Cellular Respiration
8.1 Overview
What is respiration?

Three definitions



Inspiration-expiration
Exchange of O2 for CO2 in lungs
Consumption of O2 and production of CO2 in tissues




Involves glucose
Exergonic
Produces ATP
Redox reaction
What are NAD+ and FAD?


Enzymes use these
during oxidation
respiration
FAD sometimes used
instead
What are the phases of respiration?



Glycolysis
Krebs cycle (citric acid cycle)
Electron transport chain
Cellular Respiration
8.2 Glycolysis
What is glycolysis?




Literally means _________
Happens outside mitochondrion
Goal is to generate pyruvate
Two stages

Energy investment


Phosphoryation using 2 ATP
Energy harvest

See next slide…
What happens during energy harvest?

Substrate level phosphorylization



To make ATP
Pyruvate also formed
Overall reaction:
Cellular Respiration
8.3 Krebs Cycle
What is the Krebs Cycle?




AKA the citric acid
cycle
Happens in
mitochondrial
matrix
Goal: generate ATP,
FADH2 and NADH
from pyruvate
Series of redox
reactions

A type of
metabolic pathway
What are the steps?

Prepatory step

Convert pyruvate to acetyle co-A
What happens next?

Citric Acid Cycle

Key: it’s a cycle– it repeats!
What are the products of the Krebs cycle?
Cellular Respiration
8.4 Electron transport chain
What is the electron transport chain (ETC)?



Series of redox
reactions to make
______
Happens in cristae
Oxidative
phophorylation


Consumes oxygen
Produces ATP +
H 2O
What are the steps of the ETC?


Chemiosmosis involved
Passing of


Electrons
H+
What is energy yield of oxidative respiration?

After all three stages
Cellular Respiration
8.5 Fermentation
What happens if no oxygen is present?

Anaerobic respiration



Fermentation


Inorganic molecule is final electron acceptor
Some bacteria use
Organic molecule is final electron acceptor
Different types


Alcoholic fermentation
Lactic acid fermentation
What happens in fermentation?


Glycolysis
Then


pyruvate
reduction
NAD
regeneration
What are the pros and cons of fermentation?

Pros


Oxygen not necessary
Cons

Very low ATP production
What is the metabolic pool?


Compounds oxidized
for entry into
biosynthesis
reactions
Catabolism


Deamination (in
liver)
Anabolism