4.1.1 Diseases - responses bit Flashcards

Question

factors affecting transmission - climate

Answer 1

potato and tomato blight especially common during wet summers - because the spores need water to spread malaria most common in tropical countries (humid and hot) - ideal conditions for mosquitoes (malaria vectors) to breed

Answer 2

eg. risk of HIV high in places where there's limited access to 1. good healthcare - people less likely to be diagnosed and treated for HIV - most effective anti-HIV drugs are less likely to be available - virus more likely to be passed onto other 2. good health education - to inform people about how HIV is transmitted and how it can be avoided eg. safe sex practices - condoms

Answer 3

``` skin mucous membrane blood clotting inflammmation wound repair expulsive reflexes ```

Answer 4

acts as a physical barrier, blocking pathogens from entering the body acts as a chemical barrier, produces chemicals that are antimicrobial and can lower pH, inhibiting growth of pathogens

Answer 5

protect body openings that are exposed to the environment (mouth, nostrils, ears) some membranes secrete mucus - a sticky substance that traps pathogens and contains antimicrobial enzymes

Answer 6

a mesh of protein fibres plug wounds to prevent pathogen entry and blood loss formed by a series of chemical reactions that take place when platelets are exposed to damaged blood vessels

Answer 7

swelling, pain, heat and redness triggered by tissue damage - the damaged tissue releases molecules which increase the permeability of the blood vessels, so they start to leak fluid into the surrounding area this causes swelling and helps to isolate any pathogens that may have entered the damaged tissue these molecules also cause vasodilation which increases blood flow to the affected area - this makes the area hot and brings white blood cells to fight off pathogens that may be present

Answer 8

skin is able to repair itself and reform barrier against pathogen entry the surface is repaired by the outer layer of skin cells dividing and migrating to the edges of the wound the tissue below the wound then contracts to bring the edges of the wound closer together its is repaired using collagen fibres - too many collagen fibres = scar

Answer 9

coughing and sneezing sneeze - when mucous membrane in the nostrils are irritated by dirt or dust cough - irritation is respiratory tract an attempt to expel foreign objects, pathogen, from the body AUTOMATIC

Answer 10

physical chemical

Answer 11

1. waxy cuticle - barrier to pathogen entry - stops water collecting on leaf which could reduce infection by pathogens that are transferred between plants in water 2. cell walls - barrier to pathogens that make it past waxy cuticle 3. callose - a polysaccharide that is deposited between plant cell walls and plasma membranes during times of stress (pathogen invasion) - makes it harder for pathogens to enter cells - callose deposition at the plasmodesmata may limit spread of virus between cells

Answer 12

1. produce antimicrobial chemicals (including antibiotics) which kill pathogens or inhibit their growth - saponins ---> destroy cell membranes of fungi and other pathogens - phytoalexins ---> inhibit growth of fungi and other pathogens 2. secrete chemicals that are toxic to insects - reduces the amount of insect-feeding on plants and therefore reduces the risk of infection by plant viruses carried by insect vectors

Answer 13

foreign antigens

Answer 14

molecules on the surface of cells its how body identifies cell as foreign

Answer 15

phagocytes engulf pathogens - PHAGOCYTOSIS 1. a phagocyte recognise the antigens on a pathogen 2. the cytoplasm of the phagocyte moves around the pathogen, engulfing it. - made easier by opsonins ---> molecules in the blood that attach to forgein antigens to aid phagocytosis 3. the pathogen is now contained in a phagosome (a vesicle) in the cytoplasm of the phagocytes 4. a lysosome (organelle that conatins digestive enzymes) fuses with the phagosome - the enzymes break down the pathogen 5. the phagocytes then presents the pathogens antigens - it sticks the antigens on its surface to active other immune system cells - acts as an antigen-presenting cell

Answer 16

a molecule in the blood that attach to foreign antigens to aid phagocytosis work in different ways - some hide the negative charges on the membrane of the pathogen, making it easier for the negitevly charged pharged phagocytes to get closer to the pathogen

Answer 17

a type of white blood cell that carries out phagocytosis found in blood and tissues and carry out the non-specific immune response

Answer 18

a type of phagocyte the first white blood cells to respond to a pathogen inside the body move towards a wound in response to signals from cytokines the cytokines are released by cells at the site of the wound

Answer 19

1. phagocytes activates T lymphocytes 2. T lymphocytes active B lymphocytes, which divide into plasma cells 3. plasma cells make more antibodies to a specific antigen

