Cellular Respiration

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Vivien Harvey
5 years ago
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1 Cellular

2 I can describe cellular respiration Cellular respiration is a series of metabolic pathways releasing energy from a foodstuff e.g. glucose. This yields energy in the form of ATP adenosine P i P i P i

3 ATP High Energy adenosine P i P i P i Breakdown: releasing energy Phosphorylation Build-up: needs energy adenosine P i P i P i ADP + Pi Low Energy

4 I can describe the role of ATP ATP transfers energy between catabolic and anabolic reactions.

5 I can describe phosphorylation Phosphorylation is when a phosphate group is added to a molecule e.g. low energy ADP combines with inorganic phosphate(p i ) to form high energy ATP. Phosphorylation also occurs when P i and energy are transferred from ATP to molecules of a reactant in a metabolic pathway making them more reactive.

6 I can describe the structure of mitochondria Matrix is fluid filled and contains enzymes. Cristae are folds increasing surface area.

7 To synthesise the bulk of its ATP requirements, a cell uses a source of high energy electrons to pump H + ions across a membrane. The return flow of these electrons rotates part of the membrane protein ATP synthase catalysing the synthesis of ATP. I can describe ATP synthesis

8 I can describe cellular respiration Recap Nat 5: aerobic respiration Glucose + oxygen Carbon dioxide + water + 38ATP

9 I can describe cellular respiration Cellular has three stages: 1. Glycolysis in cytoplasm 2. Citric Acid Cycle matrix of mitochondria 3. Electron Transport Chain- inner mitochondrial membrane (cristae)

10 I can describe cellular respiration Cellular respiration begins in the cytoplasm with glycolysis where glucose is broken down to pyruvate. This is a series of enzyme controlled steps.

11 I can describe cellular respiration Phosphorylation of intermediates: Energy investment phase uses 2ATP Energy payoff phase generates 4 ATP Net gain of 2ATP

12 I can describe cellular respiration First phosphorylation leads to product that can continue to a number of pathways. Second phosphorylation catalysed by phosphofructokinase is irreversible leading only to glycolysis

13 I can describe cellular respiration Pyruvate progresses to the citric acid cycle only if oxygen is present. In the absence of oxygen, fermentation occurs. Pyruvate is broken down to an acetyl group that combines with coenzyme A to form acetyl coenzymea

14 I can describe cellular respiration Acetyl coenzymea combines with oxaloacetate to form citrate followed by enzyme mediated steps of the cycle. This occurs in the matrix of mitochondria. ATP is generated, CO 2 released oxaloacetate regenerated.

15 I can describe cellular respiration Dehydrogenase enzymes remove hydrogen ions and electrons which are passed to coenzymes NAD or FAD to form NADH or FADH 2.

16 I can describe cellular respiration NADH & FADH 2 release high energy electrons to the electron transport chain on the mitochondrial membrane. Electron Transport Chain

17 I can describe cellular respiration The energy is used to pump H ions across the inner mitochondrial membrane. The return flow of H ions drives ATP synthase. Electron Transport Chain

18 I can describe cellular respiration This results in the synthesis of the bulk of ATP. Electron Transport Chain The final electron acceptor is oxygen. Water is formed.

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20 I can describe alternative respiratory substrates Starch and glycogen are broken down to glucose. Other sugars can be converted to glucose or other glycolysis intermediates.

21 I can describe alternative respiratory substrates

22 I can describe alternative respiratory substrates

23 I can discuss regulation of cellular respiration The cell conserves its resources by only producing ATP when required. ATP supply increases with increasing rates of glycolysis and the citric acid cycle and decreases when these pathways slow.

24 I can discuss regulation of cellular respiration If more ATP produced than needed, ATP inhibits action of phosphofructokinase, slowing the rate of glycolysis.

25 I can discuss regulation of cellular respiration The rates of glycolysis and citric acid cycle synchronised by inhibition of phosphofructokinase by citrate. If citrate accumulates, glycolysis slows and when citrate consumption increases, glycolysis increases supply of acetyl groups to citric acid cycle.

g) Cellular Respiration Higher Human Biology

g) Cellular Respiration Higher Human Biology What can you remember about respiration? 1. What is respiration? 2. What are the raw materials? 3. What are the products? 4. Where does it occur? 5. Why does