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Human Biosciences > MicroBiology > Flashcards

MicroBiology Flashcards

1
Q

How are trees of life generated?

A

Comparing nucleic acid sequences, specifically rRNA as present in all life

Also has a range of rates of secondary structure and double stranded and single stranded region, useful for making primers

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2
Q

What’s a monophyletic group or clade?

A

It’s a group of organisms that consists of all the descendants of a common ancestor

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3
Q

What’s a taxon?

A

Any group of species that we can designate a name

Multiple is taxons

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4
Q

What’s a node?

A

Split in branch from one lineage into another

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5
Q

Root node?

A

Common ancestor of all taxa in the tree

Point of earliest split in the tree

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6
Q

Root?

A

Branch leading up to the root node (i.e. the common ancestor of all taxa in tree)

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7
Q

What are the 3 domains?

A

Bacteria
Archaea
Eukaryota

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8
Q

What is mutational saturation?

A

Where a site changes so fast difficult to tell what is a reversion (in Analysis)

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9
Q

Challenges on finding out more about Archaea?

A

Difficult to culture in lab

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10
Q

What is metagenomics?

A

Sequence everything approach (mixtures of species/genes), then reconstruct genomes, or segments of genomes.

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11
Q

What’s a virus?

A

Infetive agent that typically consists of a nucleic acid molecule in a protein coat

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12
Q

3 theories on how viruses evolved?

A

Viruses are escaped portions of cellular organisms

Viruses are extremely derived and reduced cellular organisms

Viruses are relics from a pre-cellular world: Self-replicating units in the ancient virosphere may have gained the ability to form membranes and cell walls, leading to evolution of the three domains of life.

Or a mixture of all 3

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13
Q

Different morphologies of bacteria?

A

Coccus (sphere shaped)
Rod
Spirillum (like kidney bean)
Spirochete (coiled)
Budding and appendages bacteria (have stalk and hypha)
Filamentous bacteria (very long and thin)

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14
Q

Features of bacterial cell size?

A

Have a large surface area to volume ratio

Leads to faster uptake of nutrients

And more cells per given resource, more cells mean more evolution which drives evolution

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15
Q

Features of bacteria phospholipid bilayer?

A

= glycerol + 2 fatty acids + phosphate group

Strengthened by molecules called hapanoids, which is essential for mycoplasmas

In Bacteria and eukaryote ester bond in bilayer, whereas as ether bond in archaea

Archaea bilayer is continuous so much stronger (no small gap in middle)

There are proteins in membrane for transport

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16
Q

Feature of bacterial cell wall?

A

Made up of Peptidoglycan (2 sugars and some amino acids)

Occurs in90% gram + ves, bacteria and 10% in gram -ves bacteria

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17
Q

How is outer membrane not symmetrical to inner in gram negative bacteria?

A

The outer isn’t just phospholipids

Large polysaccharide component

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18
Q

How to count bacteria?

A

By culture, dilute to an extent so colonies can be counted then multiply up

Only tells you have many are living, not necessary all of them

So can count by them a light microscope as well, normally with an oil immersion lens

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19
Q

Equation for resolution of a lens?

A

R = (0.5 x wavelength) / numerical aperture

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20
Q

Difference of gram positive and negative bacteria and Features of the gram stain?

A

Gram positive bacteria have large petiodglycan cell wall above plasma membrane

Where as gram negative have 2 bilayer around peptidoglycan cell wall

Need to add notes on how to do the gram stain

Gram positive remain purple

Gram negative go pink

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21
Q

Cell surface structures of bacteria?

A

Capsules

Fimbriae and pili

Flagellar

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22
Q

Features of capsules?

A

Can be polysaccharide or protein or both

Play a role in pathogenesis and biofilm formation

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23
Q

What is biofilms formation?

A

Predominant bacterial phenotype in nature (their stain)

Form on solid substances with moisture

On soft tissues in living organisms

At liquid air interfaces

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24
Q

What are endospores?

A

Bacteria become them when they go into dormant stage of lifecycle

Very resistant to lots of things

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25
Q

How to antibiotics generally work?

