Interestingly, ribosomes are one of the only examples of an RNA structure that has enzymatic activity. The primary enzymatic function of the ribosome is one of a peptidyl transferase; that is, the catalysis of peptide bond formation between amino acids as those acids are brought to the nascent strand.

Interestingly, ribosomes are one of the only examples of an RNA structure that has enzymatic activity. The primary enzymatic function of the ribosome is one of a peptidyl transferase; that is, the catalysis of peptide bond formation between amino acids as those acids are brought to the nascent strand.

Interestingly, ribosomes are one of the only examples of an RNA structure that has enzymatic activity. The primary enzymatic function of the ribosome is one of a peptidyl transferase; that is, the catalysis of peptide bond formation between amino acids as those acids are brought to the nascent strand.

All of the choices presented describe functions of cell junctions. Adherens junctions and desmosomes are responsible for anchoring neighboring cells to one another. Hemidesmosomes help anchor the extracellular matrix in place, binding the cell membrane to proteins in the basal lamina or matrix. Gap junctions are an example of junctions that connect the cytoplasm of two neighboring cells and allow for communication via ions and other small molecules.

All of the choices presented describe functions of cell junctions. Adherens junctions and desmosomes are responsible for anchoring neighboring cells to one another. Hemidesmosomes help anchor the extracellular matrix in place, binding the cell membrane to proteins in the basal lamina or matrix. Gap junctions are an example of junctions that connect the cytoplasm of two neighboring cells and allow for communication via ions and other small molecules.

All of the choices presented describe functions of cell junctions. Adherens junctions and desmosomes are responsible for anchoring neighboring cells to one another. Hemidesmosomes help anchor the extracellular matrix in place, binding the cell membrane to proteins in the basal lamina or matrix. Gap junctions are an example of junctions that connect the cytoplasm of two neighboring cells and allow for communication via ions and other small molecules.

The question asks about membranes in general, not just the cell plasma membrane; therefore, all of the answers are true. The plasma membrane's most important functions are protecting the internal environment of the cell and selectively allowing nutrients into the cytoplasm (semi-permeability). The final answer describes a function of the inner-membrane of the mitochondria, which houses the electron transport chain.

The question asks about membranes in general, not just the cell plasma membrane; therefore, all of the answers are true. The plasma membrane's most important functions are protecting the internal environment of the cell and selectively allowing nutrients into the cytoplasm (semi-permeability). The final answer describes a function of the inner-membrane of the mitochondria, which houses the electron transport chain.

The question asks about membranes in general, not just the cell plasma membrane; therefore, all of the answers are true. The plasma membrane's most important functions are protecting the internal environment of the cell and selectively allowing nutrients into the cytoplasm (semi-permeability). The final answer describes a function of the inner-membrane of the mitochondria, which houses the electron transport chain.

There are many factors that determine the fluidity of cell membranes. Membranes that are composed of fully saturated, long fatty acid tails are generally less fluid then the opposite conditions. In addition, lower temperatures result in a less fluid membrane.

Membranes that have fatty acid tails with double bonds are more fluid because the double bonds make it difficult for multiple phospholipids to float next to one another. The shape of the double bond adds a another dimension to the lipid, preventing the tails from packing together. Unsaturated fatty acids are thus more fluid than saturated fatty acids.