Download role of respiration in glycolysis, co2 and h20 production

ROLE OF RESPIRATION IN GLYCOLYSIS, CO2
AND H20 PRODUCTION
AIMS AND OBJECTIVES
At the end of the lecture, student should be able to:
• Define cellular respiration
• Define metabolism
• Know role of oxygen in respiration
• Know glycolysis
• Know citric acid cycle
• Know electron transport chain
LECTURE OUTLINE
CELLULAR RESPIRATION OR 'OXIDATIVE METABOLISM'
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Set of the metabolic reactions that occur in cells to convert biochemical energy
from nutrients into adenosine triphosphate (ATP), and then release waste
products.
The reactions involved in respiration are catabolic reactions that involve the
oxidation of one molecule and the reduction of another.
METABOLISM
The fate of dietary components after digestion and absorption constitutes intermediary
metabolism. Metabolic pathways fall into three categories:
1. Anabolic pathway – synthesis of compound constituting body structure and
machinery e.g. Protein synthesis
2. Catabolic pathway – involves oxidative processes that releases free energy in the
form of high energy phosphate or reducing equivalents e.g. Respiratory chain and
oxidative phosphorylation
3. Amphibolic pathway – have more than one function and occur at the cross road
of metabolism acting as link between anabolic and catabolic pathway e.g. citric
acid cycle
OVERVIEW OF CELLULAR RESPIRATION
ROLE OF OXYGEN
Oxygen is vital to the process of cellular respiration
 Reactant in glycolysis, necessary for the breakdown of glucose into pyruvic acid
 Waste product of Kreb's cycle
 Required to build the acetylCo-A molecule
 Final electron acceptor in the electron transport chain
AEROBIC AND ANEROBIC RESPIRATION
Aerobic - Organisms using oxygen as a final electron acceptor in respiration
Anerobic – organisms not using oxygen
(C6H12O6) is oxidized to CO2 and H2O, releasing energy (ATP) in the process
C6H12O6 (aq) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)
CELLULAR RESPIRATION
Cellular respiration can be broken down into 4 stages
This process occurs partially in the cytoplasm, and partially in the mitochondria.
1. Glycolysis
2. Transition reaction
3. Citric acid cycle (kreb’s cycle/ tricarboxylic acid cycle
4. Electron transport chain (respiratory chain)
GLYCOLYSIS
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Occurs in the cytoplasm.
Metabolic pathway
Anerobic process
One Glucose (C6H12O6) is broken down to 2 molecules of pyruvic acid.
Resulting in the production of 2 ATPs for each glucose molecule
Glucose + 2 NAD+ + 2 Pi + 2 ADP → 2 pyruvate + 2 NADH + 2 ATP + 2 H+ + 2
H2O
TRANSITION REACTION
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Occurs in mitochondria
Pyruvate is oxidized to acetyl-CoA and CO2 by the Pyruvate dehydrogenase
complex(enzymes).
CITRIC ACID CYCLE (KREB’S CYCLE/ TRICARBOXYLIC ACID
CYCLE)
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Acetyl Co-A is produced in the presence of oxygen
Enters citric acid cycle
Occurs inside mitochondrial matrix
Completely oxidized to CO2 and H2O liberating ATP via oxidative
phosphorylation
NAD+ is reduced to NADH
Acetyl CoA→→→→→→→→→→2CO2
3 NAD + FAD + GDP + Pi
3NADH + FADH2 + GTP
ELECTRON TRANSPORT CHAIN
(RESPIRATORY CHAIN)
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Occurs in cristae of mitochondria
Collects and transports the reducing
equivalent and directs them to their final
reaction with oxygen to form water