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Biology > Microorganisms > Flashcards

Microorganisms Flashcards

1
Q

Why are viruses not considered living species

A

Do not consist of cells
Cannot reproduce independently
Cannot perform respiration because they don’t have mitochondria
Can survive long periods as crystals

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2
Q

What is the basic structure of a virus

A

Very small
Comprised of nucleic acid surrounded by protein capsule
Contain DNA or RNA, never both
They are acellular - do not have nucleus, cytoplasm and organelles
Some enclosed in sheath of protein and lipid molecules

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3
Q

What are the general characteristics of viruses

A

They are obligate intracellular parasites = can only reproduce inside a living cell
Can infect bacterial cells, these viruses are known as bacteriophages
All pathogenic
Reproduce by changing the host cells genetic material into viral DNA or RNA

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4
Q

Viruses are host specific, what does this mean?

A

They are capable of living in certain species

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5
Q

Which kingdom does bacteria belong in

A

Kingdom monera

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6
Q

What lifestyle do bacteria have

A

Can be autotrphic, heterotrophic, and pathogenic

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7
Q

What is the basic structure of bacteria

A

Smallest and simplest living organisms
Unicellular but cells can clump together to form filaments
Have a cell wall made from polysaccharides, proteins and lipids
Some have a slime layer to protect from dessication and our immune system
Prokaryotic = no true nucleus
DNA is concentrated in one area known as the nucleoid
Have thread like flagella for swimming

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8
Q

What are the different shapes of bacteria that can be found

A

Vibrio = comma shaped
Spirillium = spiral
Coccus = round
Bacillus = rod shaped

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9
Q

What are the general characteristics of bacteria

A

All unicellular
Prokaryotic
Autotrphic bacteria produce through photosynthesis or chemosynthesis
Most bacteria are heterotrophic; they get their food by being either parasitic, saprotrophic, or mutualistic
Reproduce asexually by binary fission

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10
Q

How can bacteria be useful to us

A

Drive nutrient cycles e.g: nitrogen cycle
Involved in food webs
Can have mutualistic relationships e.g: in our guts
Economic use e.g: sewage treatment
Decomposes

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11
Q

How can bacteria be harmful to us

A

Pathogenic

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12
Q

What is the basic structure of protists

A

All eukaryotic
Unicellular or multicellular
Mostly aquatic
Most contain cellulose cell wall but diatoms have capsules of silica
Can reproduce asexually through binary fission or sexually

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13
Q

What are the 3 Main groups of protists

A

Protozoa - animal like, unicellular and heterotrophic e.g: amoeba, paramecium, plasmodium
Algae - plant like, unicellular/multicellular, autotrophic e.g: phytoplankton - euglena and diatoms and kelp
Slime moulds and water moulds - fungus like, multicellular and heterotrophic

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14
Q

What is the basic structure of fungi

A

Can be macroscopic (multicellular) e.g: mushroom, or microscopic (unicellular) e.g: yeast
Have cell walls made from chitin
Heterotrophic
Eukaryotes
A few are parasites e.g: athletes foot and ring worm
Others live mutualistically e.g: lichens

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15
Q

What is Rhizopus

A

A multicellular mass of filaments where each each individual filament is known as hyphae

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16
Q

What is the structure of a rhizopus

A

All the filaments together are known as mycelium
Mycelium is vegetative - it has non-reproductive parts and sporangia are the reproductive parts
The reproductive structures produce spores which are wind dispersed
Terrestrial fungus (live on land; cool and dry conditions)
Three types of hyphae that make up mycelium: stolons, rhizoids and sporangiophores
Rhizopus is thallus because there are no roots, stems or leaves

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17
Q

What importance do microorganisms have as producers

A

Some bacteria can photosynthesise
Other bacteria can make organic compound from chemicals (chemosynthesis)
Chemosynthesis is only energy supply to ecosystems found at deep sea vents
Photosynthesising protists important in oceans
These microorganisms capture energy and pass it to consumers

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18
Q

What importance do microorganisms have as decomposes

A

Bacteria and fungi = main decomposers
Remove dead plant and animal matter from environment
Release nutrients from the dead organisms for re-use

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19
Q

What role do microorganisms play in the nitrogen cycle

A

Lots of nitrogen in air but it’s unavailable for plants and animals to use
Bacteria in soil and root nodules can convert nitrogen to nitrates
Plants use the nitrates to create plant protein
Animals eat plants and create animal protein from the plant protein
Animals return nitrogen into soil a urea or ammonia

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20
Q

What is the role of microorganisms in mutualistic symbiotic relationships

A

Nitrogen fixing bacteria in plants convert nitrogen into nitrates that plants can use, bacteria get carbohydrates and place to reproduce in return
E.coli lives in human gut and produces vitamin k which humans need for blood clotting, in return bacteria gets food and a place to live

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21
Q

What is fermentation

A

A process in which microorganisms undergo anaerobic respiration, converting glucose into carbon dioxide and ethanol

