POST RN BScN SEMESTER II

1. Life saving son
life saving son

2. Molecules of Life
 Molecules of life are synthesized by
living cells
Carbohydrates
Lipids
Proteins
Nucleic acids

3. Organic Compounds
 Consist primarily of carbon and hydrogen
atoms
Carbon atoms bond covalently with up to four
other atoms, often in long chains or rings
 Functional groups attach to a carbon
backbone
Influence organic compound’s properties

4. Building Organic Compounds
 Cells form complex organic molecules
Simple sugars → carbohydrates
Fatty acids → lipids
Amino acids → proteins
Nucleotides → nucleic acids
 Dehydration synthesis combines
monomers to form polymers

5. Carbohydrates –
The Most Abundant Ones
 Three main types of carbohydrates
Monosaccharides (simple sugars)
Oligosaccharides (short chains)
Polysaccharides (complex carbohydrates)
 Carbohydrate functions
Instant energy sources
Transportable or storable forms of energy
Structural materials

6. Oligosaccharides: Sucrose

7. Complex Carbohydrates:
Starch, Cellulose, and Glycogen

8. Fats
 Lipids with one, two, or three fatty acid
tails
Saturated
 Triglycerides (neutral fats )
Three fatty acid tails
Most abundant animal fat (body fat)
Major energy reserves

9. Greasy, Oily – Must Be Lipids
 Lipids
Fats, phospholipids, waxes, and sterols
Don’t dissolve in water
Dissolve in nonpolar substances (other
lipids)
 Lipid functions
Major sources of energy
Structural materials
Used in cell membranes

10. Triglyceride Formation

11. Phospholipids
 Main component of
cell membranes
Hydrophilic head,
hydrophobic tails

12. Waxes
 Firm, pliable, water repelling, lubricating

13. Steroids: Cholesterol
 Membrane components; precursors of
other molecules (steroid hormones)

14. Protein Structure
 Built from 20 kinds of amino acids

15. Four Levels of Protein Structure
1. Primary structure
Amino acids joined by peptide bonds form a
linear polypeptide chain
2. Secondary structure
Polypeptide chains form sheets and coils
3. Tertiary structure
Sheets and coils pack into functional domains

16. Four Levels of Protein Structure
4. Quaternary structure
Many proteins (e.g. enzymes) consist of two
or more chains

17. Nucleotides, DNA, and RNAs
Nucleotide structure, 3 parts:
Sugar
Phosphate group
Nitrogen-containing base

18. Nucleotide Functions:
Reproduction, Metabolism, and
Survival
 DNA and RNAs are nucleic acids, each
composed of four kinds of nucleotide
subunits
 ATP energizes many kinds of
molecules by phosphate-group transfers

19. Nucleotides of DNA

20. DNA, RNAs, and Protein
Synthesis
 DNA (double-stranded)
Encodes information about the primary
structure of all cell proteins in its nucleotide
sequence
 RNA molecules (usually single stranded)
Different kinds interact with DNA and one
another during protein synthesis

