Bio 200 Exam 1 Questions with Correct
Answers
Prions - ANSWER-This group of microbes are misfolded proteins and recently
elucidated. These microbes are causative agents for mad cow and other
neurological disorders.
Protozoa - ANSWER-This group of microbes are eukaryotic and most lack cell walls.
They have a large cellular size, are sexual/asexual, ingest nutrients from the
environment. Motility by cilia, psuedopodia, and flagella.
Viruses - ANSWER-This group of microbes are not cellular and very small. They
have a protein coat and some have a lipid envelope and obligate parasites.
Louis Pasteur set up two experiments using different flasks. In the first he used
straight neck flasks. He would sterilze them by boiling water. The flask left open to
air would spot and the flask that was covered from the air would not. In the second
experiment he used swan neck flasks which had a water trap in neck that trapped
water when boiling. It also taped containing microbes keeping them from accessing
the broth and spoiling it. If the trapped water and broth mixed it would spoil. He
concluded that once sterile, the broth stayed sterile, until contaminants were
introduced. - ANSWER-How did Louis Pasteur disprove spontaneous generation
with bacteria?
A tenant of the cell theory is that all cells come from pre-existing cells. Spontaneous
generation explained the creation of living organisms from non-living materials, not
other cells which contradicts cell theory. - ANSWER-How does the cell theory
contradict the theory of spontaneous generation?
Milkmaids that contracted cowpox did not develop smallpox because their bodies
were able to fight off the similar virus. The milkmaids that had cowpox developed
antibodies. These antibodies were then able to fight abginst smallpox becaue it was
simlar to cowpox. Therefor their immune systems were able to recognise the
antigents and fight aginst them with the developed antibodes more efficiently.
or
Cowpox and smallpox are similar diseases, with very different severities in humans.
Milkmaids would frequently contract cowpox from cows, the normal host. Cowpox is
mild in humans. After recovering from cowpox, the acquired immunity from cowpox
would also work to prevent smallpox. - ANSWER-Milkmaids frequently contracted
cowpox, but not smallpox. Given what we now know, what is the reason for this?
The source of the infection was the cadavers in the morgue. Medical students would
dissect the bodies in the morning, help deliver babies in the afternoon, and therefore
transmit the bacteria via their hands.
, Semmelweis proposed handwashing with a chlorine solution, which reduced
maternal mortality to a normal level. - ANSWER-Ignaz Semmelweis studied childbed
fever in Vienna General Hospital. What was the cause of childbed fever? What
innovation reduced maternal mortality?
Pasteurization uses heat to kill many, but not all, organisms contaminating the milk.
With fewer starting organisms, it takes a longer period of time for the bacterial
population to grow to sufficient numbers to produce enough waste to spoil the milk. -
ANSWER-Louis Pasteur invented pasteurization. How does it keep food from
spoiling?
Kosh's postulates are:
1, A pathogen must be present in every case
2, A pathoghen must be isolated and grown in culture
3, An isolated pathogen must reinfect heathy individuals
4, The same pathogen must be reisolated from the second infected individual -
ANSWER-In determining the cause of anthrax, Robert Koch came up with 4
requirements to name an organism as the cause of a disease. What are Koch's
postulates?
Isotonic - ANSWER-A solution which has the same solute concentration than your
reference cell is:
It undergoes crenation (loss of water) and may die - ANSWER-What would happen
to a red blood cell in a concentrated salt solution?
Cells require a constant supply of nutrients, and have to dispose of their wastes. If
they rely of diffusion, then the rate of diffusion will limit the size a cell can be. Larger
cells require that substances travel further and as cells get larger their surface area /
volume ratio decreases. So all these factors drive cells to be smaller. - ANSWER-
Why are cells so small?
1 micrometer - ANSWER-Approximately how big are most bacterial cells?
The acid-fast cell wall is essentially a gram positive cell wall, with the addition of
mycolic acid.
Outside the plasma membrane, the acid fast cell wall contains several thick
overlapping layers of peptidoglycan. Teichoic acid and mycolic acid is present in
between the peptidoglycan layers. There is no outer membrane. - ANSWER-
Describe the structure of the acid-fast cell wall.
The 4 reagents, in order are crystal violet, Gram's iodine, alcohol, and safranin.
After the crystal violet, both gram-positives and gram-negatives will stain purple.
After the iodine, they will both remain purple. The alcohol will remove the crystal
violet from the gram-negatives, which will now appear colorless. Gram-positives will
remain purple after alcohol. The safranin will have minor impact on the gram-
positives, so they will remain purple. Gram-negatives will stain pink. - ANSWER-
What are the 4 reagents in the Gram stain? What will a gram positive or gram
negative bacterium look like after each step?
