2What is a Cell? Cell – Basic unit of living things. Organisms are either:Unicellular – made of onecell such as bacteria andamoebas.ORMulticellular – made ofmany cells such as plantsand animals.
3Scientists to Remember Robert Hooke (1665) – Observed “cells” in cork
4Anton van Leeuwenhoek (1674) Father of MicroscopySaw tiny living things in pond water.
5Scientists Robert Hooke (1665) – Observed “cells” in cork Anton van Leeuwenhoek (1674) – Saw tiny living things in pond water.Matthias Schleiden (1838) – Plants are made of cells.Theodor Schwann (1839) – Animals are made of cells.Rudolf Virchow (1855) – New cells come from existing cells.
6Scientists Janet Plowe (1931) – Cell membrane is a physical structure. Lynn Margulis (1970) – Organelles were once free-living cells.
7Cell TheoryConfirmed discoveries that all scientists believe to be true about cells:1. Cells are the basic unit of life.2. All living things are made of cells.3. New cells are produced from existing cells.
8MicroscopesLight Microscope – magnifies tiny organisms up to 1,000 times.-Uses light and lenses.-We use these.Electron Microscope – magnifiesup to a million times.-Uses electrons.
9The Discovery of Cells Prokaryotic before nucleus Eukaryotic true
10Eukaryotes Has a nucleus with a nuclear envelope Bigger and more complex than prokaryotesHave membrane bound Organelles (golgi, ER, lysosomes…etc)DNA – double-stranded and forms chromosomes (highly organized)Can be uni- OR multicellular organismsEx: animals, plants, fungi
11Prokaryotes NO nucleus NO membrane bound organelles (just ribosomes) ALL are unicellularSmaller than eukaryotic cellsForerunner to eukaryotic cells (smaller and more simple)DNA – single strand and circularEx: ALL Bacteria11
12Similarities Contain all four biomolecules Have ribosomes Have DNA (lipids, carbs, proteins, and nucleic acids)Have ribosomesHave DNASimilar MetabolismCan be unicellularHave cell/plasma membranes or cell wall