4.3 Efficiency & regulation of cell. resp.

Question 1

Metabolic rate

Answer 1

The amount of energy that is expended per unit time in an organism

Question 2

Basal metabolic rate (BMR)

Answer 2

Metabolic rate of an organism at rest

Question 3

Beta-oxidation

Answer 3

A process in which fatty acids are broken down into acetyl-coA through catabolism

Question 4

ATP from Cellular Respiration

Answer 4

Glycolysis – 2 ATP
Citric Acid Cycle – 2 ATP
E-Transport/Chemiosmosis – 34
ATP
–> Total ATP Produced = 38 ATP per Glucose
Molecule

Question 5

Not Quite Perfect…

Answer 5

The maximum amount of ATP that can
be produced is 38, however, this value
may change due to other circumstances.

• Uncoupled proteins (H+ not powering
  ATP synthase)
• Using different electron shuttling
  molecules may yield less ATP

Question 6

Energy Efficiency

Answer 6

How efficient is aerobic respiration at
extracting the energy from glucose and
converting it to ATP?

Each ATP can produce 31 kJ/mol of energy

38 ATP X 31 kJ/mol = 1178 kJ/mol

Glucose contains 2870 kJ/mol

Efficiency = 1178 kJ/mol ÷ 2870 kJ/mol X 100 =
41%

Therefore 41% of the energy from Glucose is
converted into ATP

Question 7

Energy Efficiency

Answer 7

41% doesn’t seem like a very
efficient system but in reality it is
much more efficient than many man
made machines (cars only utilize
around 25% of the energy from fuel)

The rest of the potential energy from
glucose is released as thermal energy

Question 8

Metabolic Rate:

Answer 8

the amount of energy
that is expended per unit time in an organism

Question 9

Basal Metabolic Rate (BMR)

Answer 9

The metabolic rate of an organism at rest

Varies from individual to individual

Higher fat content decreases BMR

Slows down as we age

Question 10

Regulating Cellular Respiration

Answer 10

Your body needs to regulate cellular
processes to keep our metabolism
under control

Your body only needs a certain
amount of ATP to function properly
and so it must control its production

Question 11

Negative Feedback Loops

Answer 11

When there is an excess amount of ATP
present then ATP can bind to phosphofructokinase (an enzyme in
glycolysis) to stop ATP production

Similarly Citrate (from the citric acid
cycle) can also inhibit
phosphofructokinase and prevent a build
up of unneeded molecules

Question 12

Converting Food into Energy

Answer 12

We know Glucose can be converted into ATP
but what about Proteins, Complex
Carbohydrates and Fats?

Question 13

Proteins

Answer 13

Converted into amino acids which can
be converted into pyruvate, acetyl CoA or
fumarate

Question 14

Complex Carbs

Answer 14

Broken down into usable
glucose subunits

Question 15

Fats

Answer 15

Can be converted into G3P (glycolysis) and
Acetyl CoA

Question 16

Fats and Sugars

Answer 16

When you eat a gram of pure sugar (hydrophilic)
you also have to consume a gram of water to make
up for the amount of water that binds to the sugar
molecules

When you eat a gram of fat (hydrophobic) you only
gain the mass of the fat.

This is why many animals (yourself included) will
convert sugars to fats in order to store them (as this
is lighter)