Qualification > Reference Material
AS BIOLOGY ( C.I.E ) Notes
emzie:
Thnaxx alot!! these notes are amazing! i started preparing for bio this September, and this isreally helpful ;)
WARRIOR:
IMMUNITY
ANTIGEN : A large molecule ( GLYCOPROTEIN ) that the body recognises as FOREIGN and stimulates an IMMUNE RESPONSE
ANTIBODY : A GLYCOPROTEIN , made by the immune system as a response to the presence of ANTIGEN and is SPECIFICALLY targeted at it .
IMMUNE RESPONSE : LYMPHOCYTES response to the presence of antigen by producing ANTIBODIES
White blood cells are divided into the following
1. Neutrophils 2. Macrophages 3. T Cells 4. B cells
Phagocyte Phagocyte Lymphocyte Lymphocyte
LARGE LARGEST SMALL SMALL
Lobed Nucleus with Kidney shaped Large rounded Large Rounded
3-5 lobes Nucleus Nucleus Nucleus
Granular cytoplasm Non-granular cytoplasm Non-Granular cytoplsm Non-Granular cytplsm
Matures in Monocyte in Bone marrow Matures in Matures in
Bone marrow but matures in cells & organs Thymus Gland Bone Marrow
Phagocytes
Neutrophils : 60% of white blood cells , Short lived ,Squeeze out of capillary gaps , Increase rapidly during infection , They phagcytose
How they work?
Attraction : Neutrophils attracted to site of infection by CHEMOTAXIS due to a) Histamine released by body cells under attack b)Chemicals from bacteria
Attachment : Bacteria attached to cell surface membrane of neutrophils either directly of after being labelled by antibody
Endocytosis : Infolding of neutrophil's cell surface to engulf bacteria
Bacteria in Phagosome
Lysosome fuse with phagosome to form phagolysosome
Bacteria killed by enzymes or hydrogen peroxide
Macrophages :Long lived , Cut pathogen in antibodies and displays them on their surface to be recognised by lymphocytes
Clonal Selection : Only T and B cells with specific receptors specific to antigen will respond
Clonal Expansion : Clonal selection increase in number by mitosis
Lyphocytes: T cells and B cells
T cells develop specific Tcell receptor . 2 types of cells are developed
Take care cells ( cytotoxic cell ) Th cells ( Helper cells )
Take care cells : Punches holes in cell surface membrane of infected body cell and secretes toxic chemicals that kill cell.
Divided by mitosis to form memory T cells
Th cells : Secretes cytokines that : Stimulate B cells to differentiate into plasma cells that secrete specific antibodies and form memory B cells by mitosis .
Divided by mitosis to form memory T cells
B cells : Stimulated by Cytokines to divide by mitosis to and differentiate into plasma cells that secrete specific antibodies and memory B cells.
Primary Response : During primary infection it takes time for clonal selection and clonal expansion for the specific antibodies to specific antigens to made. After infection no. of antibodies in blood decreases but memory cells remain
Secondary Response : When infection enters the body , memory cells divide rapidly making more plasma cells . Therefore response is faster and higher conc of antibodies in blood , and more memory cells are made for future infections
STRUCTURE OF ANTI-BODIES
Glycoprotein
Made of 4 polypeptide chains : 2 heavy/long chains and 2 light/short chains
Held together by Disulfide bonds
The heavy chains have a sugar branch
Hinge region to provide flexibility to bind to antigen
Variable region specific to each type of antigen
Roles of Antibodies
Immobilise bacteria by sticking to flagellae
agglutinate (clump ) bacteria
Label bacteria to be phagocytosed
Neutralise toxins
Lysis of bacteria by making holes in their cell walls and water enters by osmosis and bacteria burst
Types of Immunity
Natural passive immunity : Where antibodies is passed from one individual to another of same species . No memory cells made , so protects for short time ( e.g Antibodies from colostrum )
Artificial passive Immunity : Giving a serum ( antibodies from one individual injected to another individual of same or different species ) , no memory cells made , so protects for short time ( e.g Antitetanus serum from horse given to MAN )
Natural Active immunity : Body exposed to infection , so body makes it's antibodies . Memory cells made so protects for a long time
Artficial active immunty : giving a vaccine , antigens , body makes its antibodies , memory cells made to protects for a long time
Most UniQue™:
Kimo Please refrain from double posting the same thing as you did in the earlier posts. All of them have been removed. I hope this wont happen again....
WARRIOR:
Infectious Diseases
Diseases Caused by pathogens that can spread from infected people to uninfected people.
Carrier of a disease : People that carry pathogen , spreads it , but has no symptoms or disease
Incubation Period : Period between entry of pathogen into person and the appearance of disease
Acute disease : Sudden , short term
Chronic : Long term
Opportunistic infection : Pathogens that infect a body with low immunity
Prophylaxis : A measure taken to prevent a disease before it happens.
endemic : Always found in population
epidemic : spreads rapidly infecting many people
pandemic : spreads worldwide !
