6Transport In and Out of Cells Diffusion – from a high to a low concentration until they are evenly spreadOsmosis – from a region of high water concentration to a region of low (weak to a strong solution) through a semi permeable membraneActive transport – from a low to a high concentration across a cell membrane
8Balanced Diets Carbohydrates Protein Lipids / Fats Vitamins Minerals FibreWater
9The Duodenum Amylase Starch Maltose Protease Proteins and polypeptides Amino acidsLipaseFatsFatty acids and Glycerol
10The Ileum Maltase Maltose Glucose Sucrase Sucrose Glucose and Fructose LactaseLactoseGlucose and GalactosePeptidasePolypeptidesAmino acidsLipaseFatFatty acids and Glycerol
11Absorption and Assimilation Glucose and amino acids are absorbed into the bloodFatty acids and glycerol are absorbed into the lacteal
12AssimilationAll digested glucose and amino acids pass into the liver in the Hepatic Portal Vein.Fats enter the lymphatic system which enters the blood and returns them to the liver.The food is used for growth, repair, respiration.Excess food is mostly stored as fat.
13Food Testing Starch – add iodine – turns black Glucose or reducing sugar – add Benedict's solution and boil – turns brick redProtein – Biuret test – add NaOH or KOH and then 1% copper sulphate – a violet colouration
14Aerobic RespirationWith oxygenC6H12O6 + 6O H2O + 6CO2 + energy
15Anaerobic Respiration AnimalsGlucose Lactic acidPlantsGlucose Ethanol and carbon dioxideOxygen debt – the amount of oxygen needed to breakdown the lactic acid accumulated
18Breathing inIs controlled by the intercostal muscles and the diaphragm.When we breathe in the intercostal muscles contract and the ribs move up and out. The diaphragm contracts and moves down.This increases the space inside the chest and air rushes into the lungs.
19Breathing out The intercostal muscles and the diaphragm relax. The ribcage drops down and the diaphragm moves upwards.This reduces the space inside the chest and pushes air out of the lungs.
20Breathing Rate and Depth Rate - how many breaths per minuteDepth – how much air is being taken in, normally ½ litre per breathMeasured with a spirometer
21% of different gases in inhaled and exhaled air Inhaled air (%)Exhaled air (%)Oxygen2016Carbon dioxide0.044Nitrogen79Water vapourVariable level100% saturated
23What makes the lung good at gaseous exchange? Large surface area – greater volume of gases exchangedGood blood supply – O2 and CO2 exchanged more quicklyThin membranes – allows diffusionMoist lining – for the gases to dissolve
24Keeping the Lungs Clean Dust, bacteria and other particles stick to the mucus secreted by cells lining the airwaysCilia attached to these cells waft the mucus and dirt out of the lungs and it is swallowed.Acid in the stomach kills the bacteria
25Effects of Smoking Tar causes cancer Nicotine is addictive Smoking removes the hairs that keep the lungs clean
29The leaf has a waxy cuticle to stop it losing water. The epidermis is a protective layer of cells and contains no chloroplasts.The palisade layer contains the most chloroplasts as it is near the top of the leaf. The chloroplasts contain the pigment chlorophyll. It is here that photosynthesis takes place.The palisade cells are arranged upright. This means the light has to pass through the cell lengthways and so increases the amount of light absorbed.
30Stomata Guard cells stoma Water moves into the guard cells by osmosis and the stoma opens
31DayDuring the daytime the rate of photosynthesis is greater than the rate of respiration
32NightDuring both the day and night respiration occurs in plants.
33Limiting FactorsPhotosynthesis is a chemical reaction, its rate depends upon temperature, how much CO2 is available, light intensity, amount of chlorophyll or water.Without enough light a plant cannot photosynthesise very fast, even if there is plenty of water and carbon dioxide. Increasing the light intensity will make photosynthesis faster.
34Sometimes photosynthesis is limited by the level of carbon dioxide Sometimes photosynthesis is limited by the level of carbon dioxide. Even if there is plenty of light a plant cannot photosynthesise if it has run out of carbon dioxide.Temperature can be a limiting factor too. If it gets too cold the rate of photosynthesis will slow right down; equally, plants cease to be able to photosynthesise if it gets too hot.
35If you plot the rate of photosynthesis against the levels of these three limiting factors you get graphs like the ones below.
36Maximising growthUnderstanding the factors that limit photosynthesis enables greenhouse farmers to maximise the conditions for plant growth. They often use paraffin lamps inside the greenhouse because burning paraffin produces carbon dioxide as well as heat, and so makes photosynthesis proceed faster. They may also use artificial light to enable photosynthesis to continue beyond daylight hours.
