7B - First Line of Defence

Question 1

innate immune system 

Answer 1

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

Question 2

first line of defence

Answer 2

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 3

second line of defence 

Answer 3

component of the innate immune system characterised by the nonspecific response to injury and/or pathogens by a VARIETY OF CELLS AND MOLECULES

Question 4

physical barrier 

Answer 4

a component
of the first line of defence that
features solid or fluid obstacles that block pathogen entry such as
skin or mucus

Question 5

chemical barrier 

Answer 5

a component
of the first line of defence that features the use of enzymes, toxins, and acids to protect against
pathogen invasion

Question 6

examples of physical defence in plants

Answer 6

Thick bark
* Waxy cuticles of leaves
* Formation of galls (abnormal outgrowth of tissues) to prevent the spread of infection
* Presence of thorns and trichomes (small hairs on plant surface) to deter insects and grazers
* Closing of stomata to prevent pathogen invasion during carbon
dioxide uptake

Question 7

Chitinases –

Answer 7

enzymes that occur in a number of different plants and have antifungal properties

Question 8

Oxalic acid –

Answer 8

a substance that can be toxic if ingested

Question 9

• Phenols –

Answer 9

secreted by wounded plants, repelling or killing invading
microorganisms

Question 10

microbiological barrier

Answer 10

component of the first line of defence in which the presence of normal flora limits the growth of
pathogenic bacteria. Also known as microbiota barrier

Question 11

normal flora

Answer 11

microorganisms that are always present on or in a person and usually do not cause any disease.

Question 12

examples of physical barriers for animals

Answer 12

Intact skin and surfaces between external and internal environments
* Mucous secretions and/or hairs in the respiratory tract that trap organisms, and
cilia that sweep them away from the airways and into the throat where they are
swallowed and destroyed by the gastrointestinal tract

Question 13

chemical barriers in animals

Answer 13

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

Question 14

microbiological defence in animals

Answer 14

Presence of bacteria on the skin, in the lower gastrointestinal tract, and the vagina