21. covalent
bonding in
carbon
backbone
hydrogen bonding
between bases

22. Metabolism
life saving son

23. Metabolism
• Metabolism – refers to all chemical reaction
occurring in body
– Catabolism – break down complex molecules
• Exergonic – produce more energy than they
consume
– Anabolism – combine simple molecules into
complex ones
• Endergonic – consume more energy than they
produce
• Adenosine triphosphate (ATP)
– “energy currency”
– ADP + P + energy ↔ ATP
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24. Energy transfer
• Oxidation-reduction or redox reactions
– Oxidation – removal of electrons
• Decrease in potential energy
• Dehydrogenation – removal of hydrogens
• Liberated hydrogen transferred by coenzymes
– Nicotinamide adenine dinucleotide (NAD)
– Flavin adenine dinucleotide (FAD)
• Glucose is oxidized
– Reduction – addition of electrons
• Increase in potential energy
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25. 3 Mechanisms of ATP generation
1. Substrate-level phosphorylation
○ Transferring high-energy phosphate group
from an intermediate directly to ADP
1. Oxidative phosphorylation
○ Remove electrons and pass them through
electron transport chain to oxygen
1. Photophosphorylation
○ Only in chlorophyll-containing plant cells
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26. Carbohydrate metabolism
 Fate of glucose depends on needs of
body cells
ATP production or synthesis of amino acids,
glycogen, or triglycerides
 GluT transporters bring glucose into the
cell via facilitate diffusion
Insulin causes insertion of more of these
transporters, increasing rate of entry into
cells
Glucose trapped in cells after being
phosphorylated
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27. Glucose catabolism / cellular respiration
1. Glycolysis
○ Anaerobic respiration – does not
require oxygen
1. Formation of acetyl coenzyme A
2. Krebs cycle reactions
3. Electron transport chain reactions
○ Aerobic respiration – requires oxygen
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28. 1
NADH + 2 H+
GLYCOLYSIS
2
2
2 Pyruvic acid
1 Glucose
ATP
1
NADH + 2 H+
GLYCOLYSIS
+ 2 H+
NADH
CO2
FORMATION
OF ACETYL
COENZYME A
2
2
2
2
2 Acetyl
coenzyme A
2 Pyruvic acid
1 Glucose
ATP
2
1
NADH + 2 H+
GLYCOLYSIS
+ 2 H+
NADH
CO2
FORMATION
OF ACETYL
COENZYME A
KREBS
CYCLE
+ 6 H+
CO2
FADH2
NADH
2
4
6
2
2
2
2
2
2 Acetyl
coenzyme A
2 Pyruvic acid
1 Glucose
ATP
ATP
2
3
1
NADH + 2 H+
GLYCOLYSIS
+ 2 H+
NADH
CO2
FORMATION
OF ACETYL
COENZYME A
KREBS
CYCLE
+ 6 H+
CO2
FADH2
NADH
2
4
6
2
ELECTRON
TRANSPORT
CHAIN
e–
e–
e–
32 or 34
O26
6
2
2
2
2
H2O
Electrons
2 Acetyl
coenzyme A
2 Pyruvic acid
1 Glucose
ATP
ATP ATP
2
3
4
Overview of cellular respiration
life saving son

29. Glycolysis
1. Glycolysis
– Splits 6-carbon glucose into 2 3-carbon
molecules of pyruvic acid
– Consumes 2 ATP but generates 4
– 10 reactions
– Fate of pyruvic acid depends on oxygen
availability
• If oxygen is scarce (anaerobic), reduced to
lactic acid
– Hepatocytes can convert it back to pyruvic acid
• If oxygen is plentiful (aerobic), converted to
acetyl coenzyme A
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30. Cellular respiration begins with
glycolysis
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31. ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
ATP
H H
H
HHO
1
H
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
OH2CP
ATP
H
HO
H
H
HH
H
H
H
HO
1
2
H
H
Phosphofructokinase
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
ADP
P
OH2CP
ATP
ATP
OH
H
HO
H
H
HH
H H
H
H
HO
H
HO
1
2
3
H
H
Phosphofructokinase
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
OH2CP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
H
H
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
H
H
+ 2H+
NADH
HCOH
C
CH2O
O
O 1, 3-Bisphosphoglyceric acid
(2 molecules)
2
P
P
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
6
H
H
2 NAD+
+ 2 P
+ 2H+
NADH
HCOH
C
CH2O
O
COOH
O
2
2 ADP
HCOH
CH2O
1, 3-Bisphosphoglyceric acid
(2 molecules)
2
3-Phosphoglyceric acid
(2 molecules)
P
P
P
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
6
7
H
H
2 NAD+
+ 2 P
+ 2H+
NADH
HCOH
C
CH2O
O
COOH
O
2
2 ADP
HCOH
CH2O
1, 3-Bisphosphoglyceric acid
(2 molecules)
2
3-Phosphoglyceric acid
(2 molecules)
COOH
CH2OH
HCO 2-Phosphoglyceric acid
(2 molecules)
P
P
P
P
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
6
7
8
H
H
2 NAD+
+ 2 P
+ 2H+
NADH
HCOH
C
CH2O
O
COOH
O
2
2 ADP
HCOH
CH2O
1, 3-Bisphosphoglyceric acid
(2 molecules)
2
3-Phosphoglyceric acid
(2 molecules)
COOH
CH2OH
HCO 2-Phosphoglyceric acid
(2 molecules)
COOH
CH2
C O Phosphoenolpyruvic acid
(2 molecules)
P
P
P
P
P
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
6
7
8
9
H
H
2 NAD+
+ 2 P
+ 2H+
NADH
2 NAD+
+ 2
HCOH
C
CH2O
O
COOH
O
2
2 ADP
P
HCOH
CH2O
1, 3-Bisphosphoglyceric acid
(2 molecules)
2
3-Phosphoglyceric acid
(2 molecules)
COOH
CH2OH
HCO 2-Phosphoglyceric acid
(2 molecules)
Pyruvic acid
(2 molecules)
COOH
CH2
2
2 ADP
C O Phosphoenolpyruvic acid
(2 molecules)
COOH
CH3
C O
P
P
P
P
P
Phosphofructokinase
Dihydroxyacetone
phosphate
CH2OH
CH2O
C O
Glyceraldehyde
3-phosphate
HCOH
CH2O
O
H
C
ADP
O
Glucose (1 molecule)
CH2OH
OH
OH
OH
4 1
3 2
5
6
Glucose 6-phosphate
O
OH
OH
OH
CH2OH
Fructose 6-phosphate
O
OH
H
OH2C 6
5
4 3
2
1
CH2O
Fructose 1, 6-bisphosphate
O
OH
H
OH2C
ADP
P
P
P
P
P
OH2CP
ATP
ATP
ATP
ATP
OH
H
HO
H
H
HH
H
H
H
H
H
H
HO
HO
H
HO
OH
1
2
3
4
5
6
7
8
9
10
H
H
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32. Formation of Acetyl coenzyme A
2. Formation of Acetyl coenzyme A
 Each pyruvic acid converted to 2-carbon
acetyl group
○ Remove one molecule of CO2 as a waste
product
 Each pyruvic acid also loses 2 hydrogen
atoms
○ NAD+
reduced to NADH + H+
 Acetyl group attached to coenzyme A to
form acetyl coenzyme A (acetyl CoA)
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33. life saving son

