BIOLOGY UNIT 1 AQA AS LEVEL

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  • Created on: 17-05-14 10:04

DISEASE

DISEASE - conditon which has a specific cause in which part of an organism is made to function in an abnormal way 

CAUSES;

  • PATHOGENS - fungi, viruses, fungi - organisms that cause disease
  • LIFESTYLE
  • AGEING e.g. artheritus 
  • GENES e.g. cystic fibrosis 

INFECTION;

takes place where there is an interface between the body and the enviroment 

process where pathogen enters body and becomes established is called an infection 

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PROTECTION AGAINST DISEASE

EYES - protected by tears, lubrication, antibacterial enzyme - lysozyme 

SKIN - keeps it out, antseptic in sweat

URINE - flushes out bacteria through uretha, antispetic 

EARS - wax, antispetic 

AIRWAYS - lined with mucus (goblet cells produce), and cilia, bacteria trapped by mucus and swept up the oesophagus by the cilia.

LARGE INTESTINE - produce harmless bacteria, out compete pathogens 

NEED TO KNOW - RESPIRATORY SYSTEM AND DIGESTIVE SYSTEM MOST OFTEN SITE FOR ENTRY OF PATHOGENS BECAUSE..... ENTRY EASY FOR MOLECULES E.G. OXYGEN SO ALSO PATHOGENIC MICROORGANISMS.

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HOW DO PATHOGENS CAUSE DISEASE

TO BE CONSIDERED A PATHOHEN IT MUST ; gain entry to host, colonise tissue of host, resist defences of host, cause damage to tissue 

BACTERIA 

  • release toxins as they multiply, these toxins affect region of infection 

VIRUS 

  • enter living cells and genetic material is passed on to host cell and insrtucts it to produce more viruses 

FUNGI 

  • grow in or on living organisms, their hyphae secretes enzymes, digest substance in tissue and grow, this growth damages tissue.

pathogens  DAMAGE HOST TISSUE or PRODUCE TOXin to affect the body 

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LIFESTYLE AND HEALTH

CoronaryHeartDisease - caused by narowing of arteries due to artherclerosis, CHD is multifactorial it doesnt have a single cause  

arthersclerosis caused by: high blood cholestrol, diet and smoking, stress, lack of excerise, high blood pressure and genetic influence 

TO REDCUE OVERALL RISK OF CHD:

  • regular excerise - lowers blood pressure, reduces cholestrol 
  • less saturated fat - reduces rate of arthersclerosis 
  • stop smoking - reduces blood pressure 
  • drink alcohol in moderation reduces blood pressure 
  • less salt - lowers blood pressure 

CANCER

uncontrollable division of cells - multifactorial, carcogenic factors put us at risk (tobacoo)

smokimg, diet, obesity, activity and sunlight increases cancer    

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MOLECULES IN OUR FOOD

MOLECULES IN OUR FOOD ARE.....

MACROMOLECULES - very large and cant be absorbed 

POLYMERS - very large and made from many smaller molecules called  MONOMERS  which are linked by CONDENSATION REACTIONS

BUILT FROM A FEW ELEMENTS - all except water have carbon, hydrogen and oxgen 

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CARBOHYDRATES

CARBOHYDRATES - carbon molecules (carbo) combined with water (hydrate)

carbon atoms - readily form bonds with other carbon atoms, allwoing a sequence to build up and it forms a back bone for others to attach to. 

MONOSACHARIDE molecules - monomers of carbohydrates, saccharide is a sugar 

POLYSACHARIDE molecules - polymers of carbohydrates, condensation reaction joins them (by a molecule of water being released from the hyroxl group) and the bond formed is called a GLYCOSIDIC BOND.  ploysacharide are large molecules so are insoluble which makes them good for STORAGE. 

hydrolisis - water is added and causes polymer to break down into monomers

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TEST FOR REDUCING SUGARS - BENEDICTS

MONOSACHARIDES ARE ALL  REDUCING SUGARS 

REDUCING SUGAR IS A SUGAR THAT CAN DONATE ELECTRONS TO ANOTHER CHEMICAL, THE CHEMICAL IN THIS CASE IS BENEDICTS RAGENT 

WHEN A REDUCING SUGAR HEATED WITH BENEDICTS IT FORMS AND INSOLUBLE RED PRECIPITATE

THE TEST 

  • ADD FOOD SAMPLE IN TO A TEST TUBE 
  • ADD EQUAL VOLUME OF BENEDICTS 
  • HEAT MIXTURE 

IF IT TURNS ORANGEY BROWN IF REDUCING SUGAR IS PRESENT 

DISACHARIDE EXAMPLES ; MALTOSE AND LACTOSE 

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TEST FOR NON-REDUCING SUGARS

CARRY OUT BENEDICTS TEST FIRST IF NEGATIVE RESULTS....