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22
Q

What is an example of traditional biotechnology

A

African people use fermentation to make amasi and umqombothi

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23
Q

What are examples of biotechnology in today’s food industry

A

Making beer - yeast ferments to create alcohol and carbon dioxide
Making wine - traps are stomped into pulp and ferment because of yeast cells in the air
Baking bread - Carbon dioxide created by yeast causes doubt to rise
Making cheese - lactic acid bacteria convert lactose into lactic acid

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24
Q

What economic use does bacteria have

A

Production of food by fermentation
Decomposition of sewage
Industrial production of enzymes, ethanol and perfumes
Production of antibiotics and steroids
Biological pest control - bacteria used to kill pests instead of pesticides
Bioremediation - getting rid of poisonous waste products

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25
Q

What economic use do protists have

A

Algae =source of food e.g: seaweed
Gelatine is harvested from algae and used in making jelly and agar
Good source of minerals in supplements and fertilisers

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26
Q

What economic use do fungi have

A

Can be eaten as foods e.g: mushrooms
Yeast used in production of bread, wine and beer
Production of some cheeses
Production of antibiotics

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27
Q

What are the effects of HIV/AIDS

A

Decreases CD4 count and immune system weakens
Flu like symptoms appear as CD4 count drops
Eventually opportunistic diseases e.g:TB and pneumonia strike
Infection now becomes AIDS
Death caused from one or more opportunistic diseases

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28
Q

What effects does HIV/AIDS have on SA’s economy

A

Mostly affects people in prime working years
Loss of workers = negative effect
Mining industry has high infection rate = indirect revenue loss due to absenteeism
Direct loss of revenue because of medicine and resources needed to take care of AIDS orphans

29
Q

What effects does HIV/AIDS have on children and families

A

Babies born HIV positive because of HIV positive parent
Breadwinner can die of HIV = children abandoned/orphans
These children get separated from their families and are institutionalised

30
Q

How do HIV cells reproduce

A

HIV attaches to helper-T cells
Uses reverse transcriptase to make DNA of itself
Viral DNA instructs host nucleus to make many parts of HI Virus

31
Q

How can HIV/AIDS be managed through testing

A

Test to know your HIV status and then to take take the necessary precautions and medications

32
Q

How can HIV/AIDS be managed through treatment

A

No cure, but treatment available to decrease viral load and increase CD4 count
Treatments: 1. ARVs to decrease viral load
2. Healthy diet to support immune system
3. Treatment of opportunistic diseases as required
4. PEP (post exposure prophylaxis) treatment within 24 hours of exposure

33
Q

How can prevention help in the management of HIV/AIDS

A

get educated aboutHIV/AIDS and take preventative measures to not get HIV/AIDS
1. Avoid sexual intercourse
2. Be faithful to one partner
3. Practise safe sex
4. Avoid direct contact with blood

34
Q

What are some beliefs and attitudes associated with HIV/AIDS

A

Carries stigma because it is life threatening, associated with negative social behaviour e.g: prostitution and requires a strong therapy that negatively affects external appearance
Stigma can lead to loss of partner, loss of job and loss of dignity

35
Q

What are some common myths associated with HIV/AIDS

A

HIV can be transmitted through sneezing and mosquito bites
An HIV positive person can become resistant to HIV by having intercourse with a virgin

36
Q

What is tuberculosis

A

Infectious disease caused by mycobacterium tuberculosis bacteria that mainly affects the lungs, but can also occur in other organs.

37
Q

How is TB spread

A

Airborne disease - transmitted through small respiratory droplets

38
Q

Which factors contribute to SA’s high TB infection growth rate

A

High rates of AIDS (TB is an opportunistic disease)
Malnutrition/poor diet in rural populations (immune system not strong bc lack of nutrients)
Overcrowding
Lack of medical infrastructure
Lack of education in rural population

39
Q

What are the effects of TB

A

Bacteria reproduce causing infection in lung
Immune system can prevent TB from spreading if it is strong enough
If immune system is weak, TB becomes active where pneumonia occurs repeatedly and disease spreads to other parts of body
Get symptoms of coughing, tiredness, weight loss, night sweating

40
Q

What effects does TB have on family and community

A

Loss of income because TB patient is off work for some months
If TB patient dies = loss of breadwinner
Stigma to having TB
May infect other family members

41
Q

How does treatment help in managing TB

A

6 month antibiotic course can be taken
Can’t infect others while on this course
Some stop taking antibiotics because they feel better = cause drug resistant TB
DOTS programme (directly observed treatment, short-course) helps in making sure people eat their treatment everyday

42
Q

How can prevention help in managing TB

A

Population can be educated on importance of healthy diet, hygienic living and fresh air
Babies can be vaccinated to build their immune system
Better immune system = disease won’t spread

43
Q

Why would an organ transplant patient be susceptible to TB

A

After transplant they’re given immunity suppressants to prevent body from rejecting the new organ, but immunity suppressants also means that opportunistic diseases can strike

44
Q

What is the difference between drug resistant, multi-drug resistant and extreme drug resistant TB

