Dealing with disease 9

Question 1

Pathogen

Answer 1

cellular and non cellular agents that cause disease
which include bacteria, viruses,
fungi, protozoa, prions, and worms

Question 2

Disease

Answer 2

• Conditions where part or all of an organisms normal bodily functions are upset or fail to function
  properly
• can be infectious, contagious and/or
  genetic

Question 3

Infectious Disease

Answer 3

-Condition that impairs normal function of an organism
- caused by the invasion
/ growth of a pathogen within an organism and can be passed from one host to another

Question 4

Endemic: (low level)

Answer 4

a disease restricted to a region or part of a region and is present in a
relatively low level of the population

Question 5

Epidemic: (mid-level)

Answer 5

• A disease that affects a large number of individuals at the same time
• Disease usually travels quickly and is easily transmitted

Question 6

Pandemic: (global)

Answer 6

-A disease that is worldwide distributed and affects everyone.
- This disease is easily
transmitted

Question 7

Control infectious disease:

Answer 7

1. Behavioural Control (Ex: Condoms/thongs/sunscreen)
2. Modifying the environment (Draining swampy ground / spraying disinfectants)
3. Treatment (Antibiotics/Antivirals)
4. Immunisation

Question 8

Transmission of disease:

Answer 8

Vector Transmission – bites from variety of animals can introduce pathogens (mosquitos / dogs)

Vehicle Transmission – transmission via medium such as blood, water, food or air

Question 9

Other disease types

Answer 9

society – drug abuse, alcohol, heart disease | environment – safe drinking water,
sanitation, food | genetics – familial, spontaneous

Question 10

Antigen

Answer 10

-a substance that is
recognized by the immune
system as either foreign or self.
-foreign antigen -->trigger an
immune response

Question 11

There are two types of antigens: Self and non self, what is non self?

Answer 11

molecule from
outside the body that is recognised
by the immune system and
initiates an immune response

Question 12

Major histocompatibility complex

(MHC) proteins

Answer 12

- a group of
proteins present on the surface of
cells that enable the immune
system to distinguish between
self/non-self material.

Question 13

Autoimmune disease

Answer 13

a condition where the immune system no
longer recognizes self-antigens as self and B and T cells attack cells
as they are seen as foreign/non-self

Question 14

Allergen

Answer 14

a non-pathogenic antigen

that triggers an allergic reaction

Question 15

Allergic reaction

Answer 15

an inappropriate
immune response to a
non-pathogenic antigen

Question 16

What are the two MHC classes and where are they present:

Answer 16

Class I MHC Antigens – on surface of all body cells (except
RBC), cells invaded by virus have Class 1 MHC Markers altered by
the viral proteins and thus recognised as non-self

Class II MHC Antigens – are restricted by antigen presenting

Question 17

what are the features/Nature of Disease and describe them,

Answer 17

Virulence – intensity of the pathogenic effect, degree pathogen inflict damage on host

Resistance – individual’s level of susceptibility to pathogen

Incubation Period – the time between infection and symptom development, depends on pathogen achieving
sufficient number, reaching target tissue and toxin accumulation

Question 18

Cellular pathogens

Answer 18

a pathogen
that has a cellular structure and
exhibits the processes of a living
organism. Examples include
bacteria, fungi, protozoa, and
parasites such as worms

Question 19

Non-cellular pathogens

Answer 19

a pathogen
that has a cellular structure and
exhibits the processes of a living
organism. Examples include
bacteria, fungi, protozoa, and
parasites such as worms

Question 20

Bacteria

Answer 20

• Unicellular prokaryotes that can infect almost any part of the body
• cellular
• meningitis, tetanus

Question 21

Fungi

Answer 21

-Eukaryotic organisms  like 
yeasts and moulds and contain long,
branching filaments called hyphae.
-cellular 
- They can cause a variety of diseases
in humans including thrush, athlete’s foot.

Question 22

Worms

Answer 22

-Multicellular invertebrate parasites
whose development include egg,
larval, and adult stages
-cellular 
- Parasite (e.g. tapeworm)
infection leading to
malnutrition

Question 23

Protozoa

Answer 23

-Single-celled eukaryotes that can be
free-living or parasitic.
-cellular 
-Plasmodium causing
malaria

Question 24

Viruses

Answer 24

-An infectious agent composed of
genetic material (DNA or RNA)
inside a protein coat (capsid) and  surrounded by a lipid
envelope. Viruses are not able to
independently reproduce, instead
they insert their genetic material
into a host’s cell and using the
cell to replicate.
- Non cellular 
- Rhinovirus causing the
common cold
-Influenza causing the flu
-Ebola virus causing
ebola

Question 25

Prions

Answer 25

-Abnormally folded proteins that can induce normal
proteins nearby to become
misfolded. Only occur in
mammals and only affect the
brain and other neural structures. Currently the only known infectious agents that don’t contain nucleic acids
- Non-Cellular  
-Creutzfeldt–Jakob
disease, Bovine spongiform
encephalopathy
(also known as
mad cow disease)

Question 26

First Line of Defence

Answer 26

A component
of the innate immune system
characterised by the presence
of physical, chemical, and
microbiological barriers to keep
pathogens out of the
host organism

Question 27

Physical barrier

Answer 27

a component
of the first line of defence that
features solid or fluid obstacles
that block pathogen entry e.g.
skin, mucus

Question 28

Chemical barrier

Answer 28

a component
of the first line of defence that
features solid or fluid obstacles
that block pathogen entry e.g.
skin, mucus

Question 29

Microbiological barrier

Answer 29

n invasion
microbiological barrier a
component of the first line of
defence in which the presence of
normal flora limits the growth of
pathogenic bacteria

Question 30

Examples of physical barriers in Human

Answer 30

• Intact skin and surfaces between external and internal environments
(e.g. respiratory, gastrointestinal, and genitourinary tracts)
• Mucous secretions and/or hairs in the respiratory tract that trap organisms,
and cilia that sweep them away from the airways and into the thr

Question 31

Examples of chemical barriers in Human

Answer 31

• Presence of lysozyme enzymes in tears and saliva that destroy bacterial
cell walls
• Antibacterial compounds in earwax
• Stomach acid that destroys pathogens that have been eaten/swallowed
• Acidic sweat that destroys pathogens growing on the surface of the body
• Antibacterial proteins in semen
• Low pH in the vagina

Question 32

Examples of microbiological barriers in Human

Answer 32

• Presence of bacteria on the skin and in the lower gastrointestinal tract
• Non-pathogenic organisms in the vagina

Question 33

Examples of physical barriers in Human

Answer 33

• Waxy cuticles of leaves
• Thick bark
• Formation of galls to prevent the spread of infection
• Closing of stomata to prevent pathogen invasion during carbon dioxide
uptake
• Presence of thorns and trichomes to deter insects and grazers

Question 34

Examples of chemical barriers in Plants

Answer 34

• Chitinases – enzymes that occur in a number of different plants and have
antifungal properties
• Oxalic acid – a substance that can be toxic if ingested
• Phenols – secreted by wounded plants, phenols repel or kill many
microorganisms
• Saponins – disrupt the cell membranes of various fungi
• Glucanases – defend plants against fungi
• Defensins – small peptides that are toxic to microbes and fung

Question 35

innate immune system: Second line of deference

Answer 35

a component of the immune
system that is comprised of
generalised and non-specific
defences and/or responses to
pathogens. Also known as the
non-specific immune system