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Lesson Overview 7.1 Life is Cellular Lesson Overview Life Is Cellular The Discovery of the Cell Schleiden, Schwann, Virchow: Matthias Schleiden (1838) = all plants were made of cells Theodor Schwann (1839) = all animals were made of cells Rudolph Virchow (1855) = new cells were created only from division of existing cells These discoveries led to the cell theory: - All living things are made up of cells. - Cells are the basic units of structure and function in living things. - New cells are produced from existing cells. The Discovery of the Cell What is the cell theory? http://www.hippocampus.org/Biology;jsessionid=3529C2F539E99E86948A8205D1D283 F3 Copyright Pearson Prentice Hall The Discovery of the Cell Hooke’s Drawing of Cork Cells Hooke saw this and came up with word “cell” Copyright Pearson Prentice Hall Lesson Overview Life Is Cellular Prokaryotes and Eukaryotes How are prokaryotic and eukaryotic cells different? Prokaryotic cell Eukaryotic cells smaller no true nucleus simple, not many structures no membrane-bound organelles ex. bacteria larger nucleus complex, many structures membrane-bound organelles ex. plant, animal cells *** Both types of cells have genetic material and a cell membrane Lesson Overview Life Is Cellular Prokaryotes and Eukaryotes http://www.hippocampus.org/Biology;jsessionid=3529C2F539E99E86948A8205 D1D283F3 7-1 The cell theory states that new cells are produced from • • • • nonliving material. existing cells. cytoplasm. animals. Copyright Pearson Prentice Hall 7-1 The person who first used the term cell was • • • • Matthias Schleiden. Lynn Margulis. Anton van Leeuwenhoek. Robert Hooke. Copyright Pearson Prentice Hall 7-1 Which organism listed is a prokaryote? • • • • protist bacterium fungus plant Copyright Pearson Prentice Hall 7-1 One way prokaryotes differ from eukaryotes is that they • contain DNA, which carries biological information. • have a surrounding barrier called a cell membrane. • do not have a membrane separating DNA from the rest of the cell. • are usually larger and more complex. Copyright Pearson Prentice Hall END OF SECTION Lesson Overview 7.2 Cell Structure http://vcell.ndsu.edu/animations/fly through/movie-flash.htm Lesson Overview Life Is Cellular Cell Organization The eukaryotic cell can be divided into two major parts: the nucleus and the cytoplasm. The cytoplasm is the fluid portion of the cell outside the nucleus. Lesson Overview Life Is Cellular The Nucleus NUCLEUS: control center of the cell, contains DNA DNA - instructions or blueprint for making proteins and other important molecules Lesson Overview Life Is Cellular The Nucleus Most nuclei also contain a small, dense region nucleolus Nucleolus – makes ribosomes (which eventually make proteins) Lesson Overview Life Is Cellular Vacuoles and Vesicles VACUOLES: large, saclike, membrane-enclosed structures that store materials such as water, salts, proteins, and carbohydrates; much larger in plant cells Lesson Overview Life Is Cellular Vacuoles and Vesicles Vesicles –”vehicles”; used to store and move materials between cell organelles, as well as to and from the cell surface. Lesson Overview Life Is Cellular Lysosomes Lysosomes - small organelles filled with enzymes that function as the cell’s “cleanup