Module 4 Section 1: Disease and the Immune System Flashcards

Question

What conditions can affect disease transmission

Answer 1

Living conditions Climate Social factors

Answer 2

Overcrowded living conditions increase the transmission of many diseases E.g. TB is spread directly via droplet infection, can also be spread indirectly because the bacteria can remain in the air and infect new people so the risk of infection is increased when lots of people live crowded together

Answer 3

Potato/tomato late blight is especially common during wet summers because the spores need water to spread Malaria is most common in tropical countries, which are humid and hot This is because these are the ideal conditions for mosquitoes to breed

Answer 4

Risk of HIV infection is high in places where there’s limited access to: Healthcare: people are less likely to be diagnosed and treated for HIV and anti-HIV drugs are less likely to be available, so the virus is more likely to be passed on to others Health education: to inform people about how HIV is transmitted and how it can be avoided (e.g. through safe sex practices like using condoms)

Answer 5

By their shape By their cell wall

Answer 6

Bacillus/ chain of bacilli (rod) Coccus/ pair, chain or cluster (sphere) Vibrio (comma) Spirillum (spiral) Spirochaete (corkscrew)

Answer 7

Gram staining Different structures of cell wall react differently with the stain

Answer 8

Gram positive appear purple/blue under light microscope Gram negative appear red under light microscope

Answer 9

The type of cell wall affects how bacteria react to different antibiotics

Answer 10

Binary fission

Answer 11

Protein shell Genetic information as RNA or DNA 0.02-0.3 micrometers No organelles Rapidly evolve Non living Always pathogenic

Answer 12

Invade other cells using attachment proteins Hijack biochemistry of the cell Insert viral DNA into host DNA Host cell transcribes and translates viral DNA Host cell copies viruses

Answer 13

Viruses: hijack and destroy cells Bacteria: produce toxins Protists: digest cell contents Fungi: saprotrophic feeding and digestion of cells

Answer 14

Eukaryotes Single celled or colonies Parasitic Often require vector Do not fall into any other categories

Answer 15

Multicellular Fungi can be saprophytes: feed on dead organisms Fungi can be parasitic: pathogenic fungi which causes disease Fungi reproduce by making millions of spores which can spread

Answer 16

Saprotrophic feeding Secrete enzymes onto surface of food Extracellular feeding Enzymes digest food leaving nutrients Fungi absorbs nutrients left by enzymes

Answer 17

Preventative measures can be used such as mosquito nets, window and door screens and long sleeves to prevent bites Preventative measures also include controlling the vector by using insecticides and removing standing water

Answer 18

Through a break in the skin E.g. during sex (HIV) From an animal bite E.g. rabies Through a wound or through sharing needles E.g. septicaemia

Answer 19

Taking in contaminated food or drink, or transferring pathogens to the mouth from the hands E.g. dysentery, diarrhoeal diseases

Answer 20

Inanimate objects such as bedding, socks or cosmetics can transfer pathogens E.g. athletes foot

Answer 21

Droplets of saliva and mucus enter the air through talking, coughing or sneezing If they contain pathogens and are breathed in by people then they can become infected E.g. influenza, tuberculosis

Answer 22

Vectors transmit communicable pathogens from one host or another These are often but not always animals E.g. mosquitoes (malaria), rat fleas (plague) Water can also act as a vector of disease

Answer 23

Direct contact of a healthy plant with any part of a diseased plant E.g. ring rot, TMV, tomato and potato blight and black sigatoka

Answer 24

Soil contamination Vectors

Answer 25

Infected plants often leave pathogens or reproductive spores from protoctista or fungi in the soil These infect the next crop E.g. black sigatoka spores, ring rot bacteria and TMV

Answer 26

Wind: pathogens can be carried by the wind Water: spores swim in the surface film of water on leaves Animals: insects and birds carry pathogens and spores from one plant to another as they feed Humans: pathogens and spores are transmitted by hands, clothing, fomites, farming practices and through transporting plants around the world

Answer 27

Planting crops that are susceptible to disease Over crowding plants Poor mineral nutrition reduces resistance of plants Damp, warm conditions increase the survival and spread of pathogens and spores Climate change causing increased rain and wind promotes the spread of disease, changing conditions allow animal vectors to spread to new areas

