Scientist Involved in Cell Theory

• Hooke-coined the word “cell”• von Leeuwenhoek- lens grinder; made

microscopes;• discovered microscopic organisms in pond water

(animacules)• Schleiden-botanist (all plants made of cells)• Schwann-zoologist (all animals made of cells)• Virchow-all cells produce more cells

Cell Theory• Proposed 200 years AFTER Hooke

coined the term cell• All living things made of cells• Cells are the basic unit of

structure and function in living things

• All cells come from other cells

Microscopes Used to View Cells

• Compound light microscope- magnifies UP TO 1500 X

• Electron Microscopes- magnify up to 1,000,000 X

Images differ Greatly

2-D image of RBCs in blood vessel (Transmission Electron Microscope (TEM)

Image of RBCs from Compound Light Microscope (40x)

3-D image of RBCs (Scanning Electron Microscope (SEM)

Cork

Lung Cancer SEM image

Deer Tick SEM image

Types of Cells• PROKARYOTES• No nucleus, no

membrane bound organelles

• Archaebacteria & Eubacteria

• EUKARYOTES• Nucleus, membrane-

bound organelles• Protists, fungi, plants,

animals • Humans have 200

types of cells (60 BILLION)

Streptococcus

Bacillus

Features Common to Both

• cell membrane-semi-permeable

• Ribosomes-sites for protein making

• DNA• Cytoplasm

Organelles Organelles Common to Eukaryotes• Cell membrane, nucleus, nucleolus• Cytoplasm, Ribosomes, Golgi apparatus• Endoplasmic Reticulum, Lysosome• mitochondria• Plastids- (CHLOROPLASTS & LEUCOPLASTS)

PLANTS ONLY• Cell wall- PLANTS (cellulose), FUNGI (chitin), &

SOME PROTISTS ONLY• CENTRIOLES-ANIMALS ONLY• Cilia=hair-like structures; Flagella = tail-like

structures

Energy Use in Cells

• NRG in sugar molecules (glucose) is RELEASED (cellular respiration) by mitochondria as ATP

• Active cells, like muscles cells, have many mitochondria

• ATP is the “gasoline” for the cell

Cell Membrane

• Fluid Mosaic model• Has 2 major

molecular components1. lipids (mostly phospholipids)

2. proteins

         

Cell Transport• PASSIVE-substances move from high

concentration to low concentration (down a concentration gradient). NO ENERGY REQUIRED

Diffusion- passive transport involving molecules OTHER THAN water through semi-permeable membrane

Facilitated Diffusion

• Type of passive transport

• Transport that is "facilitated" by proteins that span the membrane and provide an alternative route or bypass.

• Facilitated = helps

• Osmosis- passive transport of water through semi-permeable membrane

Plasmolysis-loss of water

Osmosis-Hypertonic, Isotonic, Hypotonic solutions

• Hypertonic-Contain a high concentration of solute (salt) relative to another solution (e.g. the cell's cytoplasm).

• When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel.

Osmosis-Hypertonic, Isotonic, Hypotonic solutions

• Isotonic-Contains the same concentration of solute (salt) relative to another solution (e.g. the cell's cytoplasm).

• When a cell is placed in an isotonic solution, the water diffuses into and out of the cell

• The cell’s shape will not change.

Osmosis-Hypertonic, Isotonic, Hypotonic solutions

• Hypotonic-Contain a low concentration of solute (salt) relative to another solution (e.g. the cell's cytoplasm).

• When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell.

Hemolysis

Osmosis-Hypertonic, Isotonic, Hypotonic solutions

• ACTIVE TRANSPORT- substance move from low concentration to high concentration (against the concentration gradient)

• REQUIRES ENERGY (ATP)

• In some cases, requires carrier protein

• Examples-

-Endocytosis (2 types)

-Exocytosis

• ENDOCYTOSIS-moving large molecules across the cell membrane by engulfing them

• Phagocytosis-”to eat”

• Pinocytosis-”to drink”• Dissolved solutes

carried into cell via vesicles

Exocytosis

• Requires NRG• Substances moving

out of the cell via vesicle