Using the formula determine the original cell density in the sample: OCD = Number of CFU/Amount plated x dilution factor You counted 72 colonies on a plate in your dilution series. The plate was inoculated with 1.0ml from a 10^-4 test tube, what is the OCD?

What will be an ideal response?


7.2x10^5

Biology & Microbiology

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Fungi generally digest large organic molecules ____

a. in special compartments called arbuscules b. within feeding hyphae c. in visible mushrooms d. in special compartments called haustoria e. outside of their cells

Biology & Microbiology

Limiting factors

a. produce more pronounced effects as a population grows. b. prevent indefinite, exponential population growth. c. can be either density-dependent or densityindependent. d. acting together constitute environmental resistance to population growth. e. include all of these.

Biology & Microbiology

________________ is defined as an organism's expressed physical traits.

a) Phenotype b) Genotype c) Heritable trait d) None of the above

Biology & Microbiology

Different modification of the histone have different effects on gene expression. For instance, the ninth amino acid of histone 3 is a lysine (H3K9 ) can be acetylated once or methylated up to three times. Which of the following is true regarding H3K9

modification? A) If H3K9 is acetylated, then the gene will be repressed. B) If H3K9 has a single methyl group, then the gene will be repressed. C) If H3K9 has two methyl groups, then the gene will be activated. D) If H3K9 has three methyl groups, it is maximally activated compared to only having one methyl group. E) If H3K9 has three methyl groups, then the gene will be repressed.

Biology & Microbiology