Cell Theory and Organization

Practice vocabulary flashcards based on the lecture notes on Cell Theory and Organization, including discovery history, cell structures, and comparisons.

Robert Hooke (1665)

Discovered a multitude of tiny pores by observing a thin slice of bottle cork that he named "cells".

Cella and Cellulae

The Latin words from which "cell" is derived; "cella" means a room where monks lived and "cellulae" means the six-sided cell of a honeycomb.

Anton van Leeuwenhoek (1683)

Used a microscope to find motile objects he called "animalcules" and stated that motility is a quality of life.

Robert Brown (1773-1858)

Discovered the presence of nuclei within cells and described the nucleus as a small dense, round body inside the cell.

Felix Dujardin (1801-1860)

Noted that all living things contain a thick jelly fluid which he called "sarcode".

Johannes Purkinjie (1787-1869)

Coined the term protoplasm to refer to the living matter and jelly-like material that fills the cell.

Rudolf Virchow (1855)

Discovered that cells came from pre-existing cells.

Three Tenets of Cell Theory

1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life in all living things. 3. All cells are produced by the division of preexisting cells.

Modern Cell Theory (Energy and Heredity)

States that energy flow (metabolism and biochemistry) occurs within cells and that heredity information (DNA) is passed on from cell to cell.

Cytoplasm

The largest part of the cell, composed of $90\,\%$ water (cytosol), acting as the center of all metabolic processes and housing organelles.

Plasma Membrane

A thin, semi-permeable barrier consisting of a phospholipid bilayer containing the phosphate group, glycerol, and two fatty acids.

Cell Wall

A rigid layer that gives protection, support, and shape; composed of cellulose in plants and algae, and peptidoglycan in bacteria.

Mitochondria

The sites of cellular respiration: the production of chemical energy ($ATP$).

Endoplasmic Reticulum (ER)

A membranous system of canals extending from the plasma membrane to the nuclear membrane, formed by layers of membrane folded through the cytoplasm.

Cisternae

Long, flattened, unbranched sac-like structures within the Endoplasmic Reticulum normally found in secretory cells.

Vesicles (ER)

Rounded or ovoidal structures within the ER having a diameter of $25-500\,\text{microns}$, found in abundance in pancreatic cells.

Tubules (ER)

Smooth-walled and highly branched tubular spaces in the ER that normally occur in non-secretory cells like striated muscle cells.

Rough ER (RER)

Part of the ER that produces membrane proteins and secretory proteins, such as antibodies in plasma cells and insulin in pancreatic cells.

Smooth ER (SER)

Part of the ER that synthesizes carbohydrates, lipids, cholesterol, and steroid hormones, and detoxifies drugs in liver cells.

Golgi Bodies

Organelles that receive, refine, store, and distribute chemical products of the cell.

Vacuoles

Membranous sacs that bud from the ER, Golgi, or plasma membrane.

Nucleus

The storehouse of genetic information in the form of DNA which directs all activities of the cell.

Centrioles

Microtubules found near the nucleus of animals and some protists that form spindle fibers to move chromosomes during cell division.

Ribosomes

Small spherical organelles composed of two subunits that translate genetic information in the form of mRNA into proteins.

Lysosomes

A membrane-enclosed sac of digestive enzymes found only in animal cells that breaks down macromolecules like proteins, fats, and nucleic acids.

Peroxisomes

Small vesicles containing digestive enzymes for breaking down toxic materials, energy metabolism, and lipid biosynthesis.

Chloroplast

An organelle that converts solar energy to chemical energy via photosynthesis.

Cytoskeleton

A cellular structure or scaffolding formed of proteins (microtubules, microfilaments, and intermediate filaments) that maintains cell shape and enables motion.

Plasmodesmata

Small channels that directly connect the cytoplasm of neighboring plant cells to each other, establishing living bridges.

Animal Cell Comparison

Smaller ($10-30\,\text{mm}$), irregular shape, heterotrophic, stores energy in glycogen, and produces $10$ amino acids.

Plant Cell Comparison

Larger ($10-100\,\text{mm}$), rectangular cube shape, autotrophic, stores energy as starch, and produces $20$ amino acids.

Prokaryotic Cell

A simple, single-celled organism lacking a true nucleus and other membrane-bound organelles, typically containing a loop of DNA in the cytoplasm.

Eukaryotic Cell

Organisms (protists, fungi, plants, animals) containing a nuclear membrane, many organelles, and long DNA organized into chromosomes in the nucleus.