cells and the immune system (p1)

Question 1

Each type of cell has ________ molecules on its ________ that identify
it.

Answer 1

Each type of cell has specific molecules on its surface that identify
it.

Question 2

Antigens

Answer 2

-molecules that can generate an immune response when detected by the body
-found on the surafce of cells
-_ antigens that aren’t usually found in the body are forgein anitgens/ allow idetification of celg molecules and non-self molecules
-it is the specific 3d structure that distinguishes one cell from another.

Question 3

antigens allow the immune system to identify

Answer 3

pathogens- all have antigens on their surface. which can be identified as foreign and destroyed
toxins- Are poisons. molecules not cells. is the antigen produces by bacteria. Immune system can respond to toxins and the pathogen that released them.
abnormal body cells- cancerous or pathogen-infected cells have abnormal antigens on surface triggers an immune response.
Cells from other organism of the same species/non-self material- cells reicved from anothrt person e.g transplant or blood transfusion. will have some antigens that are differnt from the recipient. foreign antigen trigger immune response.This can lead to rejection if immunosuppressant drugs aren’t taken.

Question 4

Immune response

Answer 4

antigen—->immune response——> Immediate= non-specific (e.g phagocytosis,inflammation, antimicrobial proteins).———->delayed=specific (B cells, T cells)

Question 5

Non-specific immune responses

Answer 5

-Fever
-inflammation
-interferon
-phagocytosis
-histamines

Question 6

Histamines

Answer 6

-released by most cells/damaged white blood cells.
-cause blood vessles to dialate cause local heat and redness
-higher temp prevents pathogen from reproducing
-blood vessles more leaky,plasma forced out causing pain and swelling.
E.g hayfever- antigrn such as pollen = allergic response, histmine is relase. antihistamine reduce allergic response histmaine and is simular shape to antihistamine so antihistmine bind to histamine recpectore and prevent the histamine binding

Question 7

Inflammation

Answer 7

-ofteninfection localised at one sight
-when tissue damaged white blood cells relase histamine, aterioles become leaky
-more wide spread= rash

Question 8

inteferon

Answer 8

-produced by Cells infected by viruses anti-viral proteins called interferons
-Interferons prevent viruses from spreading to uninfected cells, bind to repetors of unaffected cells
-They inhibit the production of viral proteins, preventing the virus from replicating
-They activate white blood cells involved with the specific immune response to destroy infected cells-they increase the non-specific immune response e.g. by promoting inflammatio

Question 9

Fever

Answer 9

-raise in body temperature
-helps kill pathogens prevents them reproducing
-specific response=better at a higher temp

Question 10

lysozymes

Answer 10

-enzymes in tears saliva , nasal secretions
-kills bacteria by breaking down cell walls

Question 11

a phagocyte (e.g a macrophage) is a type of ——– blood cell that carries out __________.found in blood and tissues and are first to respond to immune system trigger inside the body.

Answer 11

a phagocyte (e.g a macrophage) is a type of white blood cell that carries out phagocytosis.found in blood and tissues and are first to respond to immune system trigger inside the body.

Question 12

steps phagocytosis

Answer 12

1)phagocyte recognises foreign antigens on pathogen
2)cytoplasm of the phagocyte moves around the pathogen engulfing it
3)The pathogen is now contained in the phagocytic vacuole in the cytoplasm of the
4)a lysosome fuses with the phagocytic vacuole and the lysosymes break down the pathogens.
5)the phagocyte presents the pathogens antigens-it sticks them to it’s surface to activate other immune systems cells. The phagocyte is acting as a antigen-presenting cell.

Question 13

Types of white blood cells

Answer 13

neutrophils (70%)
lymphocytes (24%)
Monocytes (4%)
other white cells (2%)

Question 14

neutrophils

Answer 14

(phagocytes)
-leave blood capillaries by squeezing between cells
-ingest and and destroy bacteria
-80 million produce a minute and last a few days.

Question 15

lymphocyte

Answer 15

two types-B cells and T cells
-involved in immune response, including antibody production and immunity
-some last a few days others a few years

Question 16

monocytes

Answer 16

-circulate in blood for a day or 2 before moving into tissue by squeezing out
-here they become macrophages and engulf bacteria, cell debris etc
-numerous in liver,kideny,spleen and lymphnodes.