Cholera
Pathogen : Vibrio Cholerae ( Bacterium )
Method of transmission : Food borne , water borne
Incubation period : 1-5 days
Site of action of pathogen : Walls of small intestine
Symptoms : Diarrhoea , loss of water and salts , dehydration , weakness
Diagnosis : Microscopical examination of faeces
Distribution : ASIA , AFRICA , LATIN AMERICA due to
1) No clean water supply
2) No sewage system or treatment
3)Eating raw vegetable irrigated by sewage
Control : Buy clean water supply
Cook vegetable
Buy sewage system
Isolate patient
Give oral rehydration solution
Tuberculosis
Pathogen : Mycobacterium Tuberculosis , Mycobacterium Bovis
Transmitted by : Air-borne droplets ( Tuberculosis ) , Food-Borne ( Bovis) [infected meat or unpasteurised milk ]
Incubation period : Few week or months
Clinical features : racking cough , coughing blood , fever , sweating , chest pain , weight loss , breathlessness
Site of action : Lungs , lymph nodes , bones , gut
Method of diagnosis : Microscopical examination of sputum for bacteria
Chest X-RAY
Global Distribution : Worldwide , but mainly Asia , Africa and Latin America
Reasons : Malnutrition -> Less protein -> Less antibody -> less immunity -> TB is an opportunistic infection
HIV-> Low immunity -> TB is n opportunistic infection
Overcrowded areas spread air-borne infections
More immigrants and refugees
Control : Isolation of patient
Treat by anti-tuberculous drugs : Rifampicin , Isoniazid
Several drugs at a time to reduce appearance of drug resistant strains
Tracing contancts and screening for TB
BCG vaccine as prohylaxis
Milk pasteurisation and TB testing of cattle
MDRTB- multiple drug resistant strains of tuberculosis , due to stopping taking of drugs early , and because patient feels good
DOTS : Direct observation treatment short course . Health workers and family members ensure patient takes drugs for 6-8 months.
AIDS
Pathogen : HIV - HUMAN IMMUNODEFICIENCY VIRUS
Method of transmission : In semen and vaginal fluid during heterosexual and homosexual intercourse
In blood transfusion
Contaminated syringes
From mother to foetus through placenta
From mother to foetus in colostrum
Incubation period : a few weeks , but up to 10 years or more for symptoms of AIDS to develop
Clinical features HIV - flu-like symptoms , then symptomless
AIDS - opportunistic infections ( pneumonia , tb , cancers , weight loss , fever )
Site of Action : T helper lymphocyts , brain
Diagnosis : Blood test for HIV antibodies
Global distribution : WORLDWIDE , SUBSAHHARAN AFRICA , SOUTHEAST ASIA , NORTH AMERICA (DUE TO INCREASE IN HOMOSEXUALS )
Control : Advise people to use condoms or femidom
Advise people to have 1 sexual partner
Advise people to use sterile syringes
Advise people not to donate blood if they have HIV
Screening and heat-treating donated blood
Contact tracing
Drugs like Zidovudine (similar to DNA nucleotide that has thmine ) slows down onset of AIDS by stopping viral infection
AIDS is difficult to control because :
It has a long incubation period ( so carrier can spread AIDS without symptoms appearing on him)
Virus mutates , not detected by immune system , cannot make vaccine
Not all cases are diagnosed or reported
Widespread HIV testing would be an infringement of personal freedom , so governments dont do it
Malaria
Pathogen : Plasmodium Malariae , P.Ovale , P.Vivax , P.Falciparum
Method of transmission : Insect vector is the female Anopheles mosquito that bites an infected person , takes gametes of plasmodium that develops in its body to infective stage. It then bites an uninfected person and injects an anti-coagulant to prevent blood clot .
Incubation period : A week to a year
Clinical Features : Anaemia , fever , sweating , enlarged liver adn spleen
Site of action : Liver , Red blood cells , brain
diagnosis : Microscopical examination of red blood cells for protoctists
Global distribution : Tropics and Sub-tropics , Asia , Latin Ameerica , africa
Control : Oil spread on ponds , ditches to kill pupae and larvae
Using fish in ponds that eat larvae
Sprayng bacteria in ponds that kill larvae , not other organisms
Screening houses
Mosquito nets
Avoid exposure of skin at dusk
Use anti-malarial drugs , before , during , after visit to area where malaria is endemic ( Chloroquine )
If someone is infected with malaria in an area where malaria is endemic it gives him immunity !But if he leaves the area he becomes sick
Plasmodium mutates become resistant to anti-malarial drugs
Mosquito mutates become resistant to DDT
WARRIOR:
No problem ! As long as you can fix it there is no problem at all . Like you said i have space for one more chapter after that you can delete romeesa's post or do whatever you mods do :P ill inbox you when i want to add another chapter. Thanks !
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