A

DR: don’t respond to the medication
MDR: don’t respond to at least 2 of the available medication
EDR: don’t respond to any of the available medications

45
Q

What causes drug resistant TB

A

Poorly managed use of the antibiotics

46
Q

What causes malaria and how is it transmitted

A

caused by parasitic protist genus plasmodium
Transmitted by Anopheles mosquito

47
Q

In which regions is it popular

A

In tropical and sub-tropical regions

48
Q

Malaria has 2 hosts, how does this work

A

Malaria needs both mosquitos and humans to reproduce
When mosquito sucks blood of infected person, malaria enters mosquito, multiplies and moves to mosquito’s salivary glands
When mosquito sucks blood from another person it injects saliva to stop the human’s blood from clotting
Malaria enters the new person and multiplies in the liver and blood cells

49
Q

What are some symptoms of malaria

A

Flu like symptoms
Pain in the back and legs
Abdominal pain
Nausea and vomiting
Can lead to death especially in children

50
Q

How does malaria affect the economy

A

Treatment for malaria is expensive
Malaria patient is sick = off work or can die = loss of breadwinner

51
Q

How can malaria be prevented

A

Eliminate mosquito:
Spray inner walls of house with DDT (insecticide)
draining swamps
Putting film of oil on water harbouring the vectors
Stop them from biting:
Sleep under mosquito net
Wear long sleeve at night
Use bug spray
Take prophylactic medication

52
Q

What is an immune response

A

The way in which an organism protects itself from pathogenic viruses, bacteria, protist or fungi

53
Q

How does immune response work in plants

A

Only have natural immunity
Release chemicals such as salicylic acid which travels throughout the plant to warn other cells of danger (those cells produce other chemicals)
The infected cells are destroyed to prevent infection from moving

54
Q

What are examples of natural immunity in humans

A

Skin is sealed off = first line of defence
Coughing and sneezing reflexes blast pathogens out from our airways
Tears are antiseptic = wash bacteria from our eyes
Inflammation and fever slow multiplication and spread of pathogen

55
Q

How does acquired immunity work

A

After pathogens have penetrated
Pathogens have antigens on their surfaces and leucocytes identify pathogens using these antigens
Leucocytes destroy or neutralise the pathogen
Leucocytes: lymphocytes and phagocytes

56
Q

Where do lymphocytes occur

A

Spleen, lymph glands and blood

57
Q

What are the 2 types of lymphocytes

A

B-lymphocytes
T-lymphocytes

58
Q

How do B-lymphocytes work

A

Have receptor proteins which bind to specific antigens on pathogen
B-lymphocyte recognises the pathogen as foreign and reproduces more B-lymphocytes
These B-lymphocytes produce antibodies which attach to matching antigens and do one of the following:
1. Mark the pathogen for ingestion by phagocyte
2. Cause pathogens to clum together which makes them inactive
3. Cause pathogen cell to burst

59
Q

How do T-lymphocytes work

A

Recognise and destroy cells infected by a virus
Virus hides in host cell, therefore B-lymphocytes cannot find them
Antigens of virus are on host cell so T-lymphocytes are able to identify and destroy them
CD4 cells = type of T-lymphocyte

60
Q

He does a person become immune to an infection

A

When they get infection for first time B-lymphocytes and T-lymphocyte fight the infection
Some T and B-lymphocytes have memory cells that stay in the blood and immediately recognise the pathogen when a person is re-infected = faster response = don’t become ill = immune

61
Q

How do phagocytes work

A

Large amoeba like white blood cells
Engulf the pathogens = phagocytosis

62
Q

Where are phagocytes produced

A

Red bone marrow

63
Q

How do antibodies (produced by B-lymphocytes) help phagocytes

A

Pathogens marked for phagocytosis
Pathogens clumped together and inactive

64
Q

What is immunisation

A

The administration of a vaccine to develop immunity to a disease

65
Q

How do vaccines work

A

Dead or weakened form of disease is injected and body produces its own antibodies or the antibodies of another host are injected

66
Q

How can people gain acquired immunity

A

Naturally acquired immunity:
Passive - baby gets antibodies from mother through placenta and milk
Active - person gets into direct contact with pathogen and immune system produces antibodies
Artificially acquired immunity:
Passive - antibodies of another host injected
Active - weakened form of the apogee are injected

67
Q

How do antibiotics work

A

Destroy bacteria in 1 of 3 ways:
1. Weaken cell wall and cause bacterium to burst
2. Damage cell membrane and contents leak out
3. Inhibit metabolism of the bacteria

68
Q

How does resistance to bacteria happen

A

Random mutations of bacteria occurs and some bacteria are more resistant to antibiotics than others
If course of antibiotics isn’t complete, weaker bacteria are killed but more resistant bacteria survive
More resistant bacteria continues breeding

69
Q

Why does resistance to bacteria happen

A
  1. Not completing course of antibiotics
  2. Incorrect antibiotics prescribed
  3. Antibiotics prescribed for viral infections
  4. Unnecessary use of antibiotics

Biology (8 decks)

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