Answer 28

Receptors in plant cells respond to molecules from the pathogens or to chemicals produces when the plant cell wall is attacked The stimulates the release of signalling molecules that switch on genes in the nucleus This triggers cellular responses such as: Producing defensive chemicals Sending alarm signals to unaffected cells to trigger their defences Physically strengthening cell walls

Answer 29

Waxy cuticles: provide barrier against pathogen entry and stops water containing pathogens from collecting on leaf Cell walls: physical barrier against pathogens that make it through waxy cuticle Plant produce callose: makes it harder for viruses to spread and enter cells

Answer 30

Synthesised within minutes of the attack and is deposited between the cell walls and cell membrane in cells next to the infected cells These callose papillae act as barriers to prevent the pathogens entering the plant cells around the site of infection Large amounts of callose continue to be deposited in cell walls after the initial infection Lignin is added to make the mechanical barrier to invasion thicker and stronger Blocks sieve plates in the phloem, sealing off the infected part and preventing the spread of pathogens Deposited in the plasmodesmata between infected cells and their neighbours, sealing them off from the healthy cells and helping to prevent the pathogen from spreading

Answer 31

Plants produce powerful chemicals to either repel insect vectors of disease or kill invading pathogens

Answer 32

These chemicals can be used by humans to help control insects, fungi and bacteria

Answer 33

Insect repellants: pine resin Insecticides: caffeine Antibacterial compounds (including antibiotics): defensins Antifungal compounds: chitinases Anti-oomycetes: glucanases General toxins: cyanide

Answer 34

Waxy cuticle thickens Cell walls get stronger Guard cells close stomata in the leaf If microbes are attacking one section of the plant, the surrounding cells self destruct to quarantine the infection

Answer 35

Animals have a range of primary, non specific defences to prevent pathogens entering the body

Answer 36

Physical barrier Blocks pathogens from entering body Can act as chemical barrier by producing chemicals that are antimicrobial and can lower pH to inhibit the growth of pathogens Has skin flora of healthy microorganisms that outcompete pathogens for space on body surface Produces sebum, oily substances that inhibits growth of pathogens

Answer 37

Protect body openings that are exposed to the environment (e.g. mouth, nostrils, ears, genitals and anus 👅) Some membranes secrete mucus - sticky substance that traps pathogens and contains lysozymes and phagocytes

Answer 38

Blood clots are a mesh of protein (fibrin) fibres The clots plug wounds to prevent pathogen entry and blood loss Formed by a series of chemical reactions that occur when platelets are exposed to collagen from damaged blood vessels Platelets release: Thromboplastin: trigger series of reactions resulting in blood clot formation (thrombus) Serotonin: causes smooth muscle in blood vessel walls contract to reduce blood flow to the area

Answer 39

The swelling helps to isolate pathogens that may have entered the damaged tissue The vasodilation increases blood flow to the area which brings white blood cells to the area to fight off present pathogens

Answer 40

Signs include swelling, pain, heat and redness Triggered by mast cells in damaged tissue which releases: Histamines: makes blood vessels dilate causing localised heat and redness, raised temperature helps prevent pathogens reproducing Histamines make vessel walls leaky so blood plasma is forced out to become tissue fluid (tissue fluid causes swelling and pain) Cytokines: attract white blood cells (phagocytes) to the site to dispose of pathogens by phagocytosis

Answer 41

Skin is able to repair itself in the event of injury and re-form a barrier against pathogen entry

Answer 42

Epidermal cells below scab start to grow to seal the wound Damaged blood vessels regrow Tissue below the wound contracts to bring the edges of the wound closer together Wound is repaired using collagen fibres - too many collagen fibres causes a scar to form

Answer 43

E.g. coughing, sneezing, vomiting, diarrhoea Sneezes happen when the mucous membranes in the nostrils are irritated by dust or dirt Coughing stems from irritation in respiratory tract Both coughing and sneezing aim to expel foreign objects, including pathogens, from the body Happen automatically Vomiting and diarrhoea expel contents of the gut along with any pathogens

Answer 44

Tears and urine contain lysozymes Acid in the stomach Helps prevent pathogens entering the body

Answer 45

Normal body temperature is around 37°C and is maintained by the hypothalamus When pathogens invades the body the cytokines stimulate hypothalamus to increase temperature Higher temperatures inhibit pathogen reproduction Specific immune system works faster at higher temperatures

