Week Four- Energy and enzymes

Question 1

What is the first law of thermodynamics?

Answer 1

Energy cannot be created or destroyed bit simply changed from one form to another without being depleted.

Question 2

What is food?

Answer 2

Chemical potential energy

Question 3

What are the two major fuels stored in the body?

Answer 3

Glycogen and triacylglycerol

Question 4

Where is glycogen stored?

Answer 4

Liver, muscle and water

Question 5

Where is triacylglycerol stored?

Answer 5

Adipose tissue

Question 6

What does the total energy of a system relate to?

Answer 6

Potential and kinetic energy.

Question 7

How is chemical energy stored?

Answer 7

Bonds of compounds and molecules

Question 8

What are exergonic reactions?

Answer 8

• Release energy

- Energy is ‘freed up’ to the surroundings for biological work

Question 9

What are endergonic reactions?

Answer 9

• Energy is absorbed

- Typically coupled to the energy released form an exergonic reaction

Question 10

What do endergonic reaction enable?

Answer 10

• Building bodily structures, ATP or substance transportation
• Increases in potential energy.

Question 11

What is the second law of thermodynamics?

Answer 11

All of the potential energy in a system degrades to the unusable form of kinetic or heat energy.

Question 12

What type of reaction is the breakdown of food?

Answer 12

Exergonic

Question 13

Give an example of mechanical work within the body

Answer 13

Muscle contraction

Convert chemical to mechanical energy

Question 14

What type of work do all cell perform?

Answer 14

Chemical work (maintenance and growth)

Question 15

What is transport work?

Answer 15

Active transport
Low to high concentration
Essential for muscle contraction

Question 16

How is a calorie measured?

Answer 16

increase 1g of water by 1°C

Question 17

How is a Kilogram calories measured?

Answer 17

Increase 1kg of water by 1°C

Question 18

What is a joule?

Answer 18

The energy expended when 1 newton of force move a distance of 1m

Question 19

How is energy in food measured?

Answer 19

Bomb calorimeters measure the gross energy value of macronurientst

Question 20

What are Atwater general factors?

Answer 20

 4 kCal/g dietary carbohydrate
 4 kCal/g dietary protein
 9 kCal/g dietary lipid
 7 kCal/g dietary alcohol

Question 21

What is the coefficient of digestibility?

Answer 21

efficiency of the digestive processes to extract the

potential energy yield within food (digested and absorbed)

Question 22

What is an enzyme?

Answer 22

A specific protein catalyst that accelerate the forward and reverse rates of chemical reactions without being consumed or changed in the reaction

Question 23

What do enzymes do?

Answer 23

Increase the speed of reaction and lower the energy of activation for a reaction to take place.

Question 24

Is the energy released the same when an enzyme is involved?

Answer 24

Yes

Question 25

Are enzymes adapted to a specific pH?

Answer 25

Yes

Question 26

What can extreme pH do to an enzyme?

Answer 26

Permanently change enzyme structure

Question 27

What do small changes in pH do to enzymes?

Answer 27

Reduce enzyme activity by modifying biding between enzyme and substrate.

Question 28

What does an increase in temperature do to the rate of chemical reactions?

Answer 28

Increase it

Question 29

What happens when the temperature is above 50°C?

Answer 29

Thermal denature and reaction rates fall

Question 30

What is the optimal temperature range for humans?

Answer 30

30-40°C

Question 31

What are coenzymes and what do they do?

Answer 31

They are organic substances which assist with the work of enzymes.
They are also temporary carriers

Question 32

What do coenzymes help facilitate?

Answer 32

enzyme binding with substrate

Question 33

What can effect the rate of chemical reaction?

Answer 33

• Substrate concentration
• pH and temperature
• Enzyme concentration and location

Question 34

What are reversible reactions also known as?

Answer 34

Equilibrium reactions