Looking at your results of the Ames test, you find that there are many colonies growing on the agar in the presence of the chemical being tested. What is your interpretation of this result? Explain.
In: Biology
what was the purpose of transforming cells from URA3- minus to URA3+ plus?
In: Biology
31)
Which of the following would not be a consequence of an antibody:antigen interaction?
| A. |
agglutination of antigens |
|
| B. |
neutralization of toxin |
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| C. |
activation of complement |
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| D. |
opsonization |
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| E. |
prevent adherence of pathogens |
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| F. |
All are possible consequences of antibody:antigen interactions |
32)
Which statement among A-D is false regarding bacterial toxins?
| A. |
Exotoxins are not capable of stimulating an antibody response by the body and thus are undectable. |
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| B. |
Cholera toxin results in the loss of tremendous amounts of water from an affected individual. |
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| C. |
Shiga toxin, tetanus toxin, and hemolysins are all types of exotoxins. |
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| D. |
Superantigens elicit a hyperactive response by the immune system and can lead to shock. |
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| E. |
None are false, A-D are all true statements. |
In: Biology
29)
Regarding the neurotoxigenic disease caused by Clostridium tetani, which of the following among A-D is not correct?
| A. |
Infection typically occurs via a puncture wound to the skin. |
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| B. |
It results in lack of muscle contraction, causing a flaccid-type paralysis. |
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| C. |
The causative agent is a Gram-positive anaerobe that produces endospores. |
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| D. |
It inhibits release of neurotransmitter from inhibitory neurons. |
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| E. |
A-D are all correct |
30)
Which term among 1-5 is correctly matched with its proper function?
1-Defensin
2-Interferon
3-Perforin
4-PAMPS (MAMPS)
5-Pyrogen
| A. |
Secreted peptides of the innate immune system that disrupt cell membrane function: 2 |
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| B. |
Lethal protein secreted by natural killer cells: 5 |
|
| C. |
Recognized by toll-like receptors: 4 |
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| D. |
Promotes fever: 1 |
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| E. |
Protects cell against viral infection: 3 |
In: Biology
Why would plants need to evolve vascular tissue, lignin, and the different reproductive mechanisms (cone versus flower).
In: Biology
Natural killer cells target:
|
infected cells that have lost MHC I surface proteins |
||
| B. |
bacterial cells that are coated with complement |
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| C. |
infected cells bound with antibody |
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| D. |
cancerous cells |
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| E. |
Two of the above are correct |
In: Biology
These Gram-positive pleomorphic bacteria are toxin producers that cause formation of a pseudomembrane in the throat that can restrict airflow. This pathogen is
A.
Bordetella pertussis
B.
Streptococcus pyogenes
C.
Corynebacterium diphtheriae
D.
Neisseria meningitidis
E.
Streptococcus pneumoniae
In: Biology
Use the following scenario to answer question.
Island chains are known to occur along the borders of the earth’s large land plates. For example, both the Hawaiian and Galapagos Islands were born from the intense volcanic activity generated along the Pacific Ocean’s “Ring of Fire”. Hence, the number and placement of the islands can tell us approximately how many of the underwater volcanoes made islands and in what direction the plates are moving. Once formed, an island, then undergoes colonization by living organisms. We often describe a successful colonization event as one where the species lands, breeds and its offspring remain on the island to repeat its life cycle. In the case of Krakatau, which is a volcanic island in Indonesia, we have many recordings of its recolonization by life forms after the 1883 eruption which wiped the island clean of all preceding life forms. One of the first groups of organisms to colonize was that of spiders and insects.
11.What type of selection pressure would enhance the survival of the spiders and insects once they landed on the new Krakatau Island? Why? (i.e. divergent, convergent)
12.What kind of selection pressure would prevent the successful colonization by insects and spiders? Why?
In: Biology
2. List the different types of electron carriers within the electron transport system. For every pair of electrons each complex transfers, determine how many protons are translocated.
In: Biology
Biofilm formation by staphylococcus epidermidis
In: Biology
Describe the reaction of gluconeogenesis and for each step explain the type of reaction, enzyme involved, substrate and product, if the reaction is reversible or irreversible, any coenzyme or prosthetic group involved, and location.
In: Biology
Which statement among A-E is false concerning digestive system and gastrointestinal (GI) tract infections?
|
A. |
Dysentery is a more severe form of gastroenteritis producing abdominal cramps, fever, and blood. |
|
|
B. |
Rehydration and electrolyte replacement are typically the treatment for those with GI tract infections. |
|
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C. |
Invasive GI tract infections are caused by intracellular pathogens such as Salmonella and certain E coli. |
|
|
D. |
Among protozoal pathogens, Giardia is a major cause of gastroenteritis. |
|
|
E. |
Most GI tract infections are due to viruses. |
|
|
F. |
A-E are all correct. |
In: Biology
Describe the reaction of the citric acid cycle and for each step explain the type of reaction, enzyme involved, substrate and product, if the reaction is reversible or irreversible, any coenzyme or prosthetic group involved, and location.
In: Biology
In animal tissue, the rate of conversion of pyruvate of acetyl-CoA is regulated by the ratio of active, phosphorylated pyruvate dehydrogenase to inactive, unphosphorylated pyruvate dehydrogenase (PDG) complex. Explain the impact of the following regulators on the activity of pyruvate dehydrogenase complex in animal tissue extracts when treated with:
- high concentrations of acetyl-CoA
In: Biology
Explain how a white blood cell (leukocyte) uses protein-sugar interactions within a blood vessel to find the site of inflammation. Specify which proteins are involved in binding to which types of sugars during this process, and on which surface each of these ligands & receptors would be found
In: Biology