Exam 5: Organizing Principles: Lipids, Membranes, and Cell Compartments

Which of the following are processed in the Golgi apparatus?

During the translation of mRNA molecules, the new polypeptides are often directed to specific parts of the cell by the presence or absence of short sequences of amino acids called signal peptides. Which of the following would you expect to find in the polypeptides that will eventually fold to become the cytoskeletal proteins tubulin and actin, which are found in the cytoplasm?

You are investigating a particular cell type, and you notice that a protein normally found in the lysosome ends up being secreted from the cell. This appears to be the only thing wrong with these cells. Of the following conditions, which is the MOST likely cause of this defect in these cells?

A lysosomal enzyme works best at a pH of:

In a eukaryotic cell, how does mRNA get out of the nucleus?

Individuals with a condition known as exercise intolerance suffer extreme fatigue from minimal exertion. Name the organelle that, if defective, is MOST likely to cause this condition. Explain your reasoning.

All cells have:

Where is the SRP receptor located in a cell?

Prokaryotes absorb their nutrients from the environment; however, prokaryotes also have cell walls. What can you conclude from these statements?

Disorders of which organelle are often associated with defects in transport from compartment to compartment, resulting in poor sorting of protein components within the cell?

Which of the following is part of the endomembrane system of a eukaryotic cell?

A transmembrane protein in the outer membrane of the nuclear envelope would LEAST likely be found later in which one of the following cellular locations?

Imagine that you are investigating the production of insulin in normal cells to help determine the cause of faulty insulin production in cells in which insulin appears to be synthesized but fails to be secreted from the cell. You design experiments using three different pharmaceutical compounds to help pinpoint the trouble spot in the protein synthetic pathway. The first compound blocks the movement of transport vesicles in the cytoplasm. The second blocks SRP release from the ribosome and mRNA. The third compound binds to and blocks the signal sequence so that the SRP cannot recognize it. For each of these three treatments, indicate (1) whether the protein would be made at all, and if so, (2) where in the cell you would find it.

Which of the following molecules does NOT easily diffuse across a plasma membrane?

Which of the following would NOT be synthesized on the endoplasmic reticulum?

Imagine you have radioactively labeled a protein in the lumen of the endoplasmic reticulum. Where would you predict the labeled protein will end up?

A researcher is using a modified version of FRAP. She has devised a technique that allows her to label all the peripheral membrane proteins with a fluorescent tag, and has bleached a specific area of the cell membrane. After 24 hours, she notices that fluorescence has returned to the bleached area. What can she deduce from this experiment?

Which one of the following molecules would MOST likely require a transport protein to cross the plasma membrane of a red blood cell?

Imagine that you have two blades of grass. One is from a normal plant, and the other is from a mutant plant that cannot produce vacuoles. How will the structures of these two blades of grass compare?

A researcher is very surprised to find a prokaryotic cell that is greater than 100 m in diameter. How could this be possible?