Answer 20

1. a T lymphocyte is another type of white blood cell 2. their surface is covered with receptors 3. the receptors bind to antigens presented by antigen-presenting cells 4. each T lymphocyte has a different receptor on its surface 5. when the receptor on the surface of a T lymphocyte meets a complementary antigen, it binds to it - --> so each T lymphocyte will bind to a different antigen 6. this activates the T lymphocyte ---> CLONAL SELECTION 7. the T lymphocyte then undergoes CLONAL EXPANSION - it divides to produce clones of itself - different types of T lymphocytes carry out different functions

Answer 21

1. T helper cells - these release substances to activate B lymphocytes and T killer cells 2. T killer cells - these attach to and kill cells that are infected with a virus 3. T regulatory cells - these suppress the immune response from other white blood cells - this helps stop immune system cells form mistakenly attacking the hosts's body cells

Answer 22

1. B lymphocytes are covered with protiens called antibodies 2. antibodies bind to antigens to form an antigen-antibody complex 3. each B lymphocyte has a different shaped antibody on its surface 4. when then antibody on the surface of a B lymphocyte meets a complementary shaped antigen, it binds to it - so each B lymphocyte will bind to a different antigen 5. this, together with substances released from T helper cells, activates the B lymphocyte - --> CLONAL SELECTION 6. the activated B lymphocyte divides, by mitosis, into plasma cells and memory cells - ---> CLONAL EXPANSION

Answer 23

1. plasma cells are clones of the B lymphocytes 2. they secrete loads of the antibody, specific to the antigen, into the blood 3. these antibodies will bind to the antigens on the cell surface of the pathogen to form lots of antigen-antibody complex

Answer 24

Variable regions - form the antigen binding sites (differ between antibodies) - the shape of the variable region is complementary to a particular antigen Hinge region - allows flexibility when the antibody binds to the antigen Constant region - allow binding to the receptor on immune system cells - is the same in all antibodies Disulfide bridges - the bond that hold the polypeptide chains of the protein together

Answer 25

how cells communicate a cell may release a substance that binds to the receptors on another cell - causes a response

Answer 26

helps to activate all the different types of white blood cells that are needed

Answer 27

a type of cytokine binds to receptors on B lympocytes this activates the B lymphocytes eg. T helper cells signal to B lymphocytes that there's a pathogen in the body

Answer 28

1. agglutinating pathogens 2. neutralising toxins 3. preventing the pathogen binding to the human cells

Answer 29

each antibody has two binding sites so an antibody can bind to two pathogens at the same time the pathogens become clumped together phagocytes then bind to the antibodies and engluf lots of pathogens all at once

Answer 30

toxins have different shapes antibodies called anti-toxins bind to the toxins produced by pathogens this prevents toxins from affecting human cells, so toxins are neutralised the toxin-antibody complexes are also phagocytosed

Answer 31

when antibodies bind to the antigens on the pathogens, they may block the cell surface receptors that the pathogens need to bind to the host cells so the pathogens cant attach to or infect the host cells

Answer 32

slow 1. when a pathogens enter the body for the first time the antigens on its surface activates the immune system 2. arent many B lymphocytes that can make make the needed antibody 3. eventually body will produce enough of the right antibody to overcome the infection - --> meanwhile the infected person will show symptoms of the disease 4. after being exposed to an antigen ---> T and B memory cells 5. the person is now immune - immune system has the ability to respond quickly to a second infection

Answer 33

remain in the body for a long time remember the specific antigen and will recognise it a second time round memory B record the specific antibodies needed to bind the antigen

Answer 34

if the same pathogen enters the body again, the immune system will produce a stronger, quicker immune response clonal selection happens faster - --> memory B activated and divide into plasma cells that produce the right antibody to the antigen - --> memory T activated and divide into the correct type of T lymphocyte to kill the cell carrying the antigen gets rid of symptoms before you begin to show any symptoms

Answer 35

red blood cells - dont have a nucleus platelets - fragments of cells white blood cells: Lymphocyte - smaller than neutrophil, nucleus takes up most of the cell, little cytoplasm + not grainy Neutrophil - nucleus looks like three interconnected blobs (multi-lobed), cytoplasm grainy Monocyte - biggest wbc, type of phagocyte, kidney bean shaped nucleus, cytoplasm not grainy

4.1.1 Diseases - responses bit Flashcards

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