Nuclei yellow and actin red Figure 4 6

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• Nuclei (yellow) and actin (red) Figure 4. 6 x Copyright © 2003

• Nuclei (yellow) and actin (red) Figure 4. 6 x Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

THE CYTOSKELETON The cell’s internal skeleton helps organize its structure and activities • network

THE CYTOSKELETON The cell’s internal skeleton helps organize its structure and activities • network of protein fibers Figure 4. 17 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Microfilaments of actin enable cells to change shape and move • Intermediate

• Microfilaments of actin enable cells to change shape and move • Intermediate filaments reinforce the cell and anchor certain organelles • Microtubules – give the cell rigidity – provide anchors for organelles – act as tracks for organelle movement Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Actin subunit Tubulin subunit Fibrous subunits 25 nm 7 nm MICROFILAMENT 10 nm INTERMEDIATE

Actin subunit Tubulin subunit Fibrous subunits 25 nm 7 nm MICROFILAMENT 10 nm INTERMEDIATE FILAMENT Figure 4. 17 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings MICROTUBULE

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

How do cilia and flagella move? • A cilia or flagellum is composed of

How do cilia and flagella move? • A cilia or flagellum is composed of a core of microtubules wrapped in plasma membrane • Eukaryotes have “ 9+2” structure Cilia and flagella move when microtubules bend Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

FLAGELLUM Electron micrograph of sections: Outer microtubule doublet Plasma membrane Flagellum Central microtubules Outer

FLAGELLUM Electron micrograph of sections: Outer microtubule doublet Plasma membrane Flagellum Central microtubules Outer microtubule doublet Plasma membrane Figure 4. 18 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Basal body (structurally identical to centriole)

Slide 43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Slide 43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

polar head P – hydrophobic molecules nonpolar tails Phospholipid bilayer hydrophilic molecules cytosol

polar head P – hydrophobic molecules nonpolar tails Phospholipid bilayer hydrophilic molecules cytosol

Cell surfaces protect, support, and join cells Surfaces allow exchange of signals and molecules.

Cell surfaces protect, support, and join cells Surfaces allow exchange of signals and molecules. • Plant cells connect by plasmodesmata Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Walls of two adjacent plant cells Vacuole PLASMODESMATA Layers of one plant cell wall

Walls of two adjacent plant cells Vacuole PLASMODESMATA Layers of one plant cell wall Cytoplasm Plasma membrane Figure 4. 19 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Animal cells - extracellular matrix – sticky layer of glycoproteins – binds

• Animal cells - extracellular matrix – sticky layer of glycoproteins – binds cells together in tissues – can also protect and support cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Tight junctions can bind cells together into leakproof sheets • Anchoring junctions

• Tight junctions can bind cells together into leakproof sheets • Anchoring junctions link animal cells TIGHT JUNCTION ANCHORING JUNCTION • Gap junctions allow substances to flow from cell to cell GAP JUNCTION Plasma membranes of adjacent cells Figure 4. 19 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Extracellular matrix

Eukaryotic organelles fall into 4 functional groups • 1. Manufacture and transport – dependent

Eukaryotic organelles fall into 4 functional groups • 1. Manufacture and transport – dependent on network of membranes - Nucleus - Ribosomes - Rough ER - Smooth ER - Golgi apparatus Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. Breakdown – all single-membrane sacs • Lysosomes (in animals, some protists) • Peroxisomes

2. Breakdown – all single-membrane sacs • Lysosomes (in animals, some protists) • Peroxisomes • Vacuoles (plants) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

3. Energy Processing – involves extensive membranes embedded with enzymes • Chloroplasts • Mitochondria

3. Energy Processing – involves extensive membranes embedded with enzymes • Chloroplasts • Mitochondria Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

4. Support, Movement, Communication • Cytoskeleton – includes cilia, flagella, filaments, microtubules • Cell

4. Support, Movement, Communication • Cytoskeleton – includes cilia, flagella, filaments, microtubules • Cell walls • Extracellular matrix • Cell junctions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

What do these have in common? • • • HIV infection Transplanted organs Communication

What do these have in common? • • • HIV infection Transplanted organs Communication between neurons Drug addiction Cystic fibrosis hypercholesteremia

Membranes organize the chemical activities of cells • selectively permeable • hold teams of

Membranes organize the chemical activities of cells • selectively permeable • hold teams of enzymes Cytoplasm Figure 5. 10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Plasma membrane • Contact between cell and environment • Keeps useful materials inside and

