Cellular Respiration Review
Feb 22, 2016
Cellular Respiration Review
Cellular Respiration
1. Define cellular respiration.A process that releases energy from food, such as the simple sugar glucose, when there is oxygen present.
2. Name several organisms that undergo cellular respiration
Nearly all living things undergo cellular respiration*.
Exceptions include a few microscopic marine animals (Loricifera) and some bacteria.
Cellular Respiration
3. Using chemical formulas, write the balanced equation for cellular respiration.
4. Now write out the equation using words.
Oxygen + Glucose yields Carbon dioxide + Water + Energy
6O2 + C6H12O6 6CO2 + 6H2O + Energy
Cellular Respiration
5. What organelle in eukaryotes is involved in cellular respiration?
The mitochondrion
6. What is a common analogy for mitochondria? Mitochondria are sometimes
called “cellular power plants” or the “powerhouses” of the cell.
Cellular Respiration
7. Where in eukaryotes are mitochondria found?
In all cells. Depending on the organism and the type of cell, the number of mitochondria can range from one to thousands.
Root tip of a corn plant.
Mitochondria
Cellular Respiration8. What kind of human cells contain the most and least number of mitochondria?
Cells that require the most energy contain the highest number of mitochondria. The cells of the brain, skeletal muscle, heart muscle, and the eye contain the greatest number (as many as 10,000 per cell) while the skin cells, which do not require much energy, contain only a few hundred.
Skeletal Muscle
Cellular Respiration
9. Identify the mitochondria in this micrograph of a human pancreatic cell.
Pancreas cell
Nucleus
Nucleolus
Endoplasmic reticulum
Pancreas
The pancreas secretes insulin in response to glucose levels in the blood.
Mitochondria
Cellular Respiration
Identify the following structures of the mitochondrion.
10 11
12
13
Cellular Respiration
Identify the following structures of the mitochondrion.
Outer membrane
11
12
13
Cellular Respiration
Identify the following structures of the mitochondrion.
Outer membrane
Inner membrane
12
13
Cellular Respiration
Identify the following structures of the mitochondrion.
Outer membrane Inner membrane
Inner membrane space
13
Cellular Respiration
Identify the following structures of the mitochondrion.
Outer membrane
Inner membrane space
Matrix
Inner membrane
Cellular Respiration14. What are the three main stages of cellular respiration?
Glycolysis (Converting glucose to pyruvic acid)
The Krebs cycle (Breaking down pyruvic acid into CO2)
Electron Transport (Making lots of ATP)
Pyruvic acidThree Carbon dioxide
ATP
ATP
ATPATPATP ATP ATP
ATPATP
ATPATPATP
Glucose Two pyruvic acid
Cellular Respiration15. Where in the mitochondrion does each stage of cellular respiration occur?
Glycolysis takes place in the cell’s cytoplasm outside the mitochondrion
The Krebs cycle occurs in the matrix
The Electron Transport Chain operates in the inner membrane.
Cellular Respiration16. What happens during glycolysis?
Four enzymes are used to break glucose into two molecules of G3P*
Five enzymes then convert G3P into pyruvic acid**
Four ATP are produced.
Two ATP are invested to get this done.
*G3P is Glyceraldehyde-3-phosphate ** Pyruvic acid is known as pyruvate
A net of two ATP are made.
Glucose
Two G3P
Two pyruvic
acid
ATP
ATP
ATPATP
ATPATPATP
ATPTwo electron carriers pick up electrons during the process
Electron carriers
Electron carriers
Cellular Respiration17. What happens in the Krebs cycle?
Pyruvic acid enters the mitochondrial matrix where it will enter the Krebs cycle.
Acetyl CoA Oxaloacetate
Electron carriers
MatrixMitochondrion
EnzymesPyruvic acid
Cellular Respiration17. What happens in the Krebs cycle?
Here pyruvic acid will interact with enzymes and other molecules.
Acetyl CoA Oxaloacetate
Electron carriers
MatrixMitochondrion
Enzymes
Cellular Respiration17. What happens in the Krebs cycle?
Electron carriers
After a series of chemical reactions, three carbon dioxide molecules are produced.
MatrixMitochondrion
Enzymes
Cellular Respiration17. What happens in the Krebs cycle?