A

Targeting processes of bacteria which don’t have an effect on the eukaryote cell

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26
Q

Naturally occurring antimicrobials are?

A

Naturally occurring antibiotics

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27
Q

Modification of natural antibiotics results in?

A

Semi-synthetic antibiotics

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28
Q

What are ahminoglycosides and what aren’t they used today?

A

Antibiotics that contain amino sugars bonded by glycosidic linkage

Not used today as high neurotoxicity and nephrotoxicity

Only used when other antibiotics fail

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29
Q

What are macroslides?

A

Contain lactone rings bonded to sugars

Broad spectrum antibiotic that targets the 50S subunits of ribosome

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30
Q

What are tetracyclines?

A

Contain 4 rings

Widespread medical use in humans and animals

Broad-spectrum inhibition of protein synthesis

Inhibits functioning of 30S ribosomal unit

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31
Q

Example of a synthetic anti microbial drug?

A

Quinolones - causes the inhibition of DNA gyrase

Binds to the A subunits of DNA gyrase

Resistance mediated by decreased binding

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32
Q

What are the most produced antibiotics and features?

A

B-Lactam

Primarily effective against gram positive, but can be modified synthetically to target gram negative

Includes penicillin

Target cell wall synthesis§

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33
Q

Why are B-lactams effective against gram positive bacteria?

A

Because it’s mainly cell wall, whereas gram negative cell wall is protected by both phospholipids bi layers

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34
Q

What are bacteriocidals?

A

The bacterial cells still remain but they are no longer viable, so can still them under microscope but they are no longer causing disease

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35
Q

What are bacteriolytics?

A

Kill all bacterial cells via lysis but disturbing cell wall so no longer visible under a microscope

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36
Q

Features of vancomyosin?

A

Inhibits cell wall biosynthesis

But has poor bioavailability

Used for treatment of C. difficile

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37
Q

Features of methicillin?

A

Inhibits cell wall biosynthesis like penicillin

However not used anymore as caused a lot of antibiotic resistance

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38
Q

Ways in which a bacteria can be antibiotic resistant?

A

Lacks the structure the antibiotic inhibits

Organism is impermeable to antibiotic

Organism can inactivate the antibiotic

Organism may modify the target of the antibiotic

Organisms may be able to. pump out the antibiotic (efflux)

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39
Q

What does antibiotic resistance spread through?

A

R plasmids

Consist of a resistance transfer factor that enables conjugation

Contains gene conferring resistance

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40
Q

Step 1 of a gram stain?

A

Differentiates between a gram positive and a gram negative bacteria

Performed on a smear sample, which is made by spreading the bacterial cells on a microscope creating an even layer. They are then killed and fixed to the slide

Crystal Violet is applied first, it dissociates into CV+ and Cl- ions, these are taken up by both cell types, the CV+ ions bind and stain the negatively charged components of the bacterial cell wall

After one minute crystal violet washed off with water

Both types of cell are now purple

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41
Q

Step 2 of a gram stain?

A

Gram’s iodine is now used to fix the dye within the cells it is taken up by both gram negative and gram positive

It forms a complex with the CV+ ions, which are in soluble in water so they become trapped in the cell

After one minute excess gram iodine Is washed off

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42
Q

Step 3 of gram stain?

A

Add alcohol/acetone and rinse with water, to decolourise the sample

The crystal violet dye is removed from gram negative bacteria, but not from gram positive bacteria

This occurs as in gram negative bacteria the lipids that make up the outer membrane are dissolved, in both positive and negative the peptidoglycan layer is dehydrated, the gram negative only left with thin peptidoglycan outer layer so the dye leaks out, but in gram positive the peptidoglycan layer is thick enough to retain it

So after this step gram positive purple, and gram negative is colourless

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43
Q

Step 4 of gram stain

A

Stained with safranin which is taken up by both cell types and binds to the lipid cell membrane

Washed off with water after 45 seconds

Gram negative is now pink, and gram positive is now purple, so can now look at both of them under a microscope

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44
Q

What does taxonomy do?

