Respiration - Test your understanding, tips, resources and a quiz

Oxygen is the final electron acceptor. It oxidises the final carrier in the ETC on the inner mitochondrial membrane and is reduced to water.

Hydrogen ions flow from the inter membrane space into the matrix via ATP synthase, this electrochemical gradient phosphorylates ADP.

Hydrogen ions are pumped from the matrix into the inter membrane space, using the energy from the electrons flowing along the ETC. The electrons come from the oxidation of food, transferred by coenzymes NAD and FAD.

Glycolysis occurs in the cytoplasm. Link and Krebs in the matrix. Link and Krebs produce carbon dioxide by the removal of a carboxyl group.

Fermentation is just glycolysis with a different way of regenerating NAD (from NADH) by the reduction of pyruvate (or ethanal).

Substrate level phosphorylation is the direct addition of phosphate to ADP, occurs in glycolysis (4 ATP) and Krebs (once per turn), chemiosmosis is H ions flowing through ATP synthase.

Cristae give a larger surface area for oxidative phosphorylation

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Photosynthesis Tips - Notes, videos, powerpoints and a pack of long questions and then a (difficult) Quiz to test your understanding

Powerpoints and notes, a pack of long data analysis exam questions and a test on photosynthesis

Tips for Photosynthesis

LDR - occurs on the thylakoid membranes. Limiting factor is light intensity

  • Phosphorylates ADP (through chemiosmosis) - creates the Hydrogen ion gradient by the flow of electrons along the ETC in the thylakoid membrane. The flow of electrons is driven by the capturing of light by a range of different pigments which channel the energy to a chl a molecule at the reaction centre of the photosystem - which then loses an electron.

  • Reduces NADP with an electron from splitting water (photolysis) at PSII.

Light Independent Reaction (reduction of carbon dioxide) - occurs in the stroma (the cytoplasm of the chloroplast).

  • Limited by speed and quantity of RUBISCO enzyme (kinetic energy - temperature) and substrate concentration (Carbon dioxide)

  • Needs the products of the LDR - ATP and NADPH

  • NADPH and ATP are used to regenerate RUBP

  • Each time the Calvin cycle turns, a single Carbon is reduced. 3 turns - one extra Triose Phosphate. 6 turns - 2 extra TP = 1 extra glucose.

  • TP is the source of all of the carbon in all plants (and hence in all heterotrophes) - Amino acids, DNA, RNA, phospholipids etc

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