Plasma membrane • Contact between cell and environment • Keeps useful materials inside and harmful stuff outside • Allows transport, communication in both directions

Plasma membrane components § Phospholipid bilayer § Cholesterol § Proteins § Glycocalyx

Plasma membrane components § Phospholipid bilayer § Cholesterol § Proteins § Glycocalyx

polar head P – hydrophobic molecules nonpolar tails Phospholipid bilayer hydrophilic molecules cytosol

polar head P – hydrophobic molecules nonpolar tails Phospholipid bilayer hydrophilic molecules cytosol

THE PLASMA MEMBRANE phospholipids cholesterol cytoskeleton peripheral protein integral protein Cholesterol blocks some small

THE PLASMA MEMBRANE phospholipids cholesterol cytoskeleton peripheral protein integral protein Cholesterol blocks some small molecules, adds fluidity

• Membrane Proteins – span entire membrane or lie on either side –

• Membrane Proteins – span entire membrane or lie on either side – Purposes • Structural Support • Recognition • Communication • Transport

• Glycocalyx – Composed of sugars protruding from lipids and proteins – Functions

• Glycocalyx – Composed of sugars protruding from lipids and proteins – Functions • Binding sites for proteins • Lubricate cells. • Stick cells down.

• Many membrane proteins are enzymes • Some proteins function as receptors for

• Many membrane proteins are enzymes • Some proteins function as receptors for chemical messages from other cells – The binding of a messenger to a receptor may trigger signal transduction Messenger molecule Receptor Activated molecule Figure 5. 13 Enzyme activity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Signal transduction

• The plasma membrane of an animal cell Glycoprotein Carbohydrate (of glycoprotein) Fibers

• The plasma membrane of an animal cell Glycoprotein Carbohydrate (of glycoprotein) Fibers of the extracellular matrix Glycolipid Phospholipid Cholesterol Microfilaments of the cytoskeleton Proteins CYTOPLASM Figure 5. 12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Diffusion and Gradients – Diffusion = movement of molecules from region of

• Diffusion and Gradients – Diffusion = movement of molecules from region of higher to lower concentration. – Osmosis = diffusion of water across a membrane

• In passive transport, substances diffuse through membranes without work by the cell

• In passive transport, substances diffuse through membranes without work by the cell Molecule of dye Membrane EQUILIBRIUM Figure 5. 14 A & B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

(a) selectively permeable membrane H 2 O free water molecule: can fit through pore

(a) selectively permeable membrane H 2 O free water molecule: can fit through pore sugar bound water molecules clustered around sugar: cannot fit through pore (b) selectively permeable membrane sugar molecule water molecule pure water bag bursts

Osmosis = diffusion of water across a membrane • water travels from an area

Osmosis = diffusion of water across a membrane • water travels from an area of higher concentration to an area of lower water concentration Hypotonic solution Hypertonic solution Selectively permeable membrane Solute molecule HYPOTONIC SOLUTION HYPERTONIC SOLUTION Water molecule Selectively permeable membrane Solute molecule with cluster of water molecules NET FLOW OF WATER Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5. 15

Water balance between cells and their surroundings is crucial to organisms osmoregulation = control

Water balance between cells and their surroundings is crucial to organisms osmoregulation = control of water balance • Osmosis causes cells to shrink in a hypertonic solution and swell in a hypotonic solution Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

10 microns isotonic solution equal movement of water into and out of cells hypertonic

10 microns isotonic solution equal movement of water into and out of cells hypertonic solution net water movement out of cells hypotonic solution net water movement into cells

Passive transport = diffusion across membranes • Small nonpolar molecules - simple diffusion •

Passive transport = diffusion across membranes • Small nonpolar molecules - simple diffusion • Many molecules pass through protein pores by facilitated diffusion Solute molecule Figure 5. 17 Transport protein Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Active transport • transport proteins needed • against a concentration gradient • requires energy

Active transport • transport proteins needed • against a concentration gradient • requires energy (ATP) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Active transport in two solutes across a membrane FLUID OUTSIDE CELL Transport

• Active transport in two solutes across a membrane FLUID OUTSIDE CELL Transport protein First solute 1 • Na+/K+ pump Phosphorylated transport protein First solute, inside cell, binds to protein 2 ATP transfers phosphate to protein 3 Protein releases solute outside cell 5 Phosphate detaches from protein 6 Protein releases second solute into cell Second solute • Protein shape change 4 Second solute binds to protein Figure 5. 18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Exocytosis and endocytosis transport large molecules exocytosis = vesicle fuses with the membrane and

Exocytosis and endocytosis transport large molecules exocytosis = vesicle fuses with the membrane and expels its contents FLUID OUTSIDE CELL Figure 5. 19 A CYTOPLASM Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

b

b

– or the membrane may fold inward, trapping material from the outside (endocytosis) Figure

– or the membrane may fold inward, trapping material from the outside (endocytosis) Figure 5. 19 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Phagocytosis, “cell eating” —How the human immune system ingests whole bacteria or one-celled creatures

Phagocytosis, “cell eating” —How the human immune system ingests whole bacteria or one-celled creatures eat. phagocytosis food particle 1 2 3 particle enclosed in vesicle

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

pinocytosis 2 vesicle containing extracellular fluid (cytoplasm)

pinocytosis 2 vesicle containing extracellular fluid (cytoplasm)

extracellular fluid plasma membrane cytosol receptors vesicle captured molecules coated pit vesicle bacterium pseudopodium

extracellular fluid plasma membrane cytosol receptors vesicle captured molecules coated pit vesicle bacterium pseudopodium vesicle

Receptor-mediated endocytosis

Receptor-mediated endocytosis

• Cholesterol can accumulate in the blood if membranes lack cholesterol receptors LDL

• Cholesterol can accumulate in the blood if membranes lack cholesterol receptors LDL PARTICLE Phospholipid outer layer Receptor protein Protein Cholesterol Plasma membrane CYTOPLASM Figure 5. 20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vesicle

What do these have in common? • • • HIV infection Transplanted organs Communication

What do these have in common? • • • HIV infection Transplanted organs Communication between neurons Drug addiction Cystic fibrosis hypercholesteremia

actin actin troponin tropomyosin actin troponin tropomyosin actinactin actin troponin tropomyosin actin troponin tropomyosin actin
red green yellow blue violett red green yellowred green yellow blue violett red green yellow
red yellow green red yellow green blue blackred yellow green red yellow green blue black
PRO ACTIN KICKOFF MEETING PRO ACTIN Project IDEPRO ACTIN KICKOFF MEETING PRO ACTIN Project IDE
PRO ACTIN KICKOFF MEETING PRO ACTIN Project IDEPRO ACTIN KICKOFF MEETING PRO ACTIN Project IDE
Active Galactic Nuclei Active Galactic Nuclei AGN NucleiActive Galactic Nuclei Active Galactic Nuclei AGN Nuclei
Yellow journalism By Tyler Silver Yellow journalism YellowYellow journalism By Tyler Silver Yellow journalism Yellow
Figure 12 1 Actin filaments Figure 12 2Figure 12 1 Actin filaments Figure 12 2
Le figure piane Figure uguali Figure equicomposte FigureLe figure piane Figure uguali Figure equicomposte Figure
COLOR TEST PATTERN Fuchsia Yellow Violet YELLOW REDCOLOR TEST PATTERN Fuchsia Yellow Violet YELLOW RED
COLOR TEST PATTERN Fuchsia Yellow Violet YELLOW REDCOLOR TEST PATTERN Fuchsia Yellow Violet YELLOW RED
Red acadmica y Red comercial Red Acadmica RedRed acadmica y Red comercial Red Acadmica Red
B The Cytoskeletal System and Adhesion Red ActinB The Cytoskeletal System and Adhesion Red Actin
red red yellow je gri n blue bUred red yellow je gri n blue bU
char color5 red blue yellow green black redchar color5 red blue yellow green black red
red blue yellow green brown pink red bluered blue yellow green brown pink red blue
Figure 1 Actin remodeling at the site ofFigure 1 Actin remodeling at the site of
Mass predictions for neutronrich nuclei and superheavy nucleiMass predictions for neutronrich nuclei and superheavy nuclei
Figure 14 15 Figure CO 14 Figure 14Figure 14 15 Figure CO 14 Figure 14
A Figure ppt Figure B Figure 1 AntioxidantA Figure ppt Figure B Figure 1 Antioxidant
Figure 12 13 Figure 12 14 Figure 12Figure 12 13 Figure 12 14 Figure 12
Figure 26 1 Figure 26 2 Figure 26Figure 26 1 Figure 26 2 Figure 26
Figure 18 26 Figure 18 27 a FigureFigure 18 26 Figure 18 27 a Figure
Figure 14 15 Figure CO 14 Figure 14Figure 14 15 Figure CO 14 Figure 14