Nature of Infection

Question 1

what is size of prokaryotes?

Answer 1

0.5-10 micrometres

Question 2

what is size of eukaryotes?

Answer 2

5-50 micrometres

Question 3

Are prokaryotes and eukaryotes single or multi cellular ?

Answer 3

prokaryotes are often single celled and eukaryotes are multi-cellular

Question 4

what is speed of cell cycle in eukaryotes & prokaryotes (comparitively)?

Answer 4

prokaryote have rapid cell cycle and eukaryotes have mitosis/meiosis

Question 5

what is cell structure of eukaryotes?

Answer 5

-cell membrane
-nucleus
-centriole/centrosome
-nucleolus/ribsosomes
-ER
-cytosol
-mitochondria
-golgi
-cytoskeleton
-secretory vesicles (lysosomes)

Question 6

what is cell structure of prokaryotes?

Answer 6

-plasma membrane
-cell wall (peptidoglycan)
-nucleoid (DNA & associated proteins)
-ribosomes
-cytoplasm
-capsule, flagellar & pili

Question 7

what is the cytoplasmic membrane of prokaryotes?

Answer 7

-lipid bilayer
-retains cytoplasm
-selective barrier
-transport
-reaction surface e.g. respiration, lipid synthesis
*important for import/export

Question 8

what is aerobic respiration process of energy productions? (basic)

Answer 8

1. electrons released from high energy compounds in cytoplasm
2. reach membrane and passed through series of electron acceptors
3. as a consequence protons passed outside membrane producing a +ve charge and proton gradient across membrane that is used by ATP synthase for energy

Question 9

what are the 2 forms of energy production in prokaryotes?

Answer 9

aerobic and anaerobic

Question 10

what is a nucleoid?

Answer 10

• DNA & associated proteins
  not the same as nucleus = no membrane or defined locations

Question 11

what are chromosomes like in prokaryotes?

Answer 11

• chromosomes are single circular molecule
  -organised by gyrases
  -extra chromosomal replicons often exist e.g. plasmids

Question 12

what is primitive DNA segregation machinery?

Answer 12

in prokaryotes - DNA is circular and has enzymes that can be targeted with drugs

Question 13

how are our ribosomes different to prokaryote ribosomes?

Answer 13

similair in that they turn mRNA into peptides but different in that there is a whole bunch of enzymes that can be targeted by drugs

Question 14

what is structure of peptidoglycan cell wall?

Answer 14

repeated sugar chains = NAM NAG
peptide side bridges = 5 amino acids
(sugar cage cross-linked by amino acid bridges) - not in one flat dimension, it actually spirals so different places of crosslinking

Question 15

what type of environment is peptidoglycan wall more common?

Answer 15

cells that live in variable environments as peptidoglycan can cope with higher pressure

Question 16

what are components of gram +ve cell wall?

Answer 16

-rigid layer
-barrier
-repeated polysaccharide structure
-target of penicillin
-Gram +ve = multi layer & often secondary polymer

Question 17

what are components of gram -ve cell wall?

Answer 17

-rigid layer
-barrier
-repeated polysaccharide structure
-target of penicillin
-Gram -ve
= outer membrane
= often decorated with LPS (Lipopolysaccharides = important outer membrane components of gram-negative bacteria.)
= periplasmic space (space between inner &outer membrane)

Question 18

what are lipopolysaccharides (LPS)?

Answer 18

=they’re also referred to as endotoxin & linked to sepsis/septic shock

• found almost completely covering outer membrane of Gram -ve as outer membrane asymmetric

Question 19

what increases the surface area of prokaryotes?

Answer 19

flagella & fimbriae, as they can attach to far away bacterial cells and allow horizontal gene transfer

Question 20

what do flagella and fimbriae allow?

Answer 20

flagella allows movement (long)
fimbriae are shorter and allow attachement

Question 21

what are pili?

Answer 21

a slightly longer fimbriae (not as long as flagella)

Question 22

what antiobiotic targets DNA gyrases?

Answer 22

fluoroquinolones

Question 23

what structure is linked to antiobiotic uptake and inflammation?

Answer 23

outer membrane & LPS (gram -ve)

Question 24

what structure is linked to sonication & ethanol?

Answer 24

cytoplasmic or plasma mebrane - they get damaged by sonication & ethanol

Question 25

what structure is linked to penicillin and glycopeptides?

Answer 25

cell wall - (both antibiotics that target cell wall)

Question 26

describe bacterial growth curve and explain what it means?

Answer 26

-bacteria starved then exposed to nutrients so grows until used up nutrients where it then declines
4 phases:
1. lag phase
2. exponential phase
3.stationary phase
4. decline phase
=predictable pattern of bacterial growth in closed system

Question 27

what factors affect prokaryotic growth?

Answer 27

1. nutrition
2. temperature
3. hydrogen ion concentration (pH)
4. osmotic protection
5. oxygen

Question 28

how does nutrition affect prokaryotic growth?

Answer 28

-carbon, oxygen , hydrogen and nitrogen source
-trace elements (Zn, Cu, Mn, Ni)
-vitamins (small organic cofactors) e.g. biotin, folic acid, niacin

Question 29

what is psycrophiles?

Answer 29

bacteria that like low temp

Question 30

what is thermophiles?

Answer 30

bacteria that like high temp

Question 31

what is mesophiles?

Answer 31

bacteria that like body temp

Question 32

how does pH affect bacterial growth?

Answer 32

human commensals is pH 6.8-7.2

Question 33

how does osmotic protection affect bacterial growth?

Answer 33

human commensals is 0.85% NaCl

Question 34

how does oxygen affect bacterial growth?

Answer 34

-all the different types of aerobes like different levels (aerobes, obligate anaerobes, facultative anaerobes, capnophilic etc)