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MBB163 > Wainwright (Spring) > Flashcards

Wainwright (Spring) Flashcards

1
Q

Without MOs there’d be no life on Earth, why?

A
  • maintain atmospheric mix (prod and consume N, O etc. by feedback)
  • maintain soil fertility
  • remove wastes, inc sewage
  • break down leaf litter and wastes (mainly fungi)
  • cycle elements, essential for plant growth
    • -> bacteria cycle N, P and S
    • -> fungi cycle C
  • marine algae main CO2 adsorbers, phytoplankton decrease man made CO2 in oceans
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2
Q

What do all organisms req for growth?

A
  • source of energy

- C for building biomass

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3
Q

What is heterotrophy and the 2 types?

A
  • energy obtained by breaking down preformed C via resp
  • aerobic (more efficient), C –> CO2 + H20 + heat
  • anaerobic, C –> CH4 ( C also goes to form biomass)
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4
Q

What is autotrophy and the 2 types?

A
  • gain energy by performing chem reactions
  • C obtained by fixing CO2
  • chemoautotrophy (bacteria), NH4+ –> NO2- –> NO3-
  • photoautoptrophy (ps), in higher plants and algae
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5
Q

Purpose of nitrogen cycle

A
  • N req by all living organisms to make protein
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6
Q

In what form do plants take up N?

A
  • nitrate or NH4
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7
Q

Steps of nitrogen cycle

A
  • ammonification/ N-minerilisation
  • nitrification
  • denitrification
  • N fixation
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8
Q

Ammonification/ N-minerilisation

A
  • 1st step
  • converts organic N to NH4+
  • done by most aerobic and anaerobic bacteria, so occurs under most env conditions, eg. waterlogged soils
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9
Q

Nitrification

A
  • eg. of chemoautotrophy
  • bacteria Nitrosomonas ox NH4+ to NO2- and gains energy, while fixing atmospheric CO2
  • Nitrobacter ox NO2- to NO3- and gain energy while fixing CO2
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10
Q

Denitrification

A
  • under anaerobic conditions (soil waterlogging), NO3- red to N2(g) (= dinitrogen)
  • large no. heterotrophic bacteria do this
  • NO3- lost to farm land (negative process)
  • sewage operatives use to convert urea to safe waste gas
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11
Q

N fixation

A
  • symbiotic process between certain plants and Rhizobium
  • common in legumes or asymbiotic plants
  • bacteria (eg. azotobacter) live as “free living” N-fixers and not in direct symbiotic assoc w/plants
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12
Q

Where does symbiotic N-fixation occur?

A
  • root nodules
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13
Q

“Infection” process

A
  • Rhizobium attracted to plant root
  • infection occurs through crack in root
  • Rhizobium multiplies greatly and prod bacteroid
  • plant lays down nodule around bacteroid
  • plant donates C (sugars) to Rhizobium, which donates N by fixing atmospheric N2
  • this is mutualistic symbiosis
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14
Q

How is Rhizobium attracted to plant?

A
  • each plant prod own specific attractant for specific Rhizobium
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15
Q

Why is sewage treatment needed?

A
  • increasing pop, mainly Victorian London
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16
Q

Main aim of sewage treatment

A
  • removes organic faeces and urine
  • removes pathogens from drinking water
  • remove solid C wastes
  • remove N waste, urea leads to NO2- prod, toxic to newborns and NO3- prod, can cause stomach cancers
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17
Q

How did sewage systems evolve during industrial revolution?

A
  • civil engineers, eg. Bazalgette, did lots to intro sewage systems in London etc.
  • simple improvements made big difference, eg. egg shaped sewers to allow rapid flow at bottom
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18
Q

Where is sewage a major problem?

A
  • urban centres w/ large pops
  • industrial areas which prod heavy metals and pollutants
  • intense agriculture, eg. large scale beef prod on feedlots
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19
Q

How can human and animal waste spread disease?

A
  • bacteria cause cholera, food poisoning etc.

