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Biology Yr 12 > Disease > Flashcards

Flashcards in Disease Deck (108):
1

How do bacteria replicate?

A image thumb
2

3 ways to classify bacteria.

Staining

Shape

Clustering

3

2 staining outcomes.

Gram +

Gram -

4

4 bacteria shapes.

Cocci (spherical cells)

  • diplo = pairs
  • strepto = chains
  • staphylo = clusters

Bacilli (rod shaped)

Spirilla (spiral shaped)

Vibrio/filamentous (like a comma)

5

3 types of bacterial clusters.

Diplococci (pairs)

Streptococci (chains)

Staphylococci (cluster)

6

How do viruses replicate?

A image thumb
7

5 steps of viral replication.

  1. Adsorption
  2. Penetration
  3. Replication
  4. Assembly
  5. Release

8

Describe the 1st stage of viral replication (adsorption).

Viral binds to the host cell.

9

Describe the 2nd stage of viral replication (penetration).

Virus injects its genome into host cell (DNA or RNA).

10

Describe the 3rd stage of viral replication (replication).

Viral genome replicates using the host’s cell machinery.

11

Describe the 4th stage of viral replication (assembly).

Viral components and enzymes are assembled into coats.

Genome is packaged inside.

12

Describe the 5th stage of viral replication (release).

Host cell lyses and many more viral particles can infect other cells within host.

13

Describe reverse transcriptase.

Some viral particles containing RNA use it to replicate

  1. RNA is converted to DNA.
  2. They use the host cell machinery to replicate their genome (make their protein coats and RNA genome).

14

What cells do viruses infect?

Any type of cell.

15

Define bacteriophages.

Viruses that infect bacteria.

16

How are viruses classified?

Their genome

Eg: double stranded DNA, single stranded DNA, single stranded RNA, etc.

17

Define diseases.

Any malfunctions of the body/part of the body of an organism.

 

18

Define pathogens.

Disease causing agents.

19

Define infectious/communicable diseases.

Diseases that:

  • Can be transmitted from one organism to another.
  • Are caused by pathogens.

20

Define non-infectious diseases.

Diseases that:

  • Cannot be transmitted from one organism to another.
  • Aren't caused by pathogens

21

2 non-cellular pathogens.

Viruses

Prions

22

Describe viruses.

Contains DNA or RNA

Molecule encased in a protein (or two protein layers) that may be covered in a lipid layer.

Shape varies greatly.

Much smaller than bacteria (0.5 to 0.01 times the size).

Can only reproduce inside a living host.

23

Describe prions.

Small infectious proteins

24

Example of a prion.

vCDJ (variant Creutzfeldt-Jakob disease)

25

4 cellular pathogens.

Bacteria

Fungi

Protists

Minor groups of parasites

  • Endoparasites
  • Ectoparasites

 

 

26

Describe bacteria.

Microscopic

Unicellular

Prokaryotic

No membrane bound organelles and nuclei.

Cell wall made of sugars and amino acids.

Single ‘spaghetti-like’ strand of DNA

27

Describe fungi.

Eukaryotic

Generally multicellular

Microscopic fungi are generally larger than bacteria.

Reproduce using spores.

Cell walls made of chitin (carbohydrate).

Contain hyphae (branching threads) that form a mass called a mycelium.

Hyphae are usually divided along their lengths by walls called septa that have pores in them to allow nutrients to pass from one cell to adjacent cells

28

Describe protists.

Eukaryotic.

Can be unicellular or multicellular

Reproduce sexually and asexually.

Have no complex systems.

Have a variety of shapes depending on their locomotion.

Generally cannot move themselves.

29

Describe endoparasites.

Live inside another organism – usually intestines

Some use other animals as intermediate hosts and humans are the definitive host.

30

Examples of endoparasites.

Flatworms

Roundworms

Flukes

31

Describe ectoparasites.

Live on the surface of another organism.

Many are vectors for other diseases such as the plague (bacteria).

32

Examples of ectoparasites.

Fleas

Ticks

Lice

33

Define virulence.

The intensity of the effect of the pathogen.

34

Define susceptibility/resistance.

The level of response of an organism to a pathogen.

35

Define symptoms.

Characteristic effects of a pathogen on the body.

Signs of the disease in the host.

36

Define incubation period.

The time between infection and the onset of symptoms.

37

4 parts of a pathogenic infection.

  1. Infection
  2. Incubation
  3. Symptoms
  4. Recovery

38

Define endemic diseases.

Occur at a relatively constant rate within a population

39

Define sporadic diseases. 

Uncommon

Occur irregularly

40

Define epidemics.

Occur when there is an increase in the number of cases of a disease within a population is above normal 

Rapidly spread.

May be triggered by:

  • Increased virulence
  • Introduction into a novel setting
  • Changes in host's susceptibility

41

Define pandemics.

An epidemic

Infects large numbers of humans over multiple populations/continents/worldwide.

Rapid spread over multiple populations/continents/worldwide.

42

Factors involved in the spread of disease.