Question 17

lymphnodes

Answer 17

-where macrophages attack bacteria which have got into blood.
-if these don’t stop it then leads to septic shock/ blood poisoning.

Question 18

the specific response involves

Answer 18

B lymphocytes and T lymphocytes

Question 19

T lymphocytes

Answer 19

-made in the bone marrow
-mature in the thymus
-carry out the cell mediated immune response (cellular)
-this mean that can recognise and destroy abnormal cells

Question 20

The response of T lymphcytes to a foreign ________ (the cellular response)

Answer 20

The response of T lymphocytes to a foreign antigen (the cellular response)

Question 21

The response of B lymphocytes to a foreign antigen, clonal selection and the release of monoclonal _______ (the humoral response).

Answer 21

The response of B lymphocytes to a foreign antigen, clonal selection and the release of monoclonal antibodies (the humoral response).

Question 22

B lymphocytes

Answer 22

-made in bone marrow
-mature in the bone marrow
-carry out humoral immune response
-this mean are responible for antibody production

Question 23

cells that display foreign antigen on their surface

Answer 23

antigen presenting cells.

Question 24

cell mediated immunity

Answer 24

T cells only respond to antigens presnted on a body cell
this is called cell mediated immunity/cellular repsonse
recpetors on each T cell respond to single antigen

Question 25

summary of Helper T cells in cellular response

Answer 25

1.pathogen invades body cell/ is taken in by phagocytes 2.phagocyte places antigens from pathogen on its surface ( it is an antigen presenting cell) 3.Helper T cells receptors fits the particular antigen 4)attachment activates the t cell to divide by mitosis to form a clone of genetically identically cells 5) the cloned cells: -become memory cells that circulate in bloof and tossue fluid in readiness to respond to future infection same pathogen -stimulate b cells to divide -stimulate phagocytosis by phagocytes -activate cytotoxic t cells kill infection cells making holes in membrane

Question 26

Helper T cells (need to know)

Answer 26

.help humoral response by involvement in maturation of B cellls and triggering the production of antibodies by b-cells. .also trigger phagocytosis

Question 27

cytotoxic t cells

Answer 27

-kill abnormal cells that are infected by pathogens, by producing a protein called perfarin that makes holes in the cell-surface membrane, meaning it becomes fully permeablr to alll substances and the cell dies as a result.

Question 28

Memory T-cells (not require)

Answer 28

work in same way as memory b celld,ensure rapid response on subsequent exposure to the same non-self antigens.

Question 29

Suppressor T-cells (not rquired)

Answer 29

reguales the immune reponse by suppressing the activity of killer T cells.

Question 30

The response of B lymphocytes to a foreign _________, clonal _____ and the release of ______clonal antibodies (the humoral response).

Answer 30

The response of B lymphocytes to a foreign antigen, clonal selection and the release of monoclonal antibodies (the humoral response).

Question 31

B cells

Answer 31

-type of white blood cell -covered in antibodies that bind to antigens to form and antigen-antibody complex -each b-cells has a differnt shaped antibody on its membrane, so each binds to a differnt antigen

Question 32

1) antibody on the surface of the b-celll attches to the ________ antigen, the antigens enters the cell by endocytosis and gets presented on its surface. 2)Th cells bind to these processed antigens and stimulate the B cell to divde by _______ to form a clone of identical B cells (plasma cells), all of which produce the antibody specifc to the forgein antigen 3) this is called clonal ________

Answer 32

1) antibody on the surface of the b-celll attches to the complementary antigen, the antigens enters the cell by endocytosis and gets presented on its surface. 2)Th cells bind to these processed antigens abd stimulate the B cell to divde by mitosis to form a clone of identical B cells (plasma cells), all of which produce the antibody specifc to the forgein antigen 3) this is called clonal selection

Question 33

what is formed why the antibody binds to the antigen?

Answer 33

antigen-antibody complex

Question 34

cloned B-cells become....

Answer 34

plasma cells=produce and secrete specifc antibody that exactly fits the antigen on the pathogens surface which destorys it. (primary response) memory cells= cirulate in blood and tissue fluid in readiness to responsd to future infection of same pathogen by dividing and developing into plasma cell that produce antibodies.

