CLEP Biology Cell Organelle Structure/Function 5

Question 1

Tay-Sachs disease results from a deficiency of a lysosomal enzyme that normally breaks down gangliosides. In which organelle do the undegraded gangliosides accumulate?

Accepted Answer

Lysosomes

Answer

Without the functional hydrolase (hexosaminidase A), gangliosides cannot be broken down and accumulate within lysosomes, causing neuronal dysfunction.

Question 2

Which property of the plasma membrane allows it to function as a selective barrier?

Accepted Answer

The amphipathic nature of phospholipids forming a bilayer

Answer

Phospholipids are amphipathic (with hydrophilic heads and hydrophobic tails) and spontaneously form a bilayer that restricts the passage of most polar and charged molecules.

Question 3

Which organelle would you expect to be most prominent in a liver cell due to its role in detoxifying drugs and alcohol?

Accepted Answer

Smooth endoplasmic reticulum

Answer

Smooth ER contains enzymes (especially cytochrome P450s) that detoxify drugs, alcohol, and other lipid-soluble compounds, and it proliferates in liver cells exposed to these substances.

Question 4

The signal recognition particle (SRP) directs ribosomes to which cellular location during translation of secretory proteins?

Accepted Answer

The rough endoplasmic reticulum membrane

Answer

SRP recognizes the signal sequence on a nascent polypeptide and directs the ribosome-mRNA complex to the rough ER membrane, where translation continues into the ER lumen.

Question 5

Which of the following pairs correctly matches an organelle with its membrane characteristic?

Accepted Answer

Chloroplast — double outer membrane plus internal thylakoid membranes

Answer

Chloroplasts have an outer double membrane (envelope) surrounding the stroma and an internal network of thylakoid membranes where light reactions occur.

CLEP Practice Test

CLEP Practice Test

CLEP Biology Cell Organelle Structure/Function 5