History, Types and General Characteristics of Cells Packet #10 Chapter #3 Tuesday, November 13, 2018

Cytology Cytology is the study of cells. Tuesday, November 13, 2018

Cell Theory Various scientists arrived at three major thoughts All living things are composed of cells Cells are the basic units of structure and function in living things All cells come from preexisting cells These three thoughts became known as the cell theory. Tuesday, November 13, 2018

The Discovery Cells discovered by Robert Hooke in 1665 However the subcellular structures could not be seen--the organelles It wasn’t until the 1950’s, with the invention of the electron microscope that cell biology really took off Tuesday, November 13, 2018

Prokaryotic vs. Eukaryotic Cells Tuesday, November 13, 2018

Introduction of Prokaryotic & Eukaryotic Cells The discovery of cells, and their components, led to the distinction between prokaryotic cells and eukaryotic cells. Tuesday, November 13, 2018

Prokaryotic vs. Eukaryotic Prokaryotic Cells Prokaryotes are structurally simpler than eukaryotic cells. Lack organelles found within eukaryotic cells. Prokaryotic cells have a plasma membrane and typically a cell wall. In prokaryotes, DNA is located in the nuclear area or nucleoid. Prokaryotes have smaller ribosomes. Chlorophyll may be present but no chloroplasts. Do not reproduce via cellular sexual reproduction They are classified as organisms. Cells reproduce by other asexual means Tuesday, November 13, 2018

Prokaryotic versus Eukaryotic II Eukaryotic Cells Membrane bound organelles are present Nucleus and nuclear membrane are present Chlorophyll, when present, is contained in chloroplasts Ribosomes are larger Cell wall is present in some eukaryotic cells Mitosis and meiosis occurs Tuesday, November 13, 2018

Prokaryotes vs. Eukaryotes Prokaryotic Cells Eukaryotic Cells No distinct nucleus No chromosomes Circular strands of DNA known as plastids No membrane bound organelles Ribosomes are smaller No mitosis or meiosis occurs Distinct, membrane-bounded nucleus Chromosomes present on which DNA is located Chloroplasts and mitochondria may be present Ribosomes are larger Mitosis and/or meiosis occurs Tuesday, November 13, 2018

TYPES OF EUKARYOTIC CELLS Plant cells vs. Animal Cells TYPES OF EUKARYOTIC CELLS Tuesday, November 13, 2018

Eukaryotic Cells Most organisms are eukaryotes and are composed of eukaryotic cells. There are two basic types of eukaryotic cells Plant cells Animal cells Organisms Prokaryotic Prokarytic Cells Eukaryotic Eukaryotic Cells Plant Cells Animal Cells Nerve cells Muscle cells Blood cells Tuesday, November 13, 2018

Plant Cell Tuesday, November 13, 2018

Animal Cell Tuesday, November 13, 2018

Plant Cell vs. Animal Cell Similarities Differences Both Eukaryotic Cells Have membrane bound organelles Plant cells are “generally” larger than animal cells Plant cells have a cell wall of cellulose Adds stability and protection to the plant cell Plant cells have vacuoles That are used as space fillers Fulfills digestive functions in plants--similar to lysosomes that are also found in animal cells. Animal cells have centrioles Tuesday, November 13, 2018

Review Tuesday, November 13, 2018