Question

PLEASE answer all parts

These questions pertain to microbiology

a.) What is the natural role of transglycosylases in bacterial cells? (be specific)

b.) What are the major products of glucose breakdown via glycolysis? (glycolysis only)

c.) FADH2 is made during which stage of cellular respiration? (just need name)

d.) Imagine that you are working with a new species of bacteria that divides every 3 hours. If you started will 100 cells, how many cells would you end up with after one full day?

e.) Despite being primarily composed of sugar, maple syrup can be stored at room temp for a long time without any apparent microbial growth. Describe the cellular basis for this observation. What would happen if normal bacteria fell into it? (I think this has something to do with a hyper/hypotonic solution but I'm not sure)

f.) Imagine that you are working as an environmental microbiologist. Over 100 people who recently went to the beach in the town where you work have become sick and you think it is due to elevated levels of bacteria in the ocean water. Describe the most accurate and sensitive method by which to determine the actual bacteria concentration in the water.

g.) Describe the oxygen requirements of a facultative anaerobe.

h.) Where do autotrophs get their carbon from? (what type of molecule?)

i.) What is the difference between substrate-level and oxidative phosphorylation in terms of how ATP is produced?

j.) Describe how a spectrophotometer is used to measure bacterial growth.

Answer 1

a) The function of transglycolase enzyme in bacteria is to join peptidoglycan monomers (NAG-NAM) to form chains which are further cross-linked by transpeptidase enzyme to provide strength to the cell wall and enable the bacterium to resist osmotic lysis. Rather more specifically, transglycosylase is responsible for the attachment of hydroxyl group of the GlcNAc (NAG: N-acetylglucosamine) to the MurNAc (NAM: N-acetylmuramic acid) in the glycan, which will displace the lipid-PP from the glycan chain leading to growth of peptidoglycan chain which forms the cell wall of bacteria.

b) Glucose breakdown via glycolysis leads to formation of 2 molecules of pyruvate, 2 net ATP molecules, and 2 NADH molecules for every molecule of glucose that undergoes through the reaction. The overall glycolytic reaction is given as below:

Glucose + 2 NAD⁺+ 2 ADP + 2 P_i → 2 Pyruvate + 2 NADH + 2 H⁺ + 2 ATP + 2 H₂O.

c) FADH2 is made during kreb's cycle in cellular respiration during conversion of succinate to fumarate by the enzyme succinate dehydrogenase which is an inner mitochondrial membrane enzyme and is also the entry point for FADH2 to electron transport chain.

d) Bacterial growth is given by the formula: N_t = N₀2ⁿ, where n = number of generations.

In the given question, it is stated that the generation time is 3 hours, thus the total number of generations during 24 hours will be 24/3 = 8 generations. Also, N₀ = 100 cells , i.e., the starting population, hence, the number of bacterial cells after 24 hours will be:

N₂₄ = 100 x 2⁸ = 25,600 cells = 2.5 x 10⁴ bacterial cells.