General Disease Info Flashcards

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1
Q

What is a disease?

A

A disease is any condition that interferes with how an organism or any part of it, functions.

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2
Q

When is a disease infectious?

A

Disease are described as infectious (communicable), if they are caused by an invasion by a pathogen and can be transmitted from one host to another. contagious conditions that impair the functioning of an organism.

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3
Q

What is a host?

A

A host is an organism infected with a pathogen.

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4
Q

When does an infection occur?

A

Infection occurs if a pathogen has entered a host, has established itself and is replicating.

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5
Q

When do symptoms arise?

A

Unwanted signs and symptoms usually result from damage to the tissues and organs of the host.

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6
Q

How do microbiologists identify the cause of a specific disease?

A
  1. The potential pathogen must always be present when the disease occurs
  2. The organism can be isolated from the host and grown in pure culture.
  3. When organism from the pure culture are inoculated into a healthy, susceptible host and the disease develops this is further evident for a specific cause
  4. The organism can them be re-isolated, grown in pure culture and compared with the organism first injected for confirmation.
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7
Q

What is a pathogen?

A

A pathogen is an infectious agent that causes disease.

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8
Q

List all the viral diseases in this course.

A
  • Influenza
  • Ross River Virus Disease
  • Viral Diseases of Honeybees
  • Australian Bat Lyssa-virus
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9
Q

List all the bacterial diseases in this course.

A
  • Tuberculosis
  • Tetanus
  • Crown Gall Disease of Plants
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10
Q

List all the fungal diseases in this course.

A
  • Chytridiomycosis (amphibian chytrid fungus disease)
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11
Q

List all the protist diseases in this course.

A
  • Malaria
  • Phytophthora Dieback
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12
Q

What are contagious diseases?

A

Disease that are easily transmitted by close contact with an infected organism or their secretions (body fluids) are called contagious.

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13
Q

What are zoonotic diseases?

A

Zoonotic disease are infectious diseases that can be transmitted from one vertebrate group to another.

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14
Q

When can indirect contact occur?

A

May occur when a susceptible host comes into contact with areas where infected animals live or roam, where surfaces or objects have been contaminated.

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15
Q

What are the three types of contact?

A
  • Close contact
  • Direct contact
  • Indirect contact
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16
Q

What is pathogenicity?

A

A pathogen’s disease-causing capacity.

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17
Q

What are symptoms?

A

The effects the pathogens has on the body of the host

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18
Q

What is the definition for incubation period?

A

The time between infection and the onset of symptoms is known as the incubation period.

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19
Q

Why does the incubation period occur?

A

Pathogen may have to divide many times to reach number sufficient to cause disease, may take time to reach the target tissues that are susceptible to that particular pathogen, toxins produced by bacteria as waste products may take time to accumulate to a level that affects the host.

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20
Q

What are viruses ?

A

Viruses are non-cellular pathogens. they consist of one or more strands of nucleic acid inside a protein coat. they maintain this structure during the inert phase of their life cycle, that is when they are non inside a host.

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21
Q

Are viruses considered non-living?

A

Viruses are non made out of cells are therefore are non-living. they possess no metabolic machinery for processes such as cellular respiration. can’t be classified as eukaryotic or prokaryotic.

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22
Q

Describe structure of viruses.

A

Instead of cellular features such as ribosomes and mitochondria, they have some nucleic acid and a protective coat.

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23
Q

What is a obligate parasite?

A

An organism that cant function outside the host cell.

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24
Q

What is a protein coat also know as?

A

Capsid.

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25
Q

Why are viruses specific?

A

Each virus is usually limited to infected a specific host cell or organism. this is because the virus is able to recognise and bind to receptors the are expressed only on certain cells.

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26
Q

Why are viruses pathogenic

A

Becaause all viruses require host cells to replicate, and therefore all viruses are pathogenic. The host will experience symptoms when a virus is replicating inside the host’s cells.

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27
Q

Describe the cell wall of bacteria.

A

A cell wall outside their plasma membrane, made of peptidoglycan (a protein-carbohydrate compound).

28
Q

What is a bacterial tail called?

A

Flagellum.

29
Q

What is a bacteria adaptation in some species?

