63 Questions
A condensation reaction that produces a polysaccharide is an endergonic reaction.
True
Which of the following is NOT a feature of ATP?
Inorganic phosphate
Hydrolysis of ATP is an exergonic reaction.
True
Which of the following is NOT a product of glucose oxidation?
Oxygen
How many carbons are in glucose?
6
Where does glycolysis occur in the cell?
Cytoplasm
During glycolysis, how many ATP are made through substrate-level phosphorylation?
4 ATP
What happens to pyruvate if oxygen is not available for the cell?
It is reduced in fermentation
Which coenzyme acts as an electron and hydrogen carrier during glycolysis?
NAD+
The energy released by the hydrolysis of ATP is often used to drive unfavourable reactions forward.
True
Glucose is fully oxidized during glycolysis.
False
Which of the following is NOT a product of glycolysis?
NAD+
Where in the cell is pyruvate produced?
Cytoplasm
Which type of fermentation reduces pyruvate, regenerates NAD+ and produces a gas in the process?
Alcoholic
What is the primary function of mitochondria in cells?
To facilitate aerobic respiration and produce ATP
Why are muscle cells rich in mitochondria?
To meet the high energy demands of muscle contraction
What is the role of the endoplasmic reticulum (ER) in mitochondrial fission?
It marks the location where the mitochondrion will split
What is the function of the protein Drp1 in mitochondrial fission?
It forms a helix around the mitochondrion, facilitating the splitting process
What molecule provides energy for the mitochondrial fission process?
GTP
What is the primary function of the cristae in mitochondria?
To increase the surface area for ATP production
Which molecules are able to pass through the porins in the outer mitochondrial membrane?
Pyruvate and NAD
What is the primary function of cardiolipins in the inner mitochondrial membrane?
To insulate the inner membrane
Which of the following statements about the outer and inner mitochondrial membranes is correct?
Two of the above are correct
What is the primary role of the intermembrane space in mitochondria?
To allow for the exchange of molecules between the cytosol and matrix
What is the primary function of the matrix in the mitochondria?
Site of the citric acid cycle
According to the endosymbiont theory, what was the relationship between the prokaryotic cell and the eukaryotic cell?
Symbiotic
How many proteins does a mitochondrion typically produce for its own needs?
About 13 proteins
What is the main reason chloroplasts are considered plastids?
For their membranous structure
Which organelle shares a similar inner and outer membrane structure with mitochondria?
Chloroplast
The matrix is the area between the inner and the outer membranes.
False
The outer membrane contains porins, which are channels that allow unrestricted passage of moderately sized molecules like pyruvate.
True
Glycolysis and fermentation both occur in the cytoplasm.
True
Fermentation is the preferred method of ATP generation in the presence of oxygen.
False
The mitochondria is where pyruvate undergoes oxidation to produce acetyl CoA.
True
Glycolysis results in the production of 3 NADH molecules.
False
The citric acid cycle occurs in the intermembrane space of the mitochondria.
False
During the oxidation of pyruvate, carbon dioxide is released and NADPH is produced.
False
What is the fate of pyruvate in the presence of oxygen?
Moves into the mitochondria for aerobic respiration
What is the main role of pyruvate dehydrogenase in the oxidation of pyruvate?
Forms NADH and acetyl CoA
Which section of cellular respiration involves the formation of 2 pyruvate, 2 ATP, and 2 NADH?
Glycolysis
Which molecule acts as a coenzyme during the conversion of pyruvate to acetyl CoA?
Coenzyme A
What is the outcome if a cell lacks oxygen for cellular respiration?
Fermentation to produce small amounts of ATP
What happens in Step 2 of the citric acid cycle?
Two carbon dioxide molecules are released
Which molecule is very similar to NADH and is produced in the citric acid cycle?
FADH2
What is the primary function of FADH2 in the citric acid cycle?
Transfer of electrons and hydrogens
What is the role of GTP or ATP production in the citric acid cycle?
Generation of energy currency for cellular activities
How many oxaloacetate molecules are regenerated at the end of one complete turn of the citric acid cycle?
One
How many total NADH so far from one molecule of glucose at the end of the citric acid cycle?
