Cells

Cell Theory Cells are the basic units of living organisms. The cell theory states that: All living things are made of one or more cells. Cells are the basic unit of structure and function in living things. All cells come from other cells.

Biology, 9th ed,Sylvia Mader Chapter 04 Cell Structure and Function Sizes of Living Things Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 0.1 nm 1 nm 10 nm 100 nm 1 m 10 m 100 m 1 mm 1 cm 0.1 m 1 m 10 m 100 m 1 km protein chloroplast plant and animal cells mouse rose frog egg amino acid virus ostrich egg most bacteria human egg ant atom blue whale human electron microscope light microscope human eye

Characteristics of All Cells A surrounding membrane Cytoplasm – cell contents in thick fluid Organelles – structures for cell function Control center with DNA

Classification of Life Prokaryotic Eukaryotic

Cell Types Two categories: 1. Prokaryotic cells - Unicellular organisms such as bacteria are examples of prokaryotes. 2. Eukaryotic Cells - All other cells are these.

Biology, 9th ed,Sylvia Mader Chapter 04 Cell Structure and Function Prokaryotic Cells Lack a membrane-bound nucleus Structurally smaller and simpler than eukaryotic cells (which have a nucleus). Most ancient and abundant type of cells Prokaryotic cells are placed in two taxonomic domains: Bacteria Archaea Live in extreme habitats

The Structure of Bacteria Extremely small - 1–1.5 μm wide and 2–6 μm long Occur in three basic shapes: Spherical coccus, Rod-shaped bacillus, Spiral spirillum (if rigid) or spirochete (if flexible). spirillum spirochete bacillus coccus

Prokaryotic Cell Structure Have a simple cell structure

Prokaryote Cells Parts capsule: slimy outer coating cell wall: tougher middle layer cell membrane: delicate inner skin

Prokaryote cells are simply built cytoplasm: inner liquid filling DNA in one big loop flagella: for swimming ribosomes: for building proteins

Video Recap Bacteria