Microbiology: Nature of Infection

Question 1

describe how DNA is packaged in eukaryotic cells

Answer 1

• linear chromosomes
• histones
• introns/exons

Question 2

describe how DNA is packaged in prokaryotic cells

Answer 2

• single circular chromosome

- gene structure

Question 3

describe how DNA is replicated in eukaryotes

Answer 3

cell cycle

Question 4

describe how DNA is replicated in prokaryotes

Answer 4

• co-transcription/translation

- rapid cell cycle

Question 5

describe the cell wall of eukaryotes

Answer 5

no/flexible

Question 6

describe the cell wall of prokaryotes

Answer 6

rigid

Question 7

describe the nucleoid of prokaryotes

Answer 7

• contains DNA and proteins
• no nuclear membrane
• DNA replication via DNA dependant RNA polymerase
• co-ordinated transcription/translation
• single circular chromosome, plasmids are extra ones
• primitive DNA segregation machinery

Question 8

how do prokaryotes generate energy

Answer 8

through an electron transport chain located on the cell membrane

Question 9

what are peptidoglycans

Answer 9

rigid layer/barrier of repeated polysaccharide structures

Question 10

what is a gram +ve cell wall

Answer 10

one with a thick multi-layer PG

Question 11

what is a gram -ve cell wall

Answer 11

one with a thin PG layer

Question 12

what happens when a bacterial cell wall is disrupted

Answer 12

become liable to ‘bursting’

Question 13

what are lipopolysaccharides

Answer 13

glycolipids with a polysaccharide core

Question 14

where are lipopolysaccharides and whas is their role

Answer 14

• gm-ve outer cell membranes only, covers almost entire surface making it assymetrical
• structural, antigen/bacterial toxin

Question 15

flagellin

Answer 15

protein unit, multi-stranded filament with core

Question 16

what is a gram +ve flagellin

Answer 16

non-flagella fiprotein appendages

Question 17

what is a grame -ve flagellin

Answer 17

no motor, pilin repeated protein unit

Question 18

what is the function of fimbriae

Answer 18

adherence and sex

Question 19

what is the function of a bacterial pili

Answer 19

attachment and biofilm formation

Question 20

describe prokaryotic protein synthesis

Answer 20

gene -> mRNA -> ribosome -> tRNA -> protein ->1/2/3* structure -> export/assembly/processing

Question 21

what affects prokaryotic

• plasma membrane
• cell membrane
• outer membrane and LPS
• chromosome
• ribosome
• pili, fimbirae. flagella

Answer 21

• sonification and ethanol
• penicillin and glycoproteins
• antibiotic uptake and inflammation
• gyrases antibiotic target
• protein synthesis inhibitors
• attachment, motility, invasion, sex, pathology

Question 22

what do prokaryotes need for growth

Answer 22

• food (O, N, H, N), trace elements, vitamins

Question 23

what are prokaryotes living at 
- low
- high 
- body temp 
temperatures called at

Answer 23

• pycrophiles
• thermophiles
• mesophiles

Question 24

what do pH human commensal bacteria live at

Answer 24

pH6.8-7.2

Question 25

at what NaCl % do human commensals live at

Answer 25

0.85%

Question 26

what is happening during

• lag phase
• growth phase
• staitonery phase
• death phase

Answer 26

• acclimation
• quick division
• metabolite runs out
• population decreases