The sidechains of __ are positively charged at physiological pH.

Select one:

a. Asp, Glu

b. Lys, Arg

c. His, Tyr

d. Asn, Gln

Microbiology question

Q:why Quorum sensing is important to biofilm dispersion?

Antibodies are suitable for diagnostic tests, because Select one:

a. they can be used only for humans.

b. they can be readily purified.

c. they are found in very small quantities.

d. they bind very specifically to antigens with very high affinity.

e. they are found everywhere.

An experiment has been initiated in a laboratory where recombinant DNA technology has been used to substitute the gene responsible for change of colour in chameleon with another gene responsible for “glowin-the-dark”. If this experiment is successful, chameleons carrying the “glow-in-the-dark” gene will not be able to change their colours any longer. Discuss the implication of these results in terms of ethics and conservation biology.

Immune responses working to protect the host need to be carefully regulated, since overt immune function may be harmful to the host. There are several feed back inhibitory loops evolved to regulate immune cell activation. Briefly describe how B cells and T cells are equipped with such feed back regulatory circuits upon activation.

what is the typical diagnostic technique& mechanism about infectious disease? at least 5 type!!!

1)The transposon Tn5 was used to create a library of 50,000 Escherichia coli mutant strains having random Tn5 insertions in their chromosomal genes. A suicide delivery plasmid vector that carries Tn5 was used for this purpose. Explain how and why a suicide delivery plasmid was used to generate this library and give one (1) example of how you would screen this library to find mutants with Tn5 insertions in specific genes of interest, for example, in the lac (lactose) operon.

2) Describe the experiments by Robert Koch that underpin Koch’s postulates. What are FOUR (4) reasons why these postulates could be too restrictive?

Think about the variety of healthcare organizations, such as a long-term care facility, large for-profit hospital, physicians' practice, VA hospital, or state-run clinic. Consider how budgeting would be influenced depending on an organization's sources of funding. How do the purposes or uses of a budget vary according to the kind of healthcare organization it is (think nonprofit, for-profit, and governmental)?

1)Which of the following is true of enzyme characteristics? (a) enzymes catalyze reactions when a substrate binds to the allosteric site (b) enzymes catalyze reactions by increasing the activation energy (c) enzymes do not exhibit specificity and a single enzyme can catalyze various different reactions (d) enzymes lower the activation energy of specific reactions, speeding up the reaction rate

2) Microbial growth is measured by what parameter? (a) increased cell size (b) increased size of cellular components (c) increase in total number of cells (d) a & b

3)During aerobic cell respiration, most of the energy is produced during… (a) Krebs cycle (b) glycolysis (c) fermentation (d) electron transport chain

4)Which of the following is the best definition of generation time? (a) the length of time it takes for lag phase to occur (b) the length of time it takes a population of cells to double (c) the minimum length of time it takes a cell to divide (d) the length of time a culture stays in stationary phase

5)Bacteria make exoenyzmes in order to… (a) make structures within the bacterium (b) synthesize large molecules of carbohydrates, proteins, and nucleic acids (c) hydrolyze large molecules to smaller ones so that they can be transported into the bacterium (d) none of the above; bacteria do not make exoenyzmes

6)Which of the following is NOT true of using a spectrophotometer to measure bacterial growth? (a) measurement is based on turbidity of the broth culture (b) this method accounts for both dead and viable cells (c) this method uses the transmission of light through the broth culture to estimate concentration of cells (d) this method requires serial dilutions prior to measurement

answer followings

Give a general description of the light and dark reactions of photosynthesis. Light – light energy is converted into chemical energy (ATP) Dark – Carbon fixation – carbon is fixed into organic molecules (sugars) using ATP and enzymes

Which of the following statements about the tryptophan (trp) operon does not properly describe its function?

Select one:

a. The trp operon is activated in the cell when tryptophan levels rise
      

b. The enzymes expressed by the trp operon allow the cell to make tryptophan when cellular levels are low     

c. The trp operon is activated in the cell when tryptophan levels fall       

d. The trp repressor remains bound to the operon when allosterically bound by tryptophan in the cell

Most proteins destined to enter the endoplasmic reticulum

Select one:

a. are completely translated on free ribosomes in the cytosol.

b. are transported across the membrane after their synthesis is complete.
    

c. remain within the endoplasmic reticulum.

d. begin to cross the membrane while still being synthesized.   

What is the designation of the recipient cell after mating with an Hfr donor strain?

1. F-

2. F'

3. F+

D. Hfr