A Tour of the cell Chapter 6

All Organisms Are made up of Cells (6.1) Objectives Explain the main ideas of the cell theory. Describe how microscopes aid the study of cells. Compare and contrast animal cells and plant cells. Distinguish between prokaryotic and eukaryotic cells. Key Terms cell theory micrograph organelle plasma membrane nucleus cytoplasm cell wall prokaryotic cell eukaryotic cell HTTP://WWW.YOUTUBE.COM/WATCH?V=BTICXXXZQA4 Cell song

The Cell Theory Cell theory: generalization that -all living things are composed of cells - cells are the basic unit of structure and function in living things -all cells come from pre-existing cells Microscopes as Windows to Cells -Light microscopes (100X) -Electron microscopes (1,000,000) -Scanning electron microscope (SEM) -Transmission electron microscope (TEM) Micrograph A photograph of the view through a microscope 4 4

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Two major classes of Cells prokaryotic cell: cell lacking a nucleus and most other organelles eukaryotic cell: cell with a nucleus (surrounded by its own membrane) and other internal organelles 6 6

An Overview of Animal and Plant cells organelle: part of a cell with a specific function plasma membrane: thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings nucleus: in a cell, the part that houses the cell's genetic material in the form of DNA cytoplasm: region of a cell between the nucleus and the plasma membrane cell wall: strong wall outside a plant cell's plasma membrane that protects the cell and maintains its shape 7 7

MEMBRANES ORGANIZE A CELL’S ACTIVITIES (6.2) Objectives 1. Describe the structure of cellular membranes. 2. Identify functions of proteins in cellular membranes. Key Term phospholipid bilayer HTTP://WWW.YOUTUBE.COM/WATCH?V=BTICXXXZQA4 Cell song 10 10

Membrane Structure -Read paragraph 1 -Membranes help keep the functions of a eukaryotic cell organized -Membranes regulate the transport of substances across the boundary -composed mostly of proteins and a type of lipid called phospholipids. | -Phospholipids two hydrophobic fatty acids at one end (the tail) The other end (the head) of the molecule includes a hydrophilic phosphate group (PO43-) 12 12

Figure 6-7 A space-filling model of a phospholipid depicts the hydrophilic head region and the hydrophobic fatty acid tails. The simplified representation of phospholipids used in this book looks something like a lollipop (the head) with two sticks (the tails).

Membrane Structure -phospholipid bilayer: two-layer "sandwich" of molecules that surrounds a cell -Nonpolar molecules (such as oxygen and carbon dioxide) cross with ease, while polar molecules (such as sugars) and many ions do not. 14 14

The Many functions of membrane proteins Figure 6-9 Many functions of the plasma membrane involve its embedded proteins. a. Enzymes catalyze reactions of nearby substrates. b. Molecules on the surfaces of other cells are "recognized" by membrane proteins. c. A chemical messenger binds to a membrane protein, causing it to change shape and relay the message inside the cell. d. Transport proteins provide channels for certain solutes. 16 16

Dissect a plasma membrane. HTTP://WWW.YOUTUBE.COM/WATCH?V=BTICXXXZQA4 Cell song

Monday 11.14.11 Period 1 (9:20-10:00) Quiz Handback Cellquest, Lab sheet Check Egg, soak in colored water Period 2 (10:00-10:57) Observing Cells Lab H/W OUTLINE 6-3 (Do 6-3 online activity) Monday 11.14.11 18 18

Membranes Regulate the traffic of molecules (6.3) Objectives Relate diffusion and equilibrium. Describe how passive transport occurs. Relate osmosis to solute concentration. Explain how active transport differs from passive transport. Describe how large molecules move across a membrane. Key Terms diffusion equilibrium selectively permeable membrane passive transport facilitated diffusion osmosis hypertonic hypotonic isotonic active transport vesicle exocytosis endocytosis H/W -OUTLINE 6-4 (Do 6-4 online activity) HTTP://WWW.YOUTUBE.COM/WATCH?V=BTICXXXZQA4 Cell song 20 20

Diffusion -(air freshener) -diffusion -equilibrium 22 Figure 6-11 Dye molecules diffuse across a membrane. At equilibrium, the concentration of dye is the same throughout the container. 22 22

Passive Transport -selectively permeable membrane: -passive transport: -facilitated diffusion Figure 6-12 Both diffusion and facilitated diffusion are forms of passive transport, as neither process requires the cell to expend energy. In facilitated diffusion, solute particles pass through a channel in a transport 23 23

Osmosis -osmosis -hypertonic -hypotonic -isotonic 24 Figure 6-13 A selectively permeable membrane (the bag) separates two solutions of different sugar concentrations. Sugar molecules cannot pass through the membrane. 24 24

Water Balance in Animal Cells Which one is hypertonic? Isotonic? hypotonic? 25 25

