1. CH. 3 ~ CELLS

2. Robert Hooke 1665 Looked at thin slices of cork under a microscope
Did not know at the time about their structure and function.
What IS a cell?

3. 1670’s Van Leeuwenhoek….hand lens
A cell is the smallest unit of life that can carry out all the activities necessary for life.

4. THE CELL THEORY One of the foundations of modern biology. It states:
All living things are made up of one or more cells
Cells are the most basic unit of structure and function in an organism
Cells originate only from pre-existing cells
4. Energy Flow (metabolism) occurs within cells;
must maintain an internal balance (homeostasis)
5. Cells contain DNA (hereditary information) -reproduce.
Schleiden + Schwann + Virchow

5. VIRCHOW “Omnis cellula e cellula”
1855: New cells arise from pre-existing cells
Tremendous controversy….against the prevailing theory at the time
“Spontaneous Generation” aka Vitalism
Ponds dry up…..teeming with life again
Rotting meats ‘spontaneously’ give rise to maggots

6. “Spontaneous Generation” (Life evolves from non-life)
(Francesco Redi 1688)

7. Spallanzani 1700’S
Still did not believe….Blocking the “vital force”…..
Who ultimately disproved spontaneous generation?

8. PASTEUR ’S

9. TYPES OF CELLS

10. Cell Size 1 meter = 1000 millimeters (mm) 1 mm = 1000 micrometers (um)
1 um = 1000 nanometers (nm)
Cell Size

11. Why are cells so different?
Specialized
Functions! 1m

13. What Limits the Size of a Cell?
Human Body consists of about 100 trillion cells
(A string 100 trillion inches long could be wrapped around Earth more than 63,000 times)
Cell grows- needs to take in food and get rid of waste through the cell membrane.
Cell cannot grow so large that their surface area becomes too small to take in enough food and remove enough wastes
Cells volume increases faster than its surface area.
Surface area = 6s2
Volume = l x w x h

14. DEFINITIONS/DESCRIPTION
PROKARYOTIC CELL
EUKARYOTIC CELL
SIZE
Very small um
Varies, generally much larger um
ORGANISMS
Bacteria, cyanobacteria
Plants, animals and fungi
CILIA AND FLAGELLA
Yes (pili)
Yes
CELL WALL
Yes (Plants and Fungi)
No (Animals)
PLAMA (CELL) MEMBRANE
CYTOPLASM
CHROMOSOMES, DNA
Strand of DNA
(nuceloid,plasmid)
RIBOSOMES
MEMBRANE BOUND ORGANELLES No

15. Every bacterial cell
Eubacteria
Archeabacteria
Every organisms that is not bacteria: Animals – Plants – Fungus - Protists

17. Inner Life of the Cell Animation 3.12

18. Cell Membrane Surrounds ALL cells
Semi-permeable – only allows certain substances to pass through
Contains proteins that help to pass materials through.
“Phospholipid bilayer”
Flexible and “fluid”

19. Cytosol/Cytoplasm
Fluid inside the cell that contains the organelles and allows reaction to occur
Composed mostly of water and plays a role in diffusion of materials across the cell membrane.

20. Nucleus Membrane-bound organelle Found only in Eukaryotes
Controls the cell functions
and processes
Contains DNA that directs the formation of necessary proteins. (genetic blueprint)

21. Nucleolus
An organelle within the nucleus that produces ribosomes and RNA

22. Ribosomes small organelles that are sites of protein synthesis
Take information from the DNA (delivered to the ribosome by RNA) and use it to make protein
Sometimes found on the ER (or the rough endoplasmic reticulum), but also found in the cytoplasm of ALL cells

23. Endoplasmic reticulum (ER) –
Endoplasmic reticulum (ER) – detoxification and transport.
Attached to the nuclear membrane and zigzags through the cell
Rough or smooth
Rough = has ribosomes
Smooth = no ribosomes

24. Golgi Apparatus (Bodies)
Packaging and distribution
Flattened, layered, sac-like organelles which are located near the nucleus.
Works w/ ER….

25. MITOCHONDRIA “Powerhouse” of the cell Converts food into energy (ATP)
Inner and outer membrane
Has it’s own DNA (endosymbiotic theory)
Found in Eukaryotes only
Found in both plants and animals

27. VACUOLE Contains water (Can also store nutrients, waste products)
Large in plants, small in animals
Controls “turgor pressure”
in plants.

28. Lysosomes
Contain enzymes to break down old organelles or kill the cell.
Centrioles
only in animals cells. Make the spindle for cell reproduction

29. Flagella – long whip-like tail for movement
Cilia – short hairs for movement

30. T R A N S P O
lysosome
ER and Golgi

31. PLANT CELL

32. CHLOROPLASTS
Converts sunlight, water and carbon dioxide to sugar and oxygen through photosynthesis
Has chlorophyll – pigment that captures the sun’s light.
Inner and outer membrane
Found in Eukaryotes only
Found only in plants
(producers/autotrophs)

33. Cell Wall
A rigid structure found on the outside of plant, fungal and bacterial cells
Permeable – allows most substances to enter freely
Composed of cellulose and protein
Located OUTSIDE of the cell membrane
Structure relates to function:
The rigid structure of the cell wall provides support and structure for the organisms

35. Animal
Plant
No cell wall
No chloroplast
Small vacuoles
Has centrioles
Cell wall
Chloroplasts
Large vacuole
No centrioles

36. What Limits the Size of a Cell?
Intro to Cell Size Lab………
What Limits the Size of a Cell?
Human Body consists of about 100 trillion cells
(A string 100 trillion inches long could be wrapped around Earth more than 63,000 times)
Cell grows- needs to take in food and get rid of waste through the cell membrane.
Cell cannot grow so large that their surface area becomes too small to take in enough food and remove enough wastes
Cells volume increases faster than its surface area.
Surface area = 6s2
Volume = l x w x h

37. Passive Transport:
1. Diffusion – movement of molecules from an area of high concentration to an area of lower concentration.
Demos: Dye in Water
Sugar Cube
*PE vs KE Particles have…..

38. Concentration gradient (High to low) Equilibrium KE Solute Solvent
P/S
Diffusion; passive
Concentration gradient (High to low)
Equilibrium KE
Solute
Solvent
Solution