Microscopy & Morphology

Question 1

What are the 4 “processes” the microbes Do?

Answer 1

• Nutrient Production and Energy Flow
• Decomposition
• Symbiotic relationship with humans, animals, plants.
• Human Uses
  
  • Production of beer, yogurt
  • Mass production of pesticides
  • Introduce bacteria into oil spiils to clean up pollutants

Question 2

What is the simplest microscopes name/the guy who found it?

What was its max magnification?

Answer 2

Van Leeuwenhoek

200x

Question 3

What is the magnification limit for most simple light microscopes?

Answer 3

2000x

Question 4

What are the 2 factors for light microscopy?

Answer 4

Magnification

Resolution

Question 5

What is the magnification limit of a light microscope when looking at the size of an organism?

Answer 5

.2 um (200 nm)

Question 6

What types of microscopy use white light?

Answer 6

Brightfield

Darkfield

DIC - Differntial Interference Contrast

Question 7

What 2 important features make Phase Contrast a unique form of microscopy?

Answer 7

• Relies on phase rin which enhances difference sin light phase (gives you a white halo around the object)
• You can see intercellular structures!

Question 8

What makes DIC different than Phase Contrast Microscopy?

Answer 8

DIC uses polarized light

Question 9

What are the 3 features of Confocal Laser Scanning Microscopy?

Answer 9

• Uses a laser microscope and fluorescence
• Pin points focused light of only one wavelength
• Gives depth information to 3D structures

Question 10

What are the differences between TEM and SEM microscopy?

Answer 10

• Transmission
  
  • .2-2 nm resolution
  • Can see whole cell or a cross section
  • Measures electrons that pass through a sample
• Scanning
  
  • uses electron beam to scan surfaces
  • .5-10 nm resolution

Question 11

What makes Atomic Force Microscopy so unique?

Answer 11

• Not light based
• USes cantilever which floats over surfaces and defracts a laster beam to give surface contour maps
• Very high resolution
  
  • DNA atoms can be viewed
  • 30 nm horizontally and .1 nm vertically

Question 12

What are some of the reasons that different cell morphology evolved?

Answer 12

• Evolution Depended on ecology
  
  • Unstable enviornments - need to reproduce quickly sphere best for SA ratio
  • Stable Environment (low nutrient) - cell needs to grow slowly
  • Stable High nutrient - no restrictions on reproduction rates
  • Aquatic environement - need to move around - so rods, spirella, spirochete
• But we honestly don’t know!

Question 13

What are the advantages to high S/V ratio and low S/V ratio?

Answer 13

• High - greater nutrient uptake, faster reproduction, evolution, better survival
• Low - low predation

Question 14

What 2 factors determine Cell shape?

Answer 14

Proteins

Cell wall components

Question 15

How are Archaea cell walls different thatn bacteria and Eukaryotic cell walls?

Answer 15

• Archeae cell walls have ether linnkages instead of ester linkages between head and tail
• Also - no fatty acids but istead have a 5-carbon hydrocarbon isproene

Question 16

What are the functions of the cytoplasmic membranes?

Answer 16

• Prevents Leakage and diffusion into the cell
• Anchors proteins
• Procides abrrier allowing proton motive force
• Transport
• Secretion Systems

Question 17

What are the repeated subunits in peptidoglycan?

Answer 17

NAG and NAM

Question 18

What are the functions of the peptidoglycan layer?

Answer 18

• Connects plasma membrane and outer membrane
• Acts as a sieve
• Target of lysosomes (these break 1-4 Beta linkages)
• Anchors proteins in G+/G- and anchors lipoteichoic acids in G-

Question 19

What are other morphological features of microbes?

Answer 19

• Glycocalyx
  
  • capsules, slime layers
• Cellular Inclusions
  
  • C,P, S Storage, Magnetosomes, Gas, Endospores
• Fimbriae and pili
• Flagella
  
  • Lateral, Polar
• Cilia

Question 20

What are the 2 types of cell surface structures?

Answer 20

• Capsules
  
  • Polysaccharide or amino acid,
  • Thick/thin
  • Rigid/Flexible
  • Tight matrix
• Slime Layer
  
  • Polysaccharide
  • Thick/think
  • Rigid/Flexible
  • SLoughed off

Question 21

What is the function of cell surface structures like a slime layer?

Answer 21

• Aids in attachment
• Protect against osmotic stress and dessication
• Protect from predation
• protect from an immune system

Question 22

What are 3 different “types” of pili?

Answer 22

• Bacterial Sex (F-type or P-type)
• Motility/adhesion ot srufaces (Type iV)
• Secretion (Type I)

Question 23

What are the 4 types of Flagella?

Answer 23

• Peritrichous - flagella at numerous sites around the exterior of the cell
• Polar (monotrichous) - single flagellum at one end
• Lophotrichous - several flagella at one end
• Amphitrichous - two polar flagella, one on each end.

Question 24

How much ATP is used to power the bacterial flagella?

How much ATP is used to power Eukaryotic Flagella?

Answer 24

No ATP is used in bacterial flagella - proton motive force.

Don’t know exact amount of ATP used in Eukaryotic.

Question 25

What are the key differences between the Archaeal Flagella and the Bacterial Flagella?

Answer 25

• Archeae are more similar to Type IV pili
• Missing the central channel
• Growth from base, not the tip (like in bacterial flagella)

Question 26

Which “domain” of cells are cilia found?

Answer 26

ONLY Eukaryotes

Question 27

What are Cilia used for on Bacteria?

Answer 27

• Not found in bacteria, only eukaryotes
• For Eukaryotes
  
  • Short, hair-like appendages
  • Whip-like movement
  • Some used for feeding
  • Hundreds per cell

Question 28

What are the different types of “swarming” or gliding on solid surfaces??

Answer 28

• Pili - twitching
  
  • Fishing mechanism
• Slime Extrusion
  
  • Shoots directionally
• Other protein based mechanism
  
  • The tank model