Question

1.) Most sexually reproducing organisms are devided into species based on whether or not they have the potential to interbreed and produce fertile offspring. This criterion doesn't work for asexually reproducing organisms such as bacteria. By what criteria, then, are bacteria classified into species?

a) morphology (eg. cell shape)

b) the ability to carry out certain biochemical reactions

c) cellular structures (e.g. production of a capsule)

d) a & b

e) a, b, & c

2.) You are measuring growth in a closed bacterial culture. The number of viable cells remains constant, and when you check the medium, you find the carbon source has nearly run out. What phase of growth is the culture most likely in?

-lag phase

-early log phase

-late log phase

-stationary phase

-death phase

3.) Which of the following is NOT true of DNA replication in E. Coli

-DnaA triggers initiation

-It is bidirectional

-One strand is synthesized discontinuously

-It is conservative

Synthesis occurs in the 5' to 3' direction

4.) In which case is the longest lag period most likely to be observed for a bacterial culture?

-transfer from complex medium to fresh complex medium

-transfer from complex medium to minimal medium

-transfer to a lower temperature

-transfer to a different pH

-transfer to a different salt concentration

5.) The primer in bacterial DNA replication is

-an RNA primer with a free 3' OH group

-an RNA primer with a free 5' OH group

-a DNA primer with a free 3' OH group

-a DNA primer with a free 5' OH group

-a telomere with a free 5' phosphate

6.) Which is not a component of a bacterial cell wall

peptidoglycan

leicholic acids

N-actylmuramic acid

chitin

peptide cross bridge

7.) You have isolated a bacterium that you believe to be the causitive agent of a new disease in frogs. How would you test the first of Koch's postulates?

Determine the shape of the bacterial cells

Inject bacteria into a healthy frog

Isolate and grow the bacterium in pure culture from a sick frog

Show that the bacterium is not present in healthy frogs

Grow all a frog's bacterium outside the frog

Answer 1

Que 1)

Ans:

Most sexually reproducing organism are divided into species based on whether or not they have the potential to interbreed and produce fertile offspring. This criterion doesn't work for asexually reproducing organisms such as bacteria. Then, bacteria are classified into species based on criteria such as: e) a, b and c. i.e. a) morphology (cell shape), b) the ability to carry out certain biochemical reactions c) cellular structures ( e.g. production of a capsule).

Explanation:

- Bacteria are classified into species based on morphological characteristics, differential staining, biochemical tests etc.

- Morphological characteristics such as cell shape, size, arrangement of cells, arrangement of flagella, capsule, endospores, mechanism of motility.

- Biochemical tests such as catalase test etc.