Unit 6-Cellular Respiration Flashcards
Define cellular respiration
Where does it occur
O2 is consumed as glucose and broken down to CO2 and H2O: the cell captures the energy released in ATP
In the mitochondria of almost all eukaryotes
Does cellular respiration occur in plants as well or do they just do photosynthesis
They do BOTH! Remember plants are eukaryotic cells
What is the chemical equation for cellular respiration
C6H12O6 + 6O2
–>
6CO2 +6H2O + ATP
How many ATP molecules can cellular respiration produce per 1 glucose molecule
32 ATP molecules
Define redox reaction
AKA
The movement of electrons from one molecule to another
Oxidation -Reduction Reaction
Define oxidation
The loss of electrons from one substance
Define reduction
The addition of electrons to another substance
When is a molecule said to become oxidized
When it loses one or more electrons
What demonstrates the electron transfer in the cellular respiration equation
The changes in the location of the hydrogen atoms represent electron transfer because each hydrogen atom consists of an electron and a proton
Who plays an important part in oxidizing glucose
What does it become reduced to and how
Coenzyme called NAD+
Accepts electrons and becomes reduced to NADH
Define hydrogenase
An enzyme that’s strips two hydrogen atoms from the molecule
What are the three main stages of cellular respiration
1) Glycolysis
2) Pyruvate oxidation and the Citric acid cycle
3) Oxidative phosphorylation
Where does glycolysis take place
What does it do generally
Occurs in the cytoplasmic fluid of the cell
Begins cellular respiration by breaking glucose into two molecules of a three carbon compound called pyruvate
Where does pyruvate oxidation and the citric acid take place
In the mitochondria
Where does the oxidative phosphorylation stage take place
An electron transport chain moves the electrons within the inner mitochondrial membrane
What stage of cellular respiration produces the most ATP molecules
Oxidative phosphorylation
What happens in chemiosmois
The potential energy of this concentration gradient is used to make ATP
Of the three main stages of cellular respiration which used oxygen to extract chemical energy
Oxidative phosphorylation
What is substrate level phosphorylation
The process that forms ATP in glycolysis
An enzyme transfers a phosphate group from a substrate molecule directly to ADP to form ATP
What is the final product of glycolysis
2 pyruvate
Define intermediates
Pyruvate is one
For each glucose molecule processed what are the products of glycolysis
2 pyruvates
2 ATP
2NADH
Does pyruvate enter the citric acid cycle
No
It travels to the mitochondria and goes through chemical changes
What are the three reactions during the oxidation of pyruvate
1) a carboxyl group is removed from pyruvate and becomes CO2
2) rest of carbon is oxidized while NAD+ is reduced to NADH
3) Coenzyme A joins the two carbons and becomes acetyl coenzyme A
What enters the citric acid cycle
2carbon acetyl enters leaving CoA out because it is basically just the transporter
What part of acetyl CoA is recycled
CoA
What type of reaction does the 6 carbon molecule undergo in the citric acid cycle
Redox reaction
How many ATPs does the citric acid cycle produce for one turn of the cycle
1 ATP
How many NADH and FADH2 molecules produced by one turn of the citric cycle
3 NADH
1 FADH2
How many cycles typically occur for the citric acid cycle
2
What is the overall outcome of one glucose molecule in the citric acid cycle
2ATP
6 NADH
2 FADH2
What molecules are shuttled through the electron transport chain and where do they end
NADH and FADH2
At O2
What does O2 do in the electron transport chain
For each O2 molecule it accepts 2 electrons from the chain and picks up 2 H+ which forms H2O
What do the protein complexes do during the electron transport chain
Use the energy released from the electron transfers to activity transport H+ across the membrane
What does chemiosmosis do
Uses the energy stored in a hydrogen ion gradient across the membrane to drive ATP synthesis
This causes the attachment of phosphate groups to ADP to create ATP
How many molecules of ATP is produced by oxidative phosphorylation
28 molecules of ATP
What is the total amount of ATP produced per 1 glucose molecule during cellular respiration
32 ATP molecules
Define lactic acid fermentation
Happens in muscles when bacteria can regenerate NAD+
Define alcohol fermentation
Yeasts and certain bacteria recycle their NADH back to NAD+ while converting pyruvate to CO2 and ethanol
What is fermentation
Recycles NADH back to NAD+ and allows glycolysis to continue
Enables cells to produce ATP without oxygen
What is the role of oxygen in cellular respiration
It accepts electrons from the electron transport chain
When the poison cyanide blocks the electron transport chain, glycolysis and the citric cycle come to a stop, why?
They run out of NAD+ and FAD
What is the intermediate source of energy for making most of the ATP in your cells
The movement of H+ across a membrane down its concentration gradient
In glycolysis ___ is oxidized and ____ is reduced
Glucose
NAD+
Which is the first molecule becoming reduced to the second molecule A) pyruvate -> acetyl CoA B) pyruvate-> lactate C) glucose -> pyruvate D) NADH + H+ -> NAD+ + 2H E) C6H12O6 -> 6 CO2
B
What is true between cellular respiration and fermentation
NADH is oxidized by the electron transport chain in respiration only
