CELLS

Bill Nye: Cells

Discovery Cells

BASIC STRUCTURE OF A CELL

CELL THEORY1. All living things are made of cells

2. Cells are the basic unit of life

3. Cells come from other cellsTED: Cell Theory

Cell Theory Song

NUMBER OF CELLS

Unicellular – composed of one cell

Multicellular- composed of many cells that may organize into tissues

PROKARYOTES – THE FIRST CELLSNo NucleusBacteriaSimplest type of cellSingle, circular DNA

EUKARYOTIC CELL

Contain 3 basic cell structures:

NucleusRibosomesCytoplasm with organelles

CELL SIZE

CELL SIZE AND TYPESCells must be observed under microscope

Three Basic types of cells include:

Animal Cell Plant CellBacterial

Cell

WHICH CELL TYPE IS LARGER?

_________ > _____________ > ___________Plant cell Animal cell Bacteria

EXAMPLES OF ANIMAL CELLS

Muscle cells Red blood cells

Cheek cells

EXAMPLES OF ANIMAL CELLS

white blood cell

red blood cell

cheek cells

sperm

nerve cell

muscle cell

Amoeba

Paramecium

ANIMAL CELL ORGANELLESNucleolus

Nucleus

Nuclear envelope

Ribosome (attached)Ribosome (free)

Cell Membrane

Rough endoplasmic reticulum

Golgi apparatus

Mitochondrion

Smooth endoplasmicreticulum

Centrioles

EXAMPLES OF PLANT CELLS

Xylem cellsPollen

Guard Cells

EXAMPLES OF PLANT CELLS

Onion Epidermal Cells

Root Hair Cell

root hair

Guard Cells

PLANT CELL ORGANELLES

DIFFERENCES BETWEEN PLANT CELLS AND ANIMAL CELLS

Animal cells Plant cells

Irregular shapeNo cell wall

Regular shapeCell wall

presentNo chloroplast

Have chloroplastLarge central

vacuoleVacuole small

or absent

BACTERIA CELLSContain ONLY essential structures:

Plasma membraneCytoplasmCell WallCilia or FlagellaRibosomesNucleoid Region

ORGANELLES

“Mini Organs” that perform functions for the cell

In cytoplasm

1. CELL/PLASMA MEMBRANE

Composed of double layer of phospholipids and proteins

Surrounds outside of ALL cellsControls what enters or exits the cell

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel Lipid bilayer

Carbohydratechains

• Found in plants and bacteria

• Made of carbs• Supports and protects cell

Cell wall 2.CELL WALL

• Jelly-like substance

• Holds organelles• ALL cells

3. CYTOPLASM

cytoplasm

•Control center

• Contains DNA

4. NUCLEUS

5. NUCLEAR ENVELOPE/MEMBRANE

Double membrane- surrounds nucleus

Controls what exits/enters nucleus

Nuclear pores

6. NUCLEOLUS

Inside nucleusMakes ribosomes

7. NUCLEAR PORE

Allows certain things to pass through the nucleus

8. CYTOSKELETONMaintains cell shapeMade of proteinsMicrofilamentsMicrotubules

9. CENTRIOLESFound only in animal cells

Only during cell division

Pulls DNA apart

10. MITOCHONDRION(PLURAL = MITOCHONDRIA)

“Powerhouse” of the cell

Makes Energy (ATP)

Has own DNAWhat type of cell would have the most mitochondria?

Mighty Mitochondria!

11. RIBOSOMES

Make PROTEINS (protein factories)

Attached to the Endoplasmic Reticullum or Free

Workers of the cell!

12. ROUGH ENDOPLASMIC RETICULUM (ROUGH ER)

Has ribosomes on its surface

Makes membrane proteins and proteins for EXPORT out of cell

13. GOLGI BODIESLook like a stack of pancakes

Modify, sort, & packagemolecules from ERfor storage OR transport out of cell

Post Office of the cell!

Golgi Animation

Materials are transported from Rough ER to Golgi to the cell membrane by

VESICLES

14. SMOOTH ENDOPLASMIC RETICULUM

(SMOOTH ER)No ribosomesMakes cell products that are USED INSIDE the cell

Makes membrane lipids (steroids)

Detoxifies (Liver)

15. LYSOSOMESContain digestive

enzymesBreak down food, bacteria, and worn out

cell parts “Suicide sacs”

16. PEROXISOME

Break down Hydrogen Peroxide produced by lysosomes

17. VACUOLESStorage of waste, water, nutrients

Animal cells-small/absent

Plant cells-large Central

18. CHLOROPLASTSPlants onlySite of Photosynthesis

19. VESICLESmall, mobile organelles Often used to move chemicals to other locations in the cell where they might be needed

Vesicles

20. CILIA & FLAGELLA

Move cells or move something across the cell surface

Cilia-short, many (spirit fingers)

Flagella-Long hair-like structure for movement

CELL MOVEMENT WITH CILIA & FLAGELLA

CILIA MOVING AWAY DUST PARTICLES FROM THE LUNGSRESPIRATORY SYSTEM

CELL SIZE

Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?

FACTORS AFFECTING CELL SIZE

Surface area (plasma membrane surface) is determined by multiplying length times width (L x W)

Volume of a cell is determined by multiplying length times width times height (L x W x H)

Therefore, Volume increases FASTER than the surface area

CELL SIZEWhen the surface area is no longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide

Therefore, the cells of an organism are close in size

CELL SIZE

Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?

About the same size, but …

The elephant has MANY MORE cells than a mouse!