Download Cell Notes - Marshall Middle

Cells
I. Looking at Cells
A. Cells are the smallest, most basic unit of life.
B. There are approximately 60 to 100 trillion cells in the average
adult human.
C. The microscope is a tool that helps us to look inside of cells.
D. Discovery of Cells
1. 1665 - Robert Hooke used a primitive microscope to look
at thin slices of cork. He called these units “Cells”
2. Microscopes also make it possible to watch cells reproduce
by mitosis, or cellular division.
E. 1900 - The Cell Theory: 2 Parts
1. All living things are made up of cells.
2. All cells are produced by other living cells.
F. Living Things Contain Cells. 2 Groups:
1. Multi-celled Organisms =
living things made of many
cells (ex. human, elephant, tree,....)
2. Single-celled Organisms = living things made of just
one cell (ex. bacteria)
G. There are two types of cells:
1. Animal Cells
2. Plant Cells
II. Cell Organelles:
A. Organelle = ‘small organ’
B. Animal Cell Organelles:
1. Cell Membrane:
-saclike lining that surrounds the cell
-holds the insides together
-controls the flow of substances in and out of
the cell
2. Nucleus:
-’control center’/brain
-contains chromosomes which store the
directions for the cell’s ‘activities’
3. Nuclear Membrane:
-membrane that surrounds the nucleus
4. Cytoplasm:
-jellylike fluid that fills the cell
5. Endoplasmic Reticulum:
-channels/“railroad” system to transport
materials
6. Vacuole:
-stores water/food/wastes
7. Ribosomes:
-produce substances needed for growth and
other activities (‘factory’ for making
proteins)
8. Mitochondria:
-capsule-shaped body that creates energy for
the cell
C) Plant Cell = same as animal cell, but it also has 2
other organelles:
1. Cell Wall:
-stiff membrane that covers the outside of cell
membrane (box-like shape)
2. Chloroplast:
-green bodies that trap sunlight energy for
making food
-From the Greek words ’chloro’ (green) and
‘plastid’ (body)