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Bacteria Flashcards

1
Q

How is DNA stored in bacteria?

A

Bacteria have no nucleus but instead have a single circular hoop of chromosomal DNA and may also have a plasmid in addition to this.

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2
Q

How do bacteria reproduce?

A

By binary fission

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3
Q

What are the differences between a gram positive and gram negative bacteria?

A

Gram positive - thick peotidoglycan cell wall, highly polar cell wall

Gram negative - thin peptidoglycan cell wall, additional outer membrane surround

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4
Q

Pathogenic bacteria are heterotrophic. What does this mean?

A

They derive all of their nutritional requirements from complex organic substances

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5
Q

What is the name of the tightly coiled region of DNA in bacteria?

A

Nucleoid

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6
Q

The genome of a bacteria only consists of exons. T/F?

A

True - bacteria have no introns

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7
Q

Bacteria have a cytoskeleton. T/F?

A

False

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8
Q

Where in the bacteria would ‘extra’ genes be stored?

A

Plasmids

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9
Q

What advantage do R-plasmids provide bacteria with?

A

Antibiotic resistance

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10
Q

Many of the functions which are performed by membrane-bound organelles in eukoryotes are carried out by what structure in bacteria?

A

Cell membrane

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11
Q

Bacterial cells contain no organelles in their cytoplasm other than…?

A

Ribosomes

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12
Q

What proteins compose the flagellum of bacteria?

A

Flagellins

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13
Q

Give an example of a bacteria which can be classified as ‘gram stain unreliable’.

A

M.tuberculosis

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14
Q

What colour will gram negative and gram positive bacteria appear under the gram stain.?

A

Gram positive - purple

Gram negative - pink

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15
Q

Name an alternative method of staining which can be used for gram stain unreliable bacteria?

A

Ziehl-neelson method

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16
Q

What are the two types of pilli in bacteria amd what are their functions?

A

Common pilli - responsible for attachment and adhesion

Sex pilli - associated with conjugation where genes are transferred between bacteria

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17
Q

Some bacteria have capsules. What are the function of these capsules?

A

To protect the bacteria from phagocytosis

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18
Q

What is the outer membrane of gram negative bacteria anchored to?

A

It is anchored to lipoprotein molecules in the peptidoglycan layer.

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19
Q

What are the main constituents of the outer membrane of gram negative bacteria?

A

Lipopolysaccharides

Lipoprotein

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20
Q

How do hydrophilic molecules enter a gram-negative bacteria?

A

Through channels or pores from from proteins called porins

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21
Q

What is the name of the gel like layer which exists between the two membranes kf gram negative bacteria?

A

Periplasm

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22
Q

What are the three main shapes of bacteria?

A

Cocci (spherical)
Bacillus (rod shaped)
Spirilla (helical)

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23
Q

What is the shape of a bacteria determined by?

A

Its cell wall

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24
Q

Give two examples of gram positive cocci.

