Cell Theory and Organelles

Comprehensive practice flashcards covering cell theory principles, prokaryotic vs. eukaryotic features, cellular organelles, membrane structure, and plant vs. animal cell distinctions.

Unicellular

An organism composed of only one cell.

Multicellular

An organism composed of many cells that may organize into tissues, organs, and organ systems.

Cell Theory

The core biological principle stating that: 1. All living things are made of cells; 2. Cells are the basic unit of life; 3. All cells come from other cells.

Prokaryotic Cell

A unicellular organism (such as bacteria) that lacks a nucleus and membrane-bound organelles, divides by binary fission, and has cell walls made of peptidoglycan.

Eukaryotic Cell

A unicellular or multicellular organism (such as animals, plants, fungi, and protists) containing a nucleus and membrane-bound organelles that divides by mitosis.

Universal Cell Structures

The four structures shared by ALL cells: genetic material (DNA or RNA), cytoplasm, cell membrane, and ribosomes.

Organelle

Specialized structures ("mini organs") within the cell that work together to carry out cellular functions, primarily focused on making proteins.

Cell (Plasma) Membrane

A structure surrounding the outside of ALL cells made of two layers of phospholipids that controls what goes in and out of the cell.

Phospholipid Bilayer

A double-layer structure composed of lipids with hydrophilic (water-liking) heads and hydrophobic (water-disliking) tails, embedded with transport proteins and structural carbohydrates.

Fluid Mosaic Model

A model describing the cell membrane structure because it is composed of many distinct parts that can move around freely.

Cytoskeleton

Threadlike fibers made of proteins that give the cell shape, move organelles around, and provide structural support for animal cells.

Cytoplasm

A jelly-like substance mainly made up of water that holds all organelles inside the cell in place.

Mitochondria

The "power house of the cell" composed of an inner membrane and matrix; the site of cellular respiration where food is broken down to release energy as ATP.

Matrix

The fluid part inside the inner membrane of a mitochondrion where cellular respiration processes occur.

Chloroplast

An organelle found ONLY in plant cells consisting of grana (stacks) and stroma (fluid); the site of photosynthesis converting solar energy into chemical energy in sugar.

Grana

Stacks of membranes contained within the chloroplast.

Stroma

The fluid portion surrounding the grana inside a chloroplast.

Cell Wall

An outer protective layer that maintains shape, found ONLY in plant, fungi, and bacteria cells (made of cellulose in plants, chitin in fungi, and peptidoglycan in bacteria).

Central Vacuole

A single, massive central organelle found ONLY in plant cells that acts as a storage center.

Peptidoglycan

The chemical substance that makes up the cell walls of bacteria.

Chitin

The chemical substance that makes up the cell walls of fungi.

Cellulose

The carbohydrate substance that makes up the cell walls of plant cells.

Binary Fission

The method of cellular division utilized by prokaryotic organisms.

Mitosis

The method of cell division utilized by eukaryotic organisms.

Lysosome

An organelle present in animal cells containing digestive enzymes to break down waste and cellular debris.

Centrosome

An organelle involved in cell division and microtubule organization, containing centrioles in animal cells.

Ribosome

Essential cellular structure present in all cells responsible for synthesizing proteins.

Rough Endoplasmic Reticulum

A membrane network studded with ribosomes that assists in processing and transporting proteins.

Smooth Endoplasmic Reticulum

A membrane network lacking ribosomes that synthesizes lipids and performs detoxification functions within the cell.

Golgi Apparatus

A membrane-bound organelle that modifies, sorts, and packages proteins and lipids for transport.

Nucleus

The membrane-bound organelle in eukaryotic cells that houses the cell's genetic material (DNA or RNA).

Nucleolus

A dense structure contained inside the nucleus where ribosomes are produced.