A

Identifies the relationships between groups of organisms

Can be used to identify novel or previously unknown organisms

Provides universal language of classification between scientists

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45
Q

What are taxa?

A

Catergories of organism

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46
Q

What is gram positive bacteria divided into?

A

Low G + C = Firmicutes

High G + C = Actinobacteria

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47
Q

Why is so much known about gram positive and gram negative bacteria?

A

Easy to culture

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48
Q

What is an ecosystem?

A

Sum of all organisms and abiotic factors in a particular environment

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49
Q

What is symbios?

A

Mutualism and Commensalism

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50
Q

What is mutualism?

A

Both species benefit

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51
Q

Commensalism?

A

One species benefits, the other is neither harmed or benefited

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52
Q

Syntrophy

A

Two or more organisms catabolising a nutrient that can not be catabolised by one on its own

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53
Q

Species richness

A

the total number of species present in an ecosystem

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54
Q

Species abundance

A

the proportion of each species in an ecosytem

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55
Q

Why do bacteria grow so much slower in environment?

A

limiting resource of nutrients

Growing in mixed populations

Distribution of nutrients

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56
Q

steps in formation of a root nodule in a legume infected by Rhizobium?

A

The plant roots secrete a chemical called flavonoids that stimulate the growth of Rhizobia in soil, they end up growing to high densities around the root

The chemicals also induce the expression of bacterial genes, Rhizobium carry a large plasmid called the Sym, which carries nod genes which are involved in nodulation

Flavanoid binds to product of the nod gene, which binds upstream and promotes transcription of more nod genes which Creates a nod factor

These then bind to the root hairs, and create an infection thread and enter the root cells

Generate bacteroids in the cells which do nitrogen fixing

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57
Q

Are viruses living?

A

NO

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58
Q

What can viruses infect?

A

Bacteria, Archaea and Eukarya

Virophages can also infect viruses

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59
Q

2 types of verions?

A

Naked virus

Enveloped virus (encapsulated)

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60
Q

What are bacteriophages?

A

Viruses that infect bacteria

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61
Q

How do bacteriophage work (lytic pathway)?

A

Virion attaches to host cell

Penertrate/inject into it

Hijack cells DNA, and synthesise nucleic acids and proteins

Assemble and package them

Release the new virions to infect more cells

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62
Q

What is the lyosogenic pathway?

A

Virus attaches to receptor on bacterial cell wall and injects it’s DNA into the cell.

The protein coat remains outside the cell while the phage DNA inside quickly forms into a circle

Whether the phage takes the lytic or lyosgenic pathway depends on which genes dominate

If a gene called c1 (also called the lambda repressor gene) dominates, the phage will progress into the lysogenic pathway

If a gene called cross dominates the phage will progress into the lytic pathway

In this battle, RNA polymerase comes in and recognises Pl and Pr promoters (left and right), this will cause protein N and protein Cro to form

However N is an anti terminal, meaning c11 and c111 and Q will be transcribed as RNA polymerase doesn’t stop

Q is another anti terminator allowing transcription of while chromosome and the production of proteins and vision for lysis this is the lytic pathway

However, for the lyosgenicpathway to occur the c11 protein can bind to a promoter region called Pe, causing the transcription of c1, c11 can only do this if protected by c111 from proteases

On the right operator region, there are 3 binding sites c1 can bind to, when it binds to sites 1 and 2 it blocks transcription from the Pr promoter so there is no more further transcription of cro, if it binds on site 3 will also turn of production of c1 otherwise too much will be made, if it’s already won the fight

However, Cro can bind to site 3 and 2 as well reducing production of c1 , and makes more cro tipping the fight in it’s favour

You would think Cro would always win fight as it’s made first so will reach the sites first, however c1 has a higher affinity for the sites

What wins depends on the level of proteases in cells, as rely on if C11 and C111 work or not

Can then potentially go through induction and then join the lytic pathway

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63
Q

What does MreB do?

A

Protein essential in cell morphology

It’s the bacterial cytoskeleton

Coccoid cells don’t have MreB suggesting the thesis the default shape for a bacterium

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64
Q

What does a logarithmic plot allow you to work out?