A

Staphylococcus aureus

Streptococcus pneumoniae

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25
Give two examples of gram negative cocci.
Neisseria meningiditis | Neisseria gonorrhoeae
26
Give two example of gram positive bacilli
Listeria monocytogenes | Corynebacterium diptheriae
27
Give two examples of gram negative bacilli.
Escherichia coli | Salmonella species
28
What is the name of coccus bacteria which divide in two planes?
Tetrad
29
Which cocci bacteria can result from division in one plane?
Diplococcus (bacteria arranged in pairs) | Streptococcus (bacteria arranged in chains)
30
Coccus which divide in three planes produce...?
Sarcina arrangement
31
How is a staphylococcus arrangement produced?
By the division of a coccus bacteria in random planes
32
Bacilli all divide in one plane only. What is the difference between a bacillus, streptobaccilus and coccobacillus?
Bacillus - bacteria exists singularly Streptobacillus - bacilli arranged in chains Coccobacillus - bacilli exist singularly in oval shapes which resemble cocci
33
What are the three forms of spiral bacteria?
Vibrio - comma shaped rod Spirillum - thick rigid spiral Spirochete - thin flexible spiral
34
What is the minimum inhibitory concentration?
The minimum concentration of an antibacterial agent required to inhibit visible growth of a bacteria
35
What is the minimum bactericidal concentration?
The minimum concentration of an antibacterial agent required to kill a bacterium.
36
What is the name for bacteria which are capable of growing and reproducing at cold temperatures?
Psychrophilic bacteria
37
Some bacteria can be describes as facultative anaerobes - what does this mean?
The bacteria normally undergoes aerobic respiration but can undergo anaerobic respiration when oxygen is not available.
38
Thermophilic bacteria are bacteria that...?
Can grow and reproduce at high temperatures
39
What are mesophilic bacteria?
Bacteria which can grow and reproduce at moderate temperatures
40
What are spores?
Vegetative forms that some bacteria can become to enable viability under adverse conditions
41
What do endospores consist of?
Nucleic acid, cytoplasm and a tough outer coat
42
What are commensal organisms?
The natural flora which ordinarily live on our bodies
43
When are natural flora acquired and what benefits do they provide?
They are acquired soon after birth and provide many benefits including inhibiting the establishment of infection by competition and natural by-products, producing vitamins in the gut as a metabolic end-product and stimulating the immune system.
44
What are the sterile body sites?
These are body sites without commensal organism colonisation, including: blood, tissues, organ systems (other than colon and ,large intestine), CNS, lower respiratory tract, sinuses, inner and middle ear, renal system (down to posterior urethra, female reproductive tract (down to cervix) and the eye (other than the exposed conjunctivae).
45
What is an opportunistic infection?
An infection that would not normally cause infection in a healthy human hist but can cause infection when the human host is immuno-compromised.
46
What is a nosocomial infection?
An infection acquired in hospital
47
What does the term 'carrier state' mean?
A host whose symptoms are no longer present but still 'carries' the microorganism in a dormant state
48
What is the concept of the infectious dose?
This is the concept that a host must be exposed to a certain number of a particular microorganism for an infection to be present.
49
What are endotoxins?
Lipopolysaccharides in the outer membrane of gram-negative bacteria which can elicit a strong immune response from the hist and make the patient appear septic.
50
What are exotoxins?
These are produced by gram-positive bacteria and are produced intracellular,y and then released during infection. These induce a non-specific immune stimulation.
51
List some of the host and environmental factors which can influence infection.
Hist age, gender, ethnicity, personal hygiene and nutrition Medical conditions, prescription drugs Immunocompromise Presence of foreign objects (infection with commensals more likely) Vaccination history Crowding, seasonal variations, sanitation
52
List some microbiological emergencies.
Infection of a normally sterile site Meningitis/CNS infection/cerebral abscess Septic arthritis Deep ocular or periorbital infections Infections involving a breach of the GI tract Outbreak scenario or public health risk Infection where the patient is septic
53
What is sepsis?
A physiological response to severe infection involving cytokine cascades, free radical production and vasoactive mediators. In severe sepsis there is organ hypoperfusion (inadequate blood supply),. In septic shock there is hypotension (low blood pressure) despite resuscitation
54
What is a vector?
An organism which carried a disease or parasite from one organism to another.
55
What is a formite?
An object in the environment which is contaminated.
56
What is disinfection as opposed to sterilisation?
Disinfection - removal of most but not all viable microorganisms to safe levels Sterilisation - killing or removing all microorganisms including transmissible agents
57
Where does replication of the bacterial genome begin?
The origin of replication
58
What are the four phases of bacterial growth and replication?
Lag phase Log phase Stationary phase Death phase
59
What is the meaning of the term generation time?
The time it takes for the bacteria population to double
60
What is. Transposition?
The movement off transposons between bacterial plasmids or between plasmid. And chromosome
61
How do bacteria reproduce?
Asexually by binary fission
62
Why does bacterial growth change from the log phase to the stationary phase?
Due too the depletion of nutrients and build up of toxic waste products
63
What is a parasite?
An organism which gains benefit from the host at the expense of the host
64
What are the benefits which commensal organisms provide?
Competition and natural by products of commensal organisms inhibit the establishment of infection Vitamins in the gut produce metabolic end products Immune stimulation
65
What are some of the commensal organisms which reside in the nose?
Staphylococcus aureus Staphylococcus epidermidis Cornyebactrium species
66
What are some of the commensal organisms which reside in the mouth?
Streptococcus species Fusobactrium species Actinomyces species
67
What are some of the commensal bacteria which reside on the skin?
Staphylococcus epidermidis Propionibacterium acnes Pityrosporum ovale
68
What are some of the commensal organisms in the throat?
Streptococcus species Corynebacterium species Neisseria species Mycoplasma species
69
What are some of the commensal organisms in the large intestine?
``` Escherichia coli Lactobaccilus sledies Streptococcus species Clostridium species Candida albicans ```
70
Where in the body do the majority of commensal organisms reside?
Large intestine
71
What are some of the common bacteria to infect the respiratory system?
Streptococcus pneumoniae Streptococcus pyogenes Haemophillus influenza
72
What are some of the common bacteria to infect the gastrointestinal system?
Camplyobacter | Salmonella
73
What are some of the common bacteria to infect the musculoskeletal system?
Staphylococcus aureus
74
What are some of the common bacteria to infect the central nervous system system?
Neisseria meningiditis Streptococcus pneumoniae Haemophilus influenzae
75
What are some of the common bacteria to infect the renal system?
E.coli

Pathogens (3 decks)

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