Cell Structure and Function: Key Concepts for Biology

Robert Hooke

First observed cells in cork; coined the term 'cell'.

Matthias Schleiden

Proposed that all plants are made of cells.

Theodor Schwann

Stated that all animals are made of cells.

Rudolf Virchow

Advanced the concept that all cells arise from existing cells.

Cell Theory

All living organisms are composed of one or more cells.

Basic unit of life

The cell is the basic unit of life.

Pre-existing cells

All cells arise from pre-existing cells.

Light Microscopes

Use visible light to magnify specimens.

Fluorescent Microscopes

Use fluorescence to view specific cellular components.

Scanning Electron Microscopes (SEM)

Provide surface detailed images by scanning with electrons.

Transmission Electron Microscopes (TEM)

Offer high-resolution internal images by transmitting electrons through samples.

Resolution Differences in Microscopes

TEM has highest resolution, SEM is best for surface examination.

DNA

Holds genetic information.

RNA

Involved in protein synthesis and gene expression.

Ribosome

Site of protein synthesis.

Cytoplasm

Gel-like substance where cellular processes occur.

Cytosol

Fluid component of cytoplasm.

Plasma Membrane

Cellular barrier that controls entry and exit of substances.

Prokaryotes

No nucleus, smaller size (e.g., bacteria).

Eukaryotes

Possess a nucleus and organelles, larger size (e.g., plants, animals).

Carl Woese

Developed the three-domain system based on genetic data, revolutionizing classification.

Three Domains of Life

Bacteria, Archaea, Eukarya.

Capsule

Protects bacteria from phagocytosis.

Cell Wall

Provides structure and shape.

Cell Membrane

Controls transport in/out of the cell.

Nucleoid

Region housing genetic material.

Flagellum

Aids in movement.