A

Simely bacterial capsule, helps it stick to surfaces such as mucous. it is a thick, well-organised layer sitting outside the cell wall. it usually increases the virulence of a species, makes it harder for bodies immune system attach the inner bacterium.

30
Q

What are bacteria able to form?

A

Tough, dormant structure called endospores, resistance to extreme temperatures, chemicals and drying out, adaptation helps resist unfavourable conditions and facilitates dispersal to new hosts.

31
Q

Describe binary fission

A

One cell splits into two identical daughter cells, begins when the DNA of the bacterium doubles in quantity then divides into two (replicates). The bacterial cell then elongates and splits into two daughter cells, each with DNA that is identical to that of the parent cell.

32
Q

What are the two ways bacteria can reproduce?

A
  • Binary fission
  • Budding off spores
33
Q

What are there different shapes of bacteria?

A
  • Spherical, known as coccus
  • Rod-shaped, known as bacillus
  • Spiral
  • Vibrio, rather like a comma
34
Q

How do scientists classify bacteria shape?

A

Many strains of bacteria have differences in the structure and composition of their cell walls, causing them to respond differently to stains and dyes.

35
Q

All structural features of bacteria.

A
  • Are unicellular, prokaryotes
  • Have no membrane-bound organelles
  • Have circular DNA and plasmids
  • May have flagella for movement
  • Reproduce via binary fission or budding off spores
  • (endospores)
  • Are microscopic, 1-10 micrometers in length
  • Can be spherical, rod-shaped, spiral or vibrio
  • Vary in their ability to be stained (e.g. Gram stain)
36
Q

What do bacteria do once inside host?

A

Once inside a host, bacteria divide rapidly. some bacteria damage host tissues directly, while others produce powerful toxins that disrupt the functioning of cells nearby or even further away.

37
Q

How are viruses taken up by cells?

A

Viruses are small enough to be taken up by host cells via receptor-mediated endocytosis.

38
Q

How are bacteria taken up by cells?

A

Some bacteria can enter host cells via phagocytosis, this process is performed by specialist white blood cells such as macrophages. macrophages normally ingest then destroy foreign microbes.

39
Q

Structural features of fungi.

A
  • Are eukaryotic cell structure with membrane-bound
  • Organelles/nucleus
  • Have a cell wall made of chitin
  • Are unicellular or multicellular
  • Can be microscopic or macroscopic
  • Can be made up of filaments (hyphae)
  • Can have a body consisting of a mass of hyphae,
  • Known as the mycelium.
40
Q

What is a zoospore?

A

A spore with a flagellum.

41
Q

What a flagellum?

A

A flagellum is a long tail that, through whip-like motion, propels the spore form of fungi through water.

42
Q

Why are multi-cellular filaments important to fungi?

A

They play an important role in how they obtain food. filaments are long and thin. which gives them a high surface area for absorption.

43
Q

What are hyphae.

A

A network of tiny filaments that forms together to form hyphae, hyphae have strong tubular cell walls (made of chitin) surrounding the cell membrane of each cell.

44
Q

What is mycelium?

A

Hyphae grow to form an interwoven mass known as a mycelium. mycelium can infiltrate the tissues of the host on which it feeds. most fungi produce spores, either through sexual or asexual reproduction.

45
Q

What are sporangia?

A

The mature mycelium forms sporangia (singular sporangium), which release spores. when the spores make contact with a new, moist food source, they may germinate to form a new mycelium.

46
Q

Two types of protists.

A
  • Protists in the genus Plasmodium
  • Protists in the genus Phytophthora
47
Q

Key structural features of protists.

A
  • Are relatively small 2-1000 um
  • Are eukaryotes, with a membrane-bound nucleus
  • Are mostly unicellular
  • Can reproduce sexually and/or asexually
  • Can exist in different form during their life cycle,
  • Depending on their classification (for example, spores or zoospores, filaments, hyphae and mycelia)
  • Can be plant-like, animal-like or fungi-like in their structural or reproductive features.
48
Q

what are species in the genus plasmodium?

A

belong to a protista group resembling animals

49
Q

what are species in the genus Phytophtora?

A

beloong to a group fo protista resembling plants

50
Q

what are plasmodiums refered to as?

A

animal like protista are sometimes referred to as protozoa. they are classifyed into the parasitic group called sporozoa (apicomplexa). they spread through their host in the form of tiny infectious cells called sporozoites.

