Lecture #2 Cellular Anatomy. Intermediate filaments ENDOPLASMIC RETICULUM (ER) Rough ERSmooth ER...

Lecture #2

Cellular Anatomy

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Rough ER Smooth ER

Centrosome

CYTOSKELETON

Microfilaments

Microtubules

Microvilli

Peroxisome

MitochondrionLysosome

Golgi apparatus

Ribosomes

Plasma membrane

In animal cells but not plant cells:LysosomesCentriolesFlagella (in some plant sperm)

Nuclear envelope

Nucleolus

Chromatin

NUCLEUS

Flagelium

The Eukaryotic Cell

Pore complexes (TEM). Each pore is ringedby protein particles.

Nuclear lamina (TEM). The netlike laminalines the inner surface of the nuclear envelope.

Nucleus

NucleusNucleolus

Chromatin

Nuclear envelope:Inner membraneOuter membrane

Nuclear pore

Rough ER

Porecomplex

Surface of nuclear envelope.TEM of a specimen prepared by a special technique known asfreeze-fracture.

Close-up of nuclearenvelope

Ribosome

1 µm

1 µm

0.25 µm

The Nucleus

The Nuclear Envelope

Ribosomes ER Cytosol

Endoplasmic reticulum (ER)

Free ribosomes

Bound ribosomes

Largesubunit

Smallsubunit

TEM showing ER and ribosomes Diagram of a ribosome

0.5 µm

Ribosomes

Smooth ER

Rough ER

ER lumenCisternae

RibosomesTransport vesicle

Smooth ER

Transitional ER

Rough ER 200 µm

Nuclearenvelope

The Endoplasmic Reticulum (ER)

Golgiapparatuscis face

(“receiving” side ofGolgi apparatus)

Vesicles movefrom ER to Golgi Vesicles also

transport certainproteins back to ER

Vesicles coalesce toform new cis Golgi cisternae

Cisternalmaturation:Golgi cisternaemove in a cis-to-transdirection

Vesicles form andleave Golgi, carryingspecific proteins toother locations or tothe plasma mem-brane for secretion Vesicles transport specific

proteins backward to newerGolgi cisternae

Cisternae

trans face(“shipping” side ofGolgi apparatus) TEM of Golgi apparatus

0.1 0 µm16

5

2

3

4

The Golgi apparatus

Lysosome

Nucleus 1 µm

Lysosome containsactive hydrolyticenzymes

Food vacuole fuseswith lysosome

Hydrolyticenzymes digestfood particles

Lysosome containingtwo damaged organelles 1 µ m

MitochondrionfragmentPeroxisomefragment

Lysosome fuses withvesicle containingdamaged organelle

Hydrolytic enzymesdigest organellecomponents

Vesicle containingdamaged mitochondrion

Digestion

Food vacuole

Plasma membraneLysosome

Digestiveenzymes

(a) Phagocytosis: lysosome digesting food (b) Autophagy: lysosome breaking down damaged organelle

Lysosome

Digestion

Lysosome

Lysosomes

Chloroplast

Peroxisome

Mitochondrion

1 µm

Peroxisomes

3

Nuclear envelope

Nuclear envelope isconnected to rough ER, which is also continuous

with smooth ER

Nucleus

Rough ER

Smooth ER

1

Summary

Golgi pinches off transport vesicles and other vesicles that

give rise to lysosomes and vacuoles

Membranes and proteinsproduced by the ER flow in

the form of transport vesiclesto the Golgi

3

4 5

Nuclear envelope

Nuclear envelope isconnected to rough ER, which is also continuous

with smooth ER

2

3

Nucleus

Rough ER

Smooth ER cis Golgi

trans Golgi

Lysosome availablefor fusion with anothervesicle for digestion

Transport vesicle carriesproteins to plasma membrane for secretion

Transport vesicle

1

Summary

Plasma membrane expandsby fusion of vesicles; proteinsare secreted from cell

Golgi pinches off transport vesicles and other vesicles that

give rise to lysosomes and vacuoles

Membranes and proteinsproduced by the ER flow in

the form of transport vesiclesto the Golgi

3

4 5 6

Nuclear envelope

Nuclear envelope isconnected to rough ER, which is also continuous

with smooth ER

2

3

Nucleus

Rough ER

Smooth ER cis Golgi

trans Golgi

Plasmamembrane

Lysosome availablefor fusion with anothervesicle for digestion

Transport vesicle carriesproteins to plasma membrane for secretion

Transport vesicle

1

Summary

Mitochondrion

Intermembrane spaceOuter

membrane

Freeribosomesin the mitochondrialmatrix

MitochondrialDNA

Innermembrane

Cristae

Matrix

100 µm

Mitochondria

Ribosomes ( small brown dots )

Central vacuole

MicrofilamentsIntermediate filaments

Microtubules

Rough endoplasmic reticulum Smooth

endoplasmic reticulum

ChromatinNUCLEUS

Centrosome

Nuclear envelope

Nucleolus

ChloroplastPlasmodesmataWall of adjacent cell

Cell wallPlasma membrane

Mitochondrion

Golgi apparatus

Peroxisome

Tonoplast

CYTOSKELETON

Plant Cells

Central vacuole

Cytosol

Tonoplast

Centralvacuole

Nucleus

Cell wall

Chloroplast

5 µm

The Central Vacuole

Granum

Chloroplast

ChloroplastDNA

RibosomesStroma

Inner and outermembranes

Thylakoid

1 µm

Chloroplasts