Cell Biology: Organelles and Cell Theory

A set of practice flashcards covering cell theory, organelles, and plasma membrane features based on the notes.

What are lysosomes and what is their function?

Vesicles containing digestive enzymes that digest waste materials and cellular debris inside the cell.

What are the three main tenets of the cell theory?

1) All living things are made of cells; 2) The cell is the basic unit of life; 3) All cells come from existing cells.

What are peroxisomes and what do they do?

Organelles containing enzymes that target and neutralize reactive oxygen species (free radicals) to protect the cell.

What features do most cells share?

Plasma membrane, nucleus, and cytoplasm containing organelles.

What is the cytoskeleton?

The framework of the cell that provides structure and a pathway for vesicles to travel; made of fibrous proteins.

What is inside the nucleus?

Chromosomes that contain DNA and help protect it from genetic mutations.

What are centrioles and when are they active?

Typically occur in pairs and are active during mitosis; neurons lack centrioles and do not undergo mitosis.

What is the nuclear envelope?

A double-layered membrane with nuclear pores; ribosomal RNA and proteins are assembled in the nucleolus and ribosomes exit through the pores.

What are villi and microvilli?

Folded projections of the plasma membrane that increase surface area for absorption.

What is chromatin?

Uncoiled DNA when the cell is not dividing; DNA condenses into chromosomes during cell division.

What are cilia?

Hair-like projections that sweep mucus along the cell surface.

What are the main ingredients of the plasma membrane?

Phospholipid bilayer (main component), channel/transport proteins, and carbohydrate chains for cell-to-cell communication.

What is a flagellum and which human cell typically has one?

A tail-like whip that propels the cell; in humans, the sperm cell is the cell that has a flagellum.

What are the characteristics of the plasma membrane’s parts?

Head is hydrophilic and tail is hydrophobic.

What is the Golgi apparatus?

Highly folded; sorts and packages proteins made in the cell and sends them in vesicles to their destinations.

What is cytosol?

The goo that organelles are suspended in, mostly water.

What are vesicles?

Small membrane sacs that carry proteins, nutrients, and wastes around the cell; traffic from the ER to the Golgi to the cell membrane.

What are inclusions?

Nutrients and proteins floating around (smaller organelles) within the cytoplasm.

What are mitochondria and what do they do?

Organelles with highly folded inner membranes that produce ATP via cellular respiration and require a steady supply of oxygen and glucose.

What are ribosomes and where are they located?

Ribonucleoprotein particles made of protein and RNA assembled in the nucleolus; synthesize proteins and can be free-floating in cytosol or bound to the rough ER.

What is the rough endoplasmic reticulum (Rough ER)?

Ribosomes attached to the ER surface; site of protein synthesis and transport of proteins to the Golgi in vesicles.

What is the smooth endoplasmic reticulum (Smooth ER) and its function?

Detoxifies harmful chemicals (poisons, venom, alcohol, drugs, pesticides); numerous in hepatocytes (liver cells).