Climate

Population density (urbanisation)

Infrastructure

Urban areas susceptible to epidemics and pandemics

43

What are the hosts of Influenza (virus)?

Numerous animals

  • Humans
  • Mammals
  • Birds

44

What are the signs and symptoms of Influenza (virus)?

Fever

Sore throat

Cough may persist and gradually deteriorate for several weeks

Runny nose

Headache

Muscle pains

Lethargy 

45

What are the hosts of Ross River virus?

Humans

  • Mosquito (vector)
  • Animal (source such as kangaroo)

46

What are the signs and symptoms of Ross River virus?

Stiff painful joints

Rash

Swollen lymph nodes

Reduced mobility

47

What are the hosts of the Aussie bat lyssavirus?

Humans

  • Bats (particularly Flying foxes) appear to be a reservoir of the virus

48

What are the signs and symptoms of the Aussie bat lyssavirus?

Paralysis

Convulsions

Delirium

Death 

49

What are the hosts of the viral diseases of honey bees?

Honeybees

  • Potentially mites (vector)

50

What are the signs and symptoms of the viral diseases of honey bees?

Collapse of hive

Significant reduction in plant pollination

Leads to honey shortage

51

What are the hosts of Tetanus (bacterial)?

Humans

Horses

Cattle

52

What are the signs and symptoms of Tetanus (bacterial)? 

Muscle spasms (lockjaw)

Swallowing and breathing difficulties (possible breathing failure)

Abnormal heart rhythms leading to high or low blood pressure.

Painful fits

Heart attacks 

53

What are the hosts of Tuberculosis (bacterial)?

Humans

Cattle

Pigs

Birds

Dogs

Cats

54

What are the signs and symptoms of Tuberculosis (bacterial)?

Chronic cough

Coughing blood

Lethargy

Sweating

Weight loss

55

What are the hosts of the Crown of Gall affecting plants (bacterial)?

Deciduous fruits

Vine (e.g. grapes)

Berry fruits

Vegetables

Ornamentals (e.g. roses)

56

What are the signs and symptoms of the Crown of Gall affecting plants (bacterial)?

Small, pale lumps on upper root/stem

  • Develop into large asymmetrical growths
  • May stunt the growth of a young plant.

May kill plants that are stressed in dry conditions

57

What are the hosts of Chytridiomycosis (amphibian chytrid fungus disease) (fungal)?

Amphibians

  • Frogs

58

What are the signs and symptoms of Chytridiomycosis (amphibian chytrid fungus disease) (fungal)? 

Loss in body weight

Lethargy

Skin colour changes

Shedding of skin

Convulsions

Death

59

What are the hosts of Malaria (Protista)? 

Humans

  • Mosquito (vector) (Anopheles genus)

60

What are the signs and symptoms of Malaria (Protista)?

Fever

Hot and cold spells

Shaking

Headaches

Muscles aches

Weakness

61

What are the hosts of Phytophthora dieback (Protista)?

Several native species of plants:

  • Eucalyptus
  • Grass tress
  • Banksia

62

What are the signs and symptoms of Phytophthora dieback (Protista)? 

Leaves may wilt then die (outer first progressing inwards towards trunk)

Roots may darken in colour

Most plants die, particularly if under water stress

63

The spread of a specific disease involves what interrelated factors?

Growth of the pathogen population

Density of the host population

Mode of transmission

64

What facilitates the transmission and spread of disease?

Regional/global movement of organisms

65

Describe Dengue fever

Mosquitoadaptedd to living in urban environments as it can breed in artificial water pools (water tanks and buckets).

Can spread rapidly because of the high population density in urban environments and numerous water sources

66

What are the vectors of Dengue fever?

Humans

  • Mosquitos (vector)

67

What are the signs and symptoms of Dengue fever?

Fevers

Muscle aches

Headaches

Rashes

Death

68

How do pathogens evolve?

Evolve in a changing environment

Bacteria divide/reproduce once every 20 mins under ideal conditions

Numerous opportunities for mutations

New strains produced

Opportunities for a more virulent strain is endless

69

What do design interventions include?

Implementing programs

  • Vaccination programs
  • Quarantine measures

70

Management strategies used to control the spread of infectious diseases.

Quarantine

Immunisation (herd immunity)

Disruption of pathogen life cycle

Medications – antibiotics and antivirals

Physical preventative measures

71

Advantages of quarantine.

Prevent specific pathogens from crossing borders or entering a country

72

Disadvantages of quarantine.

Inadequate checks by customs can result in a disease entering a country

Borders are porous to human and other organisms’ movements.

Illegal activities

Ignorance from travellers

73

Advantages of immunisation (herd immunity).

If large proportion of population has immunity, the small number of population who are not immune are protected to some extent

They live in a population in which the spread of that disease will be interrupted or stopped by people who are immune

Greater proportion of people who are immune, greater protection of those within the population who are not immune

Mass vaccination creates a ‘herd immunity’ - whole population is protected

74

Disadvantages of immunisation (herd immunity).

