1. What are the main differences between prokaryotic and eukaryotic cells in terms of their organelles?

Provide examples of each type of cell.

Answer: Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a

nucleus and various organelles enclosed by membranes. Examples of prokaryotic cells are bacteria and

archaea, while examples of eukaryotic cells are animal, plant, fungal and protist cells.

2. What is the function of the endoplasmic reticulum (ER) and what are the two types of ER? How are they

connected to each other and to other organelles?

Answer: The ER is a network of membranous tubules and sacs that synthesizes, modifies and transports

proteins and lipids. The two types of ER are rough ER, which has ribosomes attached to its surface and is

involved in protein synthesis and processing, and smooth ER, which lacks ribosomes and is involved in lipid

synthesis and detoxification. The two types of ER are connected by transitional regions and can exchange

materials through vesicles. The ER is also connected to the nuclear envelope, which surrounds the nucleus,

and to the Golgi apparatus, which further modifies and sorts proteins and lipids.

3. What is the function of the Golgi apparatus and what are its main components? How does it receive and

send materials to other organelles or to the cell surface?

Answer: The Golgi apparatus is a stack of flattened membranous sacs that modifies, sorts and packages

proteins and lipids for different destinations. Its main components are the cis face, which receives vesicles

from the ER, the trans face, which sends vesicles to other organelles or to the plasma membrane, and the

medial region, which contains enzymes that modify the cargo. The Golgi apparatus receives materials from

the ER through vesicles that fuse with its cis face, and sends materials to other organelles or to the cell

surface through vesicles that bud off from its trans face.

4. What are lysosomes and what are their functions? How are they formed and how do they interact with

other organelles?

Answer: Lysosomes are membrane-bound organelles that contain hydrolytic enzymes that degrade various

macromolecules, such as proteins, nucleic acids, lipids and carbohydrates. They function as the digestive

system of the cell, breaking down unwanted or damaged materials. They also participate in autophagy,

which is the process of recycling cellular components, and in phagocytosis, which is the process of

engulfing external particles or pathogens. Lysosomes are formed by budding off from the trans face of the

Golgi apparatus or by fusion of endosomes with existing lysosomes. They interact with other organelles by

fusing with them or by releasing their contents into the cytoplasm.