Download Structure and function of mitochondria (Slide

Cellular Respiration 2
Structures and functions
Respiration
• Three step process:
• Glycolysis (all living cells)
• Krebs cycle
(higher animals)
• Electron transport chain
(higher animals)
Glycolysis = to split sugar
Does not need oxygen
Occurs in cytoplasm
Only releases ¼ of glucose energy
C6 sugar
= 2 C3 sugars
2 C3 pyruvate
Energy captured via 2 ATP
H+ released may be captured by
NAD in higher cells
Catabolic = energy releasing reactions
to produce pyruvate from glucose
Proteins
Carbohydrates
Amino acids
Glucose
Glycolysis
Fats
Fatty acids
Glycerol
In cytoplasm
Pyruvic acid
(Pyruvate)
Mitochondrion
Getting into the mitochondrion
• Via Link reaction
Mitochondrial
membrane
Release of CO2
3 Carbon Pyruvate
Transport protein in the membrane
uses ATP
2 Carbon Acetyl coenzyme A
• attaches to pyruvate
• can be re-used
Cytoplasm
Mitochondrion
Inside the mitochondrion
• Where O2 is present, further processing can occur by:
– Krebs cycle (in membrane space)
– Electron transport chain (on cristae)
– Energy requirements of a cell (eg muscle) indicated by:
Number of christae
Number of mitochondria
Krebs cycle
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Needs oxygen
Controlled decomposition of pyruvate
Releases carbon as CO2
H+ ions captured by NAD
Releases 2 ATP
Provides > 20 proteins for metabolic processes
Refer to p127 in Biozone
Look at position on flowchart
Electron transport chain
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Needs oxygen
Located on christae
Complex series of reactions
Releases energy to give 34 ATP
Uses oxidation product of ½ O2
Uses H+ ions from NADH
Releases H20 as final product.
But what happens when oxygen is not
available?
• Anaerobic respiration
• Is a relatively wasteful process:
– In plants it produces toxic wastes like alcohol
– In animals lactic acid must be removed to the liver,
and converted back to glucose.
• Synthesises no more ATP
• It does allow the glucose to pyruvate reaction
to continue
Cellular Respiration
Summary
In
cytoplasm
Through the Mitochondrial membrane
the LINK REACTION
In the matrix of the
mitochondrium
2 ADP
Glucose (6 carbon sugar)
broken into 2 x 3 carbon
sugars by GLYCOLYSIS
H+ in NAD
by Transport protein in
(uses ATP ADP)
oxygen present
KREBS CYCLE
2 ADP 2 ATP
2 ATP
H+ in NAD
2 ATP
On the christae of the
mitochondrium
ELECTRON TRANSPORT CHAIN
34 ADP
without oxygen
34 ATP
H2 O
Where no oxygen is present muscle cells undergo
ANAEROBIC RESPIRATION producing lactic acid
and allowing further glycolysis to occur BUT
NO MORE ATP is produced. Lactic acid can be
metabolised back to glucose in the liver
Anaerobic respiration also used by yeasts and simple
organisms eg bacteria producing often toxic wastes
like alcohol
Total ATP per glucose:
2 from Glycolosis
2 from Krebs Cycle
34 from Electron Transport Chain