Answer 46

Phagocytes are white blood cells that engulf and destroy pathogens Two main types: neutrophils and macrophages Phagocytes build up at the site of infection and attack pathogens Pus building up in wound is a result of dead neutrophils and pathogens

Answer 47

Pathogens produces chemicals that attract phagocytes Phagocytes recognise non-human proteins on the pathogens This response is not specific to a type of pathogen, instead it’s against any cell or organism that is non-self Phagocyte engulfs the pathogen and encloses it in a vacuole called phagosome Phagosome combines with a lysosome to form phagolysosome Enzymes from the lysosome digest and destroy pathogen

Answer 48

Neutrophils take under 10 mins to engulf and destroy a bacterium whereas macrophages take longer as they have a more complex process

Answer 49

When a macrophage has digested a pathogen, it combines antigens from the pathogen surface membrane with glycoproteins in the cytoplasm called the major histocompatibility complex (MHC) MHC complex moves these pathogens antigens to the macrophage’s own surface membrane It becomes an antigen presenting cell (APC) These antigens now stimulate other cells involved in the specific immune system response

Answer 50

Produced when phagocytes have engulfed a pathogen They are chemicals that act as cell signalling molecules Inform other phagocytes that the body is under attack and stimulates them to move to the site of infection or inflammation Can also increase body temperature and stimulate the specific immune system

Answer 51

Bind to pathogens and tags them so they can be more easily recognised by phagocytes Phagocytes have receptors on their cell membranes that bind to common opsonins The phagocyte then engulfs the pathogen

Answer 52

Many different types Antibodies such as immunoglobulin G (IgG) and immunoglobulin M (IgM) have the strongest effect

Answer 53

Smear sample Spreading a drop of blood thinly across the slide Can be stained to show nuclei of lymphocytes Identifying the number of different types of lymphocytes in a blood smear indicates if a non specific or specific immune response is taking place

Answer 54

T cells Mature in the thymus Have highly specific receptors in their membranes Respond to 'changed' cells (infected cells, antigen-presenting cells, 'non-self' cells, mutated cells) - this is the Cell-Mediated Response Selection of correct T cell leads to expansion by mitosis, then differentiation into variety of T cells ('T helper', 'T killer', 'T memory', 'T regulator' T cells play key roles in control and coordination of immune response

Answer 55

B cells Remain in bone marrow until mature Congregate in lymph nodes and spleen, forming the 'humoral response' - roaming protection in the fluids. Have highly specific antibodies in their membrane - each B cell can only produce one type of antibody and each B cell is unique. Selection of correct B cell leads to expansion by mitosis, then differentiation into plasma/effector cells (which produce antibodies) and memory cells.

Answer 56

T helper cells T killer cells T memory cells T regulator cells

Answer 57

Plasma cells B effector cells B memory cells

Answer 58

T killer cells: Destroy the pathogen carrying the antigen Produce a chemical Perforin which kills the pathogen by making holes in the cell membrane so it’s freely permeable

Answer 59

T memory cells: Live for a long time and are part of the immunological memory If they meet an antigen a second time, they divide rapidly to form a huge number of cloned T killer cells that destroy the pathogen

Answer 60

T helper cells: Have CD4 receptors on their cell surface membrane which bind to the surface antigens on APCs Produce interleukins (type of cytokine) Interleukins made by T helper cells stimulate the activity of B cells, which increases antibody production Stimulates production of other types of T cells Attracts and stimulates macrophages to ingest pathogen with antigen-antibody complexes

Answer 61

T regulator cells: Suppress immune system, acting to control and regulate it They stop the immune response once a pathogen has been eliminated They make sure the body recognises self antigens and does not set up an autoimmune response Interleukins are important in this control

Answer 62

Plasma cells: Produce antibodies to a particular antigen and release them into circulation Produced from B effector cells An active plasma cell lives for a few days but produces around 2000 antibodies per second while it’s alive and active

Answer 63

B memory cells: Live for a long time and provide the immunological memory They are programmed to remember a specific antigen and enable the body to make a rapid response when a pathogen carrying that antigen is encountered again

