Download Notes #1 Cell Structure

7.L.3A.1 & 7.L.3A.3
Cells #1
Cell Structure
A. Cell Theory
 all living things are made of one or more cells
 cells are the basic units of life
 all cells come from pre-existing cells
B. Cell Structure
 cells vary in size and shape, but contain many of the same major parts
Example: neuron (nerve cell), red blood cell, leaf cell, bacteria
 cell size and shape depends on the function of the cell
 cells have organelles—tiny structures inside cells that perform specific functions
Organelles:
1. cell membrane—the thin, flexible outer covering of a cell; it controls what comes in & goes
out of a cell
2. cytoplasm—the gel-like fluid inside a cell; made mostly of water; other organelles are
embedded in the cytoplasm
3. nucleus—the control center of the cell; it contains DNA—genetic material of an organism
4. vacuole—storage center of the cell (wastes, food, water)
 plant cells usually have one or more large vacuoles (help provide shape & holds
food/water)
 animal cells have smaller vacuoles, if any at all
5. chloroplasts—large green structures in a plant cell that make food; they contain chlorophyll—
green pigment that absorbs light energy
 they perform photosynthesis
6. mitochondria—energy producing sites in the cell where cellular respiration takes place
 called the ‘powerhouse’ of the cell
 they use oxygen to release energy from food
 cells that require large amounts of energy to function will have more
mitochondria
7. cell wall—rigid layer of cellulose that surrounds plant cells to provide extra support & shape
8. lysosomes—digest materials within the cell
 contain enzymes that break down food, worn out organelles, and cell waste not needed
for metabolism
--organelles have membranes that surround each one; this is referred to as being membranebound
7.L.3A.1 & 7.L.3A.3
*Use a Venn diagram to compare structures of an animal cell to a plant cell (use the
information in the chart below).
organelle
animal cell
plant cell
cell membrane
yes
yes
cytoplasm
yes
yes
nucleus
yes
yes
vacuole
sometimes
yes
chloroplasts
no
yes
mitochondria
yes
yes
cell wall
no
yes
Cells #1