1. Cell Theory
SNC 2DI

2. Robert Hooke was the first person to use the term cell to describe the small structures he saw through his microscope.

3. Cell Theory says...
The cell is the fundamental unit of structure and function in living things.
All cells come from pre-existing cells by division.
Energy flow (metabolism and biochemistry) occurs within cells.
Cells contain genetic information (DNA) which is passed from cell to cell during cell division
All cells are basically the same in chemical composition.
All known living things are made up of cells.
Some organisms are unicellular, i.e., made up of only one cell.
Others are multicellular, composed of a number of cells.
The activity of an organism depends on the total activity of independent cells.

4. Exceptions
Viruses are considered alive by some, yet they are not made up of cells. Viruses have many features of life, but by definition of the cell theory, they are not alive.
The first cell did not originate from a pre-existing cell. There was no exact first cell since the definition of cell is imprecise.
Mitochondria and chloropolasts have their own genetic
material, and reproduce independently from the rest of the cell.

5. Cell Organelles

6. Cell Membrane Found in both plant & animal cells
Animal cell membrane is more fluid than a plant cell’s membrane
Controls the movement of materials into and out of the cell (selectively permeable )
Maintains homeostasis (constant internal environment)
Protects & Supports

7. Diffusion
Diffusion is the process of moving particles from an area of high concentration (the amount of substance dissolved in solution) to an area of lower concentration
Can occur either through a fluid-like cytoplasm or a semi-permeable membrane like the cell membrane and cell wall

8. The Cell Wall Found in plant cells only
Stiff, rigid, nonliving, made of cellulose
Protects and supports the cell
Permeable

9. Cytoplasm Thick, jellylike substance in both
Provide shape/support to the cell membrane
Contains and supports cell organelles
Site for many cellular reactions like protein synthesis, lysosomal digestion

10. The Nucleus Found in both plant & animal cells Control center
Inside is chromatin and a dark region called a nucleolus which makes ribosomes (necessary for protein synthesis.)
Surrounded by a double membrane which has numerous pores to allow for the movement of materials

11. DNA Chromatin
Deoxyribonucleic acid
Contains the cell’s “blueprints” or genetic (hereditary) information for making new proteins and molecules
Thick string-like strands of DNA and proteins found in the nucleus
Condenses to form chromosomes

12. Ribosomes Cells normally have millions of these
Free-living or attached to Endoplasmic Reticulum
Composed of proteins & RNA
Responsible for building proteins in the cell

13. Endoplasmic Reticulum
Two forms – smooth & rough
Forms a tubular network throughout the cell
Transports chemicals within cells
Forms sacs to store proteins & other substances produced by the cell
Provides site for chemical reactions & synthesis

14. Golgi Bodies looks like a stack of pancakes
Acts as a packaging department ready to deliver the protein products made in the cell
Exports proteins out of the cell

15. Mitochondria Composed of a modified double unit membrane
Inner membrane infolded for form cristae
Converts energy from sugar & oxygen
Two compartments allow for a H+ ion difference

16. Chloroplast
Site of photosynthesis, which is the basic food source for the organism
When a fruit ripens, the chloroplasts in the green tissue are changed to non photosynthetic organelles and turn color

17. Vacuole
Fluid-filled membrane bound sacs with little or no internal structure used to store cell products
In plants, the central vacuole is large and helps maintain the necessary internal pressure
(called turgor pressure. )
Lysosome
Membrane bound sac (vacuoles) filled with digestive enzymes
They help break down and remove old worn out cell parts
They digest food particles brought into the cell
Only needed by animal cells

18. Cilia & Flagella used primarily by animal cells for movement
Flagella are larger single versions of cilia
Cilia are short but numerous compared to flagella.

20. Organelles and microscope Quiz on Wednesday