34. The Krebs cycle
3. The Krebs cycle
 Also known as citric acid cycle
 Occurs in matrix of mitochondria
 Series of redox reactions
 2 decarboxylation reactions release CO2
 Reduced coenzymes (NADH and FADH2)
are the most important outcome
 One molecule of ATP generated by
substrate-level phosphorylation
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35. life saving son

36. 1
C
CH2
COOH
O
Oxaloacetic acid
COOH
Citric acid
H2C COOH
COOHHOC
H2C COOH
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
H2O
CO2
NAD+
KREBS
CYCLE
NADH
CoA
CoA
1
C
CH2
COOH
O
Oxaloacetic acid
COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
H2O
CO2
NAD+
KREBS
CYCLE
NADH
CoA
CoA
2
1
To electron
transport chain
CO2
+ H+
C
CH2
COOH
O
Oxaloacetic acid
COOH
Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
NAD+
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
CoA
CoA
2
3
O
1
To electron
transport chain
CO2
+ H+
NADH
CO2
+ H+
C
CH2
COOH
O
Oxaloacetic acid
COOH
Succinyl CoA
H2C COOH
CH2
C S CoA Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
NAD+
NAD+
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
O
CoA
O
CoA
2
3
4
1
To electron
transport chain
CO2
+ H+
NADH
CO2
+ H+
C
CH2
COOH
O
Oxaloacetic acid
COOH
H2C COOH
H2C COOH
Succinic acid
Succinyl CoA
H2C COOH
CH2
C S CoA Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
NAD+
NAD+
GDP
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
ADP
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
ATP
GTP
O
CoA
CoA
O
CoA
2
3
4
5
1
To electron
transport chain
CO2
+ H+
NADH
CO2
+ H+
To electron
transport
chain
C
CH2
COOH
O
Oxaloacetic acid
COOH
H2C COOH
H2C COOH
Succinic acid
Succinyl CoA
H2C COOH
CH2
C S CoA Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
Fumaric acid
NAD+
NAD+
GDP
FAD
HC
CH
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
ADP
FADH2
COOH
COOH
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
ATP
GTP
CoA
CoA
O
CoA
2
3
4
5
6
O
1
To electron
transport chain
CO2
+ H+
NADH
CO2
+ H+
To electron
transport
chain
C
CH2
COOH
O
Oxaloacetic acid
COOH
HCOH
CH2
COOH
COOH
H2C COOH
H2C COOH
Succinic acid
Malic acid
Succinyl CoA
H2C COOH
CH2
C S CoA Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
Fumaric acid
NAD+
NAD+
GDP
FAD
HC
CH
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
ADP
FADH2
COOH
COOH
H2O
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
ATP
GTP
CoA
CoA
O
CoA
2
3
4
5
6
7
O
1
To electron
transport chain
CO2
+ H+
NADH
CO2
+ H+
To electron
transport
chain
C
CH2
COOH
O
Oxaloacetic acid
COOH
+ H+
NADH
HCOH
CH2
COOH
COOH
H2C COOH
H2C COOH
Succinic acid
Malic acid
Succinyl CoA
H2C COOH
CH2
C S CoA Alpha-ketoglutaric acid
H2C COOH
HCH
C COOH
Isocitric acid
H2C COOH
HOC COOH
HC COOH
H
Citric acid
H2C COOH
COOHHOC
H2C COOH
Fumaric acid
NAD+
NAD+
GDP
FAD
NAD+
HC
CH
+ H+
Pyruvic
acid
Acetyl
coenzyme A
C
CH3
O
CH3
C
COOH
O
To electron
transport chain
ADP
FADH2
COOH
COOH
H2O
H2O
CO2
NAD+
KREBS
CYCLE
NADH
NADH
ATP
GTP
CoA
CoA
O
CoA
2
3
4
5
6
7
8
O
life saving son

