Test: Eukaryotic Cells - 1 - MCAT MCQ

Eukaryotic cells are characterized by the presence of membrane-bound organelles, such as the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. This compartmentalization allows for the segregation of cellular functions and enables greater complexity and specialization in eukaryotic organisms.

The mitochondria are the powerhouses of the cell and are responsible for the production of ATP through the process of cellular respiration. They generate energy by converting nutrients and oxygen into ATP through a series of biochemical reactions.

Ribosomes are the cellular organelles responsible for protein synthesis. They can be found either free in the cytoplasm or attached to the endoplasmic reticulum, forming rough ER. Ribosomes translate the genetic information carried by messenger RNA (mRNA) to synthesize proteins.

The Golgi apparatus plays a key role in the modification, sorting, and packaging of proteins for transport within the cell or secretion outside the cell. It receives proteins from the rough endoplasmic reticulum and modifies them by adding carbohydrate groups or other chemical modifications.

Lysosomes are membrane-bound organelles containing hydrolytic enzymes that are involved in intracellular digestion. They break down macromolecules, old organelles, and engulfed pathogens or cellular debris through a process called hydrolysis.

The endoplasmic reticulum (ER) is responsible for the synthesis of lipids, including phospholipids and cholesterol, and plays a role in detoxification by metabolizing drugs and other harmful substances. It is composed of a network of interconnected membranes throughout the cell.

The nucleus is the control center of the cell and contains the genetic material, DNA. It regulates gene expression and directs cellular activities by transcribing DNA into RNA, which is then translated into proteins.

The cytoskeleton is a dynamic network of protein filaments that provides structural support, facilitates cell division, enables cell signaling, and contributes to cell adhesion. It consists of three main components: microtubules, microfilaments, and intermediate filaments.

Peroxisomes are specialized organelles involved in the detoxification of reactive oxygen species, such as hydrogen peroxide, by catalyzing their breakdown. They also participate in various metabolic processes, including lipid metabolism and the synthesis of bile acids.

The endomembrane system in eukaryotic cells consists of the endoplasmic reticulum (ER), Golgi apparatus, and various types of vesicles. These organelles work together to synthesize, modify, package, and transport proteins and lipids within the cell and to the cell membrane.