Cells Lecture #1

Cell Biology 4/19/2019 Why Study Cell Biology? The key to every biological problem must finally be sought in the cell, for every living organism is, or at some time has been, a cell. E.B. Wilson, 1925 G. Podgorski, Biol 1010

Cell Biology 4/19/2019 Cells are Us G. Podgorski, Biol 1010

Cilia on a protozoan Sperm meets egg Cell Biology 4/19/2019 Cells are Us Cilia on a protozoan Sperm meets egg G. Podgorski, Biol 1010

The Cell Theory 1. ______________________________________ ________________(1500’s) was first to use the term “cell” Schleiden (botanist) and Schwann (zoologist) (1800’s) make individual observations about cells and form the cell theory. Its postulates state that: 1. ______________________________________ 2. The cell is the simplest structural unit of all living things. 3. ______________________________________ Video Clip 4:40-9:00

There are about ______different cell types in mammals (one of us). Cell Biology 4/19/2019 Red and white blood cells above vessel-forming cells. Cells are Us A person contains about 100 trillion cells. That’s 100,000,000,000,000 or 1 x 1014 cells. There are about ______different cell types in mammals (one of us). nerve cell Cells are tiny, measuring on average about 0.002 cm (20 um) across. That’s about 1250 cells, “shoulder-to-shoulder” per inch. G. Podgorski, Biol 1010

A Sense of Scale and Abundance – Bacteria on the Head of a Pin Cell Biology 4/19/2019 A Sense of Scale and Abundance – Bacteria on the Head of a Pin G. Podgorski, Biol 1010

Frog eggs _________& chicken egg 1000-times larger than most plant and animal cells Note relative size of nucleated cells Most Cells are Small Note relative size of bacteria (~1/10 size of animal/plant cells) Note relative size of viruses (~_________ size of animal/plant cells)

Surface-to-Volume Ratio Rate of “stuff” movement across membranes can be limited by amounts of membrane: solved by ______ ________________________ Surface-to-Volume Ratio