10
How many total FADH2 so far from one molecule of glucose at the end of the citric acid cycle?
2
How many total CO2 so far from one molecule of glucose at the end of the citric acid cycle?
6
How many total ATP (Net!) so far from one molecule of glucose at the end of the citric acid cycle?
4
What is the primary function of Coenzyme Q in the electron transport chain?
Accepting electrons and acting as a shuttle between complexes
Which type of proteins are involved in carrying electrons through the electron transport chain?
Flavoproteins, iron-sulfur proteins, and cytochromes
Where are the mega complexes of the electron transport chain embedded?
In the inner mitochondrial membrane
What is the alternate name for Coenzyme Q used in the text?
'Ubiquinone'
Which protein acts as a shuttle moving electrons along between complexes in the electron transport chain?
Cytochrome C
At which complex in the electron transport chain does NADH enter?
Complex 1
How many hydrogen ions are pumped into the intermembrane space from the oxidation of one NADH molecule?
10
At which complex does FADH2 enter the electron transport chain?
Complex 2
Which of the following poisons blocks complex 4 of the electron transport chain?
All of the above
Which component of the electrochemical gradient is established by the accumulation of positively charged hydrogen ions (protons) in the intermembrane space?
Both the pH difference and the voltage difference
According to the chemiosmotic theory, what is the primary source of the proton gradient established across the inner mitochondrial membrane?
The electron transport chain
What is the direction of proton movement across the inner mitochondrial membrane during ATP synthesis?
From the intermembrane space into the matrix
Study Notes
Cellular Respiration
- Cells can survive using glycolysis to produce ATP, but aerobic respiration produces the most ATP
- Aerobic respiration completely oxidizes glucose to carbon dioxide and produces a large amount of ATP
- Mitochondria are the primary site of aerobic respiration and are often referred to as the "powerhouse of the cell"
- Mitochondria are found in areas of high ATP demand, such as muscle cells
- Mitochondria are dynamic, interconnected networks that can fuse and divide
- The endoplasmic reticulum plays a role in mitochondrial fission
Mitochondrial Structure
- Mitochondria have two membranes: outer and inner
- The outer membrane encapsulates the organelle, while the inner membrane folds inward to increase surface area
- The matrix is the middle compartment, and the intermembrane space is the area between the two membranes
- Cristae are the deep folds of the inner membrane, and cristae junctions are the narrow extensions
- The outer membrane contains channel proteins called porins, which allow moderately sized molecules to move freely
- The inner membrane has different chemical properties and is enriched with cardiolipin, a phospholipid that insulates the membrane
Mitochondrial Function
- Mitochondria have their own machinery to transcribe and translate proteins, but only produce about 5% of the proteins they need
- The matrix contains ribosomes and circular DNA
- The citric acid cycle takes place in the matrix
- Mitochondria can produce ATP through aerobic respiration, using the electron transport chain and chemiosmosis
Cellular Respiration Process
- Glycolysis produces 2 pyruvate, 2 ATP, and 2 NADH
- Pyruvate oxidation produces acetyl CoA, carbon dioxide, and NADH
- The citric acid cycle produces 2 CO2, 3 NADH, 1 FADH2, 1 GTP (or ATP), and 1 oxaloacetate
- Oxidative phosphorylation produces ATP using energy from redox reactions in the electron transport chain
- The electron transport chain produces a proton gradient that drives ATP synthesis through chemiosmosis
Electron Transport Chain
- The electron transport chain is a series of protein complexes that use energy from NADH and FADH2 to pump hydrogen ions into the intermembrane space
- The electron transport chain is composed of four mega complexes and uses CoQ and cytochrome C as electron carriers
- The energy from the electron transport chain is used to generate a proton gradient across the inner mitochondrial membrane
Chemiosmosis
- The proton gradient established by the electron transport chain is used to drive ATP synthesis through chemiosmosis
- The proton gradient is an electrochemical gradient, with a difference in concentration and charge across the membrane
- The energy from the proton gradient is used to phosphorylate ADP to ATP through the process of chemiosmosis
Test your knowledge on how polysaccharides are formed through condensation reactions and why this process is considered endergonic.
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