nutrition exam 2

bioenergetics

energy associated with biological systems, release and storage and use of this energy

energy derived

complete or partial oxidation of organic compounds, absorbed in the GI tract, nrg in chemical form, if animals can break they can use nrg from breaking bonds, nrg escape

trapping energy

requires systematic breaking of bonds and trapping electrons

where does energy come from

electrons

how much of diet DM is used for energy

75%

is energy a nutrient

no, it is derived from organic compounds (protein, CHO, fat) in the diet

systematic breaking of bonds

required to produce energy, glycolosis, krebs

where is chemical energy orginally from

the sun

heat

most common form of energy in biochemical reactions bc most chemical energy will be converted to this (inefficient)

inefficient metabolism

body is not 100% efficient, not all ATP energy will be used for work, heat will escape (given off), allows for optimum body temperature maintenance

calorie

unit of heat measured, the amount of heat required to raise the temperature of 1g of H2O 1 degree C from 14.5 degree C to 15.5 degree C at 1 atm

gross energy (caloric density)

total energy in a compound, measure with bomb calorimeter

bomb calorimeter

pure O2 environment, combust (ignite)- blow up, all chemical energy is converted to heat, measure heat produced and that is caloric density or gross energy

kcal/g of glucose

3.75

kcal/g for CHO

4

kcal/g for protein

4

kcal/g for fat

9

kcal/g for alcohol

7

1st law of thermodynamics

energy is not created nor destroyed, can be accounted for somewhere in the animals body

FE

fecal energy

UE

urinary energy

unavailable

FE, UE, CH4

digestible energy

gross energy-FE

meatabolizable energy

GE-FE-UE (-GPD=CH4), actual work available to tissues for metabolism

net nergy

GE-FE-UE (-GPD=CH4) -HI, actual energy used for work

energy utilization

digestion and absorption of organic compounds containing covalent bonds, excretion of energy containing compounds in feces and urine aka nrg not available to animal tissues, metabolism of compounds that breaks the covalent bonds and tranfers/releases energy, trapping of energy as atp→ work, produce heat→inefficient metabolism

food energy

all energy we get is from food, oxidation of food releases free energy form chemical bonds, oxidized CO2+H2O via enzymes

oxidation

loss of electrons from a compound, compound oxidized if reaction leads to an increase in O@ and decrease in H

reduction

gain of electrons, compound reduced if reaction leads to an increase in H and decrease in O2

redox state

determine caloric density, more reduced=more caloric dense, fat is more reduced than CHO or protein

what is the terminal electron acceptor in the body

oxygen can be reduced to H2O

electron carriers

transfer electron in redox reactions, known as coenzymes

adenosine triphosphate

ATP

ATP

produced as a result of oxidation, provides energy for muscle contraction, each phosphate group has 7.3 kcal, ATP→ADP+P+7.3kcal, ADP→AMP+P+7.3kcal, ATP→AMP+2P+14.6kcal

energy trapped and released

transfer of energy in the body will be in phosphate bonds, creatinine phosphate=10.3kcal, ATP=7.3kcal

functions of ATP

muscle contraction-creatinine phosphate+ADP→ATP+creatine, synthesis of new compounds-link AA together=protein (4ATP/link), transmission of nerve impulses, active absorption (inSI), heat production- via oxidation of foods(thermoregulation)

what is intermediary metabolism

fate of dietary components after digestion and absorption, flow of molecules through metabolic pathways and interaction between these pathways

liver

primary metabolic organ, functions to regulate blood concentration fo most metabolites (glucose, amino acids, etc)

hepatic portal vein

vein that carries absorbed nutrients from GI tract to liveer

cells in intermediary metabolism

the level at which metabolic pathways occur, glycolysis, gluconeogensis, lipolysis, Krebs cycle, beta-oxidation, electron transport

anaerobic

no oxygen present, occurs in cytoplasm

aerobic

oxygen present, occurs in mitochondria

net reaction of glycolysis

glucose + 2ADP + 2P → 2pyruvate + 2ATP + 2NADH

is glycolysis anerobic or aerobic

anerobic it occurs in cytoplasm where there is no oxygen present

net reaction of Krebs cycle

2 pyruvate→ 2AcetylCo-A +2CO2 + 2NADH

2AcetylCo-A→ 4CO2, + 6 NADH + 2FADH2 + 2ATP

is krebs cycle anerobic or aerboic

aerobic, occurs in mitochondria where there is oxygen present

net reaction for electron transport

NADH=3ATP, FADH=2ATP, NADH comes from glycolysis

is electron transport anaerobic or aerobic

aerobic, occurs in mitrochondria where oxygen is present

overall net reaction to produce ATP

glucose →6CO2 + 2ATP + 2ATP(krebs) + 2NADH + 8NADH(krebs) + 2FADH2 =36 moles ATP

1mole ATP = 7.3 kcal→ 36×7.3= 263 kcal (trapped energy)

1 mole glucose (180g)= 3.75kcal/g→ 180×3.75= 675 kcal (gross energy)

efficency of producing ATP

263 (realized) / 675 (potential) *100 = 39%

rest of the energy is lost as heat

not efficient