immunity and diseases

Question 1

what is a pathogen

Answer 1

disease-causing organism

Question 2

what is a transmissible disease

Answer 2

Pathogens are passed on from one host to another

Question 3

what are the 2 ways pathogens can be passed from host to host

Answer 3

direct contact

indirect contact

Question 4

what is direct contact

Answer 4

the pathogen is passed directly from one host to another by transfer of body fluids
(blood, semen, phlegm etc.)

Question 5

what is indirect contact

Answer 5

the pathogen leaves the host and is carried in some way to another, no man to man contact

Question 6

what are the 3 defences against pathogens

Answer 6

1) mechanical barriers
2) chemical barriers
3) cells

Question 7

what are the mechanical barriers

Answer 7

structures that make it difficult for pathogens to get past them and into the body

Skin (covers almost all parts of your body to prevent infection from pathogens)
hairs in the nose (these make it difficult for pathogens to get past them further up the nose so they are not inhaled into the lungs)

Question 8

what are the chemical barriers

Answer 8

substances produced by the body cells that trap / kill pathogens before they can get further into the body and cause disease

Mucus (made in various places in the body, pathogens get trapped in the mucus and can then be removed from the body)
HCL in stomach (strong enough to kill any pathogens that have been caught in mucus in the airways and then swallowed or have been consumed in food or water)

Question 9

what are the cell barriers

Answer 9

different types of white blood cell work to prevent pathogens reaching areas of the body they can replicate in

phagocytosis - engulfing and digesting pathogenic cells
production of antibodies

Question 10

how do antibodies work

Answer 10

clump pathogenic cells together so they can’t move as easily (known as agglutination) and release chemicals that signal to other cells that they must be destroyed

Question 11

what creates antibodies

Answer 11

B-lymphocytes

Question 12

what is active immunity

Answer 12

Making antibodies and developing memory cells for future response to infection is known as active immunity

Question 13

what are 2 ways active immunity can be formed

Answer 13

• The body has become infected with a pathogen and so the lymphocytes go through the process of making antibodies specific to that pathogen
• Vaccination

Question 14

features of active immunity

Answer 14

slow acting and provides long-lasting immunity

Question 15

what is passive immunity

Answer 15

ready-made antibodies, from another source, are introduced to the body

Question 16

features of passive immunity

Answer 16

fast-acting, short-term defence

passive immunity doesn’t form its own antibodies or memory cells

Question 17

what are 2 ways passive immunity can be formed

Answer 17

From mother to infant via breast milk

injected antibodies

Question 18

what part of the pathogen is recognised by the immune system

Answer 18

antigen

Question 19

explain how vaccination can control the spread of diseases

Answer 19

harmless pathogen used in the vaccine which is injected
lymphocytes make antibodies
antibodies attack the pathogens, causes pathogens to stick together, restricting the movement and then phagocytes engulf them
antibodies form memory cells that remember the same pathogen for faster antibody production in future infections.
this forms active immunity which creates a rapid and effective immunity against the same pathogen

Question 20

describe active transport

Answer 20

using energy from respiration, molecules move from an area of lower concentration to higher concentration, up the concentration gradient, into the cell