Electron carriers
In addition, a molecule of ATP is generated…
MatrixMitochondrion
EnzymesATP
Cellular Respiration17. What happens in the Krebs cycle?
Electron carriers* also pick up excess electrons.
MatrixMitochondrion
Enzymes
ATP
Electron carriers
* Electron carriers NAD+ and FAD
Cellular Respiration
MatrixMitochondrion
Enzymes
ATP
Electron carriersElectron carriersElectron carriersElectron carriersElectron carriers
* Electron carriers NAD+ and FAD
17. What happens in the Krebs cycle?Electron carriers* also pick up excess electrons. They then travel to the inner membrane.
Cellular Respiration
MatrixMitochondrion
Enzymes
* Electron carriers NAD+ and FAD
18. What do the carriers do with their electrons?The electron carriers drop off their electrons at the inner membrane.
Electron carriers
Electron carriers Electron
carriers
Electron carriers
Electron carriers
Cellular Respiration
MatrixMitochondrion
* Electron carriers NAD+ and FAD
The carriers then return to the matrix to pick up more electrons while other molecules are recycled.
Electron carriers
Electron carriers Electron
carriers
Electron carriers
Electron carriers
Acetyl CoAOxaloacetateEnzymes
18. What do the carriers do with their electrons?
Cellular Respiration
Matrix
Inner membrane
At the inner membrane, the electron carriers attach themselves to membrane proteins.
Outer membrane
Inner membrane
space
Cytoplasm
Electron carriers
19. What happens to the electrons at the inner membrane?
H + ions
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
The electrons are then passed to the protein.
Outer membrane
Inner membrane
space
Cytoplasm
Electron carriers
19. What happens to the electrons at the inner membrane?
H + ions
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Some of the energy from the transfer of electrons is used to pump hydrogen ions (H+) into the inner membrane space.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Meanwhile, the shuttle protein ubiquinone moves in to pick up the electrons.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
Ubiquinone
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
The shuttle will move the electrons to the next protein.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
Ubiquinone
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Some of the energy from the transfer of electrons will be used to pump more H+ ions across the membrane.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
Cytochrome C
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
The electrons will then be shuttled by cytochrome c to their last protein.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
Cytochrome C
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Again, H+ ions will be pumped across the membrane.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Finally, an oxygen atom will pick up the two electrons along with two H+ ions to form a molecule of water.
19. What happens to the electrons at the inner membrane?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
O2
H2O
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
Water will exit the mitochondrion
20. Where does the water molecule go?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
H2O
ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
As more H+ is pumped into the inner membrane space, the space becomes more acidic. This causes the pH to drop.
21. How will the pH in the inner membrane space change?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
pH 7.2
pH 7.8ATP
Synthase
Cellular Respiration
Matrix
Inner membrane
There are more H+ ions in the inner membrane space, which sets up a concentration gradient.
22. How does the concentration of H+ ions in the matrix compare to that in the inner membrane space?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
High H+ Concentration
Low H+ ConcentrationATP
Synthase
Cellular Respiration
Matrix
Inner membrane
The H+ ions will flow down their concentration gradient from the inner membrane space toward the matrix.
23. In which direction is the concentration gradient?
Outer membrane
Inner membrane
space
Cytoplasm
H + ions
Grad
ient
High H+ Concentration
Low H+ ConcentrationATP
Synthase
Cellular Respiration
Matrix
Inner membrane
The H+ ions will flow through an enzyme called ATP synthase. This flow provides the energy needed to generate ATP from ADP.
24. Through what membrane protein will the H+ ions flow?
Outer membrane
Cytoplasm
H + ions
ADP
ATP
Synthase
PATP
Cellular Respiration
Matrix
Inner membrane
One glucose molecule yields about 36 to 38 ATP (2 ATP from glycolysis, 2 ATP from the Krebs cycle, and 32 to 34 ATP from the electron transport chain).
25. About how many ATP can be generated by cellular respiration from one glucose molecule?
Outer membrane
Cytoplasm
H + ionsATP
ATP
Synthase
ATP
ATP
ATPATP
ATP
ATP
ATP
ATP ATPATPATPATP
ATP
ATP
ATP ATP
ATP
ATP
Inner membrane
space