cells. cell scientists robert hooke looked at cork under a microscope 1 st to use term “cell”

CellsCells

Cell ScientistsCell Scientists

• Robert Hooke

• looked at cork under a microscope

• 1st to use term “cell”

Cell ScientistsCell Scientists

• Anton van Leeuwenhoek

• looked at pond water

• 1st to see living cells

Cell ScientistsCell Scientists

• Schleiden, Schwann, & Virchow

• came up with the cell theory

The Cell TheoryThe Cell Theory

Parts of the Cell TheoryParts of the Cell Theory

• All living things are made of one or more cells

• Cells are the basic unit of structure & function in organisms

• Cells come only from the reproduction of pre-existing cells

Prokaryotic vs Eukaryotic CellsProkaryotic vs Eukaryotic Cells

Prokaryotic CellsProkaryotic Cells

• Appeared 3.5 billion years ago

• Primitive, simple

• Small in size

• No membrane-bound organelles

• Smaller ribosomes

• Single, circular

chromosome

• BACTERIA

Eukaryotic CellsEukaryotic Cells

• Appeared 1.5 billion years ago

• Complex

• Contain membrane-

bound organelles

• Larger ribosomes

• Paired, linear

chromosomes

• NUCLEUS

Parts of aEukaryotic Cell

Parts of aEukaryotic Cell

Plasma MembranePlasma Membrane

• Also called the Cell Membrane

• Separates

cell from its environment

Plasma MembranePlasma Membrane

• Semi-permeable• Allows only

certain molecules to enter or exit

Plasma MembranePlasma Membrane

• Phospholipid Bilayer• Embedded with

proteins

• Fluid-mosaic Model

NucleusNucleus

• “Boss” or “Brain” of the cell

• Controls cellular activities

• Contains DNA (chromosomes)

NucleusNucleus

• Nuclear Membrane• Surrounds nucleus

• Double membrane

• Contains nuclear pores (holes)

NucleusNucleus

• Nucleolus• Produces

ribosomes

• Ribosomes leave through nuclear pores

CytoplasmCytoplasm

• Cytosol• Fluid portion

• Organelles• Membrane-bound

compartments that carry out specific functions

MitochondriaMitochondria• Breaks down glucose

to CREATE ENERGY (ATP)• Active cells (muscle) ->

hundreds of mitochondria

• Inactive cells (fat) -> few mitochondria

• Have own DNA• Have a double

membrane

RibosomesRibosomes• Create proteins• Composed of 2

interlocking subunits

• Some float free in cytosol

• Some attach to the ER

Endoplasmic Reticulum (ER)

Endoplasmic Reticulum (ER)

• Intracellular highway

• 2 Types• Rough ER• Smooth ER

Endoplasmic Reticulum (ER)

Endoplasmic Reticulum (ER)

• Rough ER• Covered in

ribosomes• Produces

phospholipids and proteins

Endoplasmic Reticulum (ER)

Endoplasmic Reticulum (ER)

• Smooth ER• Lacks ribosomes• Produces lipids,

estrogen, & testosterone

• Helps detoxify drugs & poisons

• Increased use = increased smooth ER

• Possibly linked to increased tolerance

Endoplasmic Reticulum (ER)Endoplasmic Reticulum (ER)

• Transport (FedEx of the cell)

• Receive vesicles from ER

• Can modify packages en route

Golgi ApparatusGolgi Apparatus

• Lysosomes• Contain digestive

enzymes• Digest organic

molecules, worn organelles, or dying cells

VesiclesVesicles

• Cilia• Hair-like• Short &

numerous

• Flagella• Tail-like• Long & less

numerous

Cilia/FlagellaCilia/Flagella

Plant Cellversus Animal CellPlant Cellversus Animal Cell

• Cytoskeleton• Network of

microtubules & filaments

• Gives the cell shape

• Holds organelles in place

Animal Cells Only!Animal Cells Only!

• Centrioles• Used during cell

division

Animal Cells Only!Animal Cells Only!

• Cell Wall• Rigid layer

surrounding plasma membrane

• Made of cellulose

• Pores allow water, ions, & other molecules to pass

• Bacteria, some protists & fungi also have cell walls

Plant Cells Only!Plant Cells Only!

• Chloroplast• Contain

chlorophyll• Site of

photosynthesis• Energy (sunlight)

-> food• Contain own

DNA• Have a double

membrane

Plant Cells Only!Plant Cells Only!

• Central vacuole• Large, fluid-filled

organelle• Stores water, ions,

enzymes & waste• Can be up to 90%

of cell’s volume• Animals cells

have small vacuoles

• Why so big in plants?

Plant Cells Only!Plant Cells Only!