90 Questions
What is the primary function of mitochondria in energy metabolism?
To generate energy from lipid and carbohydrate breakdown
What is the role of chloroplasts in plant cells?
To convert solar energy into chemical energy
What is the site of electron-transport processes in chloroplasts?
Thylakoid membrane
What is the net result of aerobic oxidation in mitochondria?
Generation of ATP from chemical energy
What is the function of the stroma in chloroplasts?
To provide internal space for metabolic reactions
What is the primary source of energy for ATP synthesis in chloroplasts?
Sunlight
What is the role of oxidative phosphorylation in mitochondria?
To generate ATP from chemical energy
What is the approximate size of chloroplasts compared to bacterial cells?
Comparable
What is the net result of photosynthesis in chloroplasts?
Synthesis of carbohydrates from CO2 and H2O
What is the approximate number of genes in chloroplast genomes?
120
Where is the electron transport chain and oxidative phosphorylation primarily located in the mitochondria?
Inner Membrane
What percentage of the inner membrane is composed of protein?
>70%
What is the primary function of the outer membrane?
Facilitating the free diffusion of small molecules
Where is the citric acid cycle (Krebs cycle or TCA cycle) primarily located in the mitochondria?
Matrix
What is the primary function of the matrix in the mitochondria?
Conversion of pyruvate and fatty acids to Acetyl CoA
What is the result of the electron transport chain and oxidative phosphorylation in the mitochondria?
Generation of ATP
How does the inner membrane increase its surface area?
By folding into cristae
What is the result of the oxidation of Acetyl CoA in the citric acid cycle?
Production of CO2
What is the primary function of the mitochondrial genetic system?
DNA replication
What is the primary function of the phospholipid synthesis in the mitochondria?
Synthesis of phospholipids for membrane structure
What is the primary function of the mitochondrial matrix?
Energy production and storage
What is the role of the respiratory chain complexes in mitochondrial energy conversion?
To transfer electrons from NADH to oxygen
What is the net result of the citric acid cycle in terms of ATP production?
Indirect production of ATP through NADH and FADH2
What is the process by which the energy from the electron transport chain is converted into ATP?
Oxidative phosphorylation
What is the relationship between aerobic oxidation and photosynthesis?
They are opposing reactions
What is the primary function of the mitochondrial inner membrane?
To generate ATP through chemiosmosis
What is the result of the rapid conversion of ADP to ATP in mitochondria?
An increase in the ATP:ADP ratio
What is the origin of the mitochondrial DNA?
Inherited only from the mother
What is the size of the human mitochondrial genome?
Approximately 16,500 nucleotides
What is the number of genes encoded by the chloroplast genome?
Approximately 120 genes
What is the primary role of mitochondria in cellular respiration?
To break down carbohydrates and generate energy
What is the primary function of the stroma in chloroplasts?
To synthesize carbohydrates from CO2 and H2O
What is the approximate number of nucleotides in the human mitochondrial genome?
16,500
What is the primary function of chloroplasts in plant cells?
To convert sunlight into chemical energy
What is the primary source of energy for ATP synthesis in mitochondria?
Chemical energy from carbohydrates
What is the primary function of the electron transport chain in mitochondria?
To generate ATP through oxidative phosphorylation
What is the primary function of the mitochondrial matrix?
To generate ATP through oxidative phosphorylation
What is the primary function of the thylakoid membrane in chloroplasts?
To generate ATP through photosynthesis
What is the primary function of chloroplast DNA?
To encode chloroplast proteins and RNAs
What is the primary function of the mitochondrial inner membrane?
To generate ATP through oxidative phosphorylation
What is the main function of porins located in the mitochondrial outer membrane?
Free diffusion of small molecules
Which process occurs in the mitochondrial matrix?
Pyruvate oxidation
What characterizes the inner membrane of mitochondria?
Impermeable to most ions and small molecules
Which mitochondrial structure is the principal site for ATP production?
Cristae of the inner membrane
What is the effect of the cristae formation in the inner mitochondrial membrane?
Substantially increases surface area
In which compartment does the citric acid cycle occur?
Matrix
What metabolic process is facilitated by enzymes in the mitochondrial matrix?
Conversion of pyruvate to Acetyl CoA
What percentage of the inner mitochondrial membrane is composed of protein?
70%
Where are the enzymes for central reactions of oxidative metabolism located?
Matrix
Which process is NOT a function of the outer mitochondrial membrane?
ATP synthesis
What is the primary function of the citric acid cycle in mitochondria?
To oxidize the acetyl group on acetyl CoA to generate NADH and FADH2
Where does mitochondrial oxidation begin?
In the matrix space with the production of acetyl CoA from fatty acids and pyruvate
What role do NADH and FADH2 play in cellular respiration?
They donate electrons to generate a proton gradient used for ATP synthesis
How is the energy released by electrons in the respiratory chain stored?
As an electrochemical proton gradient across the inner membrane
Which process converts oxidation energy into ATP in mitochondria?
Chemiosmosis
What is a significant genetic characteristic of mitochondria?
Mitochondria are inherited only through the mother
Which statement accurately describes the Calvin cycle?
It is anabolic and consumes ATP
How do mitochondria and chloroplast genomes compare?
