Photosynthesis

• what are the 2 parts of the light dependent stage? 1- non-cyclic photophosphorylation 2- cyclic photophosphorylation
• what happens in non-cyclic photophosphorylation? 1- Photons of light are absorbed by photosynthetic pigments in PSII - electrons gain energy and bcome ‘excited’ 2- the excitation passes to chlorophyll a in the reaction centre and emit a electron - PSII recieves replacement electrons from the photolysis of water - dissociates into hydrogen ions, electrons and oxygen gas 3- electrons from chlorophyll a molecules are transferred between electron carriers found in the thylakoid membrane 4- energy lost from these electrons is used by proton pumps to transfer protons into the thylakoid space f...
• what is cyclic photophosphorylation? 7- electrons are transferred to PSI and photons of light are absorbed by accessory pigments and passed to chlorophyll a in the reaction centre - excited electrons are once again emitted from chlorophyll a in the reaction centre and recieved by electron acceptors 8- Co-enzyme NADP is reduced making NADPH2 by the addition of electrons and protons - this takes place in stroma 9- NADP is the final electron acceptor 10- Some electrons pass back through electron carriers where their energy is used in ATP productions and the electrons are returned to PSI
• what are the useful and wasteful products of the light dependent stage? useful - ATP and NADPH2 waste - Oxygen
• What happens in the light independent stage? called the calvin cycle? 1- uptake of carbon dioxide by 5C ribulose biphosphate 2- this is catalysed by the enzyme RuBisCO which then forms an unstable 6 carbon compound 3- this splits into 2x 3C glyerate phosphate 4- ATP and NADPH2 from light dependent stage are used to reduce 2x 3C glycerate phosphate into 2x 3C triose phosphate - 2 triose phosphates can also be converted into 1 glucose molecules which can be used in making starch, cellulose, sucrose etc. 5- then this is converted into 5C ribulose phosphate 6- ATPase breaks down ATP in...
• what is chemiosmosis? the synthesis of ATP using energy from H+ or proton gradients
• what is a compensation point? a certain point where a factor no longer affects the rate of the reaction because it stays the same
• what is a limiting factor? something which directly affects the rate of a process if its quantity is changed
• 3 factors that affect the rate of photosynthesis? light intensity, changes in carbon dioxide, and temperature
• how does increasing light intensity affect photosynthesis? an increase in light intensity causes the rate of photosynthesis to increase
• how does carbon dioxide concentration affect photosynthesis? higher carbon dioxide cocnentration means that the rate of photosynthesis will increase
• how does temperature affect the rate of photosynthesis? higher the temp the hiher the rate of photosynthesis
• Element Nitrogen and why it is needed for plants - Nitrates - fucntion is for amino acids and nucleic acid synthesis - deficiency symptoms = stunted growth; yellow leaves
• Element potassium and its function in leaves K+ - function= opening and closing of stomata; enzyme cofactor - deficiency symptom= stunted growth, yellow leaves, reduced flowering and fruit formation
• element phosphorus and its function in leaves phosphate - function= nucleic acid and phospholipid synthesis - deficiency symptoms= small dark-green leaves often with a red-purple edge; reduced root growth
• Sulfur Element and its function in leaves Sulphate - function= in some amino acids - deficiency symptoms= chlorosis in new leaves, reduced root growth
• calcium element and its function in leaves Ca2+ - function= formati0on of middle lamella between plant cells; enzyme cofactor - deficiency symptoms= small leaves; death of buds at end of stems
• magnesium element and its function in leaves - Mg2+ - function= component of chlorophyll; enzyme cofactor - deficiency symptoms= chlorosis