37. Electron transport chain
4. Electron transport chain
 Series of electron carriers in inner
mitochondrial membrane reduced and
oxidized
 As electrons pass through chain, exergonic
reactions release energy used to form ATP
○ Chemiosmosis
 Final electron acceptor is oxygen to form
water
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38. Chemiosmosis
Carriers act as proton pumps to expel H+
from
mitochondrial matrix
Creates H+
electrochemical gradient – concentration
gradient and electrical gradient
Gradient has potential energy – proton motive force
As H+
flows back into matrix through membrane,
generates ATP using ATP synthesis
life saving son

39. Energy from
NADH + H+
H+
Low H+
concentration in
matrix of mitochondrion
Inner
mitochondrial
membrane
Matrix
High H+
concentration
between inner and
outer mitochondrial
membranes
Outer membrane
Inner membrane
H+
channel
Electron
transport
chain
(includes
proton pumps)
1 Energy from
NADH + H+
H+
H+
Low H+
concentration in
matrix of mitochondrion
Inner
mitochondrial
membrane
Matrix
High H+
concentration
between inner and
outer mitochondrial
membranes
Outer membrane
Inner membrane
H+
channel
Electron
transport
chain
(includes
proton pumps)
1
2
Energy from
NADH + H+
H+
H+
ADP +
ATP synthase
Low H+
concentration in
matrix of mitochondrion
Inner
mitochondrial
membrane
Matrix
High H+
concentration
between inner and
outer mitochondrial
membranes
Outer membrane
Inner membrane
H+
channel
Electron
transport
chain
(includes
proton pumps)
P
ATP
1
2
3
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40. The actions of the three proton pumps and ATP
synthase in the inner membrane of mitochondria
life saving son
Space between outer
and inner mitochondrial
membranes
Inner
mito-
chondrial
membrane
Mitochondrial
matrix
H+
channel
NADH dehydrogenase
complex: FMN and
five Fe-S centers
NAD
e–
H+
+ + + + + + +
– – – – – – –
Q
NADH+ H+
1
Space between outer
and inner mitochondrial
membranes
Inner
mito-
chondrial
membrane
Mitochondrial
matrix
H+
channel
NADH dehydrogenase
complex: FMN and
five Fe-S centers
Cytochrome b-c1
complex: cyt b, cyt c1,
and an Fe-S center
NAD
e–
e–
e–
H+
+ + + + + + +
– – – – – – –
Q
Cyt c
NADH+ H+
H+
1 2
Space between outer
and inner mitochondrial
membranes
Inner
mito-
chondrial
membrane
Mitochondrial
matrix
H+
channel
NADH dehydrogenase
complex: FMN and
five Fe-S centers
Cytochrome b-c1
complex: cyt b, cyt c1,
and an Fe-S center
Cytochrome oxidase
complex: cyt a,
cyt a3,and two Cu
NAD
1 1/2 O2
e–
e–
e–
e–
e–
H+
H+
H+
+ + + + + + +
– – – – – – –
H2O
Q
Cyt c
NADH+ H+
H+
3
ADP +
ATP synthase
P
ATP
1 2 3
3

