Lecture 8

Question 1

What does organic compounds store? And in what form?

Answer 1

Free energy

In the form of chemical potential energy

Question 2

What does a cell degrade with the help of enzymes?

Answer 2

Complex organic molecules that are rich in energy to simpler products with less energy

Question 3

The most efficient catabolic pathway

Answer 3

Cellular respiration

Question 4

It is helpful to trace cellular respiration with?

Answer 4

The sugar glucose

Question 5

Explain cellular respiration

Answer 5

Glucose is oxidized in the presence of oxygen to carbon dioxide and water, with the release of free energy.

Question 6

The net equation of cellular respiration

Answer 6

C 6 H12 O6 + 6 O2 ——> 6 CO2 + 6 H2O + energy (ATP + heat)

Question 7

Energy contribution of dietary components

Answer 7

Carbohydrate - 4 kcal/g
Protein - 4 kcal/g
Fat - 9 kcal/g
Alcohol - 7 kcal/g

Question 8

What needs to be present in order for glucose to be oxidized in a living cell?

Answer 8

O 2

Question 9

In what form is energy harvested from glucose?

Answer 9

High energy electrons

Question 10

Electrons release a__________________ at each step, which is captured in the form of__________.

Answer 10

Little energy

ATP

Question 11

Some energy is released as?

Answer 11

Heat

Question 12

What do electron transfer reactions help to do?

Answer 12

Release chemical! Energy stored in organic molecules

Question 13

What happens to a substance: during oxidation?

Answer 13

It loses electrons and hydrogen

Oil ( oxidation is loss)

Question 14

In what form does substance lose energy?

Answer 14

High energy electrons

Question 15

What happens to a substance in reduction?

Answer 15

Gains electrons and hydrogen

Rig ( reduction is gain)

Question 16

What is exergonic?

Answer 16

Electron moves from higher to lower energy state

Question 17

What happens to glucose and O2 during cellular respiration?

Answer 17

Glucose is oxidized

O2 is reduced

Question 18

What happens with the oxidation of organic fuel molecules during cell respiration?

Answer 18

• Flow of electrons from glucose to oxygen
• electrons how downhill to more electronegative oxygen
• energy is released

Question 19

Energy harvest step 1

Answer 19

Glucose is oxidized to co2

NAD+ and FAD are reduced to NADH and FADH2

Question 20

Energy harvest step 2

Answer 20

NADH and FADH2 are oxidized to NAD+ and FAD

Oxygen is reduced to water

Energy is released and ATP is made

Question 21

ATP synthesis by oxidative phosphorylation

Answer 21

1. Energy is harvested in the form of high energy electrons.
2. Most of this energy is conserved in NADH and FADH2.
3. This energy is finally released when the high energy electrons are transferred to oxygen.
4. Energy harvested from glucose is temporarily stored in ATP; the energy currency of cells.