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BIO 220 Quiz 2 Topic 2 LATEST FALL-SPRING SEMESTER GCU

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BIO 220 Quiz 2 Topic 2 LATEST FALL-SPRING SEMESTER GCU

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BIO 220 Quiz 2 Topic 2 LATEST FALL-SPRING SEMESTER
GCU
Know the definition of microbe and discuss the contradictions that arise from the
word microbe. - ANSWER: Microbe: a living organism that requires a microscope to
be seen

Exceptions/ probs with def: (look in notebook for more detail)
1. Supersize Microbial Cells
2. Microbial Communities
3. Viruses

Provide examples of microbes that profoundly affected human history. - ANSWER:
1717- First sign of immunization for small pox.

1929- Alexander Fleming discovered penicillin.

14th century- bubonic plague; yersinia vestis infection

19th century- tuberculosis infection

Microbes are essential for nitrogen fixation and play big roles in the carbon cycle!
The microbe cyanobacteria greatly affects our atmosphere through nitrogen fixation
(thanks to a small cell called a heterocyst) and releases oxygen into the air using the
process of photosynthesis.

-yeasts / bacteria made foods like bread / cheese / alcoholic beverages

-20 % of the worlds copper as well as some uranium / zinc is produced by bacterial
leaching

-However, microbial acidification also consumes the stone of ancient monuments---a
process intensified by airborne acidic pollution

Understand how all life forms are categorized on the phylogenetic tree of life -
ANSWER: What are the three domains?
- Eukarya
-Archaea
-Bacteria

Archaea and Eukarya are more closely related together than they are to bacteria.

Archaea live the widest range of environmental conditions

Eukarya are the encompasses a large range of size and form

,Bacteria cells have cell walls made of peptidoglycan

Relate the biological diversity present among prokaryotes to that of eukaryotes. -
ANSWER: 1. Prokaryotes are primarily unicellular organisms while eukaryotes are
primarily multicellular organisms with a few exceptions.

2. Prokaryotes are capable of surviving in a wider range of extreme environments
and are more diverse than eukaryotes.

3.Eukaryotes contain organelles with their own DNA while prokaryotes do not
contain organelles with their own DNA.

4.Prokaryotes are able to use a wider array of energy sources (ie. carbon fixation,
nitrogen fixation, photosynthesis, etc.) than are available to eukaryotes.

5.Eukaryotes are more susceptible to mutations occurring during sexual
reproduction which creates more differences between individuals while prokaryotes
produce copies of themselves asexually.

Describe ways to detect and observe microbe organisms
- Different types of microscopes
- Staining, fluorescence, autofluorescence, etc... - ANSWER: Types of microscopes:

Light: Great for looking at surface of large cellular structure, has the lowest
resolution and magnification

Scanning electron: Scans specimen surfaces into 3 dimensional structure, shows
surface of cells.

Transmission electron: Electrons pass through the cells to reveal internal structures.

Atomic Force: Very high resolution.

X-ray crystallography: Reveals smallest cellular structures.


Ways to define cells:
Regular Staining via plain dye: Can be a simple stain such as methylene blue. Or can
be a differential stain that only stains one kind of cell but not another.

Gram staining: Invented by Hans Christian Grahm in 1884 is a type of differential
stain.

Can be gram positive which is indicated by a purple stain bound to the large amounts
of peptidoglycan in the cell wall.

, Can also be gram negative which stains pink when no or little peptidoglycan is
present.

Fluorescence : use of fluorophores to specify cells.

Be familiar with the basic shapes of microbes
-Identify what microscopic technique was employed for a particular image -
ANSWER: Bacillus- Rod shaped microbe morphology
Spirochete- Spiral shape microbe morphology
Cocci- Sphere shaped morphology
Staph- grape like clusters
Step- Chain
**look at image

Describe the structure, function and importance of microbial cell membrane. -
ANSWER: Structure: phospholipid bilayer--hydrophobic "water-fearing" phosphate
heads, hydrophilic "water-loving" fatty acid tails; membrane proteins that provide
structural support, ion passage, energy storage, and secretion of virulence factors

Function: regulates what comes in and out of the cell for survival

Importance: essential for separating the inside of the cell from its outside
environment; allows for active and passive transport, enabling the cell to remain
viable under stressors

Describe the structure, function and importance of microbial cell membrane -
ANSWER: Importance- to allow permeability

Structure- Phospholipid bilayer- consists of 2 layers of phospholipids with a
hydrophobic interior and hydrophilic exterior. The structure is also fluid mosaic

Function - contains protein channels to allow concentration gradients and keep
homeostasis.

Compare and contrast cell envelopes of Gram positive and negative bacteria. -
ANSWER: - Gram positive bacteria have more layers of peptidoglycan .

- Gram negative bacteria have a thin layer of peptidoglycan.

- Gram negative bacteria have outer membranes while Gram positive bacteria do
not.

- Gram positive bacteria retain the dye while Gram negative bacteria do not.

- Gram positive bacteria have S-layers.

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