- viruses cause polio

20
Q

Types of sewage system

A
  • septic tank
  • filter bed/contact bed
  • activated sludge process
21
Q

Septic tank

A
  • simplest system
  • aerobes at top of tank and anaerobes at bottom
  • water passed into soil into distribution field
  • MOs in soil finish purification
  • distribution field must be away from water supply
22
Q

FIlter bed/contact bed

A
  • bed made of coke/limestone, covered w/ biofilm

- works in same way as septic tank

23
Q

Activated sludge process

A
  • most efficient
  • aerobes at top of tank and anaerobes at bottom
  • solid waste moved to anaerobic digester
  • CH4 given off made into energy or sold
  • some of material taken back to beginning to stop dilution of organisms
24
Q

Testing drinking water for waste

A
  • BOD (biochem O demand)
  • full (no air bubbles), use O2 probe to measure amount, leave in dark for 3 days and measure again (so no ps), if MOs then O2 levels decrease as use O2
25
Q

Testing drinking water for pathogens

A
  • membrane coliform count (want it to be low)
  • measure non pathogenic E. Coli (indicator organism)
  • usually incubated at 37ºC, or 44ºC for faecal coliforms
26
Q

What is MRSA?

A
  • methicillin resistant staphylococcus aureus
27
Q

Methicillin

A
  • broad spectrum antibiotic

- resistant bacteria usually resistant to other penicillins

28
Q

Last resort antibiotic

A
  • vancomycin

- resistance to this also developing

29
Q

MRSA big killer

A
  • kills more is US and Europe than AIDS

- causes 1/2 soft tissue and skin infections in intensive care

30
Q

Indolent infections

A
  • slow to heal, esp in those w/ type II diabetes
31
Q

Why are alternatives to antibiotics req?

A
  • take time and money to develop

- little profit, so less incentive and req govt input

32
Q

Biotherapy

A
  • using live organisms on body

- distinct from use of chemicals prod by MOs

33
Q

Maggot therapy

A
  • treat long standing indolent antibiotic resistance wounds
  • use green blowfly, not blue
  • modern version dev by Baer = Debridement therapy
  • maggots eat rotting flesh, won’t eat bone and prod own antibiotics that aid healing
34
Q

Honey therapy

A
  • used on external indolent wounds, eg. mastectomy
  • many bacterial pathogens sensitive to antibac properties of manuka honey
  • works by:
    –> osmotic effect (low water activity as most water
    molecules assoc w/ constituent monosaccharides)
    –> H2O2 (released by slow ox of glucose, acts as
    antiseptic
    –> pH (too acidic for most bacteria to grow
    –> non-peroxide antibiotic activity
35
Q

Mycotherapy

A
  • use of living mycelium of antibiotic prod fungus on wound
  • prod penicillin, patulin and complex chemicals
  • ‘homemade penicillin’
36
Q

Danger of fungal infections

A
  • major killer in AIDS patients, as immunocompromised
37
Q

In what form can fungal infections survive?

A
  • saprophytes
38
Q

Where do fungal infections affect?

A
  • affects skin and mucus membranes, as like damp

- eg. throat, vagina, anus

39
Q

Dermatophytases

A
  • skin infections by filamentous fungi
  • eg. ringworm
  • breakdown skins keratin by prod keratinases
  • can be caught from soil or animals, =keratinophilic
40
Q

Predisposition

A
  • genetically susceptible to infections
41
Q

Mucosal yeast

A
  • eg. thrush
  • looks like large bacteria
  • reprod by budding
  • often latrogenic infections (= passed on by doctors)
  • dimorphic
42
Q

Systemic mycoses

A
  • eg. Farmers lung, airborne spores grow inside lung, mimics TB
  • can infect organs, eg. lungs, heart, liver
  • can be fatal
43
Q

Mycetoma

A
  • eg. Madura foot, grows in lymph system and blocks it, liquid build up
  • common cause of limb loss in dev countries
44
Q

Fungi infections in AIDS

A
  • P. carinii thought to be protozoa, found to have life cycle on lungs
  • thrush main killer, final infection
  • now antifungal antibiotics, but no antifungal immunisation vaccines
45
Q

Antifungal antibiotics

A
  • griseofulvin, dermatophyte skin infections
  • nystatin, thrush infections by peccary/douche
  • amphotericin B, systemic fungal infections
  • fluconazole, thrush infections, taken orally

MBB163 (7 decks)

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