A

Doubling time of bacteria

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65
Q

4 growth phases of bacteria?

A

Lag - adjusting phase
Exponential
Stationary
Death

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66
Q

What are anaerobes?

A

Micro-organisms that preferably grow under low O2 conditions

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67
Q

How does temperature affect bacterial growth?

A

Too cold - transport processes so slow that growth cannot occur

Too hot - protein denaturation, collapse of the cytoplasmic membrane, thermal lysis

Optimum growth rate will occur at cardinal temperature

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68
Q

3 things bacteria need for metabolism?

A

Energy source
Electron source
Carbon source

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69
Q

What is a phototroph?

A

Get energy source from light

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70
Q

What is a chemotroph?

A

Gets energy source from oxidation of organic or inorganic compounds

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71
Q

What are lithotrophs?

A

Get electron source from reduced inorganic molecules

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72
Q

What are organotrophs?

A

Get electron source from organic molecules

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73
Q

What are autotrophs?

A

Get carbon source from CO2, sole or principal biosynthetic carbon source

Generate it yourself

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74
Q

What are heterotrophs?

A

Get carbon source from reduced, preformed organic molecules from other organisms

75
Q

What can E.coli use instead of oxygen as it’s electron acceptor in the ETC?

A

Nitrate

76
Q

What is fermentation?

A

When an organic compound is both the electron donor and acceptor

Reduced NADH generated in glycolysis

If there is no ETC or terminal electron acceptors , the reduced NADH needs to be oxidised back to NAD+ for glycolysis

Reduced NADH can give pyruvate it’s hydrogen creating NAD+ and lactate

NAD+ used in glycolysis to generate more ATP

If other mixed products are produced instead of lactate, process is heterosexual-fermentative

77
Q

Definition of nitrifying bacteria?

A

Bacteria which are able to grow chemolithotrophically at the expense of reduced inorganic nitrogen compounds

Eg. Nitrsomonas, nitrobacter

78
Q

Differences of bacterial genomes to eukaryotes?

A

Smaller

Genes densely packed, with no introns

Genes with related function group together (operons)

Coupled transcription and translation

Chromosomes are mainly circular not linear, and only 1 or 2 per cell

Contain plasmids

79
Q

What can happen to plasmids?

A

Become integrated into the chromosomal DNA forming an episome

80
Q

What are resistant plasmids?

A

Code for proteins to aid antibiotic resistance

81
Q

2 forms of bacterial DNA replication?

A

Bi-directional replicated - occurs during cell division and during replication of some plasmids

Rolling circle replication - occurs during replication of some plasmids and during conjugation

82
Q

3 processes involved in horizontal gene transfer?

A

Transformation
Transduction
Conjugation

83
Q

Describe natural transformation?

A

Competence:
Extracellular binding

Uptake:
Conversion to single stranded DNA
Stabilisation

Integration:
Homologous recombination

84
Q

Describe transduction?

A

Generalised:
Donor DNA from any part of the donor can be transferred

Lytic cycle part:
Bacteriophage binds to bacterial cell creating phage DNA in host, creates transducer particle (contains host DNA)

Transduction part:
Transducer particle via a bacteriophage binds and injects DNA homologous recombination creates a transduced cell (can be any of the donor DNA)

Used to transfer antibiotic resistance from one cell to another

Both are bidirectional replication

85
Q

Describe conjugation?

A

Cell to cell contact

Pilus binds cells together (F+ cell donor, and F-cell recipient)

Transfer of one strand of F plasmid into other cell through pilus, it then is synthesised in the other cells and they separate

Requires DNA synthesis

This is rolling circle replication

Initiated by the nicking enzyme Trap

86
Q

Cells with an integrated F plasmid into their chromosome are called?

A

Hfr bacteria - can transfer a lot of genes through them

87
Q

Overview of Human-microbial interactions?

A

Humans are colonised by microorganisms at birth

Most microorganisms are benign - few contribute to health and fewer pose direct threat to health

88
Q

What is normal microbial flora?

