History and Structure of a Cell

A set of vocabulary flashcards covering the history of cell discovery, the cell theory, and the specific organelles and structures found in prokaryotic and eukaryotic cells.

Robert Hooke

The first person to view and name "CELLS" in $1665$ after examining a thin slice of cork (dead plant cells) under a microscope.

Anton van Leeuwenhoek

A Dutch microscope maker who, in $1673$, was the first to view living organisms using a simple, handheld microscope.

Matthias Schleiden

A German botanist who concluded in $1838$ that all plants were made of cells.

Theodore Schwann

A German zoologist who concluded in $1839$ that all animals were made of cells.

Rudolph Virchow

A German medical doctor who observed cells dividing in $1855$ and reasoned that all cells come from pre-existing cells.

Cell Theory

A theory stating that all living things are made of cells, cells are the basic unit of life, and cells come from the reproduction of existing cells.

Prokaryotes

The simplest type of cells, such as bacteria, which lack a nucleus or membrane-bound organelles and contain a single, circular chromosome.

Eukaryotes

Complex cells that include protists, fungi, plants, and animals, characterized by having a nucleus and membrane-bound organelles.

Cell Membrane

A living layer composed of a double layer of phospholipids and proteins that controls what enters or leaves the cell.

Phospholipids

Molecules with hydrophilic heads containing glycerol and phosphate, and hydrophobic tails made of fatty acids, forming a bilayer.

Integral proteins

Proteins that are embedded completely through the cell membrane to help move large molecules or aid in cell recognition.

Cell Wall

A nonliving layer found outside the cell membrane in plants, fungi, and bacteria that supports and protects the cell.

Cytoplasm

A jelly-like substance enclosed by the cell membrane that provides a medium for chemical reactions.

Nucleus

The control organelle of the cell that contains DNA in chromosomes and is bounded by a nuclear envelope with pores.

Chromatin

The form DNA takes in non-dividing cells, where it is spread out.

Chromosomes

The form DNA takes in dividing cells, where it is condensed and wrapped around proteins.

Nucleolus

A structure inside the nucleus that disappears when the cell divides and is responsible for making ribosomes.

Cytoskeleton

A network of proteins, including microfilaments made of actin and tubelike microtubules, that helps the cell maintain its shape and move organelles.

Centrioles

Paired structures found only in animal cells that help pull chromosome pairs apart to opposite ends of the cell during division.

Mitochondrion

The "powerhouse" of the cell that generates cellular energy in the form of $ATP$ through cellular respiration.

Cristae

The folded inner membrane of mitochondria that increases surface area for chemical reactions.

Rough Endoplasmic Reticulum (Rough ER)

A network of hollow membrane tubules with ribosomes on its surface that makes membrane proteins and proteins for export.

Smooth Endoplasmic Reticulum (Smooth ER)

A network that makes membrane lipids (steroids), regulates calcium in muscle cells, and destroys toxic substances in the liver.

Ribosomes

The "protein factories" of the cell made of proteins and $rRNA$ that join amino acids through protein synthesis.

Golgi Bodies

Stacks of flattened sacs that modify, sort, and package molecules from the ER for storage or transport out of the cell.

Lysosomes

Organelles containing digestive enzymes used to break down food, bacteria, and worn-out cell parts.

Apoptosis

Programmed cell death, a process where lysosomes lyse and release enzymes to break down and recycle cell parts.

Cilia

Short and numerous hair-like structures used for moving cells, fluids, or small particles across the cell surface.

Flagella

Longer, whip-like structures (usually $1-3$ per cell) used for cell movement.

Vacuoles

Fluid-filled sacks used for storage, which are large in plant cells (containing cell sap) and small or absent in animal cells.