Mitochondria, Chloroplasts, and Energy Production Flashcards
What is the endosymbiotic theory?
An evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms
What does the endosymbiotic theory state?
The organelles distinguishing eukaryote cells evolved through symbiosis of individual single-celled prokaryotes
What is symbiosis?
Close and long-term biological interaction
What are two pieces of evidence supporting the endosymbiotic theory?
- Binary fission of mitochondria and plastids
- Circular DNA inside some organelles, similar to bacteria
Are the membranes of the mitochondria and chloroplasts part of the endomembrane system?
No
What are the mitochondria and chloroplasts specialized to do?
Harness energy for the cell
T or F: Mitochondria and chloroplasts are fully autonomous organelles.
False. They are semi-autonomous
Can mitochondria and chloroplasts grow and multiply independently of other membrane-bound compartments?
Yes
T or F: Mitochondria and chloroplasts contain their own circular genomes.
True
What are mitochondria?
Specialized organelles that are the site of respiration in eukaryotic cells
What serves as the universal energy currency of the cell?
ATP
Which organelle oxidizes chemical compounds like sugars into carbon dioxide and transfers the chemical energy to ATP?
Mitochondria
What shape is the mitochondria?
Rod-shaped
Which layer of the mitochondrial membrane contains many enzymes with diverse metabolic function?
The outer mitochondrial membrane
Which mitochondrial membrane contains porins?
The outer mitochondrial membrane
What are porins?
Large channels permeable to many molecules when opened
What are the folds in the inner mitochondrial membrane called?
Cristae
What is the benefit of having cristae in the inner mitochondrial matrix?
They increase membrane surface area
Which mitochondrial membrane contains machinery for aerobic respiration and ATP formation?
The inner mitochondrial membrane
Which mitochondrial membrane is rich in cardiolipin?
The inner mitochondrial membrane
Cardiolipin is a phospholipid characteristic of what?
Bacterial membranes
What is cardiolipin needed for?
Needed for the optimal functioning of many enzymes
What are the two aqueous compartments of the mitochondria?
The matrix and the intermembrane space
What is contained within the mitochondrial matrix?
Mitochondrial ribosomes and DNA
What is the intermembrane space?
The space between the inner and outer mitochondrial membranes
What is cellular respiration?
A process that uses chemical energy stored in molecules (ex. carbohydrates and lipids) to produce ATP
What is aerobic respiration?
Cellular respiration in the presence of oxygen
What does aerobic respiration produce as a byproduct?
Carbon dioxide
What are the three stages of substrate-level phosphorylation in animal cell cellular respiration?
- Glycolysis
- Pyruvate oxidation
- The citric acid cycle
Which process produces only a small amount of the total ATP necessary for cellular functioning?
Substrate-level phosphorylation
What does it mean for a coenzyme to be oxidized?
It’s able to accept electrons
What does it mean for a coenzyme to be reduced?
It’s able to donate electrons
What are the oxidized and reduced states of NAD?
- Oxidized: NAD+
- Reduced: NADH
What are the oxidized and reduced states of FAD?
- Oxidized: FAD
- Reduced: FADH2
What does the oxidation of NADH and FADH2 allow for?
Allows electrons and energy to be transferred
During cellular respiration in animal cells, what occurs after substrate-level phosphorylation?
Oxidative phosphorylation
Which process produces the majority of ATP necessary for cellular functioning?
Oxidative phosphorylation
What are the two main steps in oxidative phosphorylation?
- Generate electrochemical gradient
- Synthesis ATP
What is the electron transport chain (ETC)?
A series of intermediate electron carriers
What is energy transfer at each complex along the ETC used for?
Used to pump H+ from the matrix into the intermembrane space and create an electrochemical gradient
What occurs at the end of the ETC?
A low energy electron is transferred to the terminal electron acceptor, resulting in the production of H2O
What is the final electron acceptor in the ETC?
Oxygen
What is the enzyme after the ETC that synthesizes ATP?
ATP synthase
What is the role of ATP synthase?
Synthesize ATP using proton movement down the electrochemical gradient
What are chloroplasts?
Organelles that convert the energy of sunlight into chemical energy
How do chloroplasts convert light energy into chemical energy?
By synthesizing simple sugars
What type of organism contains chloroplasts?
Photosynthetic eukaryotes
What is the third internal membrane of the chloroplast called?
The thylakoid
Where is the site of the photosynthetic electron transport chain?
The thylakoid
Where are light-collecting molecules contained within the chloroplasts?
The thylakoid
T or F: The thylakoid is highly folded.
True
What is chlorophyll?
The major photosynthetic pigment in the thylakoid
What do enzymes do to the light energy collected by chlorophyll?
Use carbon dioxide as a carbon source to produce carbohydrates
Why does chlorophyll appear green?
Because it is poor at absorbing green wavelengths
What is photosynthesis?
The process of building carbohydrates using energy from sunlight and CO2
What are the carbohydrates synthesized during photosynthesis used for?
- Used as a starting point for making other molecules
- Used to synthesize ATP through cellular respiration
What the two main stages of photosynthesis?
- Light-dependent reactions
- Light-independent reactions/the calvin cycle
Where do light-dependent reaction occur?
The thylakoid membrane
What is produced from light-dependent reactions?
ATP and NADPH
Does the electron movement through the photosynthetic ETC occur as part of light-dependent or light-independent reactions?
Light-dependent
Where do light-independent reaction occur?
In the stroma of chloroplasts