Question 35

Plasma cells sectrete loads of antibodies specific to the antigen these are called...

Answer 35

monoclonal antibodies

Question 36

Antibodies

Answer 36

-proteins -specificity of antibody depends on its variable regions which form antigen binding sites -each antibody have a varible region with a unique teritary structure thats complementary to a specific antigen -all have the same constant region (draw one)

Question 37

antibody has 2 binding sites......

Answer 37

-so can bind to 2 pathogen antigens at the same time -pathogens become clumped together=agglutination -phagocytes then bind to the antibodies an phagocytose many pathogens at once -this leads to destruction of pathogens carrying this antigen in the body.

Question 38

plasma cells

Answer 38

-screte antibodies into the blood plasma -survive only a few days -produce antibodies -responsible for the immediate defence of body cells

Question 39

B memory cells

Answer 39

responsible for secondary immune reponse -live longer than plasma cells -dont produce antibodies directly -when encounter same antigen they divide rapidly into plasma cells and more memory cells -provide long term immunity

Question 40

primary response

Answer 40

-when the antigen enters the body form the first time this triggers an immune reponse. -primary reponse=slow, not many B cells that make te right anitbody to bind to it -eventually makes enough antibody to overcome infection, in meantine infected person will show symptoms -after exposure both T and B cells produce memory cells, so can reposn quick to seconf infection

Question 41

T memory cells vs B memory cells

Answer 41

T- remember specific antigen and will recognise the second time round B-remeber specific antibodies need to bind to the antigen

Question 42

secondary response

Answer 42

- if the sam antigen enters the body again the body will produce a quicker and stronger immune response -clonal slection happens faster -B memory cells are activated and divide into plasma cells which secret the right anotbody for the antigen -T memory cells activated and divide into the right type of T cells to kill the cell carrying the antigen -secondary response often gets ride of the pathogen before you show symptoms

Question 43

Active immunity

Answer 43

body makes own antibodies after being stimulates by an antigen

Question 44

active natural

Answer 44

become immune after catching the disease ( specific immune reponse)

Question 45

active artificial

Answer 45

become a immune after given harmless dose of antigen in vaccine- stimulates immune reponse but doesn't cause disease

Question 46

passive immunity

Answer 46

type of immunity you get from being given antibodies made by a different organism

Question 47

passive natural

Answer 47

baby become immune due to the anitbodies it recive from it mother, though the placenta and in breast milk

Question 48

passive artificial

Answer 48

become immune when been injected with antibodies from someone else e.g if contract tetnus you can be injected with antibodies against the tetnus toxin,collected from blood donations

Question 49

active vs passive immunity

Answer 49

-Active immunity requires exposure to the anitgen, passive doesn't -active takes a while for protection to devlop, passive protection=immediate -active memory cells are produced, passive memory cells aren't produced -active p;rtection= long term as antibody is produced in response to complementary antogen being presnet ( due to memory cells), protection is short term because the antibodies are broken down

Question 50

types of vaccine

Answer 50

live (live pathogens) dead (killed pathogen) attenuated (weakened pathogen) toxioids- (toxins made harmless) DNA edible vaccines

Question 51

vaccines

Answer 51

-antigens in avccine cuase body to produce memory cells, against a partcular pathogen WITHOUT the pathogen cuasing disease -protect people that have them, reduce occurance of disease thoes around them also less likely to get the disease (herd immunity)

Question 52

Herd vaccination

Answer 52

vaccinating most or all people stops infection spreading within the population

Question 53

ring vaccination

Answer 53

vaccinate all people around the infected person, contains the spread within the ring-stops tranmission,trace and isolate contacts, travel restriction

Question 54

vaccines useually contain _____ these may be free or attached to a dead or ______ pathogen. can be injected or take orally.

Answer 54

vaccines useually contain anitgens these may be free or attached to a dead or weakened pathogen. can be injected or take orally.

Question 55

disadvantages of taking vaccine orally

Answer 55

-could be broken down by enzyme in gut -molecules in vaccine could be too large to be absorbed into the blood

Question 56

successful vaccination

Answer 56

-few side effects -means of mean of administering the vaccine properly at the appropriate time -must be possible to vaccinate vast majority of vunerable people to produce herd immunity -means of produing storying and transporting must be availble -economically availble in sufficent quanitities to immunise most of vunerbale population

Question 57

why may vaccination fail to elminate disease?

