In: Biology
1. What would be the power of magnification when using a microscope with a 10x ocular lens and a 45x objective lens?
10x
45x
55x
450x
35x
2. A Petri dish containing isolated colonies of Staphylococcus
aureus, Escherichia coli, and Pseudomonas
aeruginosa would be described as being
a pure culture.
a mixed culture.
a contaminated culture.
an axenic culture.
3. What type of media would be the best choice for isolating a
bacterial colony
nutrient broth
motility media
trypticase soy agar
trypticase soy broth
4. Mannitol salt agar contains (among other ingredients) extracts
of animal tissue and mixed proteins, along with sodium chloride,
which inhibits the growth of organisms other than those in the
genus Staphylococcus. It also includes mannitol, which is
fermented by Staphylococcus aureus, turning the medium
yellow. Other species of Staphylococcus (which do not
ferment mannitol) will still grow, but the medium remains red in
color. Mannitol salt agar could be classified as
Check All That Apply
a solid medium.a solid medium.
a liquid medium.a liquid medium.
a differential medium.a differential medium.
a selective medium.a selective medium.
a complex medium.a complex medium.
a defined medium.
1 To calculate the total magnification multiply the power of ocular lens and power of objective lens ,thus here the power of ocular lens is 10X and power of objective lens is 45X ,so
10X * 45X = 450X
Thus answer is option D 450X
2 B Mixed culture
It is called mixed culture because it contains more than one type of organism growing in a sterile medium .It is not contaminated culture as it is not contaminated from any foreign bodies and also not showing any signs like turbidity and white cloudy appearance.
3 b Motility media
as it separates between non motile and motile bacterial colonies based on their ability to move away from the line of inoculation
4 Mannitol salt agar -
Solid medium,Differential medium,selective medium,defined media
MSA is a solid state media that is both selective and differential ,and is made up of biochemicals rather than materials of biological origin seen in compex media.