Photosynthesis and Respiration Flashcards
What is the equation for photosynthesis?
6CO2+6H2O+energy->C6H12O6+6O2
What is a coenzyme that is used in photosynthesis?
-NAPD
Describe the light dependent reaction
-In PS!!, light energy excites an electron making it move to a higher energy level, these electrons move down the ETC to PS1
-Light energy splits water into protons, electrons and oxygen in order to replace the lost electrons
-Electrons lose energy as they move down energy levels, this energy is used to transport proteins into the thylakoid to create a proton gradient, when protons move across the thylakoid membrane, ATP synthase makes ATP
-Light energy in PS1 excites electrons more and makes them move to a higher energy level
-Electrons are transferred to NADP with a proton to make reduced NADP
What part of photosynthesis is chemiosmosis?
-When electrons flow down the ETC and create a proton gradient across the membrane to drive ATP synthesis
Describe the Calvin cycle
-Carbon dioxide and ribulose bisphosphate join to make an unstable 6-carbon molecule, which almost immediately splits into 2 molecules of glycerate 3-phosphate, catalysed by rubisco
-ATP is hydrolysed which provides energy used to reduce GP into triose phosphate. This also requires H+ ions which come from reduced NADP, the NADP is recycled into NADP
-1/6 molecules of TP are used to make organic compounds, the rest of them are used to regenerate RuBP, this uses the rest of the ATP produced by the LDR
How many turns of the Calvin cycle need to occur before you make a hexose sugar?
-Six
What are the limiting factors of photosynthesis?
-High light intensity of a certain wavelength
-Temperature around 25 degrees
-Carbon dioxide at 0.4%
-Water
What coenzymes are used during respiration?
-NAD
-Coenzyme A
-FAD
What are the four stages of aerobic respiration?
-Glycolysis
-Link Reaction
-Krebs cycle
-Oxidative Phosphorylation
What happens during glycolysis?
-Glucose is phosphorylated using a phosphate from from an ATP molecule, to make glucose phosphate
-Glucose phosphate is then phosphorylated to make hexose bisphosphate
-This splits into 2 molecules of triose phosphate
-Triose phosphate is oxidised to make 2 molecules of pyruvate, NAD collects the H ions and makes reduced NAD
-Net gain of 2 ATP molecules
What happens during the link reaction?
-The pyruvate molecules are decarboxylated and oxidised to form acetate and NAD is reduced to form reduced NAD
-Acetate is combined with coenzyme A to form acetyl coenzyme a
How much ATP is made during the link reaction?
-No net gain
What happens during the Krebs cycle?
-Acetyl coenzyme a combines with a 4-carbon compound to form a 6-carbon compound
-The 6-carbon compound is converted into a 5-carbon compound, decarboxylation and dehydrogenation, the hydrogen is used to produce reduced NAD
-5-carbon compound is converted into a 4-carbon compound, decarboxylation and dehydrogenation occur producing one molecule of FAD and two of reduced NAD. ATP is produced from ADP+Pi
Describe oxidative phosphorylation
-H atoms released when NADH and FADH are oxidised, these H atoms split into a proton and an electron
-Electrons move down the ETC, losing energy at each carrier
-Energy is used by electron carriers to move protons from the matrix into the intermembrane space
-Concentration of protons higher in intermembrane space than in the matrix, creating an electrochemical gradient
-Protons move down the gradient back across the membrane and into the matrix via ATP synthase
-Process of ATP production is driven by movement of H+ ions across a membrane, this is chemiosmosis
-At the end of the ETC, oxygen and H+ and electrons join to form water, oxygen is the final electron acceptor
What are the products of glycolysis and where are they used?
-2 reduced NAD=to oxidative phosphorylation
-2 pyruvate=Actively transported into matrix for link reaction
-2 ATP=Used for energy elsewhere