A

Microorganisms usually found associated with human body tissue

Found on skin (sweat glands mainly), respiratory tract, teeth, gut

89
Q

What is a pathogen?

A

Disease causing microorganism in a susceptible patient

90
Q

What is microbial pathogenicity?

A

The biochemical mechanisms whereby microorganisms cause disease

91
Q

Do all pathogens have an equal probability if causing infection and disease?

A

No

92
Q

Infection definition?

A

A successful persistence or multiplication of a pathogen on or within the host

93
Q

Disease definition?

A

An interaction which causes significant overt damage to the host

94
Q

Steps of infection and disease?

A 
Infection:
Exposure
Adherence
Invasion
Multiplication

Disease:
Toxicity or invasiveness (further growth at original and distant sites)
Tissue or systemic damage

95
Q

Low virulence against high virulence?

A

Basically low risk against high risk

96
Q

Factors that influence the severity of the disease?

A

Hosts immunological and physiological status
Genetic makeup
Route of infection
Dose- low, high

97
Q

What is LD50?

A

The infectious dose for 50% of population

98
Q

The decrease or loss of virulence of a pathogen is referred to as?

A

Attenuation

99
Q

To cause disease disease a pathogen has too?

A

Colonise host tissue

Grow within host tissue

Avoid host defence mechanisms

Cause damage to the host

100
Q

2 ways pathogen damage the host?

A

They produce effectors which damage host tissues

They evoke profound immune response which cause damage

101
Q

4 types of toxins?

A

Neurotoxins - cause paralysis

Enterotoxins - cause sickness and diarrhoea

Cytotoxins - cause cell death

Cytolytic toxins - damage cytoplasmic membrane

102
Q

What are AB toxins?

A

B portion binds to cell and facilitates translocation of A portion which possesses catalytic activity

103
Q

Toxic proteins that are released from pathogen cells as they grow are called?

A

Exotoxins

104
Q

Different cell types in immune system?

A

Innate Immunity:
Non specific general
Immediate response
No immunological memory

Humoral (in blood) examples:
Enzymes
Cytokines

Adaptive Immunity:
Specific to antigen
Lag time from exposure to response
Immunological memory after exposure

105
Q

How do antibodies work?

A

They recognise foreign pathogens and are said to opsonise them. This aids their uptake by Fc rectors in phagocytes, leading to their eventual destruction

106
Q

What are required for protection against intracellular pathogens?

A

T cells

T cells bind to infected cells

Perforin makes holes in infected cell’s membrane

Infected cell lyses

107
Q

Features of primary response in a vaccination?

A

The bacteria or virus injected needs to be attenuated (not dangerous), but still needs to be recognisable by immune system

108
Q

What are the advantages and disadvantages of subunit vaccines?

A

The pathogen can be grown and then use chemicals to break it apart and gather the important antigens

But very specific which can be risky

109
Q

What are the advantages and disadvantages of live attenuated vaccines?

A

Very broad spectrum so lots of protection

Can have side effects

110
Q

How do you knock out genes to make an attenuated pathogen?

A

Homologous recombination

111
Q

4 methods for classifying microbial diversity?

A

Morphological diversity
Metabolic diversity
Ecological diversity
Genetic diversity - looking at ribosomes

112
Q

What’s a hyperthermophile?

A

Microbe that lives in very hot temperatures

113
Q

What’s a psychrophile?

A

Microbe lives in very cold temmperatures

114
Q

What’s a halophile?

A

Microbe that lives in salty conditions

115
Q

What are barophiles?

A

Microbes that can live in very high pressures

116
Q

Largest group of bacteria known?

A

Proteobacteria

117
Q

Classification based on 3 domains of life?

A 
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Do
Kids
Prefer
Chocolate
Over
Fresh
Green
Salad
118
Q

largest organism in the world?

A

Honey fungus

119
Q

What do fungi make in manufacturing?

A

Enzymes

Drugs

Organic acids

Biofuels

120
Q

What organic matter are fungi major decomposers of?

A

Recycling Carbon and Nitrogen

121
Q

What can fungi do in toxic conditions?

