B10 diseases and immunity

Question 1

define pathogen

Answer 1

a disease-causing organism

Question 2

define transmissible disease

Answer 2

a disease in which the pathogen can be passed from one host to another

Question 3

features of viruses

Answer 3

• protein coat
• genetic material

Question 4

how is a pathogen transmitted

Answer 4

direct contact
- blood
- other bodily fluids
indirectly
- contaminated surfaces
- food
- animals
- air

Question 5

body defences against pathogens

Answer 5

• skin
• hair in nose
• mucus
• stomach acid
• white blood cells

Question 6

describe how skin defends against pathogens

Answer 6

• mechanical barrier
• block pathogens from entering body

Question 7

describe how hairs in nose defend against pathogens

Answer 7

• mechanical barrier
• trap particles that may carry pathogens

Question 8

describe how mucus defends against pathogens

Answer 8

• chemical barrier
• sticky, traps pathogens to be moved out

Question 9

describe how stomach acid defends against pathogens

Answer 9

• chemical barrier
• highly acidic
• damages/kills pathogens

Question 10

describe how white blood cells defend against pathogens

Answer 10

• surrounds and engulfs pathogen (phagocytosis) then destroy it
• produce antibodies

Question 11

how to control spread of disease

Answer 11

• clean water supply
• hygienic food preparation
• good personal hygiene
• waste disposal
• sewage treatment
• vaccination

Question 12

how does clean water supply help control spread of disease

Answer 12

• prevent water-borne diseases

Question 13

how does hygienic food preparation control the spread of disease

Answer 13

• food should be covered so flied cannot land
• kept in fridge before use
• used within limited time period
• kill with heat

Question 14

how does good personal hygiene control the spread of disease

Answer 14

• washing hands with warm water and soap (remove pathogens found in faeces and reduce transmission by touch)
• covering mouth and nose when coughing/sneezing with tissue (trap pathogens, stop from passing into air)
• dispose of used tissues, wash hands after (reduce transmission by touch)

Question 15

how does waste disposal control the spread of disease

Answer 15

• attractive source of food for many insects (at as vectors)

Question 16

how does sewage treatment control the spread of disease

Answer 16

• treatment kills pathogens
• water can be released into environment safely

Question 17

define active immunity

Answer 17

defence against a pathogen by antibody production in the body

Question 18

what are antigens

Answer 18

• substances that can cause body to produce immune response
• each pathogen has its own antigens with specific shapes

Question 19

describe antibodies

Answer 19

• proteins that bind to antigens
• leading to direct destruction of pathogens
• or marking pathogens for destruction by phagocytes
• specific antibodies have complementary shapes which fit specific antigens

Question 20

how is active immunity gained

Answer 20

• after infection by pathogen
• vaccination

Question 21

outline the process of vaccination

Answer 21

• weakened pathogens or their antigens put into body
• antigens stimulate immune response by lymphocytes which produce antibodies
• memory cells produced, give long-term immunity

Question 22

explain the role of vaccination in controlling the spread of diseases

Answer 22

• available for some pathogens
• prevent pathogens causing disease, being spread