Water Balance in PlantCells 26 26

Active Transport -active transport: 27 Figure 6-16 Like an enzyme, a transport protein recognizes a specific solute, molecule or ion. During active transport, the protein uses energy, usually moving the solute in a direction from lesser concentration to greater concentration. 27 27

Active Transport -vesicles: -exocytosis: -endocytosis: 28 Figure 6-17 Exocytosis (above left) expels molecules from the cell that are too large to pass through the plasma membrane. Endocytosis (below left) brings large molecules into the cell and packages them in vesicles. 28 28

exocytosis diffusion facilitated diffusion endocytosis osmosis Exit Slip exocytosis diffusion facilitated diffusion endocytosis osmosis H/W -OUTLINE 6-4 (Do 6-4 online activity) -Bring in thick liquid for your eggs 31 31

The cells builds a diversity of products (6.4) Objectives Identify the role of the nucleus in a cell. Describe how the functions of ribosomes, the endoplasmic reticulum, and the Golgi apparatus are related. Distinguish between the functions of vacuoles and lysosomes. Summarize the path of cellular products through membranes. Key Terms nuclear envelope nucleolus ribosome endoplasmic reticulum Golgi apparatus vacuole lysosome H/W -OUTLINE 6.5 AND 6.6 (No online activity) http://www.ted.com/talks/david_bolinsky_animates_a_cell.html Cell Animation (6:55) 32 32

Structure and Function of the Nucleus -nuclear envelope -nucleolus Figure 6-18 A cell's nucleus contains DNA—information-rich molecules that direct cell activities. 34 34

Ribosomes -Ribosomes Figure 6-19 A ribosome is either suspended in the cytoplasm or temporarily attached to the rough endoplasmic reticulum (ER). Though different in structure and function, the two types of ER form a continuous maze of membranes throughout a cell. The ER is also connected to the nuclear envelope.. 35 35

The Endoplasmic Reticulum -The Endoplasmic Reticulum -Smooth ER -Rough ER Figure 6-19 A ribosome is either suspended in the cytoplasm or temporarily attached to the rough endoplasmic reticulum (ER). Though different in structure and function, the two types of ER form a continuous maze of membranes throughout a cell. The ER is also connected to the nuclear envelope.. 36 36

The Endoplasmic Reticulum -The Endoplasmic Reticulum -Rough ER Figure 6-20 Some proteins are made by ribosomes (the red structure) on the rough ER and packaged in vesicles. After further processing in other parts of the cell, these proteins will eventually move to other organelles or to the plasma membrane. 37 37

The Golgi Apparatus -The Golgi Apparatus Figure 6-21 Golgi stacks receive, modify, and dispatch finished products. 38 38

Vacuoles -Vacuoles Figure 6-22 39 39

Lysosomes -Lysosomes Figure 6-23 Lysosomes contain digestive enzymes that break down food for cell use. 40 40

Membrane Pathways in a Cell Figure 6-24 Products made in the ER move through membrane pathways in a cell. 41 41

Exit Slip Describe the function of the organelles below nuclear envelope nucleolus ribosome endoplasmic reticulum Golgi apparatus vacuole lysosome H/W -OUTLINE 6.5 AND 6.6 (No online activity) 43 43

Chloroplasts and mitochondia energize cells (6.5) Objectives Compare and contrast the functions of chloroplasts and mitochondria. Key Terms chloroplast mitochondria ATP H/W -Chapter 6 worksheet -Prepare to present your “egg” periments 44 44

Chloroplasts -Chloroplasts Figure 6-25 A chloroplast is a miniature "solar collector," transforming light energy into chemical energy through photosynthesis. The green color of the disks is due to the presence of a pigment called chlorophyll that reacts with light. 47 47

Mitochondria -Mitochondria -ATP Figure 6-26 Cellular respiration in the mitochondria releases the energy that drives a cell. The many folds of each mitochondrion's inner membrane are the sites of ATP production. 48 48

An internal skeleton supports the cell and enables movement (6.6) Objectives Describe the role of the cytoskeleton in cell movement. Compare and contrast the functions of flagella and cilia. Explain why a cell can be described as a coordinated unit.. Key Terms microtubule microfilament flagella cilia H/W -Chapter 6 worksheet -Prepare to present your “egg” periments HTTP://WWW.YOUTUBE.COM/WATCH?V=BTICXXXZQA4 Cell song 49 49

The Cytoskeleton -microtubules -microfilaments Figure 6-27 51 51

Flagella and Cilia -Flagella -Cilia Figure 6-28 52 52

The Cell as a Coordinated Unit -Flagella -Cilia Figure 6-29 53 53

Longer animation (lecture) Exit Slip Explain why a cell can be described as a coordinated unit.. H/W -Chapter 6 worksheet -Prepare to present your “egg” periments http://www.youtube.com/watch?v=2wYJKmmLrbQ&feature=fvwrel Longer animation (music) http://www.youtube.com/watch?v=uGK9CYetCvM&feature=related Longer animation (lecture) 55 55