1.Cellular respiration2.Fermentation3.Metabolism4.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

Figure 14.18

Metabolic Pathways Involved in Cellular Respiration

Glycolysis harvests chemical energy by oxidizing glucose to pyruvic acid

Figure 6.9A

Glucose Pyruvicacid

Energy yield: 2 ATP and 2 NADH

Pyruvic acid is altered for the citric acid cycle

Figure 6.10

Pyruvicacid

CO2

Acetyl CoA(acetyl coenzyme A)

• enzymes convert acetyl to CO2 and generate NADH and FADH2 molecules

The citric acid cycle completes the oxidation of organic fuel

Figure 6.11A

Acetyl CoA

CITRIC ACID CYCLE

2CO2

Steps in the Electron Transport System

Figure 3.28

1. Set up H+ gradient using energy of e- from NADH, FADH22. Downhill flow of H+ is used to make ATP

cell

innermembrane

outermembrane

mitochondrion

• An overview of cellular respiration

Figure 6.8

High-energy electrons carried by NADH

GLYCOLYSISGlucose Pyruvic

acid

CITRIC ACID

CYCLE

ELECTRONTRANSPORT CHAIN

AND CHEMIOSMOSIS

MitochondrionCytoplasmic

fluid

• Without oxygen, cells can use glycolysis alone to produce small amounts of ATP – But a cell must replenish NAD+

Fermentation is an anaerobic alternative to aerobic

respiration

Glucose Pyruvicacid

• In lactic acid fermentation, pyruvic acid is converted to lactic acid– NAD+ is recycled

• Contributes to muscle soreness

GLYCOLYSIS

2 Pyruvicacid

2 Lactic acidGlucose

Figure 6.15B

• Pathways of molecular breakdown

Figure 6.16

Food, such as peanuts

Polysaccharides Fats Proteins

Sugars Glycerol Fatty acids Amino acidsAmino groups

Glucose G3P Pyruvicacid

GLYCOLYSIS

AcetylCoA

CITRIC ACIDSCYCLE

ELECTRONTRANSPORT CHAIN

AND CHEMIOSMOSIS

• Biosynthesis of macromolecules from intermediates in cellular respiration

Figure 6.17

ATP needed todrive biosynthesis

PolyscaccharidesFatsProteins

CITRIC ACID

CYCLE

AcetylCoA

Pyruvicacid G3P Glucose

GLUCOSE SYNTHESIS

Aminogroups

Amino acids Fatty acids Glycerol Sugars

Cells, tissues, organisms

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 RMR FFM RMR FFMRMR

(kg) (kcal) (kg) (kcal) (kg)(kcal)

30 1018 58 1623 862228

31 1040 59 1644 872249

32 1061 60 1666 882271

33 1083 61 1688 892299

34 1104 62 1709 902314

35 1126 63 1731 912336

36 1148 64 1752 922357

37 1169 65 1774 932379

38 1191 66 1796 942400

39 1212 67 1817 952422

40 1234 68 1839 962444

41 1256 69 1860 972465

42 1277 70 1882 982487

43 1299 71 1904 992508

44 1320 72 1925 1002530

45 1342 73 1947 1012552

46 1364 74 1968 1022373

47 1385 75 1990 1032595

48 1407 76 2012 1042616

49 1428 77 2033 1052638

50 1450 78 2055 1062660

51 1472 79 2076 1072681

52 1493 80 2098 1062703

53 1515 81 2120 1092724

54 1536 82 2141 1102746

55 1558 83 2163 1112768

56 1580 84 2184 1122789

57 1601 85 2206 113 2811