Cellular Respiration (intro)

SBI4U - Birrell

Why do we need energy?

many biochemical processes in our cells require energy

What is the main fuel source in animals?

Glucose

Can glucose be used as a primary energy source? Why?

NO: it has too much energy to be used as a primary energy source

Overall equation for cellular respiration

C₆H₁₂O₆ + 6 O₂ --> 6 CO₂ + 6 H₂O + 38 ATP

Cellular respiration

the release of energy through the oxidation of fuel molecules

Oxidation in biology

usually the removal of hydrogen, because they have 1 electron

The ultimate goal of cellular respiration

to extract energy from nutrient molecules and store it in a form that the cell can actually use (ATP)

4 parts of cellular respiration

1. Glycolysis

2. Pyruvate Oxidation

3. Kreb’s Cycle (aka citric acid cycle)

4. Electron Transfer Chain

5 kinds of chemical reactions involved in cellular respiration

• Phosphorylation: sticking a phosphate on (energizes the molecule)

• Dephosphorylation: taking a phosphate off

• Decarboxylation: removal of a carboxyl group

• Redox: transfer of electrons and of potential energy

• Isomerization: rearrangement

What reaction is especially important in respiration?

redox!

Redox reactions allow _______ from glucose to be _________ a little bit at a time and thus minimize loss of _____ _________

energy, extracted, free energy

ATP

Adenosine triphosphate:

• 3 phosphates

• 1 adenine nitrogenous base

• 1 ribose pentose sugar

ATP synthesis

the phosphorylation of an ADP molecule; can be made directly or indirectly

2 kinds of ATP synthesis

1. Substrate lvl Phosphorylation: an enzyme catalyszes the rxn of adding Pi to ADP

2. Oxidative Phosphorylation: a proton pump coupled to a facilitated diffusion channel catalyzes the synthesis of ATP

Substrate level phosphorylation occurs in __________ and _____, forming ATP _________ (in one step)

glycolysis, krebs, directly

Oxidative phosphorylation occurs in ___________, after the ________ ___________ ______. It forms ATP _________.

mitrochondria, electron transport chain, indirectly

purpose of ATP hydrolysis

releases energy to power many life processes

ATP hydrolysis equation

ATP + H₂O → ADP + Pi + Energy

ATP hydrolysis is a _________ rxn, which means:

reversible: the ADP can be recharged during cell. resp.

Energy Coupling in ATP hydrolysis

• when ATP loses a phosphate, it gives it to another substance

• this secondary substance is provided w energy needed to do its job

• allows for life processes that are usually non-spontaneous to proceed

cristae

the folds in the inner membrane of the mitochondria

identify the parts of the mitochondria

A: inner membrane

B: outer membrane

C: cristae

D: mitochondrial matrix