BIOL 235 Lab Exam Questions With 100%
Correct Answers
Which setting is best to view bacteria in a light microscope?
Darkfield
Why do bacteria move?
- To move towards attractive environments
- Move away from harmful environments
- To seek other bacteria and create colonies
Which bacteria is corkscrew shaped? (long and squiggly)
Spirochete
Which bacteria is comma shaped?
Vibrio
Which bacteria has two round spheres?
Diplococci
Which bacteria is rod shaped?
Bacillus
Which is neither a eukaryotic cell nor a prokaryotic cell?
Virus
What is function of the cell wall?
To provide structure and protect the bacteria from osmotic pressure
Which explains the function of the plasma membrane?
It controls which substances enter and exit the cell
How do the inclusion bodies assist the bacteria in survival?
They hold nutrients necessary for the bacteria to survive
What is the plasmid's role in survival in extreme conditions?
They can encode for proteins that provide additional benefits for the bacteria to survive the local
environment
How is the nucleoid involved in helping the vibrio bacteria survive the harsh environment?
The nucleoid encodes essential genes and for some bacteria these are genes essential for surviving
extreme cold
How does the ribosome ensure that the vibrio can survive in the extreme environment?
The cell wall would not exist without as the ribosomes translate the genetic code into protein
, The cell wall protects the bacteria. How does it protect the Vibrio in Antarctica?
To withstand the osmotic pressure from the aquatic environment
What is the growth formula?
N I = 2^n * N 0
How did the bacteria cells multiply so quickly?
By cell division. For every generation the population doubles.
What function would help you visualize all the values on the same plot and show that the bacteria
were growing between each of the measurements?
Take logarithm of measurements
The straight line indicates that there is a constant growth rate. This growth rate is defined as k. What
is it actually describing?
Generations per time period
What is the formula for the growth rate constant k?
K=n/t
How would you combine the growth rate and the growth formula?
K = log 10 (Nt / N0) / t
What happens once all the nutrients are used up?
The number of viable cells will decrease
Why do you think there is a lag before the bacterial cells start growing?
Bacteria cells adjust to the growth medium
What feature of the graph relates to the growth rate K?
The slope of the exponential phase
What technique could you use to quantify the number of viable bacteria at different time points?
Serial dilution and colony count
Why are the bacteria samples stored in the fridge?
Reduce bacterial growth
Why is it important to sterilize the wire loop?
To avoid contamination
Why do you sterilize the wire loop between streaking each quarter of the plate?
Correct Answers
Which setting is best to view bacteria in a light microscope?
Darkfield
Why do bacteria move?
- To move towards attractive environments
- Move away from harmful environments
- To seek other bacteria and create colonies
Which bacteria is corkscrew shaped? (long and squiggly)
Spirochete
Which bacteria is comma shaped?
Vibrio
Which bacteria has two round spheres?
Diplococci
Which bacteria is rod shaped?
Bacillus
Which is neither a eukaryotic cell nor a prokaryotic cell?
Virus
What is function of the cell wall?
To provide structure and protect the bacteria from osmotic pressure
Which explains the function of the plasma membrane?
It controls which substances enter and exit the cell
How do the inclusion bodies assist the bacteria in survival?
They hold nutrients necessary for the bacteria to survive
What is the plasmid's role in survival in extreme conditions?
They can encode for proteins that provide additional benefits for the bacteria to survive the local
environment
How is the nucleoid involved in helping the vibrio bacteria survive the harsh environment?
The nucleoid encodes essential genes and for some bacteria these are genes essential for surviving
extreme cold
How does the ribosome ensure that the vibrio can survive in the extreme environment?
The cell wall would not exist without as the ribosomes translate the genetic code into protein
, The cell wall protects the bacteria. How does it protect the Vibrio in Antarctica?
To withstand the osmotic pressure from the aquatic environment
What is the growth formula?
N I = 2^n * N 0
How did the bacteria cells multiply so quickly?
By cell division. For every generation the population doubles.
What function would help you visualize all the values on the same plot and show that the bacteria
were growing between each of the measurements?
Take logarithm of measurements
The straight line indicates that there is a constant growth rate. This growth rate is defined as k. What
is it actually describing?
Generations per time period
What is the formula for the growth rate constant k?
K=n/t
How would you combine the growth rate and the growth formula?
K = log 10 (Nt / N0) / t
What happens once all the nutrients are used up?
The number of viable cells will decrease
Why do you think there is a lag before the bacterial cells start growing?
Bacteria cells adjust to the growth medium
What feature of the graph relates to the growth rate K?
The slope of the exponential phase
What technique could you use to quantify the number of viable bacteria at different time points?
Serial dilution and colony count
Why are the bacteria samples stored in the fridge?
Reduce bacterial growth
Why is it important to sterilize the wire loop?
To avoid contamination
Why do you sterilize the wire loop between streaking each quarter of the plate?
