Energy transfers

• Outline ways of transferring energy

  sun to plant via photosythesis

  food chains

  energy loss through food chains

  respiration

  electric energy in action potentials

  electric energy in heart contractions
• Outline sun to plant energy transfer

  Explain LDR and Calvin cycle

  light energy from the sun has been converted into chemical energy when it is conserved in the bonds of these molecules Made from photosythesis (ATP and glucose)
• Outline energy transfers in food chains

  energy is then passed between organisms to the next stage of the food chain through consumption, when these plant materials are eaten by larger organisms as they obtain their own feeding resources. energy is transferred to each higher level of the food chain until it reaches the uppermost organisms, like humans or large mammals.
• outline energy transfer lost in food webs

  only a tiny fraction of the sun’s energy is absorbed, This limits the amount of photosynthesis which can occur, and thus limits the amount of chemical energy that can be storEd between bonds Furthermore, between each successive stage of the food chain, only around 10-20% of the energy is passed on. This is due to factors such as energy being lost in excretory or indigestible materials like urine or faeces, respiration producing heat as a by-product which releases energy to the environment, and the fact that not all of an organism can be consumed. 
• outline respiration in energy transfers

  once animals have digested the glucose, it undergoes respiration (explain) which produces ATP which is needed for muscle contraction and active transport
• outline electric energy in action potentials

  Stimuli cause influxes of positive Na+ ions into axons which initiate depolarisations and creates waves of electrical energy in the form of action potentials which travel down the neurone. When it reaches a synapse, it is converted to chemical energy (neurotransmitters), The action of the post-synaptic neurone then converts this information back into electrical energy in the form of another action potential, given that transmission is quicker in this form of energy and thus enables more rapid responses and better chances of survival.
• outline electrical energy in heart contraction

  Energy is transferred to the heart in the form of nervous impulses from the medulla oblongata to the sinoatrial node where a wave of electrical excitation spreads out across both atria, causing them to contract. However, this energy is halted at the atrioventricular septum as this is a layer of non-conductive tissue which blocks the electrical energy from passing across it. This means there is a delay before the impulse spreads to the ventricles since a further wave of electrical energy from the atrioventricular node in order to contract.