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Nutrition Semester 2 > BMS1064 - Microbiology > Flashcards

BMS1064 - Microbiology Flashcards

(48 cards)

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1
Q

All life belongs to one of which 3 lineages?

A

Bacteria, Archae or Eukarya

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2
Q

What was Koch’s postulates?

A

4 criteria to establish a causal relationship between microbes and disease

e.g.infecting mice with microbes and observing disease/effect.

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3
Q

How have Koch’s postulates (suggestions of theroy) influenced modern medicine?

A

Established systematic method for IDENTIFYING agents of disease.

Helped development of DIAGNOSTIC techniques.

Helped scientists understand the MECHANISM of disease

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4
Q

How big are bacterial cells?

A

10-100 micometers

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5
Q

What are some uses of bacteria?

A

Decompose organic matter and recycle nutrients

Breakdown of pollutants

Food/drink

Biotechnology of fuels and drugs

Immune development and human health

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6
Q

What are extremophiles (Archae)?

A

Bacteria able to live in the most extreme conditions.

e.g. high temp, salt, acid/alkali, even petrol!

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7
Q

The cell walls of bacteria contain what to provide strength?

A

Peptidoglycan

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8
Q

What is the difference between gram neg and gram pos bacteria?

A

Types of cell walls.

GRAM NEGATIVE
Have lipopolysaccharides (LPS).
Have an outer and inner membrane.
Important for evading phagocytosis and a barrier to certain antibiotics.

GRAM POSITIVE
Have teichoic acids. Thicker cell wall. Only inner membrane.

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9
Q

What is the difference between a capsule and slime layer?

A

CAPSULE = firmly attached and highly organised

SLIME LAYER - unorganised and loosely attached.

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10
Q

What are the differences in dying gram pos and neg bacteria?

A

Gram-pos:
- stain purple
- as doesn’t decolourise

Gram-neg:
- stain red
- as crystal violet and iodine decolourises and then stained by safranin

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11
Q

What are fibriae and pili?

A

Hair-like structure. Shorter, stronger and thinner than flagella.

Involved in DNA transfer (bacteria sex) and forming biofilms.

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12
Q

Endospore formation is an extreme survival strategy for Gram _____ bacteria.

Endospores are ______ forms of bacterium, highly resistant to environemtnal extremes.

Spores can be a big issues in ______.

GIve some examples.

A

positive

dormant/inactive

food

e.g. Bacillus sp. and Clostridia sp.

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13
Q

What is the name for the method in which bacteria divide and multiply?

A

Binary fission

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14
Q

What are the 4 phases of bacterial growth?

A

LAG PHASE - slow growth

EXPONENTIAL PHASE - exponential growth

STATIONARY phase - numbers remain stable

DEATH phase - population decreases in size.

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15
Q

Why is there a lag phase in bacterial growth?

A

Time required to start up cell functions

TIme needed for chemical composition of cells necessary for growth to be established.

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16
Q

What causes the shift between exponential phase and stationary phase?

A

Nutrients in excess in exponential phase.

By consuming nutrients and releasing toxic chemicals, the cels modify the growth environment until it no longer supports rapid growth.

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17
Q

How do you measure bacterial growth?

A

Directly by counting bacterial cells
- plate counts
- microscopy
- flow cytometer

Indirectly by estimating numbers based on other measurements
- optical density (spectrophotometer)
- measuring respiration (CO2 production, reduction of dye etc)

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18
Q

What colour dyes show whether cells are alive or dead?

A

Green = alive
Red = dead

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19
Q
A
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20
Q

What is colonial morphology?

Study These Flashcards
A

The visable appearance of bacterial/fungal colonies on an agar plate.

Can help to identify microbe

21
Q

How else can bacteria be identified?

22
Q

Give examples of viruses

Study These Flashcards
A

Tobacco mosaic virus
Foot and Mouth disease
SARS

23
Q

What is a virus?

Study These Flashcards
A

An infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy and is able to multiple only within the living cells of a host.

24
Q

How is genetic info stored in viruses?

Study These Flashcards
A

Encoded as one linear circular piece of DNA or RNA.