Answer 64

Divide to form the plasma cell clones

Answer 65

Y shaped glycoproteins called immunoglobulins Two identical long polypeptide chains called the heavy chains 4 polypeptide chains held together by disulfide bridges Also disulfide bridges within polypeptide chains holding them in shape Hinge region of antibody provides flexibility and allows it to bind two separate antigens, one at each of its antigen binding sites Made up of constant region which is same on all antibodies and allows attachment to phagocytes and contains only heavy chains Heavy chains extend into variable region which contains light chains and gives specificity

Answer 66

Produced by B cells in response to antigens Bind to specific antigen on pathogen or toxin that has triggered immune response Bind to antigens with a lock and key mechanism

Answer 67

Forms an antigen-antibody complex

Answer 68

Area of 110 amino acids on both heavy and light chains Known as variable region since its different on each antibody and gives them their specificity

Answer 69

Antibody in antigen-antibody complex acts as an Opsonins so complex is easily engulfed by phagocytes Most pathogens cannot invade host cells once they are part of an antigen-antibody complex Mostly done through antibodies acting alone Act as agglutinins causing pathogens carrying antigen- antibody complexes to clump together, helps prevent them spreading through body and makes it easier for phagocytes to engulf multiple pathogens at the same time Done by antibodies acting in complex Act as antitoxins by binding to toxins produced and making them harmless

Answer 70

Where T-lymphocytes respond to the cells of an organisms that have been changed E.g. by a virus, antigen processing, mutation or cells from transplanted tissue

Answer 71

1. In the non-specific defence system, macrophages engulf and digest pathogens in phagocytosis Process the antigens from the surface of pathogen and form antigen presenting cells (APCs) 2. Receptors on some T helper cells fit the antigens (clonal selection) These T helper cells are activated to produce interleukins These stimulate more T cells to divide rapidly by mitosis (clonal expansion) Form clones of identical T helper cells that all carry the antigen to bind to a specific pathogen 3. The cloned T cells can: Develop into T memory cells to respond rapidly on second infection Produce interleukins that stimulate phagocytosis Produce interleukins that stimulate B cells to divide Stimulate development of a clone of T killer cells that are specific for the presented antigen and then destroy infected cells

Answer 72

The body responds to antigens found outside the cells E.g. bacteria, fungi and APCs Humoral immune system produces antibodies that are soluble in the blood and tissue fluid and not attached to cells

Answer 73

B lymphocytes have antibodies on their cell surface membrane (immunoglobulin M) Pathogens entering the body carry specific antigens or produce toxins that act as antigens B cells with the complimentary antibodies will bind to the antigens on the pathogen or to free antigens The B cells engulfs and processes the antigens to become an APC

Answer 74

Activated T helper cells bind to B cell APC This is clonal selection: the point when the B cell with the correct antibody to overcome a particular antigen is selected for cloning Interleukins produced by the activated T helper cells activate the B cells Activated B cell divides by mitosis to give clones of plasma cells and B memory cells This is clonal expansion Cloned plasma cells produce antibodies that fit antigens on pathogen surface They bind to and disable antigens or act as opsonins and agglutanins This is primary immune response Some cloned B cells develop into B memory cells If body is infected by the same pathogen again, B memory cells divide rapidly to form plasma cell clones which produce right antibody to kill pathogen quickly This is secondary immune response

Answer 75

Primary immune response takes days or weeks to become fully effective against pathogen Symptoms are a results of the body reacting when pathogens are dividing freely, before the primary immune response is fully operational

Answer 76

When the immune system stops recognising self cells and attack healthy body tissue Can be caused by genetics, immune system responding abnormally to mild pathogen or normal bodily microorganisms or T regulator cells do not work effectively

Answer 77

Rheumatoid arthritis Lupus

Answer 78

Immune system attacks cells in joints Affects joints such as hands, wrists, ankles, feet No cure Treatment includes: immunosuppressants, pain relief

Answer 79

Affect skin and joints causing fatigue Immune system attacks cells in connective tissue Can attack any organ in the body such as liver, lungs or brain No cure Treatments include: immunosuppressants, steroids

Answer 80

An area of a plant that is under attack can warn separate areas of the infection via hormones, electrical signals or airborne compounds When the areas detect these signals, they increase production of defensive compounds This can also alert separate neighbouring plants of the infection as well Plants under attack from insects can release chemicals into the air This attract other insects (e.g. wasps) that can deter the attacking insects

