Chapter 9 Flashcards
Formula for photosynthesis
6CO2+H2O+sunlight->C6H12O6+6O2
Formula for respiration
C6H12O6+6O2->6CO2+6H2O+energy
Aerobic respiration
oxygen required
- higher multicellular organisms
- glucose completely broken down
- yields many ATPs
Anaerobic or fermentation
- no oxygen used
- bacteria and other lower forms
- partial degradation of glucose
- yields only 2 ATPs
oxidation
a substance loses electrons, electron acceptor is called the oxidizing agent
reduction
substance gains electrons, electron donor is called reducing agent
Steps of energy investment stage of Glycolysis
- one ATP transfers a phosphate group to glucose – glucose 6 phosphate molecule
- Glucose 6 phosphate is converted into fructose 6 phosphate molecule
3. A second ATP transfers phosphate to
fructose 6 phosphate forming fructose 1,6 bi-phosphate.
4. Fructose 1,6 bi-phosphate splits into
1 G3P and
1 DHAP (gets converted into G3P)
Steps of energy payoff of glycolysis
- The 2 G3P (also known as PGAL) give
up phosphate group to ADP (forming 2 ATPs) - Electrons and H+ ions are donated to
NAD to becomes NADH - The next conversion is from
3-phosphoglycerate 2-phosphoglycerate pyruvate.
(and 2 more ATPs are produced. )
products of Glycolysis
- 2 pyruvates
- 2 net atps (4 made 2 used)
- 2 NADH
- 2 H2O
Before Citric Acid Cycle Begins
- Two pyruvate molecules from glycolysis enter the mitochondrion
- With the help of Coenzyme A, one carbon atom is stripped from each pyruvate forming CO2 and Acetyl- Co A.
- NAD is reduced to NADH
Citric Acid Cycle
4.. Acetyl CoA (2 C) is merged with oxaloacetate (4 C),
to form citrate (6 carbons).
- Citrate is converted back to oxaloacetate
through a series of reactions. - During this process 1 ATP molecule, 3 NADH
and one FADH2 are formed. - 2 more CO2 are formed and released
- The same process repeats for the other
pyruvate molecule
Overview of Electron Transport
- The electron transport chain takes place in the cristae
- chain’s components are proteins, which exist in multiprotein complexes
- Redox reactions happen
- Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O
Electron Transport Chain/Phosphorlation
- Electrons and H+ from NADH and FADH2 formed during glycolysis and Citric Acid Cycle enter electron transport chains.
- They give up electrons and H+ ions are pumped from the mitochondrial matrix to the inter membrane space.
- Increases H+ ions within intermembrane
space, creating a steep concentration gradient - H+ want to diffuse back into the matrix, but
cannot cross the mitochondrial membrane. - Must cross through ATP synthase-protein
(which helps in the formation of ATP from ADP
and phosphate.) - ATP synthase uses the exergonic flow of H+ to make ATP from ADP and phosphates
This is an example of chemiosmosis, the use of energy in a H+ gradient to drive cellular work
- Last components of electron transfer
chains pass electrons to oxygen which
combines with hydrogen to form H2O.
Alcoholic Fermentation
1.2 pyruvate molecules are split to form
2 molecules of acetaldehyde and 2 CO2
- Acetaldehyde accepts electrons and H+
from NADH to form ethyl alcohol or ethanol
Lactate Fermentation and applications
NADH gives electrons and H+ to pyruvate
Converts pyruvate to lactate a three carbon compound –lactate.
Applications:
Lactate fermentation by lacto bacillus
cheese, yoghurt, buttermilk
Curing meats, pickling
