.e., missing) and which motility-related parts are still present in this mutant?

The cell wall of a Gram-positive bacterium is composed of a thick ________ layer.

You have discovered a new microorganism and would like to classify it as a eukaryote or a prokaryote. To investigate this question you prepare a slide with a simple stain and view it with a light microscope with a 40X objective lens and 10X ocular lens. You also prepare a control slide using Saccharomyces cerevisiae (a unicellular eukaryote). You can see the cells on your control slide, but you don't see cells when you look at your unknown microorganism. What can you conclude from this experiment?

The terms "run" and "tumble" are generally associated with

Which is/are a function(s) of the cytoplasmic membrane in prokaryotes?

The cytoplasmic membrane could best be described as

You are given an electron micrograph of a bacterial cell. In the micrograph you can clearly see three thin layers of different densities surrounding the cell. Based on the micrograph, you can infer that this cell is ________ and would appear ________ after application of the Gram stain procedure.

Antibiotics such as penicillin interfere with the ability of bacteria to synthesize cell walls. Explain why cell walls are a good target for a useful antibiotic and whether you think that penicillin would be effective against a bacterial cell in an isotonic environment.

In general, lipids in archaeal cytoplasmic membranes lack true fatty acids.

Compare and contrast the chemical composition and structure of the cytoplasmic membranes found in Bacteria and Archaea. What is the advantage of the archaeal membranes in relationship to the types of environments archaea may inhabit?

Lysozyme is an enzyme that can ultimately lyse and kill eukaryotic cells by breaking β-1, 4-glycosidic bonds in peptidoglycan.

When does endospore formation commence?

While examining cellular material, you find that organelle DNA is present. What organelle(s) must be within the sample?

Viewing the shape of a bacterial or archaeal cell using a microscope gives a great deal of information about the metabolism and lifestyle of the organism.

Explain why a eukaryotic cell needs membrane-enclosed lysosomes and peroxisomes.

Actin is found within ________.