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Infection and response
Organisation
Cell biology
Biological molecules
Homeostasis and response
Responding to change (a2 only)
Energy transfers (a2 only)
The control of gene expression (a-level only)
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
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1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
Britain & the wider world: 1745 -1901
Inter-war germany
World war one
2n revolution and dictatorship: russia, 1917-1953
World war two & the holocaust
1l the quest for political stability: germany, 1871-1991
The cold war
2j america: a nation divided, c1845-1877
Medieval period: 1066 -1509
The fight for female suffrage
2m wars and welfare: britain in transition, 1906-1957
2d religious conflict and the church in england, c1529-c1570
Britain: 1509 -1745
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26/03/2023
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Exchange Gas exchange in insects Ficks law: area of diffusion pathway xdifference in concentration rate of diffusion of thickness of surface over which diffusion takes place Gas exchange in insects •Spiracle tracheae • tracheoles valve - Spiracles-openings to environment; controlled • tracheae-network of fubes for gas exchange; by Kings of chitin tracheoles - smaller dead-und tubes that extend to all body tissues short diffusion pathway to the body cells with a 3 ways respiratory gases move 1. diffusion: 7 when the cells respire, it reduces the concentration at the ends of the tracheoles, diffusion gradient, causing oxygen to diffuse from the atmosphere to the cells also created opposite direction Creating > diffusion gradient for carbon dioxide is 2. mass transport-contraction of muscles Squeezes Gas exchange in fish as an Problems with water · has 20x less 0₂ than air denser/more viscous than air Gas exchange in fish 3. tracheal fluid in trachedes: > when carrying out anaerobic water potential respiration, muscle cells osmosis > water moves in from the tracheoles via > due to less water in the tracheoles, more air can ·gill flament in and out of the tracheal system. bar • gill raker ・gill filament lamellae trachea exchange medium: counter current flow water by a ; Supported enabling produce lactate, lowering the Water more go further is thin exchange surface - lamella ·large surface area-filaments and ·blood flow maintains concentration gradient Counter current exchange System parallel flow gas into them in and one lamella cell thick out Gas exchange in plants Structure of the human lungs-lobed structures made up of highly branched tubes • trachea-tube that. transports air to the lungs; Supported by rings of cartilage, with walls made of muscle...
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and lined with goblet cells and ciliated epithelium Inspiration blood • wax cuticle upper epidermis 2 palisade mesophyll air Space 7 Spongy Mesophyll stoma guard cell gas as exchange system goblet cells- line the trachea and bronchi and release mucus to trap small particles Ciliated epithelium- traps large particles macrophages- bacterial Scavengers lower epidermis 1 wax cuticle lie between the ribs blood allows gases to diffuse throughout the leaf and 7 есте contact with expiration into mesophyll cells The mechanism. of breathing air when air When air pressure of the atmosphere is forced into the lungs- inspiration pressure inside the lungs, air is forced out of the lungs-expiration The pressure changes are caused by the movement of these muscles: - diaphragm - internal intercostal muscles - external intercostal muscles large surface area for rapid diffusion 50 many stomata short diffusion pathway bronchi-2 divisions of the trachea; has some cartilage; has Ciliated epithelium, goblet cells and macrophages bronchioles-branching subdivisions of bronchi; has little cartilage; Smooth muscle controls air flow ·alvedi - tiny air sacs with collagen and elastic fibres which allow them to stretch with air and spring back to expel air; moist inner Surface to prevent drying; large surface area; Steep diffusion gradient; Surfactant prevents surfaces sticking is greater than the air greater than the air pressure inside pressure of the atmosphere the lungs, CU >diaphragm muscles contract, making it go flat active process- uses energy 2. maltose external pintercostal muscles, internal contract lipid molecule Digestion 0 Interested ribs pulled upwards and outwards, increasing the the volume thorax Muscles relax caused a reduction in pressure Gair is forced into lungs + ♦ diaphragm muscles pushed relax So it up by the abdomen I largely passive- doesn't require much energy › internal intercostal 1. Salivary amylase and pancreatic amylase-hydrolyse glycosidic bonds starch into maltose Maltase bile Salts of proteins. ooto external muscles contract intercostal muscles relax ribs move downwards and inwards, decreasing the volume of the thorax Gincreases pressure is hydrolysed to a-glucose by of lipids Gair is forced "out of lungs Exchange of gases in the lungs Adaptations of the alvedi for faster diffusion of gases: - red blood cells are slowed as they pass through pulmonary capillaries, allowing more time for diffusion - red blood cells flattered against capillary walls, reducing diffusion distance between alvedar air and RBCS -thin alveoli and capillary walls-thin diffusion pathway area large surface -concentration gradient is maintained with breathing/ventilation and blood circulation Enzymes and digestion Digestion of Carbohydrates (starch) Digestion 1. lipids monoglycerides (glycerol with by lipases to form fatty acids and 2. to speed up the action of lipases by increasing the surface of the lipids, bile salts break them up into are a tiny droplets called micelles by emulsification tidal pulmonary ventilation = volume rate (am ³) (dm ³ min) how much b volume air is taken in of air peptide peptide bonds and out of the lungs in a given time normally taken in at each breath at rest Structure of ileum. -villi and microvilli- large surface area of the breathing rate a 1. endopeptidases-hydrolyse 2. exopeptidases - hydrolyse bonds inside on the peptide molecules formed by endopeptidases to release dipeptides and Absorption of the products of digestion 00 (min) b number of breaths taken 1 minute, normally between 12 and 20 breaths in 0 healthy adult in the lining of the ileum. 3. di peptidases- hydrolyse the bond between two amino acids in a dipeptide, found in ileum lining polypeptide terminal amino acids of the single EN amino acids one cell thick thin diffusion pathway good blood supply -maintains concentration and amino acids Absorption of triglycerides 1. micelles diffuse into 2. transported to form Chylomicrons 3. chylomicrons move out of the cell 4. they enter lyruphatic capillaries called lacteals monosaccharides are gradient arbsorbed by diffusion and break down, releasing monoglycerides and fatty acids epithelial cells the exocytosis and then. endoplasmic reticulum and made into triglycerides again pass which into co-transport the easily blood and