HYDROLISE FOOD SOLUTION BY BOILING WITH HYDROCHLORIC ACID,

 ADD SODIUM HYDROCARBONATE TO NEUTRALISE

 THEN RETEST WITH BENEDCTS REGANT AND HEAT

IF IT TURNS ORANGEY BROWN THEN A NON REDUCING SUGAR IS THERE

IF IT REMAINS GREEN THEN ITS ABSENT  

DISACHARIDE EXAMPLE ; SUCROSE 

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TEST FOR STARCH

STARCH IS A POLYSACHARIDE 

  • ADD IODINE SOLUTION TO SUBSTANCE BEING TESTED IN A TEST TUBE 
  • IF BLUE - BLACK COLOUR IT MEANS THAT STARCH IS PRESENT 
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LACTOSE INTOLERANCE

WHEN SOMEONE CANNOT DIGEST LACTOSE (DISACHARIDE FOUND IN MILK) INTO GLUCOSE AND THEN GALACTOSE 

enzyme lactase which hydrolises lactose is present in all young children (when breast feeding is needed) however after this period the gene encoding lactase is normally switched off.

absence of lactase leads to lactose entering large intesting where the good bacteria there ferments it and releases substances like co2 and methane which lower water potenital in large intestine 

causes bloating and cramps 

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PROTEINS

proteins are large molecules, each organism has numerous proteins which differ from species to species.        MONOMERS- amino acids                                                    POLYPEPTIDE - when 2 or more amino acids join 

FUNCTIONS

  • Transport proteins - on cell membranes protein molecules form ion channels and carrier proteins
  • Antibodies - in the immune system 
  • Enzymes - spherical, soluble and have roles in metabolism (break down of food) 
  • Structural proteins - found in connective tissue e.g. collagen 
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STRUCTURE OF AN AMINO ACID

  • (http://upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Amino_Acid.JPG/400px-Amino_Acid.JPG)
  • side chain or group 'R' is the variation between each amino acid (its different for each one)
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BIURET TEST - PROTEINS

BIURET TEST - DETECTS PEPTIDE LINKS 

  • ADD BIURET REAGENT TO A FOOD SUBSTANCE ( sodium hydroxide and copper sulphate)
  • IF PROTEIN PRESENT IT WILL SHOW PURPLE COLOUR 
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STRUCTURAL LEVELS OF A PROTEIN

BIG COMPLICATED MOLECULES.... THEY HAVE 4 LEVELS

PRIMARY STRUCTURE - sequence of amino acids in polypeptide chain, determined by a sequence of triplet of bases in DNA which also decides its function (peptide bond)

SECONDARY STRUCTURE - hydrogen bonds form between amino acids in chain and makes it automatically coil into an alpha helix (spiral) or fold in to a beta pleated sheet (stair case)

TERTIARY STRUCTURE - coiled and folded further , more bonds form between polypeptide chain (ionic and disulphide)

QUATERNARY STRUCTRE - TWO or more polypeptides bond together to form final protein  e.g. haemoglobin contains 4!!!!!!!

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DISACHARIDES AND POLYSACHARIDES BROKEN DOWN

ENZYMES ARE SECRETED BY INTESTINAL EPTHELIUM THAT HYDROLISE DISACHARIDES AND POLOYSACHARIDES 

DISACHARIDE - MALTOSE HYDROLISED BY MALTASE IN TO GLUCOSE 

SUCROSE HYROLYSED BY SUCRASE INTO GLUCOSE AND FRUCTOSE

LACTOSE HYROLYSED BY LACTASE INTO GLUCOSE AND GALACTOSE 

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LIPIDS

2 MAIN TYPES OF LIPID ARE: TRIGLYCERIDES AND PHOSPHOLIPIDS 

TRIGLCERIDES STRUCTURE - 1 molecule of gycerol with 3 fatty acids attatched through an ESTER BOND. they also have a hydro carbon tail of fatty acids!

