Biology Ch6 - Exchange

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  • Created by: Safaxo
  • Created on: 14-06-18 00:52
Adaptations of inactive organisms (eg. viruses)?
1) Flattened shape so no cell far from surface. 2) Exchange surface with large areas so increases SA:V. 3) O2 in mito used up and CO2 formed so maintains conc. gradient
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Adaptations of exchange surfaces
1) Large SA:V so increases rate of exchange. 2) Thin so short diff. pathway. 3) Selectively permeable. 4) Movement of internal + environmental medium so maintains conc. gradient
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Fix's law?
Diffusion directly proportional to (SA x conc. gradient) / diff. pathway
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Single celled organisms exchange?
Small size so will have a large SA:V so O2 absorbed by diffusion through cell surface membrane
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Structure of gas exchange in insects?
Trachea supported by rings to prevent collapsing which divide into tracheoles so O2 brought directly to the respiring tissues for a short diff. pathway. Also increases SA.
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Ventilation in insects? pt.1
1. Along diff. gradient - when cells respiring, O2 used up from tracheoles so O2 diff. from air to tracheoles. CO2 produced in respiring tissues which diffuses in opposite direction. Diff in air is faster than water.
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Ventilation in insects? pt.2
2. Mass transport - when muscles contract they decrease the volume and increase pressure of tracheoles so air forced out. When relaxes, volume increases, pressure decreases so air forced INTO trachea.
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Ventilation in insects? pt.3
3. Ends of tracheoles filled with H2O - When respiring anaerobically, lactate produced which lowers water potential, hence water moves into the respiring cells from tracheoles by osmosis, so water diff. from air to tracheoles
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Function of spiracles?
Gases leave and enter via spiracles, open and close by valve to limit water loss by evaporation.
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Size limitations of insects?
Relies mostly on diff. so needs a short pathway so limits size of ants.
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Structure of gills?
Small SA:V so gills present. 1) Gill filaments-stacked in pile. At right angles are gill lamellae - increases SA. 2) Countercurrent flow of blood and water (opposite directions). 3) Ventilation + mass transport in blood for conc. gradient
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Countercurrent exchange system?
Blood + water flow in opposite directions so equilibrium never attained. Blood w/ lots of O2 meets water with MAX. conc. so still diff. and blood w/ little O2 meets water with some O2 so diff. occurs.
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Adaptations of leaf?
1) Stomata - no cell far from stomata so short pathway. 2) Lots of air spaces in mesophyll so short, fast diff. pathway as readily contactable. 3) Large SA of mesophyll
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Stomata?
Pores on the underside of leaf controlled by pair of guard cells that open and close to control gas exchange and water loss by evapouration
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Limiting water loss in insects?
1) Small SA:V so minimise area where O2 lost. 2) Spiracles closed at rest to reduce water loss. 3) Waterproof covering of chitin to reduce evaporation
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Limiting water loss in plants?
Can't have small SA:V as photosynthesis needs large SA:V. Hence, reduced by waterproof covering and stomatal pores.
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Xerophytes? (Limit water loss by transpiration)
1) Waxy thick cuticle so less water escapes. 2) Hairy leaves trap moist air which has reduces water potential gradient. 3) Rolling up leaves traps region of air that is saturated w/ water so high water potential= no gradient. 4) Low SA:V so SLOW diff
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Lung structure?
1) Inside body so not dehydrated. 2) Lungs ventilated, constantly replenished.
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Trachea, Bronchi and bronchioles?
1) Trachea - cartilage rings so doesn't collapse w/ pressure change. Ciliated epithelial and goblet cells produce MUCUS. 2) Bronchi - produce mucus + cilia to move dirt mucus to throat. 3) Bronchioles - muscle contracts control air flow
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Alveoli?
1) Collagen + elastic so stretches. 2) Large SA. 3) Epithelial lining - 1 cell thick. 4) Capillary network, RBC flattened so slow diff. 5) Capillary endothelial 1 cell thick. 6) Blood flow + ventilation maintains conc. gradient
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Breathing muscles?
1) Diaphragm. 2) Internal intercostal muscles. 3) External intercostal muscles
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Inspiration?
Active process. External contract and internal relax. Diaphragm contracts and flattens. Ribs pulled up and out. Vol of thorax increases. Pressure decreases. Air pressure > lung pressure - air forced INTO lungs.
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Expiration?
Passive process. Internal contract and external relax. Diaphragm relaxes + pushed up. Ribs move down and inwards. Vol decreases. Pressure increases. Air pressure < lung pressure so air forced OUT of lungs.
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Digestive system?
Oesophagus. Stomach stores and digests PROTEINS. Ileum folded into villi w/ microvilli (large SA). Large intestine absorbs water. Rectum. Salivary gland. Pancreas. Liver.
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Physical + chemical digestion?
1) Physical - teeth break down large into small pieces so LARGE SA. 2) Chemical - HYDROLYSES large insoluble to small soluble. Carried out by specific enzymes. eg. Amalayse, Lipase, Protease.
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Carb digestion?
Salivary amalayse breaks glycosidic bonds in starch to form disacc. maltose. Optimum pH is 7. Acidic stomach denatures amalayse. Pancreatic amalyase + alkaline salts hydrolyse. Membrane bound disacch. MALTASE in ileum lining hydrolyses to a-glucose.
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Lipid digestion?
Lipase produced in pancreas hydrolyses ester bond to form monoglyc. + f.a. Lipids split into droplets (MICELLES) by bile salts through emulsification = increases SA.
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Protein digestion?
1) Endopeptidases - hydrolyses peptide bonds in CENTRAL region of protein. 2) Exopeptidases - hydrolyses peptide bonds on TERMINAL amino's of peptide molecules => forms dipeptides. 3) Dipeptidases - hydrolyses between 2 amino's. Membrane bound.
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Villi adaptations?
1) Thin wall. 2) Increase SA. 3) Muscle for movement so maintains conc. gradient as products absorbed. 4) Capillary network - blood carries away absorbed material so maintains conc. gradient. 5) Microvilli - increases SA
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Absorption of triglycerides?
Monoglyc + f.a + bile salts form MICELLES. They break down again into NONPOLAR monoglyc + fa. Enter epithelial cell - goes to ER then Golgi (recombines forming triglyc). Triglyc+ cholestrol+ lipoproteins = CHYLOMICRONS exocytosis out into lacteals.
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Other cards in this set

Card 2

Front

Adaptations of exchange surfaces

Back

1) Large SA:V so increases rate of exchange. 2) Thin so short diff. pathway. 3) Selectively permeable. 4) Movement of internal + environmental medium so maintains conc. gradient

Card 3

Front

Fix's law?

Back

Preview of the front of card 3

Card 4

Front

Single celled organisms exchange?

Back

Preview of the front of card 4

Card 5

Front

Structure of gas exchange in insects?

Back

Preview of the front of card 5
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