1. Ch. 7 1. Introduction to Cells
Cell theory
Cell size
Cell shape
Cell features

2. C E L L T H E O R Y
All living things are made up of one or more cells (living = cells)
Cells are the basic unit of structure & function in organisms (smallest living part = cells)
All cells rise from existing cells (cells come from cells)

3. C E L L S I Z E ** 200 types of cells** **100 trillion cells = human body**
Cell size limited by surface
area-to-volume ratio
Surface area (cell membrane)
= big = a lot of places for
substances to go in & out
So. . . A large surface area to volume ratio = Volume (total space cell can exchange takes up) = small = a little substances bit of space to have to travel more efficiently Ex: 6:1

4. C E L L S H A P E A cell’s shape reflects its function
Shape may increase surface area for exchange
Grow in some ways & remain small in other
Nerve cells = much longer than they are thick
Skin cells = broad & flat
Makes surface area to volume larger

5. C E L L F E A T U R E S ALL CELLS HAVE…
1. Cell membrane ~ outer boundary
2. Cytoplasm ~ fluid inside cell (cytosol) & all structures suspended

6. C E L L F E A T U R E S ALL CELLS HAVE…
3. Ribosomes ~ proteins are made here!
4. DNA ~ instructions, regulates activities, enables reproduction

7. Features of Prokaryotic Cells (single celled)
DNA = a single loop near center
Ribosomes & enzymes = in cytoplasm
Cell wall surrounds membrane
Structure & support
Capsule allows cling to surfaces
Very small
Live in wide range of habitats

8. Features of a Eukaryotic Cell
Single celled or multi cellular
Complex organization = more specialized functions
Contains compartments separated by membranes = organelles (some are connected by channels)
DNA in a nucleus

9. 2. INSIDE the cell: Framework
Cytoskeleton
Helps cell move, keep its shape, & organize parts
Microfilament ~ long, thin, actin, contract to pull in
& expand to push out
Microtubules ~ thick, hollow, tubulin, info. mol.
pass thru
Intermediate fibers ~ mod. thick, anchors organelles
& enzymes

10. Cytoskeleton

11. INSIDE the cell: Directing activity
Nucleus “The Brain”
Double membrane (nuclear
envelope) which
protects & houses DNA
Pores to allow passage of RNA
& ribosome parts
Contains nucleolus, which
makes ribosome parts

12. INSIDE the cell: Directing activity
Ribosomes
Made of protein & RNA
“Free”
~makes proteins that remain in cell
“Bound”
~makes proteins that leave cell
~attached to organelle

13. INSIDE the cell: protein processing
Endoplasmic reticulum (ER)
System of internal
membranes which move stuff
Rough
w/ ribosomes
modify proteins for export
Smooth
w/o ribosomes
makes lipids, breaks down toxic substances

14. INSIDE the cell: protein processing
Golgi apparatus/body
Set of flattened sacs
Modifies proteins when they
come in by vesicle from the ER
Modifies, sorts, & packages
proteins for export
**VESICLES move these substances in & out of ER & golgi**

15. INSIDE the cell: energy production
Mitochondrion
“Power house”
Makes ATP (cellular energy) in
inner membrane
Smooth outer membrane &
folded inner membrane

16. INSIDE the cell: energy production
Chloroplast
Found in plant cells & some
protist
Uses light energy to make
sugar from carbon
dioxide & water ~ photosynthesis
Double membrane w/sacs

17. INSIDE the cell: storage & maintenance
Lysosome ~ contains enzymes that break down large molecules. Ex: food, old, damaged cell parts
Central vacuole ~ large compartment of plant cells. Stores water, ions, nutrients & waste. If full, plants stand upright (turgur pressure). If lose water, plants wilt.
Other vacuoles ~ food & contractile

20. 3. Diversity in ________. Vary in . . . shape way obtain & use energy
make up of cell walls
Movement flagella  long, threadlike
pili  short, thick, attachment

21. Diversity in ________. Animal cells Plant cells Central vacuole
Chloroplasts
Cell wall
Vary in organelles
Specialized function
Ex: muscle cells=many mitochondria