Bacteria introduction

Question 1

what colour are gram positive bacteria?

Answer 1

purple

Question 2

what colour are gram negative bacteria?

Answer 2

red/pink

Question 3

what do cocci and bacilli mean respectively?

Answer 3

cocci - spherical

bacilli - rod shaped

Question 4

what is the structure of peptidoglycan?

Answer 4

carbohydrate polymers, linked by beta 1,4 glycosidic bonds, provide strength and shape

Question 5

what is the structure of a lipopolysaccharide?

Answer 5

lipid and O antigen, illicits strong immune response.

Question 6

what are the differences in cell wall structure between gram positive and gram negative bacteria?

Answer 6

gram positive - thick peptidoglycan layer, lack of lipopolysaccharides
gram negative - thin peptidoglycan layer, presence of many more lipopolysaccharides.

Question 7

what is the function of the bacteria capsule?

Answer 7

mostly present in gram negative bacteria - helps with prevention of phagocytosis of bacterial cells via macrophages etc

Question 8

what is the function of a flagellum?

Answer 8

provides motility

Question 9

what are the 4 different classifications of flagellum attachment?

Answer 9

A monotrichous - one flagellum
B lophotrichous - attachment at only one point
C amphitrichous - attachment on both sides
D peritrichous - attached all over

Question 10

what is the function of fimbriae?

Answer 10

adherence to epithelial cells

Question 11

when would spore formation occur and why is it advantageous to the bacteria?

Answer 11

under unfavourable/stressful environmental conditions.
spores are resistant to environmental conditions and will start dividing as bacterial cells when conditions are favourable again.

Question 12

does formation of spores occur as a result of symmetrical or asymmetrical cell division?

Answer 12

asymmetrical

Question 13

what is a bacteriophage?

Answer 13

virus that infects bacteria

Question 14

what is a lysogenic cycle?

Answer 14

when DNA from the bacteriophage is integrated into the bacterial cell

Question 15

what is a plasmid?

Answer 15

small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently.

Question 16

what are some of the functions of plasmids?

Answer 16

can transfer resistance from one bacteria to another via the formation of a PILUS; a bridge between two bacterial cells that is used for communication (conjugation)

Question 17

what are the two classifications of bacteria with regards to plasmids?

Answer 17

F+ - bacteria that contains the plasmid

F - - bacteria that doesnt contain the plasmid

Question 18

how many strands of DNA are donated during conjugation?

Answer 18

1

Question 19

how do bacteria replicate?

Answer 19

binary fission - produces identical progeny

Question 20

how do bacterial cells display genetic variation?

Answer 20

spontaneous mutation and the transfer of DNA (transductions and transformations)

Question 21

how are bacteria named?

Answer 21

name is based on their genus and species