Bio 109 Lab Exam 1 Study Guide (Lab 1-6)
Questions with Complete Solutions
how they obtain their carbon... (autotrophs and heterotrophs)
how they deal with oxygen.... (obligate aerobes, obligate anaerobes, and facultative-
anaerobes)
1. Cell Surface Structures - cell wall
- capsule
- fimbriae
- pili
2. Motility - flagella
3. Internal Structures - nucleoid
- ribosomes
- plasmids
,4. Reproduction - binary fission
Shapes? •coccus
•bacillus
•spirillum
What is the most common component of bacterial cell walls? peptidoglycans
Benificial Bacteria - Bacteria in our intestines produce important vitamins.
- Prokaryotes recycle carbon and other chemical elements between organic matter and the soil
and atmosphere.
- More than half of our antibiotics from the soil bacterium Streptomyces
_Symbiotic relationships (Mitochondria and chloroplast used to be prokaryotes living within a
host)
,Gram stain steps - Crystal violet (CV) treatment - stains PG (60 sec)
-Gram Iodine treatment - forms CV-I complex (60 sec)
-Alcohol/Acetone wash (decolorization) - dehydrates PG in Gram-positive bacteria (trapping
stain), disrupts outer membrane of Gram-negative cells and removes stain from cells with a
simple PG wall (~10 sec)
-Safranin (counter stain) - stains cells redthat were not stained with CV (30 sec)
The stain responsible for giving certain bacteria a purple color is? crystal violet
The most important step in the Gram stain is the application of alcohol/acetone
8. The stain responsible for giving certain bacteria a red color is
a. crystal violet.
b. iodine.
c. alcohol/acetone.
d. safranin. d) Safranin
, Gram positive - peptidoglycan traps crystal violet.
-simpler cell walls, but with large amounts of PG
- retain the purple stain and appear purple
Gram-negative bacteria type of bacteria that stain red with Gram stain and have a thin cell
wall with an outer membrane
-crystal violet is easily rinsed away, revealing red dye.
more complex cell walls and less PG
- outer membrane on the cell wall contains LPS
- lose the purple stain, but retain the safranin and appear pink or red
monophyletic group group that consists of a single ancestral species and all its
descendants and excludes any organisms that are not descended from that common ancestor
paraphyletic group composed of some but not all members descending from a common
ancestor
Questions with Complete Solutions
how they obtain their carbon... (autotrophs and heterotrophs)
how they deal with oxygen.... (obligate aerobes, obligate anaerobes, and facultative-
anaerobes)
1. Cell Surface Structures - cell wall
- capsule
- fimbriae
- pili
2. Motility - flagella
3. Internal Structures - nucleoid
- ribosomes
- plasmids
,4. Reproduction - binary fission
Shapes? •coccus
•bacillus
•spirillum
What is the most common component of bacterial cell walls? peptidoglycans
Benificial Bacteria - Bacteria in our intestines produce important vitamins.
- Prokaryotes recycle carbon and other chemical elements between organic matter and the soil
and atmosphere.
- More than half of our antibiotics from the soil bacterium Streptomyces
_Symbiotic relationships (Mitochondria and chloroplast used to be prokaryotes living within a
host)
,Gram stain steps - Crystal violet (CV) treatment - stains PG (60 sec)
-Gram Iodine treatment - forms CV-I complex (60 sec)
-Alcohol/Acetone wash (decolorization) - dehydrates PG in Gram-positive bacteria (trapping
stain), disrupts outer membrane of Gram-negative cells and removes stain from cells with a
simple PG wall (~10 sec)
-Safranin (counter stain) - stains cells redthat were not stained with CV (30 sec)
The stain responsible for giving certain bacteria a purple color is? crystal violet
The most important step in the Gram stain is the application of alcohol/acetone
8. The stain responsible for giving certain bacteria a red color is
a. crystal violet.
b. iodine.
c. alcohol/acetone.
d. safranin. d) Safranin
, Gram positive - peptidoglycan traps crystal violet.
-simpler cell walls, but with large amounts of PG
- retain the purple stain and appear purple
Gram-negative bacteria type of bacteria that stain red with Gram stain and have a thin cell
wall with an outer membrane
-crystal violet is easily rinsed away, revealing red dye.
more complex cell walls and less PG
- outer membrane on the cell wall contains LPS
- lose the purple stain, but retain the safranin and appear pink or red
monophyletic group group that consists of a single ancestral species and all its
descendants and excludes any organisms that are not descended from that common ancestor
paraphyletic group composed of some but not all members descending from a common
ancestor