37Uses of Glucose Turned into starch for storage Converted into lipid/fat for storage – energy richNitrogen can be added and turned into proteinStored in fruitUsed in respiration
38Mineral Requirements Magnesium for chlorophyll Nitrogen for growth Phosphorus for cell membranes and DNARemember how to test leaves for starch
40The Heart Pumps blood around the body Pumps blood to the lungs To pick up oxygenRemove carbon dioxide
41Double Circulation Heart Lungs Body Greater pressure, better oxygenation,faster flow
42Arteries Veins and Capillaries Thin walls, deoxygenated blood, to the heart, valvesThick walls, oxygenated blood, away from heartLink arteries to veins, site of exchange of metabolites and waste
43Blood Red blood cells, transport oxygen, biconcave, no nucleus, White blood cells, defence, engulf bacteria, produce antibodies
44Platelets Used in the clotting of blood Damage cause them to clump and they begin the conversion of soluble fibrinogen (blood protein) into insoluble fibrin which meshes over the wound and traps red cells. They dry and form a scab
47The lymphatic system Transports excess fluid from the tissues Transports digested fatContains white blood cells that fight infection
48William Harvey 1578-1657 Observed blood flow around the body Noticed existence of valves in veinsConcluded blood pumped via veins round bodyMajor medical breakthrough!
49Galen Lived 1,000 years before Harvey Did not use the scientific methodObservation and experimentationThought blood went from side to sideDid not realise transport existed round body through capillaries
51The Plant Transport System A plant's transport system is made up of two types of tubes - strong, thick pipes called xylem vessels, and thinner tubes called phloem vessels. The cells of these vessels are modified to make them suited to performing their special functionsTogether xylem and phloem form the vascular tissue, often also referred to as the vascular bundle.
52Xylem consists of dead cells with no end walls, which contain lignin to form stiff tubes. They are impermeable.
53Phloem consists of living cells lined with cytoplasm, with walls made of cellulose and perforated end walls. They are permeable, and are surrounded by companion cells.
54Water is taken up the plant from the roots to the leaves (for photosynthesis and transpiration) - in xylem vessels .Minerals dissolved in the water are taken up the plant to the shoots and leaves - in xylem vessels.Food (the product of photosynthesis) is taken from the leaves and moved up and down the plant to any part which needs it (for growth or for storage) - in phloem vessels.
66Food Production and farming methods MonocultureHedgerow removalBiological pest controlPesticides and herbicides and insecticides
67Energy and Waste Burning fossil fuels such as coal, oil or gas Greenhouse effectSulphur dioxide and nitrous oxides are formed which dissolve in water to form acid rainReduce the demand for energy so it reaches a sustainable level- will not use up the resources or pollute the planet
73AccommodationLong distance – lens long and thin, ciliary muscle relaxed, suspensory ligaments tautNear – lens short and fat ciliary muscle contacted, suspensory ligaments loose
74Nerves Synapses and Drugs Some drugs stimulate synapses like a neurotransmitter, LSD and nicotineOthers block the enzyme that normally breaks down the neurotransmitterAlcohol depresses synaptic activity in the brain and acts as a depressant. So do solvents
76Hormones Proteins that are chemical messengers in the body Carried in the blood to target cellsResponse is slowerMay last for hoursCan stimulate more than one target
77Controlling glucose,After eating a lot of carbohydrate blood sugar level rises.Islets of Langerhans in the pancreas release insulin, the glucose is stored as glycogen in the liver.The blood sugar level drops .When blood sugar levels are low the insulin production stops.Glucagon is produced by the pancreas allowing glucose release from the liver and muscles.
78Uses of HormonesControlling fertility – the contraceptive pill, may contain oestrogen and progesterone and controls the release of pituitary hormones and ovulationMini pill, progesterone allows ovulation but makes the vagina and uterus unsuitable for spermAnabolic steroids build muscle – reduce the production of testosterone
79Uses of plant hormonesAuxins allow plants to respond to the environment – tropic responsesAuxin (IAA) causes -They stimulate shoots to grow rapidlyStops side shoots growingStimulates growth of roots from the base of stems or leavesAuxin from seeds cause fruit to swell
80Plant responses and Auxins Hormone rooting powder causes roots to grow from cut stemsSeedless fruits –grapes, cucumbers, bananas. (parthenocarpy)Selective weedkillers 2-4-D causes weeds to grow too fast and results in death, grass doesn’t take it up wellQ 3,4,5 page 102 for Wednesday
81Homeostasis Temperature Control Water Control Salt Balance Sugar controlCarbon Dioxide ControlUrea
82Temperature ControlThermoregulation keeps the body at constant temperature (37oC).Enzymes work best.Temperature is regulated by the hypothalamus.
