Ch.3 Cells 1.Plasma Membrane 2.Cytoplasm Entire contents of cell between P.M. and nucleus. 3.Nucleus or Nuclear Area Contains DNA, the genetic material The 3 Basic Parts of all Cells

–Phospholipids form a two-layer sheet Figure 5.11B Water Hydrophilic heads Hydrophobic tails

Classes of Cells Two basic types of cells: 1.Prokaryotic cells 2.Eukaryotic cells

Prokaryotic cells are …. Prokaryotic cell Nucleoid region Nucleus Eukaryotic cell Organelles Colorized TEM 15,000  Figure 4.3A

Prokaryotic Cell Nuclear area Pili Flagella Ribosomes Cell wall Plasma membrane Figure 4.3B

Eukaryotic cells Animal Cell Fig 4.4A

1. The nucleus is the cellular control center Nucleus Chromatin Nucleolus Pore Ribosomes Rough endoplasmic reticulum Two membranes of nuclear envelope Figure 4.5

2. Smooth endoplasmic reticulum, or smooth ER Synthesizes lipids Smooth ER Rough ER Nuclear envelope Rough ER Ribosomes Smooth ER TEM 45,000  Figure 4.7

3. Rough endoplasmic reticulum or Rough ER –Ribosomes on the surface Secretory (glyco-) protein inside trans- port vesicle 4 Transport vesicle buds off Sugar chain 3 Rough ER Glycoprotein 2 Polypeptide Ribosome 1 Figure 4.8

4. The Golgi apparatus finishes, sorts, and ships cell products Figure 4.9 Golgi apparatus TEM 130,000  Transport vesicle from the Golgi “Shipping” side of Golgi apparatus Golgi apparatus “Receiving” side of Golgi apparatus Transport vesicle from ER New vesicle forming

5. Vesicles: – Membrane-bound “balloons” that transport and store substances in cells

6. Lysosomes are sacs of enzymes function in digestion within a cell recycle damaged organelles

Fig 4.13 The various organelles of the endo- membrane system are inter- connected structurally and functionally

7. Mitochondria harvest chemical energy from food –Mitochondria carry out cellular respiration … Figure 4.14 Mitochondrion Outer membrane Intermembrane space Matrix Inner membrane Cristae TEM 44,880 

8. Cytoskeleton & related structures - Actin subunit Microfilament 7 nm Fibrous subunits 10 nm Intermediate filamentMicrotubule 25 nm Tubulin subunit Fig 4.17

–Microfilaments of actin –Intermediate filaments –Microtubules give the cell rigidity And provide anchors for organelles and act as tracks for organelle movement

Cilia and flagella move when microtubules bend –Eukaryotic cilia and flagella are LM 600  Colorized SEM 4,100  Figure 4.18

–Tight junctions –Anchoring junctions –Gap junctions allow substances to flow from cell to cell Anchoring junction Tight junctions Gap junctions Extracellular matrix Space between cells Plasma membranes of adjacent cells Figure 4.18B

Plant Cell – Fig. 4.6b

Plant cells also have: 1.Vacuole stores water, solutes, waste Important for growth and rigidity 2.Chloroplasts 3.Cell wall **Plant cells do not have lysosomes

Vacuoles function in the general maintenance of the cell Chloroplast Central vacuole Nucleus Colorized TEM 8,700  Figure 4.12

Chloroplasts convert solar energy to chemical energy –convert solar energy to chemical energy in sugars TEM 9,750  Chloroplast Stroma Intermembrane space Inner and outer membranes Granum Figure 4.15

Plant cells have rigid cell walls made of cellulose Plasma membrane Cytoplasm Plasmodesmata Vacuole Layers of one plant cell wall Walls of two adjacent plant cells Figure 4.22

Chapter 5: How cells Work

Transporting across membranes Solvent – Solute – –any molecule dissolved in the liquid. Selectively permeable – water can move freely through the membrane, but the membrane regulates the passage of solutes Diffusion – Osmosis – movement of water across a selectively permeable membrane.

Given a membrane that is permeable to water and glucose: Which way will water move? Which way will glucose move?

Hypertonic – high solute concentration, as compared to the other side of a membrane Hypotonic – Isotonic – equal solute concentrations on both sides of the membrane

Fig. 5.12: Diffusion

Isotonic Solutions Fig. 5.13

Fig. 5.14

Functions of membrane proteins Messenger molecule Receptor Activated molecule ATP EnzymesReceptors for messagesTransport of substances

Two types of transport across membranes 1. Passive transport (or Facilitated diffusion) –a solute moves through a membrane transport protein in the direction set by its concentration gradient

–Small nonpolar molecules such as –Other larger or polar molecules do not easily diffuse across the bilayer and transport proteins provide passage across membranes through a process called facilitated diffusion Figure 5.15 Solute molecule Transport protein

2.Active transport energy-driven transport proteins move solutes across membranes against their concentration gradient. Why? Mechanism: ATP binds to active transport pump, causing a change in its shape. The protein now has energy to pump the solute against its concentration gradient

P P P Protein changes shape Phosphate detaches ATP ADP Solute Transport protein Solute binding1Phosphorylation2 Transport 3 Protein reversion4 Cells expend energy for active transport Figure 5.18

Fluid outside cell Cytoplasm Protein Vesicle Exocytosis and endocytosis transport large molecules –To move large molecules or particles into the cell is endocytosis Figure 5.19A