Introduction to Cells and Cell Biology

Vocabulary flashcards generated from the transcript covering foundational cell biology concepts, including cell theory, surface area constraints, cell organelles, eukaryotic/prokaryotic distinctions, membrane structures, cellular energy (ATP/ADP), homeostasis, and levels of biological organization.

Main Four Elements of Living Things

Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N), which constitute most living things.

Proteins

The 'workhorses' of life that make up most living things.

Carbohydrates

The energy molecules of life.

Lipids

The energy-storing molecules of life, composed of fatty acids.

Nucleic Acids

The information molecules of life, which include DNA and RNA.

Robin Hook

The scientist who created microscopes and discovered cells in cork (a plant), coining the name 'cell'.

Cell Theory

A fundamental theory of biology formed by Schwan, Schielden, and Virchow stating that: 1) All organisms are made of one or more cells, 2) All life functions occur within cells, and 3) All cells come from already existing cells.

Surface Area to Volume Ratio

The ratio determining cell size efficiency; as cells grow larger, surface area relative to volume decreases (e.g., a $1\,\text{cm}$ side cube has $SA:V = 6$, while a $3\,\text{cm}$ side cube has $SA:V = 2$), making larger cells inefficient at meeting nutrient, oxygen, and waste transport needs.

Micron (Micrometer)

A unit of measurement equal to $1/1,000,000\,\text{meter}$ or $1/1,000\,\text{millimeter}$. The diameter of human hair is approximately $20\,\text{microns}$.

Four Common Cell Structures

The four parts shared by all cells regardless of organism type: plasma membrane, cytoplasm, ribosomes, and DNA.

Plasma Membrane

Also called the cell membrane, a thin coat of lipids surrounding a cell that forms the physical boundary between the cell and its environment ('skin' of the cell).

Cytoplasm

All cellular material inside the plasma membrane, composed of a watery substance called cytosol and other cell structures.

Cytosol

The watery substance that makes up the cytoplasm.

Ribosomes

Structures located in the cytoplasm where proteins are made.

DNA

A nucleic acid found in cells containing the genetic instructions needed to make proteins.

Prokaryotic Cells

Cells without a nucleus whose DNA is located in the cytoplasm rather than enclosed in a nuclear membrane; found in single-celled organisms called prokaryotes.

Eukaryotic Cells

Cells containing a nucleus and other organelles, found mainly in multicellular organisms.

Phospholipid Bilayer

A membrane structure composed of two layers of phospholipids with a hydrophobic (water-hating) fatty acid interior and a hydrophilic (water-loving) polar head exterior, attached by 3-carbon glycerol units.

Cytoskeleton

A cellular skeleton crisscrossing the cytoplasm made of thread-like filaments and tubules that helps maintain cell shape and holds organelles in place.

ATP

Adenosine triphosphate, known as the 'energy currency' of the cell; a high-energy molecule with three phosphate groups (alpha, beta, gamma) whose terminal bond stores significant energy to power cellular processes.

ADP

Adenosine diphosphate, a lower-energy form with two phosphate groups (alpha, beta) created when ATP undergoes hydrolysis to release energy.

Vesicle

A cellular container used to move substances either into or out of the cell.

Homeostasis

The process of maintaining a stable internal environment (such as salt and nutrient concentrations within normal ranges) inside a cell or organism through constant adjustments.

Plant Cell Structures

Structures specific to plant cells in addition to standard organelles, including a cell wall, a large central vacuole, and plastids such as chloroplasts.

Single-Celled Organism

The simplest level of cellular organization where a single cell floats freely, lives independently, and carries out all life processes without help.

Biofilm

A thin layer of bacteria that sticks to a surface where cells are alike but perform different roles, such as taking in nutrients or producing glue (e.g., sticky plaque on teeth).

Colony

An organized structure composed of many single-celled organisms living and working cooperatively, such as Volvox algae in colonies of hundreds of cells coordinating flagella to swim together.

Multicellular Organism

An organism composed of many specialized cells that depend on each other to carry out life processes and cannot survive on their own.

Levels of Cell Organization

The hierarchical structure of cellular organization ranging from Cell to Tissue, Organ, Organ System, and Organism.