(http://upload.wikimedia.org/wikipedia/commons/d/d3/Triglyceride.JPG)

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PHOSPHOLIPIDS

PHOSPHOLIPIDS ARE SIMILAR TO TRIGLYCERIDES BUT HAVE ONE LESS FATTY ACID.

THE LIPIDS IN PLASMA MEMBRANE ARE MAINLY PHOSPHOLIPIDS 

ONE OF FATTY ACIDS REPLACED BY PHOSPHATE GROUP (HYDROPHYLIC -attracts water)

THE HYDROCARBON FATTY ACID TAILS ARE HYDROPHOBIC repel water

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SATURATED OR UNSATURATED FATTY ACIDS

FATTY ACIDS CAN EITHER BE SATURATED OR UNSATURATED 

SATURATED - DONT HAVE DOUBLE BOND BETWEEN CARBON ATOMS

UNSATURATED - DO HAVE DOUBLE BONDS BETWEEN CARBON ATOMS - CAUSES CHAIN TO KINK

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MORE ON LIPIDS

INSOLUBLE IN WATER 

ROLES OF LIPIDS

  • ENERGY SOURCE - when oxidsed TWICE amount of energy as carbs
  • WATERPROOFING - insoluble 
  • INSULATION - slow condunctors of heat - help retain body heat
  • PROTECTION -stored around delicate organs like kidneys 
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TEST FOR LIPIDS

ADD ETHANOL TO FOOD SUBSTANCE 

AND SHAKE TO DISSOLVE ANY LIPIDS

ADD WATER 

SHAKE 

IF CLOUDY WHITE COLOUR IS PRESENT A LIPID IS PRESENT 

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DIGESTIVE SYSTEM

ALL ORGANS HAVE A ROLE 

OSEPHAGUS - tube mouth to stomach, contractions of perastalisis, mucus secreted from walls - lubricates 

STOMACH - small sac, lots of folds allowing expansion (4 litres), entrance controlled by sphincter, stomach walls secrete gastric juice - breaks down food it has HCL, PEPSIN AND MUCUS IN IT, pepsin hyrolysise proteins, peristalisis turns food to chyme 

SMALL INTESTINE - chyme is moved along - perstalisis, in dudoenum bile neutralise acidity, in ileum small soluble molecules are absorbed through structures called villi taht line gut wall. 

LARGE INTESTINE - absorbs water, salts and minerals. Folded walls, large surface area for absorption, 

RECTUM - stored in rectum, pass through sphincter and out **** in defecation 

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SALIVARY GLAND, PANCREAS AND DIGESTION

SALIVARY GLAND - SECRETS SALIVA WHICH HAS MUCUS, MINERAL SALT AND AMALYSE 

AMALYSE BREAKS DOWN STARCH INTO MALTOSE 

SALIVA ALSO LUBRICATES

PANCREASE - RELEASES PANCREATIC JUICE INTO DUDEONEUM THROUGH PANCREATIC DUCT 

CONTAINS - AMYLASE, TRYPISN, CHYMOTRYPSIN AND LIPASE 


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ENZYMES AND DIGESTION

STOMACH - PEPSIN - PROTEIN - PEPTIDES

PANCREASE - AMALYSE - STARCH - MALTOSE

TRYPSIN - PROTEIN - PEPTIDES

CHYMOTRYPSIN - PROTEINS - PEPTIDES

LIPASE - LIPIDS - FATTY ACIDS AND GLYCEROL

ILEUM -MALTASE -MALTOSE - GLUCOSE

SUCRASE - SUCROSE - GLUCOSE AND FRUCTOSE

LACTASE - LACTOSE - GLUCOSE AND GALACTOSE 

PEPTIDASE - PEPTIDES - AMINO ACIDS

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ENZYME ACTION

ENZYMES - globular proteins that catalyse reactions 

HAVE AN ACTIVE SITE, SPECIFIC SHAPE TO FIT A SPECIFIC SUBSTARTE 

ENZYMES - lower the activation energy of a reaction..... e.g. if two substrate molecules need to be joined the enzyme would hold them together to reduce any repulsion and if enzyme is catalysing a breakdown it would put strain on bonds to break them down quicker 

