Download Metabolism

1.
2.
3.
4.
Cellular respiration
Fermentation
Metabolism
BMR
Carbohydrate Metabolism
• The body’s preferred source to produce
cellular energy (ATP)
• Glucose (blood sugar) is the major digestive
product and serves as fuel to make ATP
Figure 14.17
Metabolic Pathways Involved in Cellular
Respiration
Figure 14.18
Glycolysis harvests chemical energy by
oxidizing glucose to pyruvic acid
Glucose
Pyruvic
acid
Figure 6.9A
Energy yield: 2 ATP and 2 NADH
Pyruvic acid is altered for the citric acid
cycle
Pyruvic
acid
Acetyl CoA
(acetyl coenzyme A)
CO2
Figure 6.10
The citric acid cycle completes the oxidation of
organic fuel
Acetyl CoA
• enzymes convert
acetyl to CO2 and
generate NADH
and FADH2
molecules
CITRIC ACID
CYCLE
Figure 6.11A
2
CO2
Steps in the Electron Transport System
1. Set up H+ gradient using energy of e- from NADH, FADH2
2. Downhill flow of H+ is used to make ATP
Figure 3.28
cell
outer
membrane
inner
membrane
mitochondrion
• An overview of cellular respiration
High-energy electrons
carried by NADH
GLYCOLYSIS
Glucose
Cytoplasmic
fluid
Figure 6.8
Pyruvic
acid
CITRIC
ACID
CYCLE
ELECTRON
TRANSPORT CHAIN
AND CHEMIOSMOSIS
Mitochondrion
Fermentation is an anaerobic alternative to
aerobic respiration
• Without oxygen, cells can use glycolysis alone to produce small
amounts of ATP
– But a cell must replenish NAD+
Glucose
Pyruvic
acid
• In lactic acid fermentation, pyruvic acid is
converted to lactic acid
– NAD+ is recycled
• Contributes to muscle soreness
GLYCOLYSIS
2 Pyruvic
Glucose
Figure 6.15B
acid
2 Lactic
acid
• Pathways of molecular breakdown
Food, such as
peanuts
Polysaccharides
Fats
Proteins
Sugars
Glycerol Fatty acids
Amino acids
Amino
groups
Glucose
G3P
GLYCOLYSIS
Figure 6.16
Pyruvic
acid
Acetyl
CoA
CITRIC
ACIDS
CYCLE
ELECTRON
TRANSPORT CHAIN
AND CHEMIOSMOSIS
• Biosynthesis of macromolecules from
intermediates in cellular respiration
ATP needed to
drive biosynthesis
CITRIC
ACID
CYCLE
GLUCOSE SYNTHESIS
Acetyl
CoA
Pyruvic
acid
G3P
Glucose
Amino
groups
Amino acids
Fatty acids Glycerol
Sugars
Proteins
Fats
Polyscaccharides
Cells, tissues, organisms
Figure 6.17
Body Energy Balance
• Energy intake = total energy output (heat +
work + energy storage)
– Energy intake from food oxidation
• Proteins, carbs have 4 Cal/gm
• Fats have 9 Cal/gm
– Energy output
• Heat is usually about 60%
• Storage energy is in the form of fat or glycogen
Regulation of Food Intake
• Body weight is usually relatively stable
– Energy intake and output remain about equal
• Mechanisms that may regulate food intake
–
–
–
–
Levels of nutrients in the blood
Hormones: leptin, ghrelin
Body temperature
Psychological factors
Metabolic Rate and Body Heat Production
• Basic metabolic rate (BMR) reflects the amount of
energy spent per unit of time by a body at rest
• Factors that influence BMR:
– Body shape (height and weight),
gender, body composition, age,
stress, food intake, genetics
• TMR = Total Metabolic Rate
– Total energy spent, includes activity above
BMR
Estimation of BMR
• Johnson: your weight in kg (# lbs/2.2) x 24
(x 0.9 if female) = Calories per day
• Your weight in kg (# lbs/2.2) x % lean mass
males usually 82-88%
females usually 75-82%
Then check table (next slide)
ESTIMATION OF RESTING METABOLIC RATE (RMR)
BASED ON FAT-FREE BODY MASS (FFM)
FFM
(kg)
RMR
(kcal)
FFM
(kg)
RMR
(kcal)
FFM
(kg)
RMR
(kcal)
30
31
32
33
34
35
36
37
38
39
40
1018
1040
1061
1083
1104
1126
1148
1169
1191
1212
1234
58
59
60
61
62
63
64
65
66
67
68
1623
1644
1666
1688
1709
1731
1752
1774
1796
1817
1839
86
87
88
89
90
91
92
93
94
95
96
2228
2249
2271
2299
2314
2336
2357
2379
2400
2422
2444
41
42
43
44
45
46
47
48
49
50
1256
1277
1299
1320
1342
1364
1385
1407
1428
1450
69
70
71
72
73
74
75
76
77
78
1860
1882
1904
1925
1947
1968
1990
2012
2033
2055
97
98
99
100
101
102
103
104
105
106
2465
2487
2508
2530
2552
2373
2595
2616
2638
2660
51
52
53
54
55
56
57
1472
1493
1515
1536
1558
1580
1601
79
80
81
82
83
84
85
2076
2098
2120
2141
2163
2184
2206
107
106
109
110
111
112
113
2681
2703
2724
2746
2768
2789
2811