High School Biology : Understanding Mitochondria and Chloroplasts
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Example Questions
Example Question #21 : Common Cell Structures
Which of the following cellular organelles is responsible for making a majority of the cell's energy?
Rough endoplasmic reticulum
Nucleus
Golgi apparatus
Mitochondria
Lysosomes
Mitochondria
Mitochondria produces most of the energy of the cell. The nucleus stores genetic information and is the site of transcription. The rough endoplasmic reticulum is the site of translation of proteins that have destinations other than in the cytoplasm. These proteins made in the rough endoplasmic reticulum are subsequently transported to the Golgi apparatus, where they are modified, packaged, and sent to their final destinations. Lysosomes have an acidic environment in which digestive enzymes break down polymers that will eventually be recycled.
Example Question #22 : Common Cell Structures
What is the "powerhouse" of the cell?
Cell membrane
Cell wall
Ribosome
Nucleus
Mitochondria
Mitochondria
The mitochondria is responsible for making the energy for the cell by cellular respiration. It does this by taking the major breakdown products of glucose (pyruvate and NADH) and converting them into ATP by the citric acid cycle and electron transport chain. This is an oxygen-dependent process.
Example Question #13 : Understanding Mitochondria And Chloroplasts
The mitochondria are commonly considered the powerhouses of the cell. The energy (ATP) necessary for cell function is created within the mitochondria via the process of oxidative phosphorylation (the electron transport chain). In order for oxidative phosphorylation to be effective, certain proteins must maintain a proton gradient between the two membranes that surround the mitochondria.
Studying the structure of the mitochondria, you will notice that the organelle has two membranes. The outer membrane is smooth, while the inner membrane has numerous inversions and folds. These folds are called cristae. What is the purpose of the cristae?
No known function exists for the cristae.
They serve as the location where proteins involved in glycolysis reside
The folds are a byproduct of the highly acidic environment caused by the proton gradient. They exist to prevent the proton gradient from damaging the outer mitochondrial membrane.
The cristae provide greater surface area for the inner mitochondrial membrane, allowing more electron transport proteins in the organelle and more energy to be produced
The cristae serve to funnel protons deeper into the organelle, aiding in oxidative phosphorylation
The cristae provide greater surface area for the inner mitochondrial membrane, allowing more electron transport proteins in the organelle and more energy to be produced
The cristae increase the surface area available within the cell. In order for oxidative phosphorylation of occur, certain proteins must be embedded in the inner mitochondrial membrane. The fold in the membrane allow for a larger surface area, which in turn allows more of these proteins to be embedded. More proteins to create energy means more energy (ATP) for the cell.
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