LOCK AND KEY MODEL -  enzyme fits to substrate same way key into lock 

new evidnece showed that the ENZYME SUBSTRATE COMPLEX changed shape slightly to complete the fit

INDUCED FIT MODEL - HELPS EXPLAIN WHY SO SPECIFIC, it doesnt just have to be the right shape to fit, it has to make active site change shape as well 

TERTIARY STRUCTURE OF ENZYME - determines shape of active site

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FACTORS AFFECTING ENZYME ACTION

TEMPERATURE - increases when temp is higher - kinetic energy - more likely to collide - if temp gets to high it denatures 

PH - all have optimum PH - above and below ph can mess up ionic and hydrogen bonds - active site changes shape - denature 

SUBSTRATE CONCENTRATION - more collison - faster reaction - more enzyme subsrate complexes 

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COMPETITIVE AND NON COMPETITVE INHIBITORS

COMPETITVE -

MOLECULES SIMILAR SHAPE - COMPETE WITH SUBSTARTES TO FIT TO ACTIVE SITE - IF THEY BIND NO REACTION - BLOCK IT SO NONE CAN FIT IN - HOW MUCH ENZYME IS INHIBITED DEPENS ON CONCENTRATION OF COMPEPTIVE INHIBITORS 

NON - COMPETIVE -

BIND TO ENZYME AWAY FROM ACTIVE SITE - CAUSES ACTIVE SITE TO CHANGE SHAPE - CAN NO LONGER FIT 

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ANIMAL CELL STRUCTURE

ORGANELLES - structures within a cell

PLASMA MEMBRANE - found on surface of animal cell, made of lipids and proteins, controls what enters and leaves, and has receptor molecules allowing it to respond to chemicals 

NUCLEUS - large, surrounded by envelope which has pores (allow substance e.g. RNA to move in), contains chromatin (DNA that controls cell functions), nucleoulus - makes ribosomes 

LYSOSYME - round organelle with no internal structure, contains digestive enzyme, digest invading cells or break down dead components 

RIBOSOME - small organelle, floats free or near rough er, synthesises proteins by joining aminos 

GOLGI APPARATUS - group of fluid filled sacs - processes and packages lipids and proteins

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ANIMAL CELL STRUCTURE 2

SMOOTH ENDOPLASMIC RETICULUM - system of membranes, synethsesises and processes lipids 

ROUGH ENDOPLASMIC RETICULUM - system of membranes covered in ribosomes, it processes proteins made at ribosome

MICROVILLI - folds in plasma membrane - found on cells involved in processes like absorption, increases sufrace area 

MITOCHONDRIA - double membrane, inner one folded to from structures called cristae, inside is matrix (enzymes involved in respiration are here), it is the site for respiration

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DIFFERENT FUNCTIONS OF ORGANELLES

  • STRUCTURE OF CELL MAY AFFECT JOB E.G. IF ITS PART OF EXHANGE SURFACE NEEDS ALOT OF MICROVILLI TO INCREASE SUFRACE AREA 
  • WHAT CELL NEEDS TO DO E.G. IF IT USES ALOT OF ENERGY IT NEEDS ALOT OF MITOCHONDRIA 
  • EXAMPLE : EPITHELIAL CELLS IN SMALL INTESTINE ARE ADAPTED TO ABSORB FOOD 
  • THE WALLS HAVE VILLI TO INCREASE SURFACE AREA 
  • THE CELLS ON VILLI HAVE MICROVILLI TO INCREASE SUFRACE AREA EVEN MORE 
  • THEY ALSO HAVE LOTS OF MITOCHONDRIA TO PROVIDE ENRGY FOR THE ABSORPTION
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MAGINIFICATION

MAGNIFICATION - how much bigger the image is than the specimen 

RESOLUTION - how detailed image is 

MAGNIFICATION = LENGTH OF IMAGE 

                            ----------------------------------

                            LENGTH OF SPECIMEN 

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CELL FRACTIONATION

  • HOMGENISATION - blend cells, breaks plasma membrane and release organelles in solution
  • FILTRATION - homogenate solution is filtered to remove debris 
  • ULTRACENTRIFUGATION - put into a tube and spun in an ultra centrigufuge which seperates heaviest organeele in a pellet at bottom , the rest are at the top in a supernatant 
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MICROSCOPES

LIGHT - USE LIGHT, LOW RESOLUTION (O.2 UM) , MAXIMUM USEFUL MAGNIFICATION IS X1500

ELECTRON - USES ELECTRONS, HIGH RESOLUTION (O.OOO1 UM), MAXIMUM USEFUL MAGNIFICATION IS X1500000

ELECTRON MICROSCOPES ARE EITHER SCANNING (scan a beam of electrons over specimen, shows 3d image and is good for thick specimen - lower resolution then TM'S)

OR... TRANSMISSION (electromagnets to beam electrons, give high resolution, but only used on thin specimens) 

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PLASMA MEMBRANE

PARTIALLY PERMEMBALE - small molecules can pass through membrane with ease e.g. oxygen, however bigger molecules e.g. ions have to go through ion channels and transport proteins.

STRUCTURE MAILY COMPOSED OF LIPIDS (PHOSPHOLIPIDS), PROTEINS AND CARBOHYDRATES (ATTACHED TO LIPID OR PROTEIN) - 1972 FLUID MOSAIC MODEL SHOWED ARRANGEMENT 

PHOSPHOLIPIDS FORM A CONTINIOUS DOUBLE LAYER (ONE LAYER POINTS IT HYDROPHILIC HEADS TO THE CELL CYTOPLASM INTERACTING WITH THE WATER THERE WHILE THE OTHER LAYER HAS ITS HYDROPHLIC HEADS POINTED OUT INTERACTING WITH WATER ON OUTSIDE OF CELL)

, PROTEIN MOLECULES ARE SCATEERD THROUGH THE LAYER

extrinisic porteins - partially embeddded in it - give mechanical support - or cell receptors for molecules

intrinsic proteins - span whole way across bi layer - act as transporters - others are enzymes  

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DIFFUSION

MOVEMENT OF MOLECULES FROM AN AREA OF HIGH C TO LOW CONCENTRATION

PASSIVE 

PARTICLES CAN DIFFUSE ACROSS PLASMA MEMBRANE AS LONG AS THEY CAN MOVE FREELY BETWEEN IT E.G. OXYGEN 

RATE OF DIFFUSION IS AFFECTED BY;

  • CONCENTRATION GRADIENT 
  • THICKNESS OF EXCHANGE SURFACE 
  • SUFRACE AREA E.G MICROVILLI 
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OSMOSIS

DIFFUSION OF WATER ACROSS PARTIALLY PERMEABLE MEMBRANE FROM AN AREA WITH HIGH WATER POTENIAL TO LOW CONCENTRATION 

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FACILITATED DIFFUSION

DIFFUSION THAT NEEDS TO PASS THROUGH.... 

PROTEIN CHANELS - PORES IN MEMBRANE FOR CHARGED PARTICLES TO DIFFUSE THROUGH 

CARRIER PROTEINS - A LARGE MOLECULE ATTATCHES TO CARRIER PROTEIN IT THEN CHANGES SHAPE AND RELEASES IT ON THE OTHERSIDE OF MEMBRANE 

BECAUSE LARGER MOLECULES AND CHARGED ATOMS CANT PASS THROUGH

PASSIVE 

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ACTIVE TRANSPORT

METABOLIC ENERGY IN THE FORM OF ATP NEEDED 

GOES AGAINST GRADIENT 

CARRIER PROTEINS NEEDED (SAME PROCESS JUST NEEDS ATP TO MOVE AGAINST GRADIENT)

CO TRANSPORTERS NEEDED - BIND 2 MOLECULES AT A TIME, CONCENTRATION OF ONE OF THE MOLECULES HELPS THE OTHER MOLECULE TO MOVE AGAINST GRADIENT 

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ABSORPTION FROM SMALL INTESTINE

WHEN CARBOHYDRATES ARE BROKEN DOWN IN SMALL INTESTINE THERES A HIGHER AMOUNT OF GLUXOES IN THERE THEN IN BLOOD - IT DIFFUSES THROUGH EPITHELIAL CELLS

