Disease and the Immune system

Question 1

define the term disease

Answer 1

a condition that impairs the normal functioning of an organism

Question 2

what is a pathogen

Answer 2

an organism that causes disease

Question 3

what is a communicable disease

Answer 3

a disease that can be spread between organisms

Question 4

what type of pathogen causes TB and what does it commonly affect

Answer 4

bacterium, animals typically humans and cattle

Question 5

what type of pathogen causes bacterial meningitis and what does it commonly affect

Answer 5

bacteria and humans

Question 6

what type of pathogen causes ring rot and what does it commonly affect

Answer 6

bacteria, potatoes and tomatoes

Question 7

what type of pathogen causes HIV and what does it commonly affect

Answer 7

virus and humans

Question 8

what type of pathogen causes tobacco mosaic virus and what does it commonly affect

Answer 8

virus, plants

Question 9

what type of pathogen causes influenza and what does it commonly affect

Answer 9

animals, including humans

Question 10

what type of pathogen causes ringworm and what does it commonly affect

Answer 10

fungus and cattle

Question 11

what type of pathogen causes athletes foot and what does it commonly affect

Answer 11

fungus and humans

Question 12

what type of pathogen causes potato/tomato late blight and what does it commonly affect

Answer 12

protoctist and potatoes/tomatoes

Question 13

what type of pathogen causes malaria and what does it commonly affect

Answer 13

protoctist and animals including humans

Question 14

what type of pathogen causes black Sigatoka and what does it commonly affect

Answer 14

fungus and banana plants

Question 15

what is direct transmission and what type of diseases can be transmitted this way

Answer 15

when a disease is transmitted directly from one organism to another through droplet infection, intercourse or touch
HIV and athletes foot

Question 16

what is indirect transmission and what examples of disease can be transmitted this way

Answer 16

when a disease is transmitted via a medium
malaria

Question 17

what factors affect transmission

Answer 17

living conditions, social factors, climate

Question 18

what are some non specific defence mechanisms against pathogens

Answer 18

skin- physical and produces chemicals which are antimicrobial
mucous membrane- traps pathogens
inflammation- swelling helps isolate pathogens that have entered damaged tissue and vasodilation increases blood flow to affected area
wound repair- skin repair using collagen fibres
expulsive reflexes- sneezing

Question 19

what are some examples of plant physical defences

Answer 19

waxy cuticle acts as a physical barrier
cell walls
callose deposited between plant cell walls and plasma membranes which can make it harder for pathogen to enter the cell

Question 20

what are antigens

Answer 20

molecules found on the surface of cells

Question 21

describe the process of phagocytosis

Answer 21

phagocyte recognises antigens on a pathogen
cytoplasm of phagocyte moves around pathogen, engulfing it
this is made easier by opsonins that are in blood and attach to foreign antigens to aid phagocytes
pathogen is contained in a phagosome
a lysosome fuses with the phagosome
the phagocyte then presents the pathogen’s antigens and is known as an antigen-presenting cell

Question 22

what type of white blood cell are a type of phagocyte

Answer 22

neutrophils

Question 23

what proteins act as messenger molecules send signals to neutrophils

Answer 23

cytokines

Question 24

What is a T lymphocyte

Answer 24

a type of white blood cell covered in receptors

Question 25

how do t lymphocytes work

Answer 25

the receptors on the surface bind to a complimentary antigen and this activates the t lymphocyte known as clonal selection, the t lymphocyte then undergoes clonal expansion and it divides to produce clones of itself

Question 26

what are the different types of t lymphocytes and what are their functions

Answer 26

T helper cells- release substances to activate B lymphocytes and T killer cells T killer cells- attach and kill cells that are infected with a virus T regulatory cells- suppress the immune response from other white blood cells, to stop immune system cells from mistakenly attacking the hosts body cells some activated T cells become memory cells

Question 27

describe the process of B lymphocyte activation and plasma cell production

Answer 27

B lymphocytes are covered in antibodies each b lymphocyte had a different shaped antibody so bind to different shaped antigens to form antigen-antibody complex this, together with substances released from T helper cells activates the b lymphocyte this is another example of clonal selection activated b lymphocyte then divides by mitosis in plasma cells and memory cells another example of clonal expansion

Question 28

how is cell signalling used in the immune response

Answer 28

T helper cells release interleukins that bind to receptors on B lymphocytes

Question 29

name three types of white blood cells

Answer 29

monocyte, lymphocyte, neutrophil

Question 30

what is the structure of an antibody

Answer 30

glycoproteins made up of four polypeptide chains- two heavy chains and two light chains variable regions form the antigen-binding sites hinge region allows flexibility when antibody binds to antigen constant regions allow binding to receptors on immune system cells disulphide bridges hold chains together

Question 31

what are the three main ways antibodies help clear infection and give a brief description of each

Answer 31

agglutinating pathogens- antibody binds to two pathogens and they become clumped together, then undergoes phagocytosis neutralising toxins- anti-toxins can bind to the toxins produced by pathogens so they don't affect human cells preventing the pathogen binding to a human cell- antibodies bind to antigens on pathogens so block cell-surface receptors that pathogens need to bind to host cells

Question 32

what is the primary immune response

Answer 32

when a pathogen enters the body for the first time and the antigens on the surface activation the immune system

Question 33

what do both T and B lymphocytes produce

Answer 33

memory cells

Question 34

what does the term immune mean

Answer 34

immune system has the ability to respond quickly to a second infection

Question 35

compare primary and secondary response

Answer 35

primary- enters first time, slow, B and T lymphocytes, symptoms secondary- enters for second time, fast, memory cells, no symptoms

Question 36

what is active immunity and what are the two types

Answer 36

when immune system makes its own antibodies after being stimulated by an antigen natural- when you become immune to a disease after catching it artificial- immune after vaccination

Question 37

what is passive immunity and what are the two types

Answer 37

type of immunity when you get given antibodies made by a different organisms natural- when a baby receives antibodies through placenta and breast milk artificial- getting injected with antibodies from someone else

Question 38

what are the differences between active and passive immunity

Answer 38

active- requires exposure to antigen, takes a while to develop, protection is long term, memory cells produced passive- no exposure to antigen, production is immediate, short-term, memory cells not produced

Question 39

what is an autoimmune disease and give an example

Answer 39

when an immune system cannot recognise self antigens so are treated like foreign antigens, lupus

Question 39

how does vaccination work

Answer 39

vaccines contain substances that cause your body to produce memory cells without the pathogen causing disease substances tend to be dead or attenuated pathogen can also be mRNA designed to code for antigens on a pathogen

Question 40

what is herd immunity

Answer 40

when a large percentage of a population is vaccinated so even those who haven't been vaccinated are unlikely to get the disease

Question 41

define the term vaccination

Answer 41

the administration of a substance designed to stimulate the immune system

Question 42

what are antibiotics

Answer 42

chemicals that kill or inhibit the growth of bacteria

Question 43

what causes antibiotic resistant bacteria

Answer 43

genetic variation due to mutations and that allele being passed on to offspring

Question 44

what are the problems with antibiotic resistant bacteria

Answer 44

increased use of antibiotics increases antibiotic resistant strains developing

Question 45

how are doctors trying to prevent the development of antibiotic resistant bacteria

Answer 45

developing new antibiotics or modifying existing ones reduce distribution of antibiotics take all the antibiotics to make sure infection is fully cleared