The Endoplasmic Reticulum

– Produces an enormous variety of molecules

– Is composed of smooth and rough ER

Nuclearenvelope

Ribosomes

Rough ERSmooth ER

After the rough ER synthesizes a molecule it packages the molecule into transport vesicles

Transport vesiclebuds off

Ribosome Secretoryprotein insidetransportvesicle

ProteinRough ER

Polypeptide

12

3

4

The Endoplasmic Reticulum

The Golgi Apparatus

– Works in partnership with the ER– Refines, stores, and distributes the products of cells

Transportvesiclefrom ER

“Receiving” side ofGolgi apparatus

Golgi apparatus

New vesicle forming

Transport vesiclefrom the Golgi

“Shipping” side ofGolgi apparatus

Plasma membrane

• A lysosome is a membrane-enclosed sac

Lysosomes

– It contains digestive enzymes– The enzymes break down macromolecules– They break down damaged organelles

(b) Lysosome breaking down damaged organelle

Lysosome

Damagedorganelle

Digestion

VacuolesVacuoles are membranous sacs

Rough ER

Transportvesicle from ER

Golgiapparatus

Secretoryvesicle from Golgi

Secretoryprotein

Vacuole Lysosome

Plasma membrane

The Endomembrane System

Clicker Question #2

2. Highly phagocytic cells (cells that take part in lots of phagocytosis), like some of your immune cells, need __________ to degrade their phagocytosed particles. 

A. peroxisomesB. phagosomesC. lysosomesD. cytoskeletal proteinsE. ribosomes

Mitochondria are the sites of cellular respiration, which involves the production of ATP from food molecules

Figure 4.18

Outermembrane

Innermembrane

Cristae

Matrix

Space betweenmembranes

Cellular energy conversion

Cytoskeleton● Provides mechanical support to the cell and maintain its shape

The Cytoskeleton

*microfilaments (actin filaments)

*intermediate filaments

*microtubules

Microfilaments

Microtubules*centrosome *centrioles

Cilia and flagella are motile appendages

Cilia and Flagella

• Flagella propel the cell in a whiplike motion

• Cilia move in a coordinated back-and-forth motion

“9 + 2”

basal body

Cilia and Flagella

The Cytoskeleton

dynein – motor molecules

Cytoskeleton

Mitochondrion

Nucleus

Rough endoplamsicreticulum (ER)

Ribosomes

Smoothendoplasmicreticulum (ER)

Golgi apparatus

Plasmodesmata

Plasmamembrane

Chloroplast

Cell wall

Centralvacuole

Not in animal cells

Plant Cells

Plant cells are encased by cell walls

Walls of two adjacentplant cells

Vacuole

Plasmodesmata(channels between cells)

Plant Cells

Chloroplasts are the sites of photosynthesis, the conversion of light energy to chemical energy

ChloroplastsInner and outermembranes ofenvelope

Space betweenmembranes

Stroma (fluid inchloroplast)

Granum