41. Summary of cellular respiration
life saving son

42. Glucose anabolism
Glucose storage: glycogenesis
○ Polysaccharide that is the only stored
carbohydrate in humans
○ Insulin stimulates hepatocytes and skeletal
muscle cells to synthesize glycogen
Glucose release: glycogenolysis
○ Glycogen stored in hepatocytes broken down
into glucose and release into blood
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43. Glycogenesis and glycogenolysis
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44. Formation of glucose from proteins and
fats: gluconeogenesis
○ Glycerol part of
triglycerides, lactic
acid, and certain
amino acids can be
converted by the liver
into glucose
○ Glucose formed from
noncarbohydrate
sources
○ Stimulated by cortisol
and glucagon
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45. Lipid metabolism
 Transport by
lipoproteins
 Most lipids nonpolar
and hydrophobic
 Made more water-
soluble by combining
them with proteins to
form lipoproteins
 Proteins in outer shell
called apoproteins (apo)
○ Each has specific
functions
○ All essentially are
transport vehicles
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46. Apoproteins Apoproteins categorized and named according to density
(ratio of lipids to proteins)
◦ Chylomicrons
 Form in small intestine mucosal epithelial cells
 Transport dietary lipids to adipose tissue
◦ Very low-density lipoproteins (VLDLs)
 Form in hepatocytes
 Transport endogenous lipids to adipocytes
◦ Low-density lipoproteins (LDLs) – “bad” cholesterol
 Carry 75% of total cholesterol in blood
 Deliver to body cells for repair and synthesis
 Can deposit cholesterol in fatty plaques
◦ High-density lipoproteins (HDLs) – “good” cholesterol
 Remove excess cholesterol from body cells and blood
 Deliver to liver for elimination
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47. Lipid Metabolism
 2 sources of cholesterol in the body
Present in foods
Synthesized by hepatocytes
 As total blood cholesterol increases, risk
of coronary artery disease begins to rise
Treated with exercise, diet, and drugs
 Lipids can be oxidized to provide ATP
Stored in adipose tissue if not needed for ATP
 Major function of adipose tissue to
remove triglycerides from chylomicrons
and VLDLs and store it until needed
98% of all body energy reserves
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48. Lipid Metabolism
• Lipid catabolism: lipolysis
– Triglycerides split into glycerol and fatty
acids
– Must be done for muscle, liver, and adipose
tissue to oxidize fatty acids
– Enhanced by epinephrine and
norepinephrine
• Lipid anabolism: lipogenesis
– Liver cells and adipose cells synthesize
lipids from glucose or amino acids
– Occurs when more calories are consumed
than needed for ATP production
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49. Pathways of lipid metabolism
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50. Protein metabolism• Amino acids are either oxidized to produce
ATP or used to synthesize new proteins
• Excess dietary amino acids are not excreted
but converted into glucose
(gluconeogenesis) or triglycerides
(lipogenesis)
• Protein catabolism
– Proteins from worn out cells broken down into
amino acids
– Before entering Krebs cycle amino group must be
removed – deamination
• Produces ammonia, liver cells convert to urea,
excreted in urine
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51. Protein anabolism
Carried out in ribosomes of almost every cell in the body
10 essential amino acids in the human
○ Must be present in the diet because they cannot be
synthesized
○ Complete protein – contains sufficient amounts of all essential
amino acids – beef, fish, poultry, eggs
○ Incomplete protein – does not – leafy green vegetables,
legumes, grains
10 other nonessential amino acids can be synthesized by
body cells using transamination
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52. Various points at which amino acids
enter the Krebs cycle for oxidation
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53. Key molecules at metabolic
crossroads
• 3 molecules play pivotal roles in
metabolism
• Stand at metabolic crossroads –
reactions that occur or not depend on
nutritional or activity status of individual
1. Glucose 6-phosphate
– Made shortly after glucose enters body cell
– 4 fates – synthesis of glycogen, release of
glucose into blood stream, synthesis of
nucleic acids, glycolysis
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54. Key molecules at metabolic
crossroads
2. Pyruvic acid
 If there is enough oxygen, aerobic cellular respiration
occurs
 If there is not enough oxygen, anaerobic reactions can
produce lactic acid, produce alanine or gluconeogenesis
2. Acetyl Coenzyme A
 When ATP is low and oxygen plentiful, most pyruvic acid
goes to ATP production via Acetyl CoA
 Acetyl CoA os the entry into the Krebs cycle
 Can also be used for synthesis of certain lipids
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55. Metabolic adaptations
• During the absorptive state ingested
nutrients are entering the blood stream
– Glucose readily available for ATP production
• During postabsorptive state absorption
of nutrients from GI tract complete
– Energy needs must be met by fuels in the
body
– Nervous system and red blood cells depend
on glucose so maintaining steady blood
glucose critical
– Effects of insulin dominate
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56. Metabolism during absorptive state
Soon after a meal nutrients enter blood
○ Glucose, amino acids, and triglycerides in
chylomicrons
2 metabolic hallmarks
○ Oxidation of glucose for ATP production in all body
cells
○ Storage of excess fuel molecules in hepatocytes,
adipocytes, and skeletal muscle cells
Pancreatic beta cells release insulin
○ Promotes entry of glucose and amino acids into cells
life saving son