A

Remove metals and radioisotopes

122
Q

What did Paul Nurse do?

A

Used fungus to investigate the cell cycle

123
Q

What type of people is fungi disease most dangerous for?

A

People who have a suppressed immune system

124
Q

Features of fungi?

A

Eukaryotic

Unicellular growth (yeasts) or filamentous growth (hyphae giving rise to mycelium)

Some are dimorphic so can switch between yeast form and filamentous form

Heterotrophs - an organism which cannot fix carbon from inorganic sources but uses organic carbon for growth

Fungi absorb externally digested nutrients, secrete enzyme through wall, absorb soluble nutrients through wall

Final wall made of Chitin and glucans

Fungal cell membrane - have ergosterol instead of cholesterol

Have haploid nuclei

Produce sexual and aseual spores

125
Q

What are heterothallic fungi?

A

Require 2 compatible partners to produce sexual spores, whereas homothalic ones ae capable of sexual reproduction by themselves

126
Q

2 way of growing fungi/

A

Solid state fermentation:
Just lay fungi on trays, still used to make soy sauce

Submerged fermentation:
Grown in chemostats (fermenters), can be batch or continuous culture

127
Q

95% of all fungal enzymes come from?

A

Aspergillus niger

128
Q

What are viroids?

A

Only infect plants

Very very small

129
Q

What are mycoplasmas?

A

Very small

Lack enveloped nucleus

Lack true wall

Look like fried eggs or spirals

Cause plant and animal disease

130
Q

4 species of malaria and features?

A 
Plasmodium falciparum:
90% cases in Africa
50% south East Asia
Causes most deaths, main cause of cerebral malaria
Doesn't have a dormant liver stage
Plasmodium vivax:
90% cases in Asia, South America 
50% in south east Asia 
Immunity for people with the Duffy Antigen
Can cause severe malaria 1/5 times
Does have a dormant liver stage

Plasmodium malariae:
Little bit everywhere
Milder symptoms
No dormant liver stage

Plasmodium ovale:
A bit in Africa
Milder symptoms
Does have a dormant liver stage

131
Q

Features of the plasmodium parasite (malaria causing)?

A

One end (the apex) of the sporozoite cell contains a complex of organelles specialised for penetrating host cells and tissues

Contain a unique organelle that comprises a type of plastid called a apicoplast

132
Q

Names of lifecycle stages of malaria?

A

Sporozoites - a motile spore-like stage in the life cycle of some parasitic sporozoans ( e.g. the malaria organism), that is typically the infective agent introduced into a host

Schizonts

Merozites - non motile stage

Trophozoite - the activated, feeding stage in the life cycle

Hypnozoite - sleeping stage

133
Q

What transmits malaria?

A

Female mosquitos

134
Q

Describe the actual lifecycle of malaria?

A

Sporozoites are developed in salivary glands from micro or macro gametocytes of female mosquitos and are injected with the salvia

Invade liver cells within 30-60 minutes

In hepatocyte divide asexually leading to schizonts in 6-7 days (some sporozoites enter a dormant phase called hypnozoites in some forms of malaria)

Each schizont gives birth to thousands of merozoites released into the blood from ruptured hepatocytes

Merozoites actively invade Red blood cells

Turns into a trophozoite and injests the cytoplasm

Budding forms more merozoites which burst out and infect more red blood cells

In RBC some parasites enter sexual cycle and differentiate into micro or macro gametocytes which circulate into blood and can infect mosquitos

135
Q

What causes fever in malaria?

A

Bursting of the red blood cells

Can be used to diagnose which type you have

136
Q

Advantages and disadvantages of living in a red blood cell?

A

Adv:
Is a rigid cell that supports the stress exerted by blood flow

Dis:
Nutrient poor environment
Short life cycle
They are continuously recycled in the liver/spleen and therefore exposed to the immune system

137
Q

Modifications plasmodium falciparum makes to red blood cells?

A

Promotes formation of new channels for the import and export of nutrients

Breaks down haemoglobin into amino acids

Places adhesive proteins on the surface of infected RBCS that induce adherence to the endothelium avoiding clearance by host, makes appearance looks nobbly

138
Q

2 types of trypanosome in Africa?

