Note! Please see 3.7 Cell Respiration Core prior to using this presentation.

Assessment Statements 8.1.1 State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen. 8.1.2 Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation. 8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs. 8.1.4 Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen. 8.1.5 Explain oxidative phosphorylation in terms of chemiosmosis. 8.1.6 Explain the relationship between the structure of the mitochondrion and its function.

8.1.1 State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen.

O I L R G Oxidation Is Loss Reduction Gain

Loss and gain of what? hydrogen electrons oxygen + e- O O + O2 H + H+ Oxidation Reduction + e- X X+ X+ + e- X X X X X + O2 O O + O2 X H X + H+ X + H+ X H

Respiration involves oxidation and reduction. An organic compound (glucose) is oxidised while ADP is reduced to ATP In cell processes biochemical processes are coupled to the oxidation of ATP to ADP

8.1.2 Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation.

Aerobic respiration, gives a higher yield of ATP. ADP + Pi ATP Aerobic respiration glycolysis link reaction Kreb’s cycle electron transport chain oxidative phosphorylation

Glycolysis (sugar splitting) phosphorylation ATP C C C C C C ADP + Pi Glucose 6C P C C C C C C P lysis P C C C C C NAD+ C P NADH+ + H+ oxidation C C C CYTOPLASM C C C 2 x 3C pyruvate

Phosphorylation 2 ADP + Pi 2 ATP There is an increase in energy Phosphorylation uses 2 ATP to add 2 phosphate groups to glucose. This makes the glucose molecule more unstable so it becomes easier to break bonds. The phosphate groups also allow the hexose bisphosphate to bind more effectively with its enzyme. Energy 2 ADP + Pi 2 ATP Time

Lysis hexose diphosphate triose phosphate Triose phosphate or TP is an intermediate in many biochemical reactions. The phosphate groups help the TP to bind to its enzyme.

Oxidation (ATP formation) There are 2 TP molecules made from each glucose. A total of 4 ATP molecules are made. But, we used 2 during phosphorylation. So, we have a net production of 2 ATP NAD+ 2 ADP + Pi reduction oxidation 2 ATP NADH+ + H+

What is NAD+?

Watch the video and then summarise of the key points of glycolysis

Summary Takes place in the _________ No _________ needed 6C ________ is converted into 3C _________ __ ATP made and __ ATP used cytoplasm oxygen glucose pyruvate 4 2 Net gain 2 ATP 2 NADH+ + 2H+ 2 3C pyruvate

8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs. 8.1.6 Explain the relationship between the structure of the mitochondrion and its function.

Mitochondria

Site of aerobic respiration Pyruvate is further oxidised to release more ATP. Only found in eukaryotic cells. Cells that need a lot of energy will have many mitochondria ( liver cell) or can develop them under training (muscles cells).

Features of mitochondria Surrounded by a double membrane. Inner membrane folded to form 'cristae'. LSA for ATP production. Space between the two membranes which is narrow creating a place to concentrate H+

The inner space is called the matrix. It contains the enzymes needed for respiration.especially those of the Kreb’s cycle. An example of compartmentalisation (isolation of substances needed for a particular function) Mitochondria also contain some of their own DNA (mDNA). http://genome.wellcome.ac.uk/doc_WTD0208 76.html

PPQ Review (a) Draw a labelled diagram showing the structure of a mitochondrion as seen in an electron micrograph (4) (b) Explain the relationship between the structure of the mitochondrion and its function (3)

(a) Award marks for any of the following clearly drawn and correctly labelled. cristae; inner membrane; outer membrane; intermembrane space; matrix; ribosomes; DNA; 4 max (b) cristae provide surface area for oxidative phosphorylation; inner membrane contains electron transport chains/ATP synthase (which carry out oxidative phosphorylation); outer membrane separates the mitochondrion from the rest of the cell; mitochondrial DNA/ribosomes make (mitochondrial) proteins; small volume intermembrane space allows for higher concentration of protons; matrix has enzymes for the Krebs cycle; 3 max

8.1.4 Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen.

Link Reaction Decarboxylation - removal of carbon from the pyruvate CoA NAD+ Carbon forms carbon dioxide C NADH + H+ CO2 2C Acetyl group binds temporarily with Coenzyme A CoA C C Acetyl CoA

Kreb’s Cycle citric acid NADH + H+ FADH2 ATP FAD NAD+ ADP + Pi NAD+ CO2 NADH + H+ NADH + H+ C C C C C NAD+ C CO2

This is a metabolic cycle. Each step requires enzymes to reduce the activation energy. The reactions take place in the mitochondrial matrix. This reaction occurs within the matrix where each intermediate becomes the substrate for the next step.

Watch this:

8.1.5 Explain oxidative phosphorylation in terms of chemiosmosis.

Watch these:

Task Reorder the sentences in the booklet to explain the process of chemiosmosis (answers on the next page)

The inner membrane is folded into cristae and embedded in this membrane are proteins which form an electron transport chain Reduced NAD+ and FAD are oxidised releasing electrons and H+ ions. The electrons are passed along the chain while the H+ are pumped by the membrane proteins into the inner membrane space. These H+ ions accumulate and their concentration increases. When they diffuse back to the matrix they pass through a membrane protein called ATP synthase. The flow of electrons through ATP synthase drives an enzyme reaction which converts ADP + Pi to ATP.

ATP synthase is an enzyme embedded in the cristae membrane. H+create an electrochemical gradient (chemical potential energy). The H+pass through a channel in the enzyme driving the motor. The motor spins bringing together ADP and Pi to produce ATP

NADH + H+, FADH2, O2 ATP, H2O, NAD+, FAD