25
How do viruses multiply?
Inject DNA into host cell. Host cell makes viral proteins, which assemble and burst out of cell.
26
What are enteric viruses?
Viruses spread through the faecal oral route.
27
Does viral multiplication occur in foods?
No - food acts as a passive vehicle
28
What is Poliomyelitis?
(Also known as Polio) ssRNA virus. Produces headache, fever and sore throat after 3-5 days. Can be asymtomatic in children. Sometimes progresses to persistent viraemia leading to invasion of nervous system --> paralysis/death Those who survived were trapped in devices to help them breathe.
29
What is Hepatitis A?
ssRNA virus. transmitted via faecal oral route. Transmitted person to person but also caused by contamination of food handler who is infected -> milk, strawberries, lettice... Also from shellfish and sewage Early symptoms include anorexia, fever, nausea, abdominal pain and vomiting. 90% children have no symptoms. Symptoms may be followed by liver damage --> dark urine and jaundice.
30
What is Norovirus?
ssRNA virus. Causes inflammation of stomach or intestines. 24-48 hours. Actute gastroenteritis: - diarrhoea - vomiting - nausea - stomach pain - fatigue No vaccine currently available. Control good hygiene.
31
What are Fungi?
Eukaryotes - contain membrane-bound organelles. Single to multicellular organisms. Primary decomposters of dead organic matter.
32
How can fungi be classified?
- Morphology - by the structures produced during sexual reproduction - By evolutionary relationships.
33
Filamentous fungi consist of thin, threadlike filamets called ________. Some contain cross-walls (____) which divide them into distinct unicleate cell-like units. Nono-filamentous fungi (e.g. _____) can look like bacteria and form colonies on plates. _____ or _____ shaped cells. Some fungi exhibit _______ - able to exist in both forms of growth.
hyphae septa Yeasts Round or oval Dimorphism
34
How do fungi survive?
They are heterotrophs - they do not make their own food but instead obtain nutrients from pre-formed sources of organic carbon. Fungi are the principle decomposers in every ecosystem (saprotrophs). Like animals, they store their food as glycogen.
35
GIve 2 examples of fungi which affect plants.
Rice blast disease Late potato blight
36
What are the roles of fungi in foods?
Yeasts -> bread, fermented dairy products etc Protein and vitamins -> mushrooms, plant-based meat alternative (e.g. quorn)
37
What is the fungus found in Quorn? How is it's structure similar to meat? What is it also good for use in?
Fusarium Venenatum A micro fungus - has microscopic spore structures. The hyphae are similar in length and width to animal muscle fibres. Also good as substitute for fat in dairy products and cereal in breakfast snacks/cereals.
38
How is Quorn produced?
Fungus grown in aerobic conditions in vessels. The culture is fed glucose and trace minerals for growth. Temp kept at 28-30 degrees C. Filtration used to harvest it. Dried and blsended with a binder (rehydrated egg white).
39
Give an example of fungus in cheese.
Roqueforte cheese Sheeps milk. Anti-intflammitory properties have been linked to this product.
40
40
What are protists? What is Protozoa?
One of the 6 kingdoms of life. Eukaryotic Seen as evolutionary bridge between bacteria and multi-celled organisms. Protozoa is another name for these animal-like protists.
41
What are 2 examples of protozoan diseases?
Malaria and Toxoplasmosis
42
Which protozoa should we be concerned about related to foods/water?
Giardia and Entamoeba Cryptosporidium and Toxoplasma (propagated via spores)
43
Describe Giardia lamblia
Eukaryotic. Found in animal and human faeces (changing nappies). Thrives in contaminated food, water and soil. Survives outside of host for long time. Most common way to get it is through drinking contaminated water -> swimming pools, lakes etc From food is less common due to heat treatment.
44
Describe Entamoeba histolytica.
Causes ulcerated colon and diarrhoea. Endemic in poor communities. More common in tropical areas. Usually transmitted via faecal-oral route, but emergy as an STD. Survives as cyst in the environment.
45
Describe Cyptospordium
Causes diarrhoea (also can cause persistent cough). Becomes an issue in immuno-compromised. Outbreaks most commonly linked to pools ,cattle and childcare.
46
Describe Toxoplasma gondii.
A single cell parasite Causes an infection called toxoplasmosis. World-wide problem. Persists for long time in humans (and animals) - even for life. Very few symptoms BUT pregnant women and individuals with compromised immune systems should be cautious -> flu symptoms... Sever toxoplasmosis causes damage to brian, eyes or other organs. Small % of infected new borns have serious eye/brain damge. CAUSES: undercooked meat/shellfish, cross contamination from knives etc, Drinking contaminated water, contact with cat faeces, ingesting contaminated soil
47
How to control these protozoea infections?
Improve hygiene Cooking meat and shellfish properly Good water treatment facillities -> monitoring

Nutrition Semester 2 (23 decks)

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