Some terrific guidance and definitions here - from AQA but applies to all exam boardsRead More
Exam practise webinars now open for enrolment - join now to save your seatRead More
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The new style linear A level Biology exams have a very different approach to assessment so I made recorded lessons of guides to the new specification sample and 2017 A level papers and to the 2016 AS Papers. This one is available for free on my VOD siteRead More
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 phosphorylationRead More
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
AS OCR Breadth in biology H020/01 June 2017 Multiple Choice Questions as an auto-marking online quizRead More
OCR released the OCR A June 2017 H420 papers. I combined the Biological DIversity 420/02 paper with the markscheme to make it easier to follow and interpret.Read More
OCR released the OCR A June 2017 H420 papers. I combined the Unified Biology 420/03 paper with the markscheme to make it easier to follow and interpret.Read More
OCR released the OCR A June 2017 H420 papers. I combined the Biological Processes 420/01 paper with the markscheme to make it easier to follow and interpret.Read More