Answer 57

just a few.. -may fail to induce immunity in some indivivduals -pathogen may mutate frequently -indiviudals may object to vaccination for religous or ethical reasons, or medical

Question 58

ethical issues of vaccines

Answer 58

-all vaccines tested on animals -animal base substance may be used to produce the vaccine -tesing vaccine on humans may be risky ( put them selves at unecessary risk of contracting as belive to be fully protected) -risk of sideeffects -if epidmic and rush to reicve vaccine diffucult decision as to who recieves first have to be made

Question 59

monoclonal antibodies

Answer 59

-produced from a single group of gentically identical B cells (plasma) -all identical in structure

Question 60

monoclonal antibodies in anti cancer drug targeting cancer cells

Answer 60

1) cancer cell have antigens-called tumour markers not found on normal body cells. 2)monoclonal anrtibodies that bind to the tumor makers can be made 3)anticancer drugs can be sttached the antibodies which will bind to the tumour markers and block chemical signal that stimulate uncontrolled cell growth 4)so drug will only accumlate in body where there are cancer cells, so side affected of antibody-based drugs less than other as only accumlate near specific cells.

Question 61

Monoclonal antibodies is medical diagnosis

Answer 61

used for diagnoses of influenza,hepatitas,chlamydia infections and certain cancers.

Question 62

monoclonal antibodies in pregnancy tests

Answer 62

pregancy tests decect hormone hCG which is found in urine of pregnat women 1)application area contains antibodies that are complementary to the hCG prteins bound to a coloured bead (blue) 2)when applied to the application area any hCG in the urine will bind to the antobody on the beads forming and antibody-antigen complex 3)urine moves up the strip carrying the beads with in 4)test strip contains antibodies to hCG which are immobilised (stuck in place) 4)if there is hCG present test strip will turn blue as immobilised antibody binds to the hCG- this concerntates the hCG- antibody complex with the blue bead attached if hCG not presnt there will be no colour change as the beads willl pass through the test strip without binding to anything

Question 63

The ELISA test

Answer 63

-enzyme-linked immunosorbant assay -allows to see whether a patient has an antibody to any antigen or and antigen to any antibody -can be used in medical diagnoses to test for pathogenic infections,allergies-almost anything you can make an anitbody for -

Question 64

how does the ELISA test work

Answer 64

-an antibody with enzyme attached used . -enzyme can react with a substrate to produce a coloured product -causes the solution in the reaction vessel to change colour -if colour change demonastates antibody or antigen being tested for is present in the sample -in some ELISA tests quanity of antibody/ antigen can be identified by the intensity of the colour chnage -there are direct and indirect ELISA tests

Question 65

HIV structure

Answer 65

-virus particle has a spherical structure -core containing genetic material (two copies of mRNA) and some proteins (including some reverse transcriptase needed for viral replication) -outer coating protein called a capsid -an extra outer layer called an envelope (made from the membrane from previous host cell, consits of glycoproteins and lipid bilayer) -attchment proteins=glycoproteins = gp120 molecules -sticking out out from the envelope are lots of attachment protein help HIV attach to host helper T-cell

Question 66

antigenic variation

Answer 66

where pathogens change their antigens (different antigens are formed as a result of changes in the genes of the pathogen)

Question 67

why can antigenic variation cause you to be ill again, if infected with the same pathogen

Answer 67

-memory cells from first infection will not recognise the anitgens -primary response aginst these antigens has to be carried out -this takes time, which is why symptoms develop and you become ill again

Question 68

antigenic variation affect on vaccines

Answer 68

-makes it hard to develop vaccine against some pathogens -examples of pathogens that show agentic variation are HIV and influenza virus

Question 69

HIV can only _____ inside cells of an organism. HIV replicates inisde helper _ cells pf host. It doesn't have the equipment to replicate on its own so it uses thoes of the host cell

Answer 69

HIV can only reproduce inside cells of an organism. HIV replicates inisde helper T cells pf host. It doesn't have the equipment to replicate on its own so it uses thoes of the host cell.