REMAINING GLUCOSE IS ABSORBED BY ACTIVE TRANSPORT 

THE SODIUM IONS ARE ACTIVLEY TRANSPORTED THROUGH OUT THE EPITHELIAL CELLS TO THE BLOOD  THROUGH A CO TRANSPRTER THIS MEANS A GLUCOSE MOLECULE HAS TO COME WITH IT TO PROVIDE ENERGY 

THIS CREATES A DIFFUSION GRADIENT FOR THE SODIUM IONS AS MORE IN LUMEN THAN IN CELLS

SO MORE COME THROUGH CO TRANSPORTER BRINGING MORE GLUCOSE THROUGH WITH IT 

CONCENTRATION OF GLUCOSE IN CELL INCREASES SO IT DIFFUSES INTO BLOOD THROUGH A PROTEIN CHANNEL 

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PROKARYOTIC

SINGLE CELLED ORGANISMS E.G. BACTERIA 

STRUCTURE 

  • FLAGELLUM - long hair like, rotates to help it move 
  • PLASMA MEMBRANE - controls movement of substances inand out 
  • CELL WALL - supports 
  • DNA - floats free in cytoplasm 
  • PLASMIDS - small loops of DNA - contain things like antibiotic resistance and can pass it on 
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CHOLERA

CHOLERA BACTERIA RELEASES A TOXIN WHICH CAUSE CHLORIDE ION CHANNLES IN SMALL INTESTINE TO OPEN 

THE CHLORIDE IONS MOVE INTO SMALL INTESTINE LUMEN AND LOWER WATER POTENTIAL

WATER MOVES ACROSS FROM THE BLOOD AND THE MASSIVE SECRETION OF WATER INTO THE LUMEN CAUSES SEVERE DIOREAHA 

CAUSING THE BODY TO BECOME DEHYDRATED 

ORAL REHYDRATION SOLUTIONS ARE USED TO TREAT IT .... drink that contains a high amount of salts and sugars dissolved in water, sodium ions are included to increase glucose absorption - this rehydrates

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LUNGS

SPECIALISED ORGANS FOR GAS EXCHANGE 

THE PROCESS OF GAS EXCHANGE 

  • as you breathe in air enters trachea
  • this splits into two bronchi - one going to each lung 
  • each bronchus splits into smaller tubes called bronchioles
  • bronchioles have alveoli at the end 
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VENTILATION

CONSISTS OF INSPIRATION AND EXPIRATION 

INSPIRATION - breathing in - intercostal and diaphram contract - ribcages moves up - diaphram flattens - volume of thorax increases - as volume of thorax increases the lung pressure decreases causing air to flow into lungs - active process 

EXPIRATION - muscles relax - ribs move down and in - diaphram curved again - volume of thorax decreases causing air pressure to increase- air is forced out - passive 

