t5 energy transfers Flashcards
adaptations of chloroplasts for the LDR
-thylakoid membranes provide large SA to increase no of LDRs that occur
-network of proteins in grana that hold chlorophyll for max light absorption
-grana membranes have ATP synthase channels (for production of ATP) and are selectively permeable (proton gradient established)
-chloroplasts contain DNA and ribosomes so can quickly make proteins needed
adaptations of chloroplasts for LIDR
-stroma contains all enzymes needed for LIDR
-stroma fluid is membrane bound, allowing high conc of enzymes to be maintained
-stroma fluid surrounds grana so products of LDR can readily diffuse into stroma
-chloroplasts contain DNA and ribosomes so can quickly make proteins needed
process of light dependent reaction (LDR)
- photoionisation
- electron carriers & transport chain
- chemiosmosis
- NADP to reduced NADP
- photolysis of light replace electrons
process of light independent reaction (LIDR)
- CO2 diffuses into leaf
- CO2 reacts w ribulose bisphosphate (RUBP), catalysed by rubisco enzyme, to make 2 mols of glycerate-3-phosphate (GP)
- reduced NADP used to reduce GP to 2 mols of triose phosphate (TP) using ATP
- NADP reformed and goes back to LDR
- 1/6 TP mols used to produce organic mols eg. starch, amino acids, cellulose, lipids
- 5/6 TP mols used to reform RUBP, using ATP
process of phosphorus cycle
-p ions in rocks released into soils by weathering
-p ions taken up by plants and transferred to consumers during feeding
-p ions in waste products and dead organisms released into soil during decomposition by saprobionts
-p ions can be taken up and used again by producers or trapped in sediments that turn into sedimentary rock over long periods of time
4 stages of nitrogen cycle (brief)
- nitrogen fixation
- ammonification
- nitrification
- denitrification
what happens during nitrogen fixation
-nitrogen fixing bacteria convert n gas into ammonia, which forms ammonium ions that can be used in plants
what happens during ammonification
-organic material in waste products and dead organisms is broken down by saprobionts to release ammonium ions into soil
what happens during nitrification
-ammonium ions in soil are converted into NITRITES (by nitrifying bacteria) and then into NITRATES that can be used by plants
-nitrifying bacteria need oxygen
what happens during denitrification
-when soils become waterlogged and have low oxygen conc, there is an increase in anaerobic denitrifying bacteria
-denitrifying bacteria convert soil nitrates into gaseous nitrogen
what are saprobionts
-organisms (such as bacteria and fungi) that decompose organic matter to release nutrients that would otherwise be locked up as complex molecules that cannot be recycled
what is mycorrhizae
-fungi that form a network of filaments around plant roots that increase the SA of plant roots for absorption of water and minerals
-can also form connections between different plants to transport minerals from an area of surplus to an area of deficit.
-type of mutualistic fungi
what is biomass
-total mass of living material in a specific area at a given time
stages of aerobic respiration (brief)
- glycolysis
- link reaction
- krebs cycle
- oxidative phosphorylation
process of glycolysis
- glucose is phosphorylated using 2 ATP mols into phosphorylated glucose
- phosphorylated glucose splits into 2 Triose Phosphate mols
- hydrogen is removed from each of the 2 TP mols and used to reduce NAD, forming 2 reduced NAD
- TP mols converted to 2 Pyruvate mols (3C) resulting in net gain of 2 ATP mols (4 produced total)
products of glycolysis
- 2 pyruvate mols
- 2 ATP (net)
- 2 reduced NAD
link reaction process
- pyruvate mols actively transported into matrix of mitochondria
- pyruvate oxidised to Acetate (2C) and loses a CO2 molecule and 2 hydrogens
- hydrogens used to reduce NAD
- Acetate combines with Coenzyme A to produce Acetylcoenzyme A (2C)
krebs cycle process
- acetylcoenzyme A combines w 4-C compound to produce Citrate (6C)
- Citrate loses CO2 and hydrogen, forming reduced NAD
- citrate converted to 5-C compound which loses another Co2 and undergoes dehydrogenation to produce 2 mols of reduced NAD, 1 mol of reduced FAD and ATP. regenerates 4-C compound
krebs cycle products
- 2 CO2
- ATP
- 2 reduced NAD
- 1 reduced FAD
process of oxidative phosphorylation
- reduced NAD and FAD release hydrogen atoms which split into H ions and electrons.
- electrons enter electron transport chains and lose energy between each carrier in a series of oxidation-reduction reactions
- energy released used to actively transport H ions from matrix to inter-membrane space, creating a conc gradient
- this allows the diffusion of H ions through ATP synthase channels, generating ATP
- electrons leave electron transport chain and are combined w oxygen and hydrogen ions to form water (oxygen is terminal electron acceptor)
role of oxygen in respiration
terminal electron acceptor during oxidative phosphorylation
where does oxidative phosphorylation occur
-between matrix and inter-membrane space of mitochondria
where does glycolysis occur
cytoplasm
process of anaerobic respiration in animals
pyruvate + reduced NAD – lactate + NAD
1. glucose converted into Pyruvate by glycolysis
2. reduced NAD is oxidised and releases 2 H, forming 2 NAD
3. pyruvate becomes an electron acceptor and is reduced to form Lactate (lactic acid)
process of anaerobic respiration in plants and fungi
pyruvate + reduced NAD – ethanol + NAD + CO2
1. glucose converted to pyruvate by glycolysis
2. reduced NAD is oxidised and releases 2 Hs, forming 2 NAD.
3. pyruvate decarboxylated to produce ethanal and CO2
4. ethanal then reduced to produce ethanol
features of aerobic respiration (for comparison)
- occurs where there is plentiful oxygen
- releases more ATP (36 net gain)
- involves glycolysis, link reaction, krebs cycle, oxidative phosphorylation
-occurs in cytoplasm and mitochondria
-produces co2 and water
features of anaerobic respiration (for comparison)
- occurs where there is little oxygen
- releases less ATP (2 net gain)
- involves glycolysis and fermentation (of ethanol or lactate)
-occurs in cytoplasm - produces lactate OR Co2 and ethanol
where does anaerobic respiration occur
cytoplasm (glycolysis)
