BI234 EXAM 2 QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
What do all organisms need to grow?
Their chemical and physical requirements met
What are some chemical requirements?
Source of
-Carbon
-Oxygen
-Nitrogen
-Phosphorus
Describe the chemical requirement of oxygen
Using molecular oxygen comes at a cost... free radical
- An organism must have a specific enzyme to neutralize free radicals, there for they
must have genes to code for the enzymes
- Most Eukarya are obligate aerobes
** Aerobic organisms can handle free radicals and anaerobic organisms cannot
Where do organisms grow with different levels of oxygen?
What are some physical requirements?
, Certain range of
-Temperature
-pH
-Moisture
How is the cell membrane affected by temperature?
Too cold: becomes rigid and fragile
Too hot: becomes too fluid (melts)
What is the pH scale based on?
The concentration of H+
0= Most acidic
7= Neutral
14= Most basic
What is an endospore?
a dormant, tough, and temporarily non-reproductive structure produced by certain
bacteria.
** Very hard to get rid of
What is generation time?
Time it takes for microorganism to double its population
Describe the different phases of cell growth
COMPLETE SOLUTIONS VERIFIED
What do all organisms need to grow?
Their chemical and physical requirements met
What are some chemical requirements?
Source of
-Carbon
-Oxygen
-Nitrogen
-Phosphorus
Describe the chemical requirement of oxygen
Using molecular oxygen comes at a cost... free radical
- An organism must have a specific enzyme to neutralize free radicals, there for they
must have genes to code for the enzymes
- Most Eukarya are obligate aerobes
** Aerobic organisms can handle free radicals and anaerobic organisms cannot
Where do organisms grow with different levels of oxygen?
What are some physical requirements?
, Certain range of
-Temperature
-pH
-Moisture
How is the cell membrane affected by temperature?
Too cold: becomes rigid and fragile
Too hot: becomes too fluid (melts)
What is the pH scale based on?
The concentration of H+
0= Most acidic
7= Neutral
14= Most basic
What is an endospore?
a dormant, tough, and temporarily non-reproductive structure produced by certain
bacteria.
** Very hard to get rid of
What is generation time?
Time it takes for microorganism to double its population
Describe the different phases of cell growth
