Microbiology Answers

why was the belief in spontaneous generation consider as an obstacle to the development of microbiology as a scientific discipline

1.    Compare between the structure of the ribosomes in prokaryotic and eukaryotic cells? (1 point):  

2. Explain how exo-enzymes produced by bacteria which digest different macro-molecules in the surrounding environment, won’t digest these molecules inside the bacterial cells? (1 point):  

3. In the peptidoglycan layer of bacterial cells: give a reason why the tetrapeptide side chain is only binding to the NAM molecule and not to the NAG?

4.   Two types of prokaryotic cells can be distinguished: bacteria and archaea. How do these cells differ from each other? Compare their cell wall structure, patterns of cytoplasmic membranes and ribosomal entities and 16S-rRNA? (1.5 points): 

5.Compare between the structure of cell wall in prokaryotic and eukaryotic cells?

a.    Determine the number of individuals in the original population of hamsters that are heterozygous for coat colour. Show all steps used to determine your answer. (3 marks)

b.    How many individuals in the original population of hamsters possess a pink coat colour? (1 mark)

c.     Determine whether evolution has taken place from the original generation to the new generation. Show all steps used to determine your answer. (3 marks)

For the cell to function, a greater amount of ATP is needed. The breakage of ATP to release energy is through hydrolysis, a process of breaking the chemical bonds using water. How does this affect your everyday intake of water?

Let R(t) be exponentially decaying with decimal reduction time D = 30 min.  

How long does it take for R(t) to decay from 10⁷ to 10³?

A group of researchers at the U.S. Department of Agriculture isolate a new bacterium

from the lungs and lymph nodes of several young horses that became ill and died at a

local stable. Prior to death, their symptoms included disorientation and loss of motor

function, so the researchers suspected central nervous system involvement, which was

confirmed by the observation of brain lesions in the dead animals. Based on 16S rRNA

comparisons, the bacterium was distantly related to Neisseria meningitidis, and they

subsequently named it Neisseria equiniae. The researchers believe that N. equiniae may

be responsible for the brain lesions observed in a small percentage of older horses that die

of apparent dementia. What four criteria must be satisfied in order for the researchers to

prove that the brain lesions in these older horses are caused by N. equiniae? Provide at

least three modern molecular experiments that could be performed to satisfy these

criteria.

1.      70-75% ethanol is the most common disinfectant/sterilizing-sanitizing agent used in a microbiology laboratory. Explain why 70-75% ethanol is more effective than 95-99% ethanol. (5 marks).

2.      List TWO GLPs and discuss its importance. (5 marks).

3.      Why should Good Laboratory Practices be followed strictly? State TWO reasons. (5 marks).

4.What does ISO stand for? What is its significance? 

  From personal online research, list the MICROBIOLOGICAL STANDARDS OF QUALITY for the following (provide references); (16 marks).

-         Potable mineral water

-         Bottled water

-         Non-pasteurized milk

-         Pasteurized milk

-         Ice Cream

-         Edible Ice

-         Powdered Formulae for Infants

-         Ready to eat spices

70-75% ethanol is the most common disinfectant/sterilizing-sanitizing agent used in a microbiology laboratory. Explain why 70-75% ethanol is more effective than 95-99% ethanol. 

Explain the process of or the steps involved in retroviral replication.