Lecture 2 Outline (Ch. 6) I. Cell Background II. Organelles A. Nucleus, ribosomes B. Endomembrane System C. Energy Organelles i. Mitochondria ii. Chloroplasts III. Cytoskeleton Extracellular Spaces V. Lecture Concepts

How are cells studied?

Microscopy Bright field Transmission electron microscopy (TEM) Contrast Stained or unstained Scanning electron microscopy (SEM) Fluorescence Laser scanning microscopy

Prokaryotes vs. Eukaryotes - Archae and Bacteria nucleoid (DNA) ribosomes pili plasma membrane cell wall capsule flagella 1-10μm

Prokaryotes vs. Eukaryotes - Protists, Fungi, Plants, Animals - Several organelles - Larger 10-100μm 333 μm

Eukaryotic Organelles

Eukaryotic Organelles Nucleus – genetic material • chromosomes (DNA + proteins) • nuclear envelope -double bilayer • nucleolus -ribosome RNA made • nuclear pores • nuclear matrix

Ribosomes – protein synthesis • Made in nucleolus • Made of RNA & proteins • Bound or free • Two subunits

Endomembrane System 1. Endoplasmic reticulum (e.r.) • Extensive membrane • Continuous with nuclear envelope • Inside - lumen • Two types – rough, smooth – ”bleb” off in vesicles Rough e.r. – proteins for membrane or secretion Smooth e.r. – detoxification, lipid and carbohydrate synthesis

Endomembrane System 2. Golgi apparatus • Shipping and receiving • Protein modification & direction • Flattened sacs • Vesiscles – transport around cell

Endomembrane System 3. Lysosomes • Cellular digestion • Not in plants “phagocytosis” “autophagy” • Bleb off Golgi or cell membrane • Acidic inside – food particles (a) or old cell parts (b)

Endomembrane System 4. Vacuoles • Storage/maintenance compartments Plant cell Animal cell • Central vacuole • Food vacuole • Water vacuole -contractile vacuole • Disposal for by-products

Endomembrane System 5. Plasma membrane • Lipid bilayer – selective barrier • Membrane-associated proteins – depend on cell type • Present in bacteria, animals, and plants

Endomembrane System

Energy production 1.Mitochondria • energy from nutrients  ATP • Two membranes, each bilayer -inner -outer • Folds – cristae • Own DNA! • Own ribosomes! • Intermembrane space • Matrix

Energy production 2. Chloroplasts • Light to chemical energy • Only in plants • Own DNA • Own ribosomes • Outer and inner membranes - bilayer • Internal membranes – thylakoids, stacks called grana • Spaces – intermembrane, stroma, thylakoid

Organelle summary In animal cells only: Lysosomes (Flagella) In plant cells only: Chloroplasts Central vacuole

Self-Check Ribosomes Rough E.R. Smooth E.R. Golgi Plasma Membrane Organelle Name Function Part of Endomembrane System? In Bacteria? Plants? Animals? Nucleus Store genetic info no P, A Ribosomes Rough E.R. Smooth E.R. Golgi Plasma Membrane Lysosomes Vacuoles Mitochondria Chloroplasts Cytoskeleton

Cytoskeleton overview • Shape/support • Cell movement • Internal transport • Cell division Unique to eukaryotic cells - essential to cell survival/function

Cytoskeleton Components Three types of cytoskeletal elements: • Actin filaments (microfilaments) • Intermediate filaments • Microtubules

Actin filaments • Localized at membrane • Cell movement • Muscle fiber contraction • Cytoplasmic streaming (plants) • Pseudopodia

Microtubules • Radiate from center • Internal transport, motile structures • Inside flagella • Make centrioles • Inside cilia

Intermediate filaments • Dispersed throughout cell • Strength/support keratin • Animal cells lamins

Extracellular Spaces – Cell wall • In plants - made of cellulose Why? • plasma membrane • secondary wall • primary wall • Thick • cells connected

Extracellular Spaces – Extracellular Matrix • Animal cells - glycoproteins Ex. collagen • ECM – cell communication, movement

Extracellular Spaces – Junctions • Animal cells - three types tight junctions (seal cells) 2. desmosomes (anchoring) 3. gap junctions (communicating)

Lecture 2 concepts List at least 3 types of microscopy and pros & cons for each Explain differences between prokaryotic and eukaryotic cells *For each organelle mentioned, list the name, function and whether it is present in bacteria, plant, & animal cells* Name the three fibers of the cytoskeleton and describe the function for each one Discuss the cell wall in plants, include purpose and material Explain the extracellular matrix of cells, include purpose and material/composition Describe how plant and animal cells are connected Write out a list of new terminology and provide descriptions