83Temperature ControlHeat is made in most cells but in particular muscle and liver.Heat is lost by convection, conduction and radiation.Evaporation of water from a surface removes heat.
84Keeping CoolVasodilation, more blood flows nearer the skin and heat is lost.Sweating, evaporation causes heat loss.Hairs lie flat allowing more heat out.
85Keeping WarmVasoconstriction - less blood flows to the skin’s surface, keeping heat in. You may look pale!!Decrease in sweat.Shivering generates heat (respiration).Hairs stand up and trap insulating air.
86Carbon dioxideExcess carbon dioxide results in a drop in the body’s pH (acidic).Breathing out removes this excess.The rate and depth of breathing will alter to suit the amount of CO2.
90The kidneys have four functions: Regulation of blood water levelsReabsorption of useful substances into the bloodAdjustment of the levels of salts and ions in the bloodExcretion of urea and other metabolic wastes
92Kidney transplantThis is when the diseased kidney is surgically removed and replaced by a fully functioning kidney from a deceased or a live donor.It is only possible after a satisfactory tissue-match. Even after a successful tissue-match the recipient's immune system has to be drugged or suppressed to stop it from rejecting the new kidney.
93Kidney failureIn the event of kidney failure due to infection or disease, the kidney can no longer remove metabolic waste products from the body. Excretion of metabolic waste is a vital function and their accumulation will result in eventual death.There are two solutions to the problem of kidney malfunction or failure:Kidney transplantKidney dialysis
95Kidney dialysisIn the absence of a suitable donor kidney, the alternative solution is for the patient to be hooked-up to a dialysis machine every days.A dialysis machine mimics the functioning of the kidney. Blood from an artery in the patient's arm is pumped into the kidney machine which removes urea and excess salts from it.The blood is checked for air bubbles before being returned to a vein in the arm.
96OsmoregulationIs keeping the water and salt levels constant in the blood.They are regulated by the hypothalamus.Water moves into the cells by osmosis and could cause them to burst.
97Blood concentration too high The hypothalamus senses too little water in the blood.A message is sent to the pituitary gland to release anti-diuretic hormone.This stops the kidneys removing water and going to the loo!!
98Blood concentration too low. Too much water in the blood stops the hypothalamus signalling the pituitary.Water is removed by the kidneys.Large amounts of dilute urine produced.
101DNADNA structure discovered by Crick and Watson
102Genetic and Environmental causes of Variation Variation is inheritedGenetic – skin colourEnvironmental – hair lengthBoth – height, weight, intelligence
103Asexual reproductionProduces identical copies called clones – onions, strawberries, potatoes, greenflyThis type of cell division is mitosisCuttings and grafting in plantsMicropropogation used by growers
104MutationsChange in the DNA of an organism caused by an error when it is copiedRadiation and certain chemicals such as cigarette smoke can cause mutationsMost are harmful and leads to illness or deathUseful ones are rare but have a dramatic impact on a species and its evolution
105Harmful mutations Down’s syndrome – an extra chromosome number 21 Cystic fibrosis is caused by a mutation in the DNA. It is a recessive allele which affects 1 in 2000 children.It causes sticky mucus which blocks the lungs and pancreas
106Genetic Engineering Is the ability to alter DNA A gene from one organism can be transferred into the DNA of a completely different organismIn some cases the all the DNA is removed from a cell and replaced with the DNA from another organismDolly the sheep was the first example of genetic cloning
107Selective BreedingIn animals – dogs, cows, sheep, cats and so on. To produce certain traitsIn plants for taste, texture, shelf lifeIs done by choosing parents with the required traits. These are then bred to produce offspring.Sexual reproduction will ensure variation
108MendelStudied peas and concluded that characteristics were passed on from one generation to another.Law of segregation – the 2 alleles separate when gametes are formed, one allele into one gamete and the other into anotherLaw of independent assortment – any gamete of the father can fertilise any gamete of the mother
111Evolution Most organisms overproduce Population numbers remain constantSexual reproduction ensures that all offspring exhibit variationThese variations are inherited from the parentsFrom these Darwin produced his theory of evolution
113New Species – Survival of the Fittest The peppered mothPale ones no longer camouflaged during the Industrial Revolution – were no longer camouflagedDarker ones survived to reproduce and some of their offspring were even darkerThis is survival of the fittest