Problems

Problem : Identify the cell nucleus, mitochondria, and peroxisomes in the following diagram.

Figure %: Eukaryotic cell

Figure %: Solution

Problem : What is the name of the structures into which DNA is packaged inside the cell nucleus?
DNA is packaged into chromosomes with proteins in the cell nucleus.

Problem : Does the nucleus allow molecules to pass across its double membrane?
Yes. The nuclear membrane contains pores that allow only certain molecules to pass across its membrane either in or out of the cell.

Problem : Why does the mitochondria have two distinct sub-compartments?
Mitochondrial membranes have two layers—an inner and outer membrane. As a result, there are two distinct spaces in the organelle. One between the inner and outer membranes, called the intermembrane space, and one within the inner membrane, called the matrix space.

Problem : What is the chemical process that occurs in the peroxisomes?
Oxidation. The peroxisomes contain enzymes that oxidize intracellular molecules like fatty acids.

Problem : Identify the endoplasmic reticulum, golgi apparatus, and lysosome in the following diagram.

Figure %: Eukaryotic cell

Figure %: Solution

Problem : Why is it called "rough" endoplasmic reticulum?
It is called rough endoplasmic reticulum because it is coated with small ribosomal particles that for a bumpy coat on the cytosolic side of the ER membrane. It is contrasted with smooth ER which lacks these ribosomes.

Problem : How are proteins segregated in the golgi apparatus for secretion?
Most proteins contain a signal sequence at its end that tell the golgi to where in the cell it should be secreted.

Problem : Into which face of the golgi apparatus do proteins from the ER enter? Which face do they exit from?
Proteins enter the golgi apparatus through the cis face and exit through the trans face.

Problem : What is the function of the lysosome?
The lysosome functions to remove intracellular debris by digesting it with the acidic enzymes found inside it.