A

West - Trypanosoma Brucei gambiense - chronic disease

East - Trypanosoma Brucei rhodesiense - acute disease

139
Q

Lifecycle trypanosome Brucie?

A

Start in mammalian blood

Taken up by tsetse fly during feeding

Development of infective form in salivary glands

Past on during feeding in salvia

140
Q

Disease progression of trypanosome Brucie?

A

A skin lesion (chancre) may form at the bite site. Then parasite enters the blood

Parasite enters the nervous systems

Fever

Severe sleep disturbances

Coma

Death

141
Q

How does trypanosome Brucie avoid the immune system?

A

The parasites surface contains variant surface glycoproteins

Survives by changing expression of these genes, so different proteins made, so not recognised by the immune system

Done via Array, telomeric or segmental VSG conversion. Or transcriptional switch

142
Q

Features of Trypanosome cruzi?

A

South America
Affects diverse range of mammalian hosts
Infective forms develop in the hindgut in the triatomine insect
Infect you because you scratch bite, poo goes into blood

143
Q

Different phases of Trypanosome cruzi?

A

Acute:
Fever for a few weeks, can infects mucous membranes

Chronic:
Can occur 10 years later as the disease has survived in the cytoplasm of macrophages and muscle cells and neurones
Causes servere cardiacc lesions, or intestinal lesions

144
Q

How to diagnose Trypanosoma?

A

Staining blood and observing for them via microscopy

For cruzi if it’s In chronic stage, can’t see in blood so get bitten by new clean bug, then check it’s offspring for the disease = Xenodiagnosis

For brucei in late stages have to examine spinal fluid, late stage drugs very toxic can even kill the patient

145
Q

What did T. cruzi most likely Start in?

A

Bats, as they contain loads of different versions

146
Q

Advantages of living in the intestines?

A

Nutrients

147
Q

Challenges of living in the intestines?

A

Transmission
Oxygen
Movement of food
Immune system

148
Q

How is Giardia diagnosed?

A

Microscope stool

String test

149
Q

What does Entamoeba histolytic cause?

A

Ameobiasis

Can cause travellers diarrhoea

150
Q

Features of Balantidium coli?

A

Only known human infectious ciliate

Rare, but more common with people who work with pigs

Fecal-oral route of transmission

Diarrhoea with blood and muscus when symptomatic

151
Q

Features of Blastocystis?

A

Only known mammalian pathogen within the stremonophiles

May be linked to IBS

152
Q

Features of cryptosporidium?

A

Often deadly diarrhoea disease of AIDS patients

Found commonly in immune competent people

Have sporozoites stage which attach to epithelial cells using adhesive zone

Indice fusion of microvilli so the parasite becomes encapsulated by host membrane so hidden from the immune system

153
Q

What absorbs atmospheric CO2 in the sea?

A

Marine protists because they have chlorophyl

Coccolithophores

Diatoms

Dinoflagellates

154
Q

Structure of coccolithophores?

A

Are part of the group haptophyta

Enclosed by calcareous plates called coccoliths, which are made inside the organism

Each cell contains 2 brown chloroplasts which surround the nucleus

Growth not inhibited by UV light

Turn water turquoise

Produce loads of CaCO3

155
Q

Function of coccoliths?

A

Protection

Energy production

Added weight so can sink to more nutrient rich areas

156
Q

Features of Diatoms?

A

Made of silica (glass)

Have 2 different sections

Found in nutrient rich water

157
Q

Features of Dinoflagellates?

A

Can cause red tides (sea turns red)

Can flouresce bright blue so if eaten their predator will glow in dark so will be easier to be preyed on so they will avoid eating them in first place

Have lifecycle where they replicate in corals, they provide lots of energy for the corals as well

158
Q

What do termites produce a lot of?

A

Methane

Have microbes in gut which breaks down cellulose overall with Archae produces methane from H2

Similar in cows

159
Q

When can you study protist fossils?

A

When embedded in Amber (tree sap)

160
Q

What’s the Archezoa hypothesis?