Answer 81

Molecules that can stimulate an immune response Our own antigens are recognised as ‘self’, foreign antigens stimulate the production of antibodies Specific to the organism

Answer 82

Usually protein or glycoproteins with specific structure On or inside the cell surface membrane

Answer 83

Body produces T and B memory cells after being infected with pathogen If you meet a pathogen for a second time, your immune system recognises the antigens more quickly and launches a secondary immune response before the pathogen causes disease

Answer 84

Active artificial immunity occurs when you become immune after you’ve been given a vaccination containing a harmless dose of antigen

Answer 85

Artificial passive immunity is when you become immune after being injected with antibodies from someone else E.g. being given antibodies to beat a disease via blood donation

Answer 86

Passive immunity is when you are given antibodies made by a different organism - your immune system doesn’t produce any antibodies of its own

Answer 87

Natural passive immunity is when a baby becomes immune due to the antibodies it receives from its mother, through the placenta and in breast milk This lasts until the immune system of the baby begins to make its own antibodies The antibodies received are likely to be relevant to pathogens in its environment

Answer 88

Natural Active immunity results from having actually been infected by a pathogen. This activates the immune system, leading to antibodies being formed by B cells.

Answer 89

Requires exposure to antigen Takes a while for protection to develop Protection is long term Memory cells are produced

Answer 90

No exposure to antigens Protection is immediate Protection is short term Memory cells aren’t produced

Answer 91

Killed or inactivated bacteria and viruses Attenuated (weakened) strains of live bacteria or viruses Toxin molecules that have been altered and detoxified Isolated antigens extracted from the pathogen Genetically engineered antigens

Answer 92

Pathogen is made harmless so that the antigens are intact but there is no risk of infection Small amounts of the safe antigen, known as the vaccine, are injected into the blood The primary immune response is triggered by the foreign antigens and your body produces antibodies and memory cells as if you were infected with a live pathogen If you come into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer symptoms of the disease

Answer 93

When a communicable disease spreads rapidly to a lot of people at a local or national level

Answer 94

When a disease spreads rapidly across a number of countries and continents

Answer 95

This prevents the spread of the pathogen into the wider population When vaccines are being deployed to prevent epidemics, they often have to be changed regularly to remain effective

Answer 96

This is when a significant number of people in the population have been vaccinated This gives protection to those who do not have immunity There is minimal opportunity for an outbreak to occur

Answer 97

These make sure that memory cells are produced These can be given several years after first vaccination

Answer 98

Vaccination is the administration of a substance designed to stimulate the immune system Immunisation is the process by why you develop immunity Vaccination causes immunity

Answer 99

MMR: Protects against measles, mumps and rubella and is given to children as an injection at around a year old and again before they start school Contains attenuated measles, mumps and rubella viruses Meningitis C vaccine: Protects against bacteria that cause meningitis C First given as an injection at 3 months and boosters are given to 1 year olds and teenagers

Answer 100

The flu vaccine changes every year This is because antigens on the surface of the influenza virus change regularly to form new strains of the virus Memory cells produced from vaccination with one strain of the flu will not recognise other strains with different antigens (strains are immunologically distinct) Every year there are different trains of the influenza virus circulating in the population This means a different vaccine must be made

Answer 101

Laboratories collect samples of these different strains Organisations, such as the WHO (world health organisation) and CDC (centre for disease control), test the effectiveness of different influenza vaccines against them New vaccines are developed and one is chosen every year that is most effective against the recently circulating influenza viruses Governments and health authorities then implement a programme of vaccination using the most suitable vaccine

Answer 102

Sometimes people are given a vaccine that protects them from a strain causing an epidemic in another country This helps stop the strain spreading globally

Answer 103

The process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains

Answer 104

A gradual process of genetic change that leads to more variety for each type of influenza virus due to there being different types of antigens on the surface

Answer 105

When a pathogen enters the body for the first time, the antigens on its surface activate the immune system as the primary response This response is slow because there aren’t many B lymphocytes that can make the antibody needed to bind to it Eventually the body will produce enough of the right antibody to overcome the infection, this means that the person will show symptoms T and B lymphocytes produce memory cells, which remains in the body for a long time and can remember the specific antigen and will recognise it the second time. This means that the person is now immune