51
Q

features of plasmodium protista

A

they have no chlorophyll or cell walls.

52
Q

features of apicomplexians

A

apicomplexians were given this names because at one end, the apex, the sporozoite cell contains specialised organalles for penetrating host cells. they have no means of locomotion.

53
Q

what is special about phytophtora

A

they have a cellulose-based cell wall. Phytophthora is classified into a group called Stramenopiles because they have a distinguishable flagellum. and a set of flagella, (one hairy, one smooth) for locomation, and an extensive network of filaments that allow for nutrient uptakes.

54
Q

what is special about phytophtora spores

A

part of the pathogen’s life cycle includes the production and release of large quantities of spores that effectively transmit these pathogens to new hosts. phytophtora spores are flagellated and therefore can be referes to as zoospores. zoospores can only be found in some protists and chytrid fungi.

55
Q

describe the stages of lifecycles of a virus

A
  • Virus binds to specific host cell
  • Host cell engulf virus via endocytosis
  • Virus is unpackaged in host cells
  • Virus DNA/RNA integrates into host DNA
  • Host cell makes copies of viral DNA/RNA and
    proteins
  • Viral components repackaged
  • New viruses expelled from cell via exocytosis
56
Q

Antiviral chemical therapies

A

when binding to target cell
virus would be blocked from engry and unble to replicate

being unpacked in target cell
virus DNA/RNA would not be copied and be unable to replicate/spread

57
Q

Antiviral chemcial therapies pt.2

A
  • repacking virus
    virus not assembled and not able to spread
  • expelling virus via exocytosis
    virus not released and doesn’t spread
  • between entry into host +entry into target cell
    virus would not reach target cell and unable to replicate
58
Q

thing to talk about when comparing pathogens

A
59
Q

what are mucous membranes

A

Mucous membranes are surfaces that are moistened with slimy, sticky, viscous mucous. Mucous membranes are found in the human respiratory, gastrointestinal, and reproductive tracts.

60
Q

difference between a symptom and a sign of a disease.

A

A symptom is a subjective experience felt by a patient, such as nausea or pain
a sign is an objective and measurable experience of a pathogen host that is directly observable: elevated body temperature, breathing rate, pulse rate and/or blood pressure are important ‘vital’ signs of disease.

61
Q

methods of direct transmission

A

Direct contact = tranmision of a pathogen through physical touch between the infect host and a susceptible host via skin or body fluids.

close contact = transmitted through airbourne droplets when there si close proximity (usually within 1.5 meters) between infect and susceptible host, particularly by sneezing, singing, or coughing.

from a reservoir = transmission can occur from a reservoir directly to susceptible host.

62
Q

methods of indirect transmission

A

living vectors are usually a vertebrate or an arthropod that transmits a pathogen from an infected host to a susceptible host. Bats and mosquitos can be vectors

airborne droplets. Pathogens can be transmitted inside airborne droplets (aerosols) that are sneezed or coughed into the air and are suspending in the air currents for a period of time before being inhale or landing on a surface such as a tale or tissue (a fomite).

Soil, water, food, and fomites. Non-living objects can carry a disease-causing agent from one host to another during the life cycle of a pathogen. Fomites are surfaces or objects that can carry an infectious agent. Such as a car, tyres, clothing ,eating utensils and mobile phones. Some diseases can also survive in soil and water until they find a suitable host. Crown gall and phytophthora are two examples of diseases that can be spread by non-living objects.

63
Q

what is a reservoir

A

A reservoir is a living or non-living site in which a pathogen normally resides and possibly replicates. The pathogen may be dormant in this site.

64
Q

difference between direct and indirect transmission

A

Direct transmission is the transfer of a pathogen from an infected host, or other reservoir, to a susceptible host by direct contact or close contact. Indirect transmission is the transfer of a pathogen from a reservoir to a host through vectors (inanimate vehicles or living intermediaries) or suspected air particles.

65
Q

difference between direct and indirect transmittion via airborne droplets.

A

Direct transmission of air borne droplets occurs when the host inhales the droplets whilst they are still suspended in the air. Indirect transmission of air borne droplets occurs when the droplets land on a surface of tissue (a fomite). Transmission is indirect because it does not occur until later, when a susceptible host touches the fomite or inhales droplets.