Bioenergetics 2: ATP

Question 1

What is the general energy flow through life and through an individual organism

Answer 1

1. From the sun, autotrophs will use light energy in photosynthesis to make organic molecules and O2 which is an anabolic process
2. The mitochondria uses these products in a catabolic process to produce ATP, CO2 and H2O to use in the cell.

Question 2

What are the major fuel stores in the body

Answer 2

Glycogen stores in Liver, Protein, Glycogen stores in the muscle and Fat which is the majority .

Question 3

What makes ATP better than other energy stuff (UTP, GTP and creatine phosphate)

Answer 3

Although ATP isn’t as powerful it has the phosphoanhydride bond more stable in water at physiological pH

Question 4

What are the components of delta H - the change in enthalpy

Answer 4

q (heat) + w (work done)

Question 5

What is the three stages of catabolism (in getting energy)

Answer 5

1. Hydrolysis of complex molecules to their monomers
2. Conversion to Acetyl CoA
3. Oxidative phosphorylation

Question 6

Where does the phosphate released from ATP go

Answer 6

This terminal phosphate has the most stored energy. It has a charge and some of the amino acids can accept this and then the structure of the protein changes until it is released

Question 7

What is the 2 laws of thermodynamics

Answer 7

1. energy cannot be created nor destroyed only transferred or transformed.
2. The universe tends towards disorder (greater entropy). This leads to equilibrium

Question 8

Which phosphate in ATP has the most energy released by hydrolysis

Answer 8

the terminal (3rd) phosphate of the anhydride bond hydrolysis

Question 9

Where is energy stored in chemical compounds

Answer 9

stored in reduced bonds (C=O, C-C and C-H) which is ultimately transferred to ATP following their oxidation

Question 10

What are the important sources of fuel in diet that contribute to ATP synthesis in order of the most energy gotten from it

Answer 10

Carbohydrates, protein, fat and then alcohol. This is because the enzymes we use to oxidise bonds work on C-H and O-H only. The molecules must be rearranged into the right bond.

Question 11

Why is fat a good fuel store for the body

Answer 11

It has slightly less energy per bond and can’t be metabolised without O2 but it stores well because it is hydrophobic so it doesn’t trap water.