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GAS EXCHANGE IN ALVEOLI

HUGE AMOUNT OF THEM - HIGH SURFACE AREA 

SURROUNDED BY NETWORK OF CAPPILARIES 

02 DIFFUSES OUT OF ALVEOLI INTO BLOOD  ACROSS ALVEOLAR EPITHELIUM 

CO2 DIFFUSES IN TO ALVEOLI AND BREATHED OUT 

FEATURES THAT SPEED UP DIFFUSION - large surface area and thin exchange surface 

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PULMONARY VENTILATION

PULMONARY VENTILATION = TIDAL VOLUME X VENTILATION RATE 

TIDAL VOLUME IS THE VOLUME OF AIR IN EACH BREATH

VENTILATION RATE IS THE NUMBER OF BREATHS PER MINUTE 

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PULMONARY TUBERCULOSIS

LUNG DISEASE CAUSED BY BACTERIA - MYCOBACTERIUM TB

IMMUNE SYSTEMS BUILD WALL AROUND BACTERIA IN LUNGS, FORMS SMALL HARD LUMPS CALLED TUBERCULES 

INFECTED TISSUE WITHIN DIES, GAS EXCHANGE SURFACE SO TIDAL VOLUME DECREASES

SYMPTOMS - COUGHING, BLOOD AND MUCUS, CHEST PAIN, SHORTESS OF BREATH

DROPLET INFECTION.... SPREAD EASY IN CROWDED CONDITIONS 

PREVENTED WITH BCG VACCINE 

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FIBROSIS

FORMATION OF SCAR TISSUE - DUE TO SUBSTANCES LIKE DUST

SCAR TISSUE IS THICKER AND LESS ELASTIC

LUNGS LESS ABLE TO EXPAND, CANT HOLD AS MUCH AIR

REDUCTION IS GAS EXCHANGE - DIFFUSION SLOWER OVER THICJER SURFACE

SYMPTOMS - CHEST PAIN, COUGH SHORTNESS OF BREATHE  

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ASTHMA

AIRWAYS BECOME INFLAMMED AND IRRITATED USUALLY DUE TO ALLERGIC REACTIONS E.G. POLLEN 

ASTHMA ATTACK - SMOOTH MUSCLE LINING BRONCHIOLES CONTRACTS 

CAUSES CONSTRICTION RESTRICITNG AIRFLOW 

TIGHT CHEST AND SHORTNESS OF BREATH 

INHALER TO RELAX BRINCHIOLE 

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THE HEART

LEFT SIDE PUMPS OXYGENATED BLOOD TO THE BODY                                                     RIGHT SIDE - DEOXYGENTAED TO LUNGS

The left ventricle has thick muscley walls than the right becasue it needs to pump it all around the body

Atria have thinner walls then ventricles beacsue they have to push it through the whole body whilst atria only through to ventricles 

AV (atrioventriuclar valve) stops blood flowing back in atria 

SL (semilunar valves) stop blood flowing back into the heart 

THE VALVES - THEY ONLY OPEN ONE WAY, WHETHER THEY OPEN DEPENDS ON THE RELATIVE PRESSURE BEHIND - IF HIGH PRESSURE BEHIND IT WILL OPEN 

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STRUCTURE OF THE HEART

(http://click4biology.info/c4b/h/images/h5/hrt3.gif)

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BEATING OF THE HEART

CARDIAC MUSCLE IS MYOGENIC - it can contract and relax without recieving signals from nerves

SAN NODE - wall of right atrium, pace maker, sends regular electrical activity

this causes left and atria to contract at the same time 

collagen tissue stops waves getting to ventricles 

the waves get transfered to the atrioventricular node 

it passes on to the bundle of his and the bundle of his conducts it through to the purkyne fibres

purkyne fibres carry waves to bottom of ventricels and make them contract from botttom up 

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CARDIAC OUTPUT

CARDIAC OUTPUT = STROKE VOLUME X HEART RATE

HEART RATE = NUMBER OF HEARTBEATS A MINUTE

STROKE VOLUME = VOLUME OF BLOOD PUMPED OUT EACH HEART BEAT 

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IMMUNE SYSTEM

ANTIGENS TRIGGER IMMUNE RESPONSE - found on as a cell on surface of pathogen - they are identifiesd as forign

PHAGOCYTE - type of wb cell, recognises antigens, cytoplasm of phagocyte engulfs it, contained in phagocytic vacoule, lysosome fuses with it and releases enzymes to break it down, it then presents the pathogens antigens on its sufrace to activate other immune system cells

T-CELLS - phagocytes activate tcellls, they have proteins on sufrace that bind to antigens, some release substances that activate b cells others attach to pathogen and kill it 

B-CELLS - covered with antibodies( porteins that bind together to from antibody antigen complex) all antibodys complementary to an antigen, itattaches to antigen and activates, it then divides into plasma cells

PLASMA CELLS - identical to b cells, secrete a load of antibody specific to antigen 

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ANTIBODY

(http://www.biology.arizona.edu/immunology/tutorials/antibody/graphics/antibody.gif)ANTIBODIES are proteins, made up of amino acids, specifity depends on variable regions - complememnrtary to different antigens, DISLUPHIDE BOND links them! 

FUNCTIONS - coat pathogen to make it easier to engulf and to prevent it entering host cells, binding to and neutralising toxins produced.

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ANTIBODY

(http://www.biology.arizona.edu/immunology/tutorials/antibody/graphics/antibody.gif)ANTIBODIES are proteins, made up of amino acids, specifity depends on variable regions - complememnrtary to different antigens, DISLUPHIDE BOND links them! 

FUNCTIONS - coat pathogen to make it easier to engulf and to prevent it entering host cells, binding to and neutralising toxins produced.

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