Topic 10

Question 1

What is a microorganism

Answer 1

A very small living thing

Question 2

What are pathogens

Answer 2

Microorganism that causes disease

Question 3

Transmissable/communicable disease

Answer 3

Caused by a pathogen and can be passed from one host to another

Question 4

4 types of pathogens

Answer 4

Viruses
Bacteria
Fungi
Protists

Question 5

Ways in which pathogens are spread (7)

Answer 5

• Contaminated food
• Sharing needles
• Contaminated surfaces
• Sexually transmitted
• Bloodily fluids
• Airborne droplets
• Animals

Question 6

How can a pathogen be transmitted?

Answer 6

Direct contact
Indirect contact

Question 7

Examples of direct contact

Answer 7

. Blood
. Bloodily fluids

Question 8

Examples of indirect contact

Answer 8

. Contaminated surfaces
. Air
. Food
. Animals

Question 9

The body’s primary defences (5)

Answer 9

Trying to prevent pathogens from entering the body
- Eyelashes
- Hair in the nose
- Skin
- Stomach
- Mucus

Question 10

Examples of mechanical barriers for body

Answer 10

. Hair in the nose -> traps the pathogens in the air
. Skin -> mechanical physical barrier
-> If you damage the skin, platelets clot to seal wound

Question 11

Example of chemical barriers in body

Answer 11

. Stomach -> contains HCL
-> kills any pathogens
. Mucus -> chemical cells in trachea and bronchi produce mucus
-> trap pathogens

Question 12

How do pathogens cause harm?

Answer 12

1) They can reproduce and they can damage cells
2) Produce toxins
- When pathogens infect us, the WBCs fight pathogens

Question 13

Phagocytosis

Answer 13

• Engulf and digest pathogenical material
  . By phagocytes
  . They recognise ‘foreign’ pathogens and elngulf them
  . Not specific

Question 14

Antigens

Answer 14

• All pathogens have their own unique ‘markers’ on the cell membrane, antigens, which have specific shapes

Question 15

Anti-body production

Answer 15

• By lymphocytes
  1) Lymphocytes encounter ‘foreign’ antigens and will produce complimentary shaped proteins called antibodies
  2) Antibodies secreted by the lymphocytes bind to the antigens on pathogem
  -> They either destroy the pathogen of marks it for destruction by a phagocyte

Question 16

Antibodies

Answer 16

. Proteins that bind to antigens leading to direct destruction of pathogens fro destruction by phagocytes

• Made put of protein
• Specific antibodies have complimentary shapes which fit specific antigens

Question 17

Preventing disease (6)

Answer 17

. Vaccination
. Treated sewage
. Waste disposal
. Good food hygiene
. Good hygiene
. Clean water supply

Question 18

Hygenic food preparation

Answer 18

• Reduces spread of pathogens from work surfaces, chooping boards, etc, to food

Question 19

Good personal hygiene

Answer 19

Simple hygiene measures (eg. washing your hands after going to the toilet)

Question 20

Waste disposal

Answer 20

Not letting rubbish build up + safely dispose things such as bandages or needles

Question 21

Clean water supply

Answer 21

Access to clean, fresh water for drinking and cooking -> reduces spread of water-borne pathogens

Question 22

Sewage treatment

Answer 22

Good sewage systems prevent sewage from contaminating drinking water -> reduces spread of water-borne pathogens

Question 23

Cholera

Answer 23

. Caused by a bacterium
. Transmitted through spread of water

Question 24

How can we prevent the spread of water?

Answer 24

. Sewage treatment
. Clean water

Question 25

How does cholera cause these effects?

Answer 25

1) Bacterium produces a toxin 2) This causes secretion of chloride ions into the small intestine 3) The water potential in your small intestine decreases 4) Water moves into small intestine down water potential gradient (osmosis) 5) loss of water and mineral ions through diarrea

Question 26

Symptoms of cholera

Answer 26

. Dehydration . Diarrhea . Loss of mineral ions

Question 27

Passive immunity

Answer 27

Short- term defence against a pathogen by antibodies made by another individual

Question 28

Active immunity

Answer 28

Long-term defence against a pathogen by the production of antibodies and memory cells

Question 29

Passive immunity examples

Answer 29

. Babies have not yet fully developed -> antibodies can pass from mother to feetus across placenta . Breastfeeding

Question 30

Process of vaccination (active immunity)

Answer 30

1) Inject a weakened pathogen or inactive antigens from pathogen 2) This triggers an immune response and your lymphocytes produce antibodies against the pathogen 3) Some of the lymphocytes remain circulating the blood as memory cells for many years

Question 31

Active immunity

Answer 31

. Long-term . Produces memory cells . Production of antibodies . Slower process . Developed by vaccinations . Developed after infection

Question 32

Passive immunity

Answer 32

. Short term . No memory cells . Faster process . Passed on via breastmilk or across the placenta

Question 33

Importance of breast-feeding

Answer 33

Important as immune system of infants isn't fully developed and functional at birth (greater risk of infection)

Question 34

Controlling spread of disease through vaccination

Answer 34

People vaccinated against disease are immune so they can't develop infection and pass it on -> prevents spread of disease as there's fewer people that have it