Cellular Respiration Flashcards
Is Cellular Respiration Endergonic or Exergonic and why
It is exergonic because it releases energy
Where does Cellular respiration take place
In the mitochondria of eukaryotic cells
What actually happens in cellular respiration
Glucose is broken down to carbon dioxide and water and the cell captures SOME of the released energy to make ATP
in other words: a process that transfers energy from the bonds in glucose to form ATP
Respiration vs Cellular Respiration
Although the two relate, they are not the same.
Respiration is when an organism brings in oxygen from the environment and releases Carbon Dioxide (CO2).
Cellular respiration uses that oxygen
In other words: Breathing happens in order to do cellular respiration
How much ATP is produced from each glucose molecule in cellular respiration
28 - 32 ATP molecules (usually closer to 32)
What percent of energy originally stored in the glucose is captured in cellular respiration
About 34%
Why not just have one chemical reaction that releases all of the energy from the glucose molecule?
If there was just one reaction that went very fast, the energy would burn and we wouldn’t be able to use it. However, with the slow process that gradually releases energy in small amounts (stored in the form of ATP), this is avoided.
Redox Reaction
The movement of electrons from one molecule to another
Reduction (in redox reaction)
The ADDITION of electrons to a substance
that substance gains electrons and therefor gains energy, but in terms of charge, it goes down (because electrons are negatively charged)
Oxidation (in redox reaction)
The LOSS of electrons from a substance
Oxygen “Steals” electrons from them
That substance loses electrons and therefor loses energy, but in terms of charge, it goes up (because electrons are negatively charged)
Cellular respiration equation
Glucose loses its hydrogen atoms (and electrons) and becomes oxidized to CO2 (carbon dioxide)
Oxygen gains hydrogen atoms (and electrons) and becomes reduced to H2O (water)
NAD+
- is an important enzyme in oxidizing glucose
- accepts electrons
- becomes reduced to NADH
4 Stages of Cellular Respiration (in order)
Stage 1 - Glycolysis
Stage 2 - Pyruvate Oxidation
Stage 3 - Citric Acid Cycle
Stage 4 - Oxidative Phosphorylation
Cellular Respiration Equation
Where does Glycolysis occur? What goes in and what comes out in Glycylosis?
Occurs in Cytoplasm
GOES IN: 1 Glucose (2 ATP)
COMES OUT: 2 Pyruvate, 4 ATP (net 2 ATP because 2 in, 4 out), and 2 NADH
Where does Pyruvate Oxidation (grooming) occur? What goes in and what comes out in Pyruvate Oxidation?
Occurs while pyruvate molecules are entering mitochondria
GOES IN: 2 Pyruvate
COMES OUT: 2 AcetylCoA, 2 NADH, 2 CO2
Where does Citric Acid Cycle occur? What goes in and what comes out in Citric Acid Cycle?
Occurs in the Matrix (center of the mitochondria)
GOES IN: 2 AcetylCoA
COMES OUT: 6 NADH, 2 FADH2, 2 ATP, 4 CO2
Where does Oxidative Phosphorylation (ETC) occur? What goes in and what comes out in Oxidative Phosphorylation (ETC)?
Occurs in the inner membrane of the mitochondria
GOES IN: 10NADH, 2FADH2 (sub 2)
COMES OUT: about 28 ATP molecules
What are the two types of Phosphorylation that occur in cellular respiration and when do they occur?
- Substrate-level phosphorylation (occurs in glycolysis and the citric acid cycle)
- Oxidative phosphorylation (occurs in Oxidative Phosphorylation also known as ETC)
Explain Substrate-Level Phosphorylation
An enzyme transfers a phosphate group from a substrate molecule to ADP, ultimately forming ATP
What are the two main phases of glycolysis
- The energy investment phase
- The energy payoff phase
What happens in the energy investment phase of Glycolysis?
- energy consumed as two ATP molecules is used to energize a glucose molecule
What happens in the energy payoff phase of Glycolysis?
- 4 ATP molecules are generated (net 2 because 2 were consumed in energy investment phase)
What happens to the pyruvate formed in glycolysis?
it is transported from the cytoplasm into a mitochondria where the citric acid cycle and oxidative phosphorylation will occur (this all happens through pyruvate oxidation)
how many molecules of pyruvate are produced for each molecule of glucose that enter glycolysis?
2
What is Cellular Respiration
the process by which organisms use oxygen to break down food molecules to get chemical energy for cell functions