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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