Energy Transfer 1 - After midterm

Question 1

biogenetics

Answer 1

Biogenetics is the scientific study of the principles and processes governing the production of living organisms from other living organisms, including the mechanisms of heredity.

Question 2

energy is extracted from food how

Answer 2

extracted from food incrementally
Photosynthesis: Chemical reactions in plants
convert light from the sun to stored chemical
energy
* Humans obtain energy by eating plants and
animals

Question 3

substrate level

metabolism, how does it work

what does all energy eventually degrade down to

Answer 3

energy substrates include carbs, protein, fats, which are broken down in our body to release energy

Chemical pathways in animals and humans
convert substrates to energy through stepwise
metabolic reactions
* Metabolism: The chemical reactions in the body
collectively
* All energy eventually degrades to heat

Question 4

oxidative level phosphorylation

substrate level phosphorylation

Answer 4

• Substrate-level phosphorylation: ATP generated
  independently of oxygen
• Oxidative phosphorylation: ATP producing reactions with the use of oxygen

Question 5

two main types of energy and the role of ATP

Answer 5

Total energy (of a system) = Kinetic + Potential
* Potential energy
* “Trapped” energy
* Energy of position or structure
* Kinetic energy
* Energy of motion

breaking of phosphate is the release of energy

Question 6

biological work in humans
3 types

Answer 6

mechanical work, chemical work, transport work
move muscles, converting chemicals into others, active transport

Question 7

two types of TEF

Answer 7

TEF is OF
Obligatory thermogenesis:
- Digesting and processing food
- Growth
- Pregnancy
Facultative thermogenesis:
- Superimposed on obligatory thermogenesis
- Control of thermoregulation
E.g. shivering in muscles

Question 8

First law of thermodynamics

second law

Answer 8

Energy cannot be created or destroyed, only converted
Food is converted into potential energy, transferred to ATP, used in contraction

spontaneous transfer of potential energy decreases the capacity to do work. Potential energy degrades over time as converted to kinetic, non-usable energy increases(heat)
as macronutrients are oxidized, the products each have less potential energy

Question 9

Human efficiency

Answer 9

How much of the energy that we get is converted to
mechanical work?
* Phosphorylative coupling efficiency ~60%
* Proportion of energy released in catabolism of (potential) energy
substrates that is captured as ATP
* Mechanical coupling efficiency ~50%
* Proportion of total chemical energy stored in ATP that is converted to
mechanical work in the hydrolysis of ATP
* Overall efficiency ~30%
* ~70% is lost as heat!

Question 10

Work and Power equations

Yesterday, Keenan rode his bike 116 km in 4 hr. Assuming he averaged 150 W…
* How much work did he perform overall?
* How much work did he perform per hour?

During his ride, Keenan ate:
* 2 granola bars (500 kcal)
* Handful of candies (300 kcal)
* Some chips (150 kcal)
* How many kJ did he consume?
* 1 kcal = 4.18 kJ

2160 kJ of mechanical work
* Only ~30% of energy expended
Mechanical energy = External work / Energy expenditure
* Total energy expenditure = _____ kJ = _____ kcal
* 3971 kJ (950 kcal) consumed
did he eat enough

Answer 10

Work (J) = Force (N) * Distance (m)
Power (W) = Work (J) / Time (s)

2160KJ, 540Kj/h

3971 KJ eaten

2160/0.3 = 7200KJ, total energy, only 30%

convert 7200 into kcal
7200/4.18 =

1723 kcal
no he didnt, only ate 950 kcal