Chloroplast genomes are about 10 times larger than mitochondrial genomes
Which of these processes is considered anabolic?
The Calvin cycle
What is a common feature of both mitochondria and chloroplasts?
Both are surrounded by two membranes
What is the primary energy source for ATP synthesis in mitochondria?
Fatty acid oxidation
What is the byproduct of ATP synthesis in chloroplasts?
Reducing power
Which process occurs in the mitochondrial matrix?
Krebs cycle
What is the role of the stroma in chloroplasts?
Internal space enclosed by membranes
What is the primary function of the mitochondrial inner membrane?
Increased surface area for ATP synthesis
What is the result of aerobic oxidation in mitochondria?
Generation of ATP
What is the primary function of the thylakoid membrane in chloroplasts?
Site of electron transport processes
What is the relationship between aerobic oxidation and photosynthesis?
Aerobic oxidation occurs in mitochondria, while photosynthesis occurs in chloroplasts
What is the primary function of the mitochondrial genetic system?
Regulation of mitochondrial protein synthesis
What is the approximate number of nucleotides in the human mitochondrial genome?
16,500
What is the primary function of the mitochondrial inner membrane folding into cristae?
To increase the surface area for ATP synthesis
Which metabolic process occurs in the mitochondrial matrix and involves the conversion of pyruvate and fatty acids to Acetyl CoA?
Citric acid cycle
What is the primary function of the mitochondrial outer membrane integral transmembrane channel proteins (porins)?
To facilitate the transport of small molecules
What is the net result of the electron transport chain and oxidative phosphorylation in the mitochondria?
The production of ATP
Which compartment is responsible for the synthesis of ATP in the mitochondria?
Inner membrane
What is the primary function of the enzymes in the mitochondrial matrix?
To catalyze central reactions of oxidative metabolism
What is the primary function of the mitochondrial inner membrane in terms of metabolite transport?
To import pyruvate and fatty acids
What is the characteristic of the inner membrane of mitochondria?
Essentially impermeable to most ions and small molecules
Where does the oxidation of Acetyl CoA to CO2 occur via the citric acid cycle?
Matrix
What is the primary function of the mitochondrial genetic system?
To maintain the genetic material of the mitochondria
What initiates mitochondrial oxidation in the matrix space?
Production of acetyl CoA from fatty acids and pyruvate
What describes the relationship between aerobic oxidation and photosynthesis in eukaryotes?
Their overall reactions are the reverse of each other
What is the source of energy that drives ATP synthesis on the inner mitochondrial membrane?
Electrochemical proton gradient
What is the key function of the citric acid cycle?
Generate NADH and FADH2 for the respiratory chain
What are mitochondria primarily inherited through?
Mother only
Which genetic system encodes most of the proteins in mitochondria?
Nuclear DNA
What process rapidly converts ADP to ATP in mitochondria to maintain a high ATP/ADP ratio?
Respiratory chain electron transport
What significant cellular process is affected by the chemiosmotic mechanism in mitochondria?
Oxidative phosphorylation
How does the size of mitochondria compare to bacterial cells?
Comparable in size
Which component of the mitochondrial genome is notably smaller than its chloroplast counterpart?
Human mitochondrial genome
Study Notes
Metabolic Pathway and Energy Conversion
- Metabolic organelles are specialized compartments where many metabolic activities take place
- Mitochondria and chloroplasts are devoted to energy metabolism and ATP production
- Mitochondria generate energy from lipid to carbohydrate breakdown, while chloroplasts use energy captured by sunlight to generate energy ATP and the reducing power needed to synthesize carbohydrates
Properties and Functions of Chloroplasts
- Found in plant cells
- Comparable in size to whole bacterial cells
- Provides energy by converting solar energy into chemical energy
- Generates ATP to convert CO2 to sugar
- Electron-transport processes occur in thylakoid membrane
- Stroma is an internal space enclosed by membranes
- Chlorophyll and other chloroplast products are exported to cell cytosol
Properties and Functions of Mitochondria
- Found in most eukaryotic cells
- Comparable in size to whole bacterial cells
- Site of aerobic respiration and energy production
- Surrounded by two membranes
- Matrix contains enzymes, DNA, mRNA, and ribosomes
- Mitochondria are inherited only through the mother
Mitochondrial Organisation
- Metabolic functions are localized within the mitochondria
- Outer membrane: phospholipid synthesis, fatty acid desaturation, and fatty acid elongation
- Inner membrane: electron transport, proton translocation for ATP synthesis, oxidative phosphorylation, pyruvate import, fatty acyl CoA import, and metabolite transport
- Matrix: pyruvate oxidation, citric acid cycle, ATP synthesis, β-oxidation of fats, DNA replication, RNA synthesis, and protein synthesis
Energy Conversion in Mitochondria and Chloroplasts
- ATP is generated from chemical energy or sunlight
- Two processes primarily responsible for the conversion: aerobic oxidation (aerobic respiration) conducted in mitochondria and photosynthesis conducted in chloroplasts of plants
This quiz covers the processes of glycolysis, citric acid cycle, and mitochondrial oxidation in cellular respiration, focusing on ATP production. It explores the roles of acetyl CoA, NADH, and FADH2 in the respiratory chain.
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