Unit 4 AoS 1

Question 1

ch 7 - pathogen

Answer 1

• An agent that causes disease
• cellular (eg. bacteria) or non-cellular (eg. prion)
• extracellular (eg. worms) or intracellular (eg.virus)

Question 2

ch 7 - antigen

Answer 2

• A molecule that may trigger an immune response
• may be attatched to a cell/pathogen
• can exist as DNA, RNA, sugars and proteins

Question 3

ch 7 - major histocompatibility complex class I markers

Answer 3

• a group of proteins expressed on surface of all nucleated body cells, marks them as ‘self’ and prevents immune system from attacking them

(not RBCs)

Question 4

ch 7 - major histocompatibility complex class II markers

Answer 4

• group of proteins displaying a foreign antigen expressed on surface of APCs which interact with T helper cells in antigen-presentation

Question 5

ch 7 - non-self antigens

Answer 5

• antigens that immune system recognises as foreign, and attacks

Question 6

ch 7 - autoimmune disease

Answer 6

• a malfunction in the immune system where it recognises self-antigens and non-self and launches an attack on self cells

Question 7

ch 7 - allergen

Answer 7

• a non-pathogenic antigen that triggers an immune response - an allergic reaction
• eg. peanuts, dust, pollen

(non-pathogenic - no disease)

Question 8

ch 7 - allergic reaction

Answer 8

• an overreaction of the immune system due to the presence of an allergen - a non-pathogenic antigen that the immune system recognises as non-self

Question 9

ch 7 - disease

Answer 9

• an abnormal condition that disturbs the normal structure or function of an organism, causing harm

Question 10

ch 7 - bacteria

Answer 10

• mostly extracellular pathogens
• prokaryotic - reproduce asexually via binary fission
• can cause disease by producing toxins or enzymes that disrupt cell function or cause cell death
• eg. Clostridium tetani - tetanus

Question 11

ch 7 - protozoa

Answer 11

• extracellular pathogens
• eukaryotic single-celled - can reproduce sexually and asexually
• free-living or parasitic
• cause disease by : disrupting nucleic acid or protein systhesis, disrupting cellular respiration
• plasmodia - malaria

Question 12

ch 7 - fungi

Answer 12

• extracellular pathogens
• eukaryotic single/multicellular - reproduce sexually and asexually (spores)
• cause disease by multiplying and spreading through body tissues
• have long filaments - hyphae
• eg. Candida albicans - thrush

Question 13

ch 7 - worms

Answer 13

• extracellular pathogens
• eukaryotic multicellular parasites - reproduce sexually - complex cycle
• cause disease by behaving as a parasite, taking nutrients/resources from host
• helminthes cause tapeworm

Question 14

ch 7 - virus

Answer 14

• intracellular pathogens made up of DNA/RNA, caspid surrounding genetic material, and sometimes an envelope.
• infectious non-living agents - rely on host cell mechanisms to reproduce
• cause disease by causing cell lysis during viral replication, can lead to cancer by affecting gene expression
• eg. influenza virus - the flu

Question 15

ch 7 - prions

Answer 15

• extracellular pathogens
• non-living pathogens that are abnormally folded proteins
• only affect brain and other neural structures in mammals
• cause nearby proteins to misfold throughout a tissue
• eg. bovine spongiform encephalopathy (mad cow’s disease)

Question 16

ch 7 - the first line of defence

Answer 16

A component of the innate immune system characterised by the presence of physical and chemical barriers in plants and animals, and microbiological barriers in animals that aim to prevent pathogen entry and spread

Question 17

ch 7 - physical barrier

Answer 17

• A component of the first line of defence that features solid or fluid barriers that physically block pathogen entry and spread

Question 18

ch 7 - chemical barrier

Answer 18

• a component of the first line of defence that features the use of chemicals like enzymes, toxins or acids to prevent pathogen entry and spread

Question 19

ch 7 - physical barriers in plants

Answer 19

• waxy cuticle: repels water and blocks pathogen entry
• galls: localised swelling that contains an infection
• closing of stomata: prevent pathogen invasion during gas exchange

Question 20

ch 7 - chemical barriers in plants

Answer 20

• oxalic acid production: toxic to herbivores, insects and pathogens
• chitinase production: breaks down fungal cell walls
• defensin production: toxic to fungi and microbes

Question 21

ch 7 - physical barriers in animals

Answer 21

• mucous membranes lining airways: trap invading pathogens, preventing entry
• intact skin: strong barrier preventing pathogen entry
• cilia and hair: sweep trapped particles and pathogens out of airways

Question 22

ch 7 - chemical barriers in animals

Answer 22

• lysozymes in tears and saliva: digest bacteria and other pathogens
• hydrochloric acid in stomach: kills ingested pathogens
• acidic sweat: prevents bacteria growth on skin

Question 23

ch 7 - microbiota barriers

Answer 23

• A component of the first line of defence that features the presence of non-pathogenic bacteria (normal flora) in lower gastrointestinal tract, on skin and in vagina
• these bacteria prevent growth of pathogenic bacteria by taking up space and nutrients, some produce antimicrobial chemicals

Question 24

ch 8 - natural active immunity

Answer 24

• protection from a disease through the production of memory cells and/or antibodies by individuals own adaptive immune system
• without medical intervention

Question 25

ch 8 - natural passive immunity ## Footnote plus examples

Answer 25

* when individual acquires antibodies from a natural external source * no medical intervention * from mother: from breastfeeding/milk, through placenta

Question 26

ch 8 - artificial active immunity ## Footnote VACCINES!!!

Answer 26

* protection from a disease through production of memory cells and/or antibodies by individuals own adaptive immune system * via medical intervention

Question 27

ch 8 - artificial passive immunity

Answer 27

* when an individual acquires antibodies from an external source via medical intervention * eg. antivenom ## Footnote antibodies short lived - no immune memory

Question 28

ch 8 - vaccine ## Footnote plus types

Answer 28

* medical treatment typically containing pathogenic antigens * designed to stimulate adaptive immune response - create immunity to pathogen without causing disease * attenuated (weak pathogens), inactivated (dead pathogens), toxoids (modified toxins - don't cause disease), pathogenic proteins, RNA

Question 29

ch 8 - primary immune response

Answer 29

* the reaction of the adaptive immune system to an antigen it has not previously been exposed to * a slower and less strong immune response * occurs after 1st vaccination

Question 30

ch 8 - secondary immune response

Answer 30

* the heightened reaction of the adaptive immune system to an antigen it has previously been exposed to * much stronger and faster * occurs after 2nd vaccination

Question 31

ch 8 - vaccination program

Answer 31

* a series of vaccinations designed to create long-term immunity to a disease

Question 32

ch 8 - booster vaccine

Answer 32

* vaccination given much after vaccination program, after some memory cells died and immunity decreased * enhance immunity against the disease

Question 33

ch 8 - herd immunity

Answer 33

* when high percentage of a population is immune to a disease, often via vaccination, leading to non-immune individuals being protected and less likely to be infected