AP Bio 4.5-4.6
Describe two characteristics shared by chloroplasts and mitochondria. Consider both function and membrane structure.
Both involved in energy transformation, mitochondria in cellular respiration and chloroplasts in photosynthesis. both have multiple membranes that separate interiors into compartments. both organelles, innermost membranes—cristae, or infoldings of the inner membrane, in mitochondria, and the thylakoid membranes in chloroplasts—have large surface areas with embedded enzymes that carry out their main functions.
How do cilia and flagella bend?
Dynein arms, powered by ATP, move neighboring doublets of microtubules relative to each other. Because they are anchored within the organelle and with respect to one another, the doublets bend instead of sliding past each other. Synchronized bending of the nine microtubule doublets brings about bending of both cilia and flagella.
A classmate proposes that mitochondria and chloroplasts should be classified in the endomembrane system. Argue against the proposal.
Mitochondria and chloroplasts are not derived from the ER, nor are they connected physically or via transport vesicles to organelles of the endomembrane system. Mitochondria and chloroplasts are structurally different from vesicles derived from the ER, which are bounded by a single membrane.
Do plant cells have mitochondria? Explain.
Yes. Plant cells make own sugar by photosynthesis, but mitochondria in eukaryotic cells are the organelles that are able to generate energy from sugars, a function required in all cells.
Males afflicted with Kartagener's syndrome are sterile because of immotile sperm, and they tend to suffer from lung infections. This disorder has a genetic basis. Suggest what the underlying defect might be.
defects in the microtubule-based movement of cilia and flagella. sperm can't move because of malfunctioning or nonexistent flagella, and the airways compromised because cilia that line the trachea malfunction or don't exist, and so mucus cannot be cleared from the lungs.
