Hooke

• looked at cork
• came up with the term cell

Leeuwenhoek

• observed many small organisms under the microscope
• Ex: sperm, bacteria, protists

Brown

Schleiden

All plants are made of cells

Schwann

All animals are made of cells

Virchow

All cells come from existing cells

3 Parts of the Cell Theory

1. All organisms are made of cells
2. Cells come from existing cells
3. Cells are the basic unit of structure and function

Surface-to-Volume Ratio

An objects volume increases with the cube of its diameter, but the surface area increases only with the square

Plasma Membrane

• selectively permeable
• thin outermost membrane

Nucleus

Contains DNA in eukaryotic cells

Cytoplasm

Fluid filling the inside of the cell between the plasma membrane and the nucleus

2 Types of Cells

1. Prokaryotic Cell
2. Eukaryotic Cell

2 Types of Eukaryotic Cells

1. Plant Cell
2. Animal Cell

Prokaryotic Cell

• No nucleus
• DNA is free floating within the nucleoid
• No membrane bound organelles
• Most are unicellular

Eukaryotic Cell

• Contains a nucleus
• DNA is contained inside the nucleus
• Has membrane bound organelles
• Are either unicellular or multicellular

Organelle

A membrane bound structure that performs a function inside cells

Nucleus

• Contains DNA
• Largest organelle
• Surrounded by a double membrane - nuclear envelope
• Filled with nucleoplasm

Nucleoid

• In prokaryotic cells
• Region of the cytoplasm that is not enclosed in a membranous sac where the DNA is located

Nucleolus

• Organelle within the nucleus
• Makes ribosomes
• Makes RNA

Nuclear Envelope

• Outermost portion of the nucleus
• Two lipid bilayers with proteins embedded in it

The Cytomembrane System is made of...

Endoplasmic Reticulum

Golgi Bodies

Vesicles

Endoplasmic Reticulum

• Series of folded membranes
• Is continuous with nuclear envelope
• Transports substances to Golgi Apparatus
• "Highway of the Cell"
• 2 types - Rough and Smooth

Smooth ER

• No ribosomes
• Makes (synthesizes) lipids

Rough ER

• Has Ribosomes
• Makes (synthesizes) proteins

Golgi Bodies

• Enzymes finish making proteins and lipids, sorts them and packages them in vesicles
• "Post Office"

Vesicles

• Small membrane bound organelle that transport, store and digest substances
• 2 Types - Lysosomes, Peroxisomes

Lysosome

• Intracellular digestion
• Enzymes breakdown proteins, carbohydrates, nucleic acids
• "Garbage Truck"

Peroxisomes

• Enzymes break down fatty acids and amino acids
• Enzymes convert HO into HO and oxygen
• Liver and Kidney are full of these organelles

Mitochondria

• Makes (synthesizes) ATP
• Double membrane
• Inner membrane highly folded called cristae
• Muscle cells contain thousands
• Have their own DNA - endosymbiotic theory
• "Powerhouse of the Cell"

Plastid

• Specializes in photosynthesis or functions in storage
• Only in plant cells
• 3 Types - Chloroplasts, Chromoplasts, Amyloplasts

Chloroplast

• Type of plastid
• Only in Plant cells
• Convert sunlight energy into chemical energy
• Contains thylakoid and stroma
• Contains pigments - chlorophyll, carotenoid

Stroma

Fluid inside the chloroplast

Thylakoid

Disk-shaped compartments in chloroplasts

Granum

Stack of thylakoids in chloroplasts

Chlorophyll

• Pigment molecule inside chloroplast
• Green pigment

Carotenoid

• Pigment inside chloroplast and chromoplasts
• Pigment color orange, yellow, red

Chromoplasts

• Type of plastid
• Only in plant cells
• Lack chlorophyll but has lots of carotenoid pigments
• Source of red-to-yellow color in flowers, autumn leaves, ripening of fruit and carrots

Amyloplasts

• Type of plastid
• Only in plant cells
• Lack pigment molecules
• Store starch grains
• Abundant in stems, potato, seeds

Vacuole

• In plant and animal cells
• Stores substances
• Plant cells have 1 large vacuole (central vacuole).  Takes up most of the plant cell
• Animal cells have many small vacuoles

Microtubules

• Part of cytoskeleton of cells
• Long hollow cylinders
• Made of tublin - 2 polypeptide chains folded into a globular shape
• Shows polarity
• Helps in cell division and cell movement
• 9 + 2 array in flagella and cilia

Colchicines

• In plants
• Inhibits assembly and promotes disassembly of microtubules

Taxol

• In animal
• Prevents formation of new tubules
• Used in cancer treatment

Microfilaments

• Part of cytoskeleton
• Thinnest of cytoskeleton elements
• Made of actin
• Involved in movement

Intermediate Filaments

• Part of cytoskeleton
• most stable element of cytoskeleton
• strengthen cells and help maintain shape
• present only in animal cells of specific tissues

Pseudopods

• "False Feet"
• Type of cell movement
• Microtubule or microfilament lengthen and shorten

Flagella

• Tail like structure
• Helps cells move
• 9 + 2 array of microtubules

Cilia

• Short hair like structures
• Help cells move
• 9 + 2 array of microtubules

Centrioles

• Organelle that gives rise to micrtubules

Basal Body

Cell Wall

• Surrounds the plasma membrane
• Protects and supports the cell
• In plant and fungal cells
• Porous so water and solutes can move through

Plasmodesma

• Cell to cell junction in plants
• Channel in walls of plants

Tight Junction

• In animal cells
• Links cells of epithelial tissue
• Seals adjoining cells together, water tight
• Ex: gastric juice cannot leak across stomach

Adhering Junction

• In animal cells
• joins cells in tissues of skin, heart and other organs subject to stretching

Gap Junctions

• In animal cells
• Link cytoplasm to neighboring cells open channels
• Ex: neurons