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

From the following list of compartments and locations in the cell, build a pathway that a protein would follow from its initial synthesis to its secretion. Not all structures/compartments listed will necessarily be used. endoplasmic reticulum transport vesicle lysosome Golgi apparatus mitochondrion nucleus cytosol plasma membrane cell wall chloroplast

Some drugs are now being delivered into cells through liposomes, in which the drug is surrounded by a phospholipid bilayer. Explain how the drugs enter the cell.

An amphipathic molecule is one that:

Molecules that have both hydrophilic and hydrophobic regions are referred to as _____.

A protein with an internal signal sequence is MOST likely to be located in:

Of the major taxonomic groups of organisms mentioned in Chapter 1 (Section 1.3), list those whose cells have a plasma membrane.

Explain why the plasma membrane is permeable to some substances, while others require a channel, or carrier, protein to cross the membrane.

List in order each compartment that a secreted protein passes through from its initial synthesis until it is released to the outside of the cell.

You successfully extract the nucleus of a cell. Will this method remove all of the cell's DNA?

Put the following events in the CORRECT sequence for a protein that will be secreted from the cell. A. SRP binds to the growing polypeptide chain and to the ribosome. B. Translation resumes. C. SRP binds to its receptor. D. The signal sequence is cleaved. E. Protein synthesis begins in the cytosol. F. Translation pauses.

Given that both plant and animal cells have mitochondria, chloroplasts are actually unnecessary in plant cells.

Paramecium is a unicellular organism that lives in fresh water. Suppose you are studying two populations of this organism: one population lives in a pond in northern Ontario, Canada, and the other lives in a pond in southern Florida. If you examined the plasma membranes of both of these populations at the same time of year, what difference would you expect to find between the two populations' cell membranes?

Purified phospholipids gather together and form membranes only if the appropriate enzyme is present.

Phospholipase is an enzyme that cleaves the phosphate head group off a phospholipid molecule. The plasma membrane is not, however, permeable to the enzyme. Imagine a cell where phospholipid A is present in the layer of phospholipds facing the exterior of the cell, and phospholipid B is present in the layer of phospholipds facing the interior of the cell. After adding phospholipase to the medium in which the cell is growing, what would you expect to find in the fluid surrounding the cell?

Many cellular disorders exist in which the synthesis of certain proteins and their transport to specific locations in the cell are affected. Which organelles are involved in these disorders and why?

Synthesis of a protein destined to function in the nucleus occurs:

Molecular oxygen (O₂), which is required for the production of ATP by mitochondria, must pass through at least three membranes to get to the enzymes where it is used. O₂ is also produced in chloroplasts and must pass through at least four membranes to be released from the plant. How does O₂ move across biological membranes?

MOST proteins containing a signal sequence located at their amino terminal ends are sorted to:

The genetic material of a prokaryotic cell is located in its:

The process of a vesicle fusing with the plasma membrane and depositing its contents into the extracellular space is referred to as: