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www.denniskunkel.com

www.denniskunkel.com

Tour of the Cell Today’s Topics •  Properties of all cells •  Prokaryotes and Eukaryotes •  Functions of Major Cellular

Organelles –  Information

•  Nucleus, Ribosomes –  Synthesis&Transport

•  ER, Golgi, Vesicles –  Energy Conversion

•  Mitochondria, Chloroplasts –  Recycling

•  Lysosome, Peroxisome –  Structure and Movement

•  Cytoskeleton and Motor Proteins

•  Cell Walls

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Common features of all cells •  Plasma Membrane

– defines inside from outside

•  Cytosol – Semifluid “inside” of the cell

•  DNA “chromosomes” -  Genetic material – hereditary

instructions

•  Ribosomes –  “factories” to synthesize proteins

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Bacterial (Prokaryotic) Cell

Ribosomes!

Plasma membrane!

Cell wall!

Flagella!

Bacterial chromosome!

0.5 !m!

No internal membranes

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Contains internal organelles

Eukaryotic Cell Figure 6.2b

1 mm

100 µm

10 µm

1 µm

100 nm

10 nm

1 nm

0.1 nm Atoms

Small molecules

Lipids Proteins

Ribosomes

Viruses Smallest bacteria

Mitochondrion Most bacteria Nucleus

Most plant and animal cells

Human egg

Ligh

t mic

rosc

opy

Elec

tron

mic

rosc

opy

Super- resolution

microscopy

1 cm

Frog egg

2

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Rough ER Smooth ER

Centrosome

CYTOSKELETON

Microfilaments

Microtubules

Peroxisome

Lysosome

Golgi apparatus

Ribosomes

In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm)

NUCLEUS

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Mitochondrion

Plasma membrane

Figure 6.9

endoplasmic reticulum nucleus

mitochondrion lysosome

Golgi apparatus cytosol

ribosomes

cytoskeleton You should know everything in Fig 6.9

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Rough ER Smooth ER

Centrosome

CYTOSKELETON

Microfilaments

Microtubules

Peroxisome

Lysosome

Golgi apparatus

Ribosomes

In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm)

NUCLEUS

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Mitochondrion

Plasma membrane

Figure 6.9

Nucleus

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Nuclear envelope

Figure 6.10

Nucleus

Nucleus Nucleolus

Chromatin

Nuclear envelope: Inner membrane

Outer membrane

Pores

Rough ER

Pore complex

Surface of nuclear envelope.

Pore complexes (TEM). Nuclear lamina (TEM).

Close-up of nuclear envelope

Ribosome

1 !m

1 !m

0.25 !m

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–  Carry out protein synthesis ER

Cytosol Free Ribosomes

Membrane Bound Ribosomes

Large subunit

Small subunit

TEM showing ER and ribosomes

Diagram of a ribosome

0.5 !m

Figure 6.11 RNA & Protein Complex

Make Proteins to be Exported

Make Cytoplasmic Proteins

Ribosomes

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Rough ER Smooth ER

Centrosome

CYTOSKELETON

Microfilaments

Microtubules

Peroxisome

Lysosome

Golgi apparatus

Ribosomes

In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm)

NUCLEUS

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Mitochondrion

Plasma membrane

Figure 6.9

Endoplasmic Reticulum

Golgi apparatus

Ribosomes

12 4 5 6

Nuclear envelope is connected to ER

Nucleus

Rough ER Smooth ER

Golgi

transport vesicles

Golgi pinches off Transport Vesicles, Lysosomes, etc.

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3

2

Figure 6.16 Plasma membrane expands by fusion of vesicles.

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Smooth ER

•  Synthesis of membrane lipids

•  Synthesizes steroids •  Stores calcium •  Detoxifies poison

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Rough ER

•  Synthesis of – secreted proteins – membrane proteins

Has attached ribosomes

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Adds oligosaccharides (glycosylation)

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Cis Golgi

Close To Rough

ER

Trans Golgi

Away From

Rough ER

Golgi Apparatus: protein secretion Processing, packaging and sorting center

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NUCLEUS

Figure 6.9

Mitochondria (and chloroplasts)

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Mitochondria: Powerhouses of the cell

Food -> ATP

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Chloroplast

Chloroplast DNA

Ribosomes

Stroma

Inner and outer membranes

Thylakoid

1 !m

Granum

Chloroplasts capture energy from the sun

Photosynthesis

Sunlight -> ATP, Sugar 20

Rough ER Smooth ER

Lysosome

ENDOPLASMIC RETICULUM (ER)

Figure 6.9 Lysosome (animals only)

Peroxisome

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Rough ER Smooth ER

CYTOSKELETON

Microfilaments

Microtubules

NUCLEUS

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Figure 6.9

Cytosol

Cytoskeleton

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There are three types of

fibers that make up the cytoskeleton

Table 6.1

Microtubules Microfilaments Intermediate Filaments

Tubulin 25 mM dia

Actin 7 mM dia various

8-15 mM dia

Cell shape Organelle movt Chromosome separation Flagellar mvt

Cell shape Cell cleavage Cytoplasmic streaming Muscle contract

Nuclear lamina Tension bearing elements Anchors

Motors: Dynein Kinesin

Motors: Myosin

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Movement of Vesicles along Microtubules

Vesicle ATP

Receptor for motor protein

Motor protein (ATP powered)

Microtubule of cytoskeleton

(a) Motor proteins that attach to receptors on organelles can “walk” the organelles along microtubules or, in some cases, microfilaments.

Microtubule Vesicles 0.25 !m

(b) Vesicles containing neurotransmitters migrate to the tips of nerve cell axons via the mechanism in (a). In this SEM of a squid giant axon, two vesicles can be seen moving along a microtubule. (A separate part of the experiment provided the evidence that they were in fact moving.) Figure 6.21 A, B

What evidence do we have that they actually move?

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Three kinds of Movement

•  Filament anchored: motor “walks” along filament (transport vesicles)

•  Motor anchored: filament moves (muscles)

•  Both anchored: bending (cilia and flagella)

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Motor MAPs transport vesicles

MTOC

Dynein inbound

outbound kinesin

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Fig. 6-24

0.1 !m!Triplet!

(c) Cross section of basal body!

(a)!Longitudinal section of cilium!

0.5 !m!

Plasma membrane!

Basal body!

Microtubules!

(b)!Cross section of cilium!

Plasma membrane!

Outer microtubule doublet!Dynein proteins!

Central microtubules!

0.1 !m!

Cilia and Flagella Have 9+2 arrangement of microtubules and motor proteins.

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CYTOSKELETON

Ribosomes (small brown dots)

Central vacuole/Tonoplast

Microfilaments Intermediate filaments

Microtubules

Rough endoplasmic reticulum

Smooth endoplasmic reticulum

NUCLEUS

Chloroplast

Plasmodesmata Wall of adjacent cell

Cell wall

Golgi apparatus

Peroxisome Plasma membrane

Mitochondrion

Figure 6.9

Plants have 2 other support mechanisms

•  Cell Wall •  Vacuole or

Tonoplast

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Central Vacuoles (Tonoplasts) –  Only in plants

Central vacuole

Cytosol

Tonoplast

Central vacuole

Nucleus

Cell wall

Chloroplast

5 !m

Figure 6.15

Acts like a “balloon in a box” to hold plant cells rigid

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Extra Cellular Matrix

glycoproteins