Large proportion of population decide not to have the treatment for themselves (or their children) - large population is at risk.

Epidemics are much more likely.

Resistant strains are more likely to develop in these circumstances that in time can affect the vaccinated.

75

Advantages of the disruption of pathogen life cycle.

If disease is spread by vector, transmission can be interrupted if vector is eradicated

76

Disadvantages of the disruption of pathogen life cycle.

Mosquito eradication programs (e.g. malaria) will not remove the mosquito entirely.

Insects become resistant to insecticides.

Removal of suitable breeding places not possible in tropics and sub-tropics where disease is endemic.

77

Advantages of medications (antibiotics/antivirals).

Successful treatment for infectious disease (e.g. antibiotics) normally reduces transmission.

Early intervention (usually prior to becoming contagious) minimises spread.

78

Disadvantages of medications (antibiotics/antivirals).

Pathogens frequently develop a resistance to drugs.

79

Advantages of physical preventative measures.

Isolation necessary to reduce the spread.

Reduce exposure to public. 

Special equipment used by health workers such as respirators, gloves and special clothing

Washing hands to prevent direct contact or faecal-oral routes.

Preventative measures include sterilisation of all soiled (contaminated) equipment, clothing, bedding and treatment of human wastes

Barriers such as condoms prevent the transmission of several venereal diseases (e.g. HIV)

Early diagnosis essential to containment

80

Disadvantages of physical preventative measures.

Communicable diseases are still transferred to health workers and those closest to patients

May occur through error or ignorance of the disease

Health workers occasionally contact disease (e.g. Ebola in west Africa) despite protective clothing and masks

81

Define nosocomial infections.

Infections spread by healthcare workers.

82

Describe the immune system.

Made up of different cells that protect our bodies from foreign organisms

Homeostatic mechanism

Protects against foreign organisms, alien chemicals, cancerous/abnormal cells

83

Define antigens.

Any substance capable of causing an immune response.

84

Define antibodies.

Specialised proteins that are produced in response to a non-self antigen.

They attach to a specific antigen (lock and key model) and destroy or inactivate the foreign antigen

85

86

4 modes of action by antibodies to inactivate antigens.

Bind to Virus Surface

Coat Bacteria

Combine with Foreign Enzymes or Bacterial Toxins

Agglutination

87

Describe the action of antigen binding to virus surface.

Prevent the viruses from entering cells

88

Describe the action of antibodies coating the bacteria.

Bacteria are more easily consumed by phagocytes (white blood cells)

89

Describe the action of antibodies combining with foreign enzymes or bacterial toxins.

Either one of these:

  • Inhibits reactions with other cells/compounds
  • Dissolves organisms
  • Reacts with soluble antigens and makes them insoluble 

90

Describe agglutination.

Causes particles (bacteria/viruses/foreign blood cells) to clump together

91

Steps in immune response

  1. Primary response-first exposure to antigen
  2. Large amounts of antibodies are built up to fight antigen (takes several days)

  3. Primary response leaves the immune system with memory cells of the specific antigen

  4. Secondary response-subsequent exposures result in a much faster response because of the memory cells

92

Define immunisation.

Programming of the immune system to allow the body to rapidly respond to infecting micro-organisms.

Results in a secondary response

Can occur naturally or artificially

93

94

Describe passive (no memory cells) immunity.

Natural

  • Antibodies enter bloodstream across the placenta/in breast milk

Artificial

  • Antibodies injected into bloodstream (snake antivenom)

95

Describe active (memory cells) immunity.

Natural

  • Attack of a disease results in the ability to manufacture antibodies

Artificial

  • Antigens provided by a vaccination results in the ability to manufacture antibodies

96

Define vaccination.

The artificial introduction of antigens of pathogenic organisms so that the person can produce a secondary response of antibodies without the person having to suffer the disease

97

Define antibiotics.

Chemicals able to either:

  • Inhibit the growth of micro-organisms
  • Kill micro-organisms

98

Define antiviral drugs.

Chemicals that disable viral proteins

99

4 types of vaccines.

Living attenuated micro-organisms (reduced virulence)

Dead micro-organisms

Toxoids (inactivated toxins)

Sub-unit (fragment of the organism)

100

What do living attenuated microorganisms protect against?

Measles

Mumps

Rubella

Rabies

Tuberculosis

101

What do dead microorganisms protect against?

Cholera

Bubonic plague

Typhoid

Whooping cough

102

What do toxoids protect against?

Tetanus

Diphtheria

103

What do sub-units protect against?

Hepatitis B

Human papilloma virus (HPV)

104

Define herd immunity.

When vaccinations reduce the chance of disease and increase the immunity of the population

When a particular proportion of a population is immune, susceptible individuals are also better protected.

105

How are diseases classified?

Environmental

Genetic

Cardiovascular

Cancer

Injuries

Blood and immune system

Infectious and parasidic

 

106

Define phages.

Viruses that infect bacteria.

107

Define viroids.

Plant pathogens consisting of circular RNA.

108

Define capsids.

Protein shells with the shape depending on the type of virus.