CELL RESPIRATION Topic 3.7 IB Biology Miss Werba

CARBS, LIPIDS & PROTEINS 3.5 TRANSCRIPTION & TRANSLATION TOPIC 3 - BIOCHEMISTRY 3.1 ELEMENTS & WATER 3.2 CARBS, LIPIDS & PROTEINS 3.3 DNA STRUCTURE 3.4 DNA REPLICATION 3.5 TRANSCRIPTION & TRANSLATION 3.6 ENZYMES 3.7 CELL RESPIRATION 3.8 PHOTOSYNTHESIS J WERBA – IB BIOLOGY 2

THINGS TO COVER Cell respiration Substrates/products aerobic respiration Substrates/products anaerobic respiration Glycolysis & Kreb’s Cycle (basics) J WERBA – IB BIOLOGY 3

CELL RESPIRATION Command term = DEFINE Cell respiration: The controlled release of energy from organic compounds in cells to form ATP ATP = adenosine triphosphate Chemical equation: C6H12O6 + 6O2 + (36 ADP + 36 Pi) → 6CO2 + 6H2O + (36 ATP) J WERBA – IB BIOLOGY 4

GLYCOLYSIS Command term = STATE Process: The breakdown of glucose (6 carbons) into two molecules of pyruvate (2 × 3C) Location: Occurs in the cytosol (cytoplasm) Energy yield: Results in a small yield of ATP (net gain = 2 ATP) Aerobic/anaerobic: Either – not O2 dependent J WERBA – IB BIOLOGY 5

GLYCOLYSIS Command term = STATE J WERBA – IB BIOLOGY 6

ANAEROBIC RESPIRATION 3.5.3 ANAEROBIC RESPIRATION Location: in the cytosol of the cell Energy yield: a small yield of ATP (only the 2 ATP molecules from glycolysis) Oxygen requirement: oxygen absent Results in: lactic acid (animal cells) ethanol + CO2 (plant cells = fermentation) J WERBA – IB BIOLOGY 7

ANAEROBIC RESPIRATION 3.5.3 ANAEROBIC RESPIRATION J WERBA – IB BIOLOGY 8

AEROBIC RESPIRATION Location: in the mitochondria of the cell 3.5.3 AEROBIC RESPIRATION Location: in the mitochondria of the cell Energy yield: a large yield of ATP 2 ATP molecules from glycolysis 2 ATP molecules from Krebs Cycle 32 ATP molecules from the Electron Transport Chain Oxygen requirement: oxygen present Results in: carbon dioxide (CO2) + water (H2O) J WERBA – IB BIOLOGY 9

3.7 CELL RESPIRATION J WERBA – IB BIOLOGY 10

3.7 CELL RESPIRATION J WERBA – IB BIOLOGY 11

Sample questions Q1. Which process produces the most ATP per molecule of glucose? A. Anaerobic respiration in a yeast cell B. Aerobic respiration in a bacterial cell C. Glycolysis in a human liver cell D. The formation of lactic acid in a human muscle cell J WERBA – IB BIOLOGY 12

Sample questions A1. B J WERBA – IB BIOLOGY 13

Sample questions Q2. Compare how pyruvate is used in human cells when oxygen is available and when oxygen is not available. (5 marks) J WERBA – IB BIOLOGY 14

Sample questions A2. aerobic cell respiration if oxygen available and anaerobic if unavailable; pyruvate enters mitochondrion for aerobic respiration; whereas pyruvate stays in the cytoplasm for processing under anaerobic conditions; pyruvate converted aerobically into carbon dioxide and water; whereas pyruvate converted anaerobically to lactate; large ATP yield when oxygen available/from aerobic cell respiration; no (further) ATP yield without oxygen; J WERBA – IB BIOLOGY 15