Cells Part I

Cells I

Living Things: Highly organized Convert energy

for their own use Control internal

environment (Homeostasis)

Have adaptations Respond to stimuli Grow Reproduce Have emergent properties

Characteristics of Living Things

Discovery of Cells 17th CenturyRobert Hooke

observed cork in a microscope.

Anton van Leeuwenhoek described “animalcules” he found in tooth plaque.

Cell Theory

1. The cell is the smallest unit of life.

2. All organisms are made from one or more cells.

3. Cells arise from pre-existing cells.

Schleiden & Schwann

Different types of microscopes are used to

study cells

Light MicroscopeMost cells

Stereo Microscope1-celled organisms

Electron MicroscopeCells small molecules

Scanning Electron Microscope 3-D images

Two Categories of Cells Prokaryotes “Before” nucleus Simple structure Bacteria Archaebacteria

Eukaryotes True nucleus holds DNA Many cell parts with

special functions One cell or

multicellular organisms Plants! Animals!

People!

Hierarchy of organization in complex organisms

Tissues and organs have specialized functions

Cells have structures specialized for:

Providing a barrier between cell & environment

Storing information for building & maintaining cell(software)

Manufacturing cell parts & machinery Maintenance Energy processing Support, movement & communication

All cells have: Cell membrane Surrounds, contains, protects Cytoplasm “Cell gel” fills interior of cell Ribosomes Help make proteins for cells DNA Coded instructions for cell

(software)

Stop here. Explore cell parts using GSLC website or

Cells Alive

Prokaryotic cells may also have: Cell wall – surrounds cell membrane;

protects, maintains shape Capsule – additional protection;

“glue” Prokaryotic Flagellum – movement Pili – attach bacteria to surfaces

Escherichia coli (E. coli): a simple bacterial cell

Helicobacter (causes ulcers)