57. Principal metabolic pathways during the
absorptive state
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58. AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
1
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
HEPATOCYTES IN LIVER
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Fatty acids
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
+ H2O +CO2 ATP
1
2
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
HEPATOCYTES IN LIVER
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Triglycerides
Fatty acids
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
+ H2O +CO2 ATP
1
2
3
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
GLUCOSE
HEPATOCYTES IN LIVER
SKELETAL
MUSCLE
Storage
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Fatty
acids
Triglycerides
Glyceraldehyde
3-phosphate
Glucose
Fatty acids
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
GlycogenGlycogen
+ H2O +CO2 ATP
1
2
3
4
4
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
GLUCOSE
HEPATOCYTES IN LIVER
SKELETAL
MUSCLE
Storage
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Triglycerides
Fatty
acids
Triglycerides
Glyceraldehyde
3-phosphate
Glucose
Fatty acids
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
GlycogenGlycogen
+ H2O +CO2 ATP
1
2
3
4 5
4
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
GLUCOSE
HEPATOCYTES IN LIVER
SKELETAL
MUSCLE
Storage
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Triglycerides
Fatty
acids
Triglycerides
Glyceraldehyde
3-phosphate
Glucose
Keto acids
Fatty acids
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
GlycogenGlycogen
+ H2O +CO2 ATP
1
2
3
4 5
6
4
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
GLUCOSE
HEPATOCYTES IN LIVER
SKELETAL
MUSCLE
Storage
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Triglycerides
Fatty
acids
Triglycerides
Glyceraldehyde
3-phosphate
Glucose
Keto acids
Fatty acidsProteins
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
GlycogenGlycogen
+ H2O +CO2 ATP
1
2
3
4 5
6
7
4
AMINO ACIDS GLUCOSE TRIGLYCERIDES
(in chylomicrons)
Blood
GLUCOSE
GASTROINTESTINAL
TRACT
GLUCOSE
HEPATOCYTES IN LIVER
SKELETAL
MUSCLE
Storage
+ H2O +CO2
MOST TISSUES
Oxidation
ATP
Triglycerides
ADIPOSE TISSUE
VLDLs
Triglycerides
Fatty
acids
Triglycerides
Glyceraldehyde
3-phosphate
Glucose
Keto acids
Fatty acidsProteins
Triglycerides
Glyceraldehyde
3-phosphate Glycogen
Glucose
GlycogenGlycogen
ProteinsProteins
+ H2O +CO2 ATP
1
2
3
4 5
6
7
8
4
life saving son

59. Metabolism during postabsorptive state
About 4 hours after the last meal absorption in
small intestine nearly complete
Blood glucose levels start to fall
Main metabolic challenge to maintain normal
blood glucose levels
Glucose production
○ Breakdown of liver glycogen, lipolysis,
gluconeogenesis using lactic acid and/or amino
acids
Glucose conservation
○ Oxidation of fatty acids, lactic acid, amino acids,
ketone bodies and breakdown of muscle glycogen
life saving son

