Bacteria

Question 1

what 3 divisions can bacteria be split into according to their nutritional requirements?

Answer 1

simple needs
complex needs
unknown needs

Question 2

what do bacteria with simple needs require?

Answer 2

only basic needs (e.g. glucose, phosphate, sulphate) as they can make complex substances themselves

Question 3

what do bacteria with complex needs require?

Answer 3

growth factors and other substances (e.g. amino acids/nucleotides) as they cannot create these on there own

Question 4

what are bacteria with complex needs also known as?

Answer 4

fastidious bacteria

Question 5

can bacteria with unknown needs survive outside the host?

Answer 5

no - cannot be grown in a lab

Question 6

what are the pH requirements of most bacteria?

Answer 6

neutral or slightly alkaline

Question 7

what is bacteria’s optimum temperature?

Answer 7

varies between bacteria depending on their target host. Those that live in mammals have an optimum temperature of 35-37 degrees

Question 8

how do strictly (obligate) aerobic bacteria respire?

Answer 8

use O2 at all times

Question 9

how do microaerophillic bacteria respire?

Answer 9

in limited oxygen (e.g. 5%) and can be killed by high oxygen concentrations

Question 10

how do facultatively anaerobic bacteria respire?

Answer 10

can grow without o2 but do not need to. Are metabolically flexible

Question 11

how do strictly anaerobic bacteria respire?

Answer 11

without oxygen

Question 12

what can the respiration style of a bacteria tell us about their location in the body?

Answer 12

how reliant they are on air can illustrate if they function best in the intestine (low or no o2) or elsewhere where o2 is higher

Question 13

what 2 byproducts are there of respiration and metabolism in bacteria?

Answer 13

hydrogen peroxide and superoxide radical

Question 14

what is hydrogen peroxide taken up by?

Answer 14

catalase

Question 15

what is superoxide radical taken up by?

Answer 15

superoxide dismutase

Question 16

do anaerobic bacteria produce hydrogen peroxide and superoxide radical?

Answer 16

no

Question 17

how do strictaerobic bacteria acquire energy?

Answer 17

aerobic respiration

Question 18

how do microaerophillic bacteria acquire energy?

Answer 18

aerobic respiration

Question 19

how do facultative anaerobic bacteria acquire energy?

Answer 19

aerobic respiration
anaerobic respiration
fermentation

Question 20

how do strict anaerobic bacteria acquire energy?

Answer 20

anaerobic respiration

fermentation

Question 21

do strict aerobic bacteria have a detox system?

Answer 21

yes - catalase and superoxide dismutase

Question 22

do microaerophillic bacteria have a detox system?

Answer 22

yes - only superoxide dismutase

Question 23

do facultative anaerobic bacteria have a detox system?

Answer 23

yes - catalase and superoxide dismutase

Question 24

do strict anaerobic bacteria have a detox system?

Answer 24

no

Question 25

what are barriers on a bacterial cell to nutrient uptake?

Answer 25

outer membrane and plasma membrane

Question 26

what are not barriers on a bacterial cell to nutrient uptake?

Answer 26

capsule and peptidoglycan

Question 27

what are the 3 mechanisms for nutrient uptake?

Answer 27

passive diffusion active diffusion active transport

Question 28

what are the by products of fermentation?

Answer 28

acids, CO2, hydrogen, alcohols

Question 29

what does fermentation produce?

Answer 29

ATP NADH2 NADPH2

Question 30

what are the products of respiration?

Answer 30

CO2, ATP, NADH2 and NADPH2

Question 31

what is the terminal electron acceptor for aerobic respiration?

Answer 31

oxygen

Question 32

what are the terminal electron acceptors for anaerobic respiration?

Answer 32

nitrogen sulfates carbon dioxide

Question 33

what are the types of media used to grow bacteria in labs?

Answer 33

nutritionally simple enriched (non-specific) selective differential

Question 34

what is the benefit of selective media over other types?

Answer 34

can inhibit or suppress other bacteria and enrich wanted bacteria

Question 35

what does differential media allow for?

Answer 35

viewing visual differences in bacterial colonies

Question 36

describe the bacterial growth curve in a closed sytem

Answer 36

lag - log - stationary - death

Question 37

what happens during the lag phase of bacterial growth?

Answer 37

bacteria adapts to environment (e.g. selects enzymes that work best at host temperature and pH)

Question 38

what happens during the log phase of bacterial growth?

Answer 38

bacteria multiply exponentially

Question 39

what happens during the stationary phase of bacterial growth?

Answer 39

a factor inhibits further bacterial growth so number remain steady

Question 40

what happens during the death phase of bacterial growth?

Answer 40

bacteria either poison themselves or starve

Question 41

how can doubling times vary between bacteria?

Answer 41

some can double every 20 minutes (E. Coli) others may take 24 hours (Mycobacterium bovis/TB)

Question 42

what does the slow doubling time of TB mean for testing?

Answer 42

very difficult to find an effective test for

Question 43

what is the value of studying bacteria?

