Introduction to Bacteria 2

Question 1

<p>What are the key differences between gram positive and gram negative bacteria?</p>

Answer 1

<p>Gram positive bacteria remain coloured with gram staining even after washing. Gram negative bacteria do not retain their stain.Gram positive bacteria do not have an outer membrane (lipopolysaccharide and protein)Gram positive bacteria have a smooth cell wall with 70-80 percent peptidoglycan/ Gram negative bacteria have a wavy wall that comes in contact with the plasma membrane. The wall contains 10-20 percent peptidoglycan.+ - No porins present- - Porins or hydrophilic channels occur in the outer membrane. </p>

Question 2

<p>What is the gram stain appearance of gram positive bacteria?</p>

Answer 2

<p><u><span>Purple</span></u></p>

Question 3

<p>What is the gram stain appearance of gram negative bacteria?</p>

Answer 3

<p><u><span>Red</span></u></p>

Question 4

<p>What is the gram stain appearance of cocci?</p>

Answer 4

<p>Spherical</p>

Question 5

<p>What is the gram stain appearance of bacilli?</p>

Answer 5

<p>Rod shaped</p>

Question 6

<p>What can you find on the cell surface of bacteria?</p>

Answer 6

<p>Plasma membrane</p>

<p>Penicillin binding sites</p>

<p>Peptidogylcan</p>

<p>Lipopolysaccharides</p>

<p>(in gram negative bacteria)</p>

Question 7

<p>What is the function of the murein / peptidoglycan?</p>

Answer 7

<p>Strength and shapeCounteracts the high osmotic pressure of the bacterial protoplast.</p>

Question 8

<p>What is the response to lipopolysaccharides in animals and humans?</p>

Answer 8

<p>Strong immune response</p>

Question 9

<p>What are frimbriae and what is the function?</p>

Answer 9

<p>A series of thread like projections used for adherence</p>

Question 10

<p>What are spores?</p>

Answer 10

<p>Highly resistant dominant structures. A unit of asexual reproduction - Used in unfavourable conditions</p>

Question 11

<p>How do bacteria replicate?</p>

Answer 11

<p>Binary fission - identical progeny</p>

Question 12

<p>How is genetic variation increased in bacteria?</p>

Answer 12

<p>Spontaneous mutation</p>

<p>Transfer of DNA</p>

Question 13

<p>What is a bacteriophage?</p>

Answer 13

<p>A virus which parasitizes a bacterium by infecting it and reproducing inside it.</p>

Question 14

<p>How do you see an individually cultured bacteria?</p>

Answer 14

<p>MicroscopeStain</p>

Question 15

<p>How do you view a colony of individual bacteria?</p>

Answer 15

<p>Seen by eye, they are cultured on solid medium (agar)</p>

Question 16

<p>A bacteria name is the combination of the genus and the species. What is the difference?</p>

Answer 16

<p>The genus name forms the first part of the name for each species within the genus.</p>

Question 17

<p>What is used to identify strains within a species?</p>

Answer 17

<p>DNA typing techniques</p>