Answers
Prions - ANSWER-This group of microbes are misfolded proteins and recently
elucidated. These microbes are causative agents for mad cow and other
neurological disorders.
Protozoa - ANSWER-This group of microbes are eukaryotic and most lack cell walls.
They have a large cellular size, are sexual/asexual, ingest nutrients from the
environment. Motility by cilia, psuedopodia, and flagella.
Viruses - ANSWER-This group of microbes are not cellular and very small. They
have a protein coat and some have a lipid envelope and obligate parasites.
Louis Pasteur set up two experiments using different flasks. In the first he used
straight neck flasks. He would sterilze them by boiling water. The flask left open to
air would spot and the flask that was covered from the air would not. In the second
experiment he used swan neck flasks which had a water trap in neck that trapped
water when boiling. It also taped containing microbes keeping them from accessing
the broth and spoiling it. If the trapped water and broth mixed it would spoil. He
concluded that once sterile, the broth stayed sterile, until contaminants were
introduced. - ANSWER-How did Louis Pasteur disprove spontaneous generation
with bacteria?
A tenant of the cell theory is that all cells come from pre-existing cells. Spontaneous
generation explained the creation of living organisms from non-living materials, not
other cells which contradicts cell theory. - ANSWER-How does the cell theory
contradict the theory of spontaneous generation?
Milkmaids that contracted cowpox did not develop smallpox because their bodies
were able to fight off the similar virus. The milkmaids that had cowpox developed
antibodies. These antibodies were then able to fight abginst smallpox becaue it was
simlar to cowpox. Therefor their immune systems were able to recognise the
antigents and fight aginst them with the developed antibodes more efficiently.
or
Cowpox and smallpox are similar diseases, with very different severities in humans.
Milkmaids would frequently contract cowpox from cows, the normal host. Cowpox is
mild in humans. After recovering from cowpox, the acquired immunity from cowpox
would also work to prevent smallpox. - ANSWER-Milkmaids frequently contracted
cowpox, but not smallpox. Given what we now know, what is the reason for this?
The source of the infection was the cadavers in the morgue. Medical students would
dissect the bodies in the morning, help deliver babies in the afternoon, and therefore
transmit the bacteria via their hands.
, Semmelweis proposed handwashing with a chlorine solution, which reduced
maternal mortality to a normal level. - ANSWER-Ignaz Semmelweis studied childbed
fever in Vienna General Hospital. What was the cause of childbed fever? What
innovation reduced maternal mortality?
Pasteurization uses heat to kill many, but not all, organisms contaminating the milk.
With fewer starting organisms, it takes a longer period of time for the bacterial
population to grow to sufficient numbers to produce enough waste to spoil the milk. -
ANSWER-Louis Pasteur invented pasteurization. How does it keep food from
spoiling?
Kosh's postulates are:
1, A pathogen must be present in every case
2, A pathoghen must be isolated and grown in culture
3, An isolated pathogen must reinfect heathy individuals
4, The same pathogen must be reisolated from the second infected individual -
ANSWER-In determining the cause of anthrax, Robert Koch came up with 4
requirements to name an organism as the cause of a disease. What are Koch's
postulates?
Isotonic - ANSWER-A solution which has the same solute concentration than your
reference cell is:
It undergoes crenation (loss of water) and may die - ANSWER-What would happen
to a red blood cell in a concentrated salt solution?
Cells require a constant supply of nutrients, and have to dispose of their wastes. If
they rely of diffusion, then the rate of diffusion will limit the size a cell can be. Larger
cells require that substances travel further and as cells get larger their surface area /
volume ratio decreases. So all these factors drive cells to be smaller. - ANSWER-
Why are cells so small?
1 micrometer - ANSWER-Approximately how big are most bacterial cells?
The acid-fast cell wall is essentially a gram positive cell wall, with the addition of
mycolic acid.
Outside the plasma membrane, the acid fast cell wall contains several thick
overlapping layers of peptidoglycan. Teichoic acid and mycolic acid is present in
between the peptidoglycan layers. There is no outer membrane. - ANSWER-
Describe the structure of the acid-fast cell wall.
The 4 reagents, in order are crystal violet, Gram's iodine, alcohol, and safranin.
After the crystal violet, both gram-positives and gram-negatives will stain purple.
After the iodine, they will both remain purple. The alcohol will remove the crystal
violet from the gram-negatives, which will now appear colorless. Gram-positives will
remain purple after alcohol. The safranin will have minor impact on the gram-
positives, so they will remain purple. Gram-negatives will stain pink. - ANSWER-
What are the 4 reagents in the Gram stain? What will a gram positive or gram
negative bacterium look like after each step?