Answer 43

identify it learn how it may be killed (e.g. infection control) vaccine production

Question 44

what does the morphology of bacteria describe?

Answer 44

its gross structure and shape

Question 45

what are the 4 main bacteria shapes?

Answer 45

coccus bacillus coccobacillus pleomorphic

Question 46

what are the 9 main parts of a bacterial cell?

Answer 46

``` mesosome nucleoid ribosome inclusion bodies capsule surface proteins cell wall plasma membrane flagellum ```

Question 47

what is in the nucleoid of bacterial cells?

Answer 47

area of DNA

Question 48

what is the function of the mesosome?

Answer 48

holds proteins in one place

Question 49

what makes up the protoplast of a cell?

Answer 49

plasma membrane, cytoplasm and contents

Question 50

what are hopanoids used for in the bacterial plasma membrane?

Answer 50

stabilising the membrane

Question 51

describe the features of a gram positive cell wall

Answer 51

plasma membrane on the inside, peptideoglycan layer on the outside which can close gaps within itself if the bacteria is in a dry area

Question 52

where are gram positive cells often found?

Answer 52

outside the body (in dry areas)

Question 53

describe the features of a gram negative cell wall

Answer 53

two plasma membranes with a peptidoglycan layer in the centre. On the external plasma membrane there are lipopolysaccarides which contain antigens that keep immune cells away from the sensitive plasma membrane

Question 54

what are glycocalyx?

Answer 54

capsules/slime layers outside the cell wall which interfere with immune response

Question 55

what are flagella used for?

Answer 55

movement

Question 56

what are fimbriae (pili) used for?

Answer 56

used to stick to surfaces

Question 57

what are gram stain tests able to tell us?

Answer 57

the environment which the tested bacteria prefer

Question 58

what colour will a negative gram stain show?

Answer 58

purple

Question 59

what colour will a positive gram stain show?

Answer 59

pink

Question 60

where is bacterial DNA found?

Answer 60

nuclear region

Question 61

how many chromosomes do bacteria have?

Answer 61

1

Question 62

what shape are chromosomes in bacteria?

Answer 62

circular/double stranded and super coiled

Question 63

what are plasmids made up of?

Answer 63

extra-chromosomal circular DNA

Question 64

what is the function of plasmids?

Answer 64

auxillary genes, give the bacteria extra functions

Question 65

what types of plasmid are there?

Answer 65

``` resistance virulence colicin fertility degradative ```

Question 66

what does variation of bacteria affect?

Answer 66

virulence resistance to host defences resistance to treatments

Question 67

how does mutation affect variation?

Answer 67

affect resident genome

Question 68

how does recombination affect variation?

Answer 68

relies on new DNA gained by taking up plasmoids

Question 69

when is variation retained?

Answer 69

were it causes and increase in fitness

Question 70

what is the name of bacteria which is free living in the environment?

Answer 70

saprophytes

Question 71

what is the name of the bacteria which live on/in animals?

Answer 71

parasites

Question 72

what are the 3 types of parasitic bacteria?

Answer 72

symbiotic commensal pathogenic

Question 73

what happens in a host parasite relationship with symbiotic bacteria?

Answer 73

bacteria and host gain (e.g. cellulase producing bacteria in the rumen)

Question 74

what happens in a host parasite relationship with commensal bacteria?

Answer 74

bacteria gain but cause no harm

Question 75

what happens in a host parasite relationship with pathogenic bacteria?

Answer 75

bacteria gain and cause harm

Question 76

what are the 2 types of pathogenic bacteria?

Answer 76

obligate and facultative

Question 77

how do facultative pathogenic bacteria cause infection?

Answer 77

normally harmless but with altered host conditions some have the facility to be pathogenic given this changed opportunity

Question 78

what are the 2 sources of infection by bacteria?

Answer 78

environment/other hosts | animals own commensal flora

Question 79

what is bacterial infection by environment/other hosts called?

Answer 79

exogenous infection

Question 80

what is bacterial infection by animals own commensal flora called?

Answer 80

endogenous infection

Question 81

what are the 3 opportunities for facultative pathogens?

Answer 81

new body site altered body site reduced defences

Question 82

what are examples of facultative infection caused by new body site?

Answer 82

e.coli - harmless in the gut but during surgery can be released into peritoneal cavity causing peritonitis staph aureus - harmless in the nose but can lead to abscess if introduced through skin or septicemia if introduced into blood stream

Question 83

what are examples of opportunities for facultative infection caused by altered body site?

Answer 83

temperature pH commensal flora change

Question 84

what two things can cause alteration in commensal flora leading to growth of facultative bacteria?

Answer 84

antibiotic use - can wipe out all bacteria leaving those that are resistant room to grow rapid nutritional change - alter commensal gut flora

Question 85

what are examples of opportunities for facultative infection caused by reduced defences?

Answer 85

``` extremes of age malnutrition immunosuppressants primary infection stress ```

Question 86

what are examples of stress that could lead to facultative infection caused by reduced defences?

Answer 86

``` transport crowding temperature extremes wounding trauma birth fatigue feed changes (e.g. weaning) ```