Question 70

how HIV replicates

Answer 70

1)attcahment protein attches to recpetor molecule (CD4 receptors) on the cell membrane of host helper T cells, virus envelope fuses with cell surface membrane. 2)capsid relased into cell, where it uncoats and release geneti,c material (RNA) into cells cytoplasm 3)Reverse transriptase (enzyme for reverse transcription) used to make complemntary strand of DNA from viral RNA template 4) from this doubke stranded DNA is made and inserted by intergrase (enzyme) into human DNA 5)host cell used to make viral proteins from viral DNA found in human DNA 6)viral proteins assembled into new viruses, which bud fromt he cell and go to infect other cells

Question 71

why is HIV called a retro virus

Answer 71

uses reverse transcription to replicate

Question 72

Host killer T cells recognise and destroy heavily infected helper T cells....

Answer 72

- results in a reduction of helper T cells, meaning activation of many macrophages and T killer cells doesn't take place -therfore, normal functioning of T helper cells is lost/ reduced -leaving the idividual vunerable to secondary infection

Question 73

Factors that affect the progression of HIV into aids

Answer 73

existing infections strain of HIV age access to healthcare

Question 74

AIDs

Answer 74

acquired immune deficiency virus condition where immune system deteriates and ecentually fails, makes thoes with it more vunerable to infections

Question 75

why antibiotics don't work for viruses

Answer 75

1) antibitics kill bacteria by interfering with metabolic reactions 2)bacterial enzymes and ribosome=diff to humans. antibiotic deigned to target bacterial only os don't damage human cells 3)viruses don't have own enzymes and ribosomes-use host cells. antibiotics can't inhibits them as they dont target human processes 4|) most antivrial drus are deigned to target the few virus-specifc enzymes. e.g HIV uses reverse transcriptase to repliacte, humans celjls dont use this enzyme so drugs can be designed to inhibit without affecting host cell. reverse transcriptase inhibitors.

Question 76

Is there a cure or vaccine for HIV

Answer 76

no but antiviral drugs can be used to slow the progression of HIV infection and AIDs in an infected person

Question 77

symptoms of HIV

Answer 77

.1week-10days after HIV infection symptoms can occur, a result of the body reacting to the infection -most common symptoms= severe flu like symptoms,sore throat,fever,raash on chest,fatigue,nausea,diarrhoea

Question 78

4 main stages of HIV

Answer 78

1)acute HIV syndrome 2)asymptomatic chronic stage 3)symptomatic disease 4)advanced AIDs

Question 79

how is HIV passed on

Answer 79

infected blood,semen,vaginal fluids,rectal secretions or breast milk

Question 80

treatments

Answer 80

-education -work on developing vaccines is limited -drug therapy, antiviral drugs which stimulates the immune system

Question 81

Direct ELISA test

Answer 81

-uses a single antibody for the antigen you are testing for -antigens from patient sample bound to inside of a well in a well plate. -detection antibody attached to enzyme, that is complementary to antigen of interest is added. -if antigen of interest present will be immobilised on the inside of the well and the detection antibody will bind to it -well washed out to remove any unbound antibody and substrate solution is added -if antibody is present the enzyme reacts with substrate =colpur change -this is a pos result for presence of the antigen

Question 82

The indirect ELISA test

Answer 82

-uses 2 different antibodies e.g indirect elisa test can be used to see if patient has antibodies for HIV: 1)HIV antigen bound to bottom of well in well plate 2)sample of patient blood plasma is added. if there any HIV specific antibodies in the sample they will bind to the antigens stuck on the bottom of the well. well is washed to remove any unbound antibodies 3)secondary antibody with specific enzyme attached is added to the well, this will bind to the HIV specific antibody (primary antibody). well washed put to remove any unbound secondary antibody. if no primary antibody presnt all secondary antibody will be washed out as there's nothing to bind to 4.substrate solution added,reacts with enzyme attached to secodnary antibody to produce coloured product, colour change means pateint has HIV antibodys and is infected with HIV (colour change pos result)

Question 83

ethical issues of using monoclonal antibodies in medicine

Answer 83

-mice used to produce monoclonal antibodies -informed consent need by pateins-have been some deaths assciated with their use in treatments of MS -testing new drugs presents certain dangers (health issues associated to drug trials.)