Answer 106

If the same pathogen enters the body, the immune system will produce a quicker, stronger immune response (secondary response) Clonal selection happens faster as memory B lymphocytes are activated and divide into plasma cells that produce the right antibody to the antigen Memory T lymphocytes are activated and divided into the correct type of T lymphocytes to kill the cell carrying the antigen This gets rid of the pathogen before you begin to show any symptoms

Answer 107

Pathogen enters first time Slow response B and T lymphocytes activated Show symptoms

Answer 108

Pathogen enters for 2nd time Response is fast Memory cells activated No symptoms

Answer 109

Many are manufactured using natural compounds found in plants, animals or microorganisms E.g. penicillin is obtained from penicillium fungus, cancer drugs can be made using soil bacteria, daffodils are now grown to produce a drug used to treat Alzheimer’s disease Organisms that have already been studied could still prove to be useful sources of medicines as new techniques are developed for identifying, purifying and testing compounds

Answer 110

Species could die out before we get a chance to study them and we may never create cures for diseases such as AIDS

Answer 111

This is a combination of drugs that work with your individual combination of DNA Doctors can analyse your genetics and only prescribe drugs which will be most effective for you This can mean that more effective drugs can be manufactured in the future using this information

Answer 112

Your genes determine how your body responds to certain drugs and different people respond to the same drug in different ways This determines whether a drug is more effective or not

Answer 113

This involves using technology to design and make things like artificial proteins, cells and even microorganisms This can be applied to medicine where scientists can engineer bacteria to destroy cancer cells, while leaving healthy body cells intact by producing drugs which would otherwise be too rare, expensive or unavailable

Answer 114

This can also use nanotechnology where tiny, non natural particles are used for biological purposes e.g. to deliver drugs to specific sites within cells of pathogens or tumours

Answer 115

Phase 1: small number of healthy volunteers (establish how drug works and likely dose required Phase 2: small number of patients (can be controlled, double blind or randomised experiments) Phase 3: larger study of patients (assess and compare drug to existing treatments) Licensing: if drug appears to have high efficacy, is safe, and meets manufacturing standards then it can be sold by licence holder in regions covered by regulatory authority

Answer 116

Chemicals which kill or inhibit the growth of bacteria Used by humans as drugs to treat bacterial infections They target bacteria cells without damaging body cells

Answer 117

We have been able to beat bacterial infections easily using antibiotics so the death rate has fallen This have been happening since the discovery of penicillin (from penicillium mould) by Alexander Fleming and the chemical’s use during the Second World War

Answer 118

Can develop severe allergic reactions in some people Antibiotic resistance

Answer 119

There is genetic variation in a population of bacteria Genetic mutations make some bacteria naturally resistant to an antibiotic The ability to resist an antibiotic is an advantage over competition as the bacteria are able to survive in a more hostile environment (due to antibiotics providing selection pressure) so they live longer and reproduce by binary fission Resistance alleles are also passed laterally through the population by conjugation in the form of plasmids The allele for antibiotic resistance is passed on to lots of offspring So resistance spreads and becomes more common in a population of bacteria over time

Answer 120

If the bacteria has developed resistance then the infection cannot be treated as easily using antibiotics so the infection can become more severe which could lead to death

Answer 121

Can lead to the development of superbugs that are resistant to most known antibiotics These are becoming more common We are less able to treat some potentially life threatening bacterial infections

Answer 122

Stands for Meticillin resistant staphylococcus aureus This causes serious wound infections such as septicaemia It is resistant to several antibiotics (including meticillin) Carried by up to 30% of population on skin or in nose

Answer 123

Clostridium difficile Infects the digestive system which causes problems in people who have already been treated with antibiotics Could be caused by harmless bacteria that are present in the digestive system which are killed by the antibiotics, which C. difficile is resistant to Causes C.difficile to flourish due to lack of competition It produces a toxin causing severe diarrhoea, fever or cramps

Answer 124

Doctors should not prescribe antibiotics for minor infections Should not prescribe them to prevent future infections (except patients with weak immune systems, e.g, elderly people or HIV patients) Patients should take all the antibiotics they’re prescribed to fully clear the infection and all bacteria are killed

Answer 125

Primary response starts around the 5th - 10th day Secondary starts around 25-28 days

Answer 126

Polysaccharide