60. Principal metabolic pathways during the
postabsorptive state
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61. 1
Liver glycogen
Glucose
LIVER
Blood
HEARTADIPOSE TISSUE
SKELETAL MUSCLE TISSUE
OTHER TISSUES
1
Liver glycogen
Glucose
LIVER
Glycerol
Blood
HEART
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
SKELETAL MUSCLE TISSUE
OTHER TISSUES
2
Fatty acids
1
Liver glycogen
Glucose
LIVER
Lactic acid
Glycerol
Blood
HEART
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
SKELETAL MUSCLE TISSUE
OTHER TISSUES
3
2
Fatty acids
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Lactic acid
Glycerol
Blood
HEART
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
OTHER TISSUES
ProteinsAmino acids
Amino acids
4
4
3
4
2
Fatty acids
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Lactic acid
Glycerol
Blood
HEART
Fatty acids
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
OTHER TISSUES
Fatty acids
ProteinsAmino acids
Amino acids
Fatty acids
ATP
ATP
ATP
4
5
5
4
3
5
4
2
Fatty acids
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Lactic acid
Glycerol
Blood
HEART
Fatty acids
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
OTHER TISSUES
Fatty acids
ProteinsAmino acids
Amino acids
Fatty acids
Lactic acid
ATP
ATP
ATP
ATP
4
5
5
6
4
3
5
4
2
Fatty acids
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Lactic acid
Glycerol
Blood
HEART
Fatty acids
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
OTHER TISSUES
Fatty acids
ProteinsAmino acids
Amino acids
Fatty acids
Lactic acid
ATP
ATP
ATP
ATP
ATP
4
5
5
6
7
4
3
5
4
2
Fatty acids
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Fatty acids
Lactic acid
Ketone bodies
Glycerol
Blood
NERVOUS
TISSUE Ketone
bodies
Glucose
Starvation
HEART
Fatty acids
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
Ketone bodies
OTHER TISSUES
Fatty acids
ProteinsAmino acids
Amino acids
Fatty acids
Ketone bodies
Lactic acid
ATP
ATP
ATP
ATP
ATP
ATP
ATP
ATP
ATP ATP
4
5
8
5
6
8
8
7
4
3
5
4
2
8
1
Liver glycogen
Keto acids
Glucose
Amino acids
LIVER
Fatty acids
Lactic acid
Ketone bodies
Glycerol
Blood
NERVOUS
TISSUE Ketone
bodies
Glucose
Starvation
HEART
Fatty acids
Muscle proteins
Fatty acidsGlycerol
Triglycerides
ADIPOSE TISSUE
Fasting or
starvation
SKELETAL MUSCLE TISSUE
Ketone bodies
OTHER TISSUES
Fatty acids
ProteinsAmino acids
Glucose
6-phosphate
Pyruvic acid
Lactic
acid
Muscle glycogen
(aerobic) (anaerobic)
Amino acids
Fatty acids
Ketone bodies
Lactic acid
ATP
O2
ATP
ATP
ATP
ATP
ATP
ATP
ATP
ATP
ATP
ATP ATP
+ O2–
4
5
8
5
6
8
8
7
4
3
9
5
4
2
8
life saving son

62. Hormones and autonomic nervous
system regulate metabolism during
postabsorptive state
As blood glucose decline, insulin secretion falls
○ Glucagon – increases release of glucose into blood
via gluconeogenesis and glycogenolysis
Sympathetic nerve endings of ANS release
norepinephrine and adrenal medulla releases
epinephrine and norepinephrine
○ Stimulate lipolysis, glycogen breakdown
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63. Heat and energy balance
 Heat – form of energy that can be
measured as temperature and can be
expressed in calories
calorie (cal) – amount of heat required to raise 1
gram of water 1°C
Kilocalorie (kcal) or Calorie (Cal) is 1000 calories
 Metabolic rate – overall rate at which
metabolic reactions use energy
Some energy used to make ATP, some lost as heat
Basal metabolic rate (BMR) – measurement with
body in quiet, resting, fasting condition
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64. Body temperature homeostasis
Despite wide fluctuations in environmental
temperatures, homeostatic mechanisms
maintain normal range for internal body
temperature
Core temperature (37°C or 98.6°F) versus
shell temperature (1-6°C lower)
Heat produced by exercise, some
hormones, sympathetic nervous system,
fever, ingestion of food, younger age, etc.
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65. Heat and engery balance
• Heat can be lost through
– Conduction to solid materials in contact with
body
– Convection – transfer of heat by movement of a
gas or liquid
– Radiation – transfer of heat in form of infrared
rays
– Evaporation exhaled air and skin surface
(insensible water loss)
• Hypothalamic thermostat in preoptic area
– Heat-losing center and heat-promoting center
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66. life saving son