Alanna was cleaning out her pantry and opened a jar of jam to find a strange odour and a white-ish substance growing on top of the jam. Alanna thinks the jam has been contaminated by a bacterium. Which type of extremophile is likely to be the one responsible for the growth on top of the jam? 

A.   Psychrophile

B.   Thermophile

C.   Alkaliphile

D.   Halophile

(i)   Which response (A-D) is the best choice? (1 mark)

(ii)  Briefly explain your reasoning for your choice (2 marks)

Which bacterial gene transfer process is most sensitive to extracellular nucleases?

A.   Transduction

B.   Conjugation

C.   Transformation

D.   Recombination

(i)   Which response (A-D) is the best choice? (1 mark)

(ii)  Briefly explain your reasoning for your choice (2 marks)

Some species of Bacteria are susceptible to the antibiotic penicillin whereas Fungi are not. Which one of the following is the best explanation for this?

A.   Fungi do not have a cell wall.

B.   Fungi are structurally different to bacteria, making penicillins ineffective. 

C.   Fungi do not have specialised structures such as flagella.

D.   Fungi are not pathogens and thus antibiotics are not designed to target them.

(i)  Which response (A-D) is the best explanation? (1 mark)

(ii ) Briefly explain your reasoning for your choice (2 marks)

The genes a bacterium uses to produce the amino acid arginine form part of the arg operon.  In this operon, when arginine binds to the repressor protein, transcription of the structural genes of the arg operon is blocked.  What type of operon is the arg operon?

A.   An inducible operon

B.   A repressible operon

C.   A catabolite operon

D.   The genes are constitutively expressed

 (i)   Which response (A-D) is the best choice? (1 mark)

(ii)  Briefly explain your reasoning for your choice (2 marks)

You are performing a Gram stain on an unknown bacterium.  You proudly show your pink bacilli to your facilitator who sadly shakes her head and says they should have been purple.  Which one of the following is the best explanation for where you went wrong?

A.   You forgot to add the carbol fuschin

B.   You forgot to add the iodine

C.   You skipped the alcohol decolourisation step

D.   You didn’t fix your cells to the slide before staining

(i)   Which response (A-D) is the best choice? (1 mark)

(ii)  Briefly explain your reasoning for your choice (2 marks)

You wish to view a live bacterial cell that contains no natural pigments or fluorophores.  Which one of the following would be the most appropriate microscope for this task?

A.    A bright field microscope

B.    A phase contrast microscope  

C.    A fluorescent microscope

D.    An oil immersion microscope

(i)  Which response (A-D) is the best choice? (1 mark)

(ii ) Briefly explain your reasoning for your choice (2 marks)

Early investigators conducted experiments to seemingly demonstrate the theory of “spontaneous generation”.  Which one of the following best explains the apparent success of these experiments?

A.  Oxygen was available in the system

B.  Mild heat was applied to the system

C.  The food source was able to support life

D.  Microorganisms were already present

(i)  Which response (A-D) is the best explanation? (1 mark)

(ii ) Briefly explain your reasoning for your choice (2 marks)

Streptococcus pneumoniae (pneumococcal pneumonia) is one of the most common causes of bacterial pneumonia.  S. pneumoniae is a Gram-positive, encapsulated coccus that grows in short chains.  It is commonly treated in both children and adults with the β-lactam antibiotic amoxicillin.  Briefly describe how amoxicillin targets this bacterium and rleate this to whether it has a bactericidal or bacteriostatic effect.       (3 marks)

There are three common mechanisms of horizontal gene transfer used by bacteria:

• Conjugation
• Transformation 
• Transduction 

A.  Give one contrasting or unique feature for each of the above three mechanisms of horizontal gene transfer.     (3 marks)

B.  A very small number of bacteria are considered to be naturally competent or transformable.  Which feature of these bacteria makes them "transformable"?     (1 mark)

C.  When genetic material is transferred from one bacterium to another, there are three possible fates for the transferred DNA.  Choose one of those fates and briefly explain the outcome in terms of the recipient cell.       (1 + 2 marks)

There are 4 major classes of antimicrobial resistance mechanisms employed by bacteria:

1. Drug target modification
2. Drug molecule modification
3. Altered permeability / efflux
4. Metabolic bypass

Nalidixic acid is an antibiotic that inhibits enzymes involved in the DNA replication process. Some strains of Pseudomonas aeruginosa are resistant to nalidixic acid and have been shown to have lower intracellular concentrations of the antibiotic when compared with sensitive strains. Which ONE of the following most likely explains the mechanism of resistance of P. aeruginosa to nalidixic acid?