Metabolism
1
Metabolism
• Metabolism = Anabolism + Catabolism
• Photosynthesis requires Respiration
• Respiration requires Photosynthesis
• Energy Production = Energy Consumption
2
Cell Metabolism
The chemical reactions that occur in living organisms,
comprising anabolism and catabolism; may be qualified
to mean the chemical reactions undergone by a
particular substance, or class of substances, in a living
organism.
General Metabolism
• Anabolic metabolism: synthesizes large molecules
from smaller subunits; increases biomass
• Catabolic metabolism: breaks large molecules into
smaller ones, usually energy extraction  ATP and
NADH
3
METABOLISM
Anabolism= building reactions
(Photosynthesis, Citric acid cycle,etc,)
Catabolism= breaking down compounds
into simpler compounds
molecules or atoms. (Respiration, etc)
4
Breakdown (Catabolism)
Proteins to Amino Acids, Starch to Glucose
Metabolism
Larger Molecules
Smaller Molecules
Energy
Synthesis (Anabolism)
Amino Acids to Proteins, Glucose to Starch
5
The importance of Anabolism and
Catabolism
Catabolism Importance
• Production of Energy
for
• Transport of
nutrients
• Biosynthesis
• Other life
metabolism
Anabolism
(biosynthesis)
Importance
– For Macromolecules
and other cell
components
6
7
• Primary metabolism:
Primary metabolism encompasses reactions
involving those compounds which are formed as
a part of the normal anabolic and catabolic
processes. These processes take place in most,
if not all, cells of the organism.
8
Secondary metabolism:
Metabolism of secondary compounds, defined simply
as compounds other than primary compounds. A
compound is classified as a secondary metabolite if it
does not seem to directly function in the processes of
growth and development. Even though secondary
compounds are a normal part of the metabolism of an
organism, they are often produced in specialized cells,
and tend to be more complex than primary
compounds. Examples of secondary compounds
include antibiotics, and plant chemical defenses such
as alkaloids and steroids.
9
Plant Respiration
10
Plant Respiration
• Respiration is the stepwise release of
energy that was captured and stored in
photosynthesis.
• So the basic overall equation for
respiration is:
• C6H12O6+ 6 H2O + 6 02
6 CO2+ 12 H2O + ENERGY
11
Respiration
• Overview;
–
–
–
–
Glucose to Carbon dioxide + Water +Energy
C6H12O6 + O2  6CO2 + 6H2O + 38 ATP
Glucose is highly reduced; contains energy
Oxygen receives the electrons to form energy
• 4 separate reactions
– Glycolysis, Transition Reaction, Krebs Cycle, Electron
Transport, Chemiosomosis
• Requires Oxygen
12
Steps in Respiration
• Electron Donors
– Organic Compounds (Glucose
preferred)
• Electron Carriers
– NAD to NADH
– FAD to FADH
• Electron Acceptors-Terminal
– O2 to H2O
• Phosphorylation Reactions
– ADP to ATP
• Chemiosmosis Reactions
13
Glycolysis- 10 steps
• Glucose is Phosphorylated to form Fructose
1,6-diphosphate
• Split to form 2 Glyceraldehyde 3-phosphate
• Final Products are:
– 2 Pyruvic Acid (C3H4O3)
• Compare to original glucose - C6H12O6
– 2 NADH
– 2 ATP
14
15
GlucoseATP
ADP
Glucose 6-phosphate
Fructose 6-phosphate
ATP
ADP
Fructose 1,6-diphosphate
Dihydroxyacetone phosphate
Glyceraldehyde 3-phosphate
+
NAD
NADH
1,3-diphosphoglyceric acid
ADP
ATP
3-phosphoglyceric acid
Glycolysis
2-phosphoglyceric acid
phosphoenolpyruvic acid
ADP
ATP
pyruvic acid
Click here to see glycolysis animations
16
Transition Reaction
• Pyruvic Acid  Acetyl - Co A + CO2 +
NADH
17
Kreb’s Cycle
Acetyl CoA  Carbon Dioxide
– C2H4O2 to CO2
– Energy produced/Acetyl CoA (x2 for
/Glucose)
• 3 NADH
• 1 FADH
• 1 ATP
• Metabolic Wheel
– Fats, amino acids, etc. enter or leave
– Citrate is product of first reaction
• Simmons Citrate Media
18
The Krebs Cycle
Pyruvic acid (6C)
NAD+
CoA
CO
2
NADH
Acetyl CoA (2C)
Oxaloacetic acid (4C)
CoA
Citric acid (6C)
NADH
H2O
NAD+
Malic acid (4C)
Isocitric acid+ (6C)
NAD
NADH
H O
2
CO
2
Fumaric acid (4C)
FADH2
FAD
alpha-Ketoglutaric acid (5C)
CoA
Succinic acid
CoA
(4C)
GTP
NADH
Succinyl CoA
GDP
NAD+
(4C)
CO2
19
Electron Transport Chain
• NADH oxidized to NAD
• FAD reduced to FADH
• Cytochromes shuffle electrons finally to O2
– Cytochrome Oxidase important in G - ID
• H2O formed and ATP
• 3 ATP / 1 NADH
• 2 ATP / 1 FADH
20
21
22
23
24
25
Fermentation Products from
Pyruvate
• Homolactic = Lactic Acid
– Yogurt, Lactobacillus
•
•
•
•
•
•
Alcohol + CO2
Propionic Acid
Butyric Acid
Acetic Acid
Succinic Acid
Butylene to Acetoin
– basis for VP Test (Vogues-Proskauer)
26
Fermentation Products
• Alcohol and Carbon Dioxide
– Yeast mostly
• Lactic Acid
– Humans, muscles without oxygen
– Bacteria (Lactobacillus-yogurt)
• Butyric Acid
– Rancid butter, Clostridium-gangrene
• Acetoin
– Butanediol fermentation in Klebsiella
• Propionic Acid
– Swiss Cheese
27
Glucose
Glyceraldehyde 3-phosphate
NAD+
NADH
CO2
Pyruvic acid
+
NAD
NADH
Acetaldehyde
Fermentation
Ethanol
28
Fermentation in Yeast
29
Fermentation in Muscle
30
31
32