Cellular Respiration!

What’s the

point?

TO MAKE ATP!!

Energy! Forms of energy include chemical, radiant (heat

and light), mechanical and electrical Chemical energy is contained in the chemical

bonds of molecules Radiant energy travels in waves (ex: visible light) Energy can be transferred from one form to

another Law of Thermodynamics

Energy cannot be created or destroyed - can be converted from one form to another

Usable energy is lost during transformations

Composed of adenine base, ribose sugar, and 3 phosphate groups (PO4)

Phosphorylation – the addition of a phosphate group

Substrate-level phosphorylation – enzymes help break and down and convert those high energy PO4 bonds

When the bond is broken it releases energy, a phosphate group and ADP

ATP!!

Enzymes in Metabolic Pathways!

Biological catalysts Speeds up chemical reactions Weakens existing bonds in substrates which

lowers the amount of activation energy needed NADH – a second energy carrying molecule in

mitochondria and produces 3 ATP FADH2 – a third energy carrying molecule in the

mitochondria and produces 2 ATP

I ♥ NADH!

Mitochondria!

Has a smooth, outer membrane and a folded inner membrane

Cristae – folds of inner membrane – electron transport chain occurs here

Matrix – space inside cristae and contains DNA and ribosomes – Krebs cycle takes place here

Site of aerobic respiration

Cellular Respiration Overview!

C6H12O6 + 6O2 6CO2 + 6H2O (heat and ATP)

Controlled release of energy from organic molecules

Glucose is oxidized (loses e-) and oxygen is reduced (gains e-)

Carbon atoms of glucose is released as CO2

One glucose molecule generates 36 ATP

3 steps Glycolysis Kreb’s Cycle Electron Transport Chain (ETC)

Glucose rhymes with

lumos!

Glycolysis! Occurs in cytoplasm Summary of steps

2 ATP added to glucose (6C) to energize it Glucose splits into two PGAL (3C) H+ and e- is removed from each PGAL and given to

make 2 NADH NADH – energy and electron carrier Each PGAL is rearranged into pyruvate (3C) with

energy and transferred to make 4 ATP Creates 4 ATP but glycolysis requires 2 ATP so the

net product is 2 ATP If oxygen is available then the pyruvate will move

to the mitochondria and being aerobic respiration

Glycolysis (cont.)

If no oxygen is available (anaerobic) the pyruvate will be fermented by the addition of 2 H from the NADH, which changes it to NAD+ and keeps glycolysis going

Net yield of Glycolysis 4 NADH2

2 CO2

2 ATP

Kreb’s Cycle! AKA Citric Acid cycle Requires 2 cycles to metabolize glucose Acetyl Co-A (2C) enters the Kreb’s cycle and

combines with oxaloacetic acid (4C) to make citric acid (6C)

Citric acid is oxidized releasing CO2, free H+, and e- forming ketoglutaric acid (5C)

Free e- reduce NAD+ to NADH2 and FAD+ to FADH2

Ketoglutaric acid is also oxidized releasing more CO2, free H+, and e-

Kreb’s Cycle (cont.) The cycle continues oxidizing the carbon compounds

producing more CO2, NADH2, FADH2, and ATP

H2O is added to supply more H+

CO2 is a waste product and leaves the cell

Oxaloacetic acid is regenerated to start the cycle again NADH2 and FADH2 migrate to the ETC

Net yield from Kreb’s Cycle (2 turns) 6 NADH2

2 FADH2

4 CO2

2 ATP

Electron Transport Chain!

Found in the cristae Contains 4 protein-based complexes that works

in sequence moving H+ from the matrix across the inner membrane (proton pumps)

A concentration gradient of H+ between the inner and outer membrane occurs

H+ concentration gradient causes the synthesis of ATP by chemiosmosis

Energized e- and H+ from 10 NADH2 and 2 FADH2 are transferred to O2 to produce H2O