Various species of bacteria were inoculated into tubes of agar, the lids were lightly attached, and then incubated at 37°C for 24 hours.  The results are shown in the figure below:

(i)   For tubes A-E above, classify these bacteria in terms of their oxygen utilisation (e.g. aerobes/anaerobes)?     (5 mark)

(ii)  Referring to microbial metabolic processes, explain how does each bacterium (in A-E above) generate energy?     (6 marks)

A particular bacterium can grow with and without oxygen:

a) What type of metabolism does it mainly depend on. 

b) List/draw out all the possible growth patterns that this bacteria might have. 

Barry is a student beginning his Honours year and needs to decide how to conduct a preliminary experiment on differentiating different strains of bacteria in a clinical sample.

a. What kind of media should Barry grow his cultures on? Include a rationale for your choice. (2)

b. Suggest a simple method of how Barry should separate strains of bacteria and produce pure cultures to study in this sample. (3)

c. Barry used a Gram stain to stain two distinctly different cultures in his pure incubated samples. Under the microscope one culture is pink whilst the other is purple; what does this indicate for Barry’s cultures, why does the same stain stain differently? (1+3)

You are going to participate in a national academic competition. This competition involves a simulated game called Bacteria War. You are required to design a new bacteria cell which exhibits the highest infection capacity.

a) Draw and label the significant structural features of the new bacteria cell : cell shape, cell wall, one additional cytoplasmic structure.

b) What microscopy techniques are employed to examine bacterial samples and distinguish between morphological characteristics like Gram-positive and Gram-negative? Additionally, provide a brief overview of the selected method's procedural steps.

c) When you are using the microscope, your lab partner suggests the resolution of the microscope and refraction of light should be aware of. Distinguish between resolution and refraction.

You and your lab partner accidentally discovered a new species of bacteria. Good job, future Nobel Prize winners!

a.  You have decided to name it “sciencerus. Pharmacoccus” according to its species and genus. Is the name correct according to the naming conventions of bacteria, if not how would you change it?    (1 mark)

b.  You hypothesised that this bacteria can act as an intracellular pathogen in the infected host, which type of immune response do you think would be activated in order to remove the pathogen?   (2 marks)

c.  This bacteria is getting out of control and will soon infect the whole school! List one physical method and one chemical method that will kill the bacteria on experiment equipment.  (2 marks)

d.  Oh no, your hypothesis is wrong! It is an extracellular pathogen. Unfortunately, you have been infected with the bacteria. The symptom is fever and that you drool excessively in your sleep. Luckily, you are healed after 6 days, thanks to your adaptive immune system. Describe (or draw) the process in which your adaptive immune cells kill this bacteria, include key effector cells.  (5 marks)

How are antigens presented in the adaptive immune response, and why is this process crucial?

You have the flu (influenza) and a friend suggests you take antibiotics to make you better.

a)  Would this be a good idea, explain your reasoning? (2 marks)

b)  What are two undesirable, but likely, outcomes of following your friend's advice? (2 marks)

Normally, bacteria reproduce by the process of binary fission, however, some bacteria reproduce via budding. Briefly explain the differences between these two processes.

You are investigating an unknown bacteria, you find it is susceptible to penicillin and appears pink after a Gram stain is performed.

a)  Do you think these results were expected?  Give a brief rationale to explain your choice.  (4 marks) 

b)  Given your suggested cause in part a, what  would your next step be? (1 mark)