LT1 Metabolism

Question 1

What do thermodynamics tell us?

Answer 1

Whether a process is energetically favourable

Question 2

What is the 1st law of thermodynamics?

Answer 2

Energy is neither created nor destroyed

It is converted from one form to another
(total energy before and after conversion is the same)

Question 3

What is the 2nd law of thermodynamics?

Answer 3

When is energy is converted from form to another, so of that energy becomes unavailable to do work

No energy transformation is 100% efficient

Usable energy (free energy) and Unusable energy

Question 4

What is the equation for free energy change?

Answer 4

Energy of products - Energy of reactants

Question 5

What is the free energy change of food?

Answer 5

Food intake

Release of nutrients by digestion

Energy product = stored energy - (heat loss + excretion)

Question 6

What is the energy product gotten from food?

Answer 6

Stored energy - (heat loss + excretion)

Question 7

Reactions involve change in what?

Answer 7

Enthalpy = heat content

Entrophy = randomness; disorder
(it takes energy to impose order on a system, otherwise it will be randomly arranged or disordered)

Question 8

What is the most important change involved in reactions?

Answer 8

Free energy

ΔG = ΔH - TΔS

T = temp in Kelvin

Question 9

What did Sanctorus 1614 discover?

Answer 9

Most food lost through “insensible perspiration”

Weighted himself before/after daily activities

Question 10

What did Boyle 1670 discover?

Answer 10

Established that a “vital gas” is required for combustion and to sustain life

Candle flame extinguished as gas consume in a sealed container

Question 11

What did Mayow discover?

Answer 11

First calorimeter prototype

Question 12

What did Priestly/Lavoisier 1774 discover?

Answer 12

Oxygen identified as “vital gas” and its role in respiration studied

Indirect calorimtery = volumetric measurement of O2 consumption at reat, after meal and exercise

Question 13

What did Regnault/de Reiset 1849 discover?

Answer 13

Introduction of closed-circuit calorimetry

Template for precise application of thermodynamic principles to human calormetry

Question 14

What did Kleiber 1947 discover?

Answer 14

Metabolic rate scales with body mass to the 2/3 powering in animals

Evolutionary drives, which link metabolic needs to body plant & lifestyle

Question 15

What did Keys 1950 discover?

Answer 15

Minnesota Expt

Establishes common measurements that are used today to monitor metabolic health

Question 16

What is the Calorie?

Answer 16

Unit definition of ENERGY use

Heat input required to raise the temp of 1L of water by 1 degree Celsius

Question 17

What do Calories link?

Answer 17

Mass (kg)
Energy (J)
Force (N)

Question 18

How does Closed Ciruit Calorimetery work?

Answer 18

Organism sealed in container
O2 added and CO2 absorbed

Temperature changes recoreded

Question 19

How was temperature change measured
in Closed Circuit Calorimetery?

Answer 19

ΔT determined by change in heat required to maintain constant temp

Question 20

How was change in oxygen measured in Closed Circuit Calorimetery?

Answer 20

ΔO2 consumption determined by manometer change needed to maintain even pressure in the system

Question 21

How was carbon dioxide measured in Closed Circuit Calorimetery?

Answer 21

ΔCO2 produced determined by change in mass of soda-lime

Question 22

Who came up with Calorimeter for Man?

Answer 22

Atwater & Benedict 1965

Question 23

What is basal metabolic rate (BMR)?

Answer 23

Minimal caloric requirement measured in an AWAKE individual in absolute physical and mental rest after 12h fasting and at env temp of 22.5 degrees C

Question 24

What 8 factors affect BMR?

Answer 24

Gender, Age, Diet, Genetics
Exercise, Body fat, Body mass
THYROXIN

Question 25

How does gender affect BMR?

Answer 25

Males have a higher BMR by 10%-15% than females

Question 26

How does age affect BMR?

Answer 26

Drops 2% by decade

Question 27

How do genetics affect BMR?

Answer 27

Depends on mitochondrial phenotype

Question 27

How does diet affect BMR?

Answer 27

Restrictive diets can cause BMR to fall 20%

Question 27

How does thyroxin affect BMR?

Answer 27

Increased thyroxin increases BMR

Question 28

What does thyroxine do?***

Answer 28

Thyroxine stimulates the release of energy from stored nutrients in all cells of the body. This speeds up cellular metabolism, which in turn speeds up growth and development.

Question 29

How does body fat affect BMR?

Answer 29

More exercise decreases body fat % Decreased body fat % increases BMR

Question 30

How does body mass affect BMR? ***

Answer 30

Kleiber's Law = metabolic rate scales 3/4 power of body mass

Question 31

What is Kleiber's law? ***

Answer 31

Metabolic rate scales 3/4 power of body mass

Question 32

What is total daily energy expenditure composed of?

Answer 32

BMR = 60%-70% Thermic effect of food = 10% Activity thermogenesis = 20% -30%

Question 33

What is activity thermogenesis?

Answer 33

Spontaneous physical activity (SPA) Non-exercise actiivty thermogenesis (NEAT)

Question 34

What factors set the boundaries for ATP production?***

Answer 34

Oxygen delivery rate Rate of glucose uptake

Question 35

What is the predictive equation for BMR of male?

Answer 35

66.5 + (13.8 x mass[kg] + 5xheight[cm] ) - 6.8xage [years]

Question 36

What is the predictive equation for BMR of female?

Answer 36

665.1 + (9.6 x mass[kg] + 1.9xheight[cm]) - 4.7xage [years]

Question 37

What are BMR units?

Answer 37

kcal per day