A

Ribosomal RNA sequencing suggesting several early branches protists don’t have mitochondria

161
Q

What’s a hydrogenosome?

A

is a membrane-enclosed organelle of some anaerobic ciliates, trichomonads, fungi, and animals.

162
Q

What’s an apicoplast?

A

Organelle

Surrounded by 4 membranes, so formed via secondary endosymbiosis ( protist takes in a protist which has taken in a cyanobacteria eg. containing a mitochondria or chloroplast)

It’s essential, so a target in malaria protist

163
Q

What is endosymbiosis?

A

When a protist took up a cyanobacteria containing an organelle which eventually becomes part of the cell

Key role in mixing up vertical ancestry in tree of life in eukaryotes

164
Q

5 Main supergroups of eukaryotes?

A 
Opisthokonta
Amoebozoa
Excavata
Archaeplastida
Sar

Unikonts contains Opisthokonta and Amoebozoa

Chromalveolata and Rhizaria are the 2 base groups of SAR

165
Q

Features of Chanoflagellates?

A

They Opisthokonta

Have flagellum for movement in water

Obtain food by trapping it in their microvilli and engulfing it

166
Q

Features of Microsporidia?

A

Only live within cells

Cause disease in fish and immunocompromised people

167
Q

Features of Plasmodial slime moulds?

A

Amoebozoa

Move via mass cytoplasmic streaming

Eats bacteria and yeast

168
Q

Features of cellular slime moulds?

A

Amoebozoa

Under nutrient starved conditions swarm to form a slug which moves

169
Q

Types of excavata?

A

Euglena - mixotroph
Kinetoplastids -medically important vector Borne pathogen

All types are normally water borne

170
Q

Types of Archeaplastida?

A

Made up of plants and algae

171
Q

Features of stramenopiles?

A

Sar

Have a characteristic flagellum with numerous fine hair like projections

Includes:
Diatoms - glass cell wall
Oomycetes

172
Q

Features of Alveolates?

A

Sar

Sac bellow their plasma membranes

Includes:
Ciliates
Dinoflagellates
Apicocomplexans

173
Q

Features of Rhizaria?

A

Sar

Foraminifera - largest single celled organism in deep sea

174
Q

5 types of Firmicutes (Low G + C and gram positive)?

A

Lactobacillus - Lactic acid producers, human commensal

Streptococcus - many human pathogens and commensals

Staphylococcus - some human pathogens

Bacilus - endospores and some human pathogens

Clostridium - Anaerobes, endspores and human pathogens

175
Q

3 types of actinobacteria (high G + C and gram positive)?

A

Actinomyces - Filamentous, branching and some human pathogens

Frankia - symbiotic nitrogen fixers

steptomyces - filamentous and produce antibiotics

176
Q

4 types of alpha Proteobacteria (gram negative)?

A

Agrobacterium - plant pathogen
Bradyrhizobium - symbiotic nitrogen fixer
Nitrobacter - Nitrifying
Rhizobium - symbiotic Nitrogen fixer

177
Q

1 type of beta Proteobacteria (gram negative)?

A

Neisseria - human pathogen

178
Q

3 types of gamma (Y) Proteobacteria (gram negative)?

A

Shigella - human pathogen
Escherichia - human commensal, some pathogens
Salmonella - human pathogen

179
Q

1 type of Delta (δ) Proteobacteria (gram negative)?

A

Bdellovibrio - uses other bacteria as host

180
Q

2 types of epilson (ε) Proteobacteria (gram negative)?

A

Campylobacter - human pathogen

Helicobacter - human pathogen

181
Q

Features of pesticides eg. chloroaromatics?

A

Many percolate through soils, sediments, into ground water and the subsurface, accumulate exceeding inter government limits and are toxic

182
Q

Toxicity within the environment is associated with?

A

Human health implications including reproductive, teratogenic, mutagenic and carcinogenic effects

183
Q

Exam is referenced

A

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Also show outside reading and innovation

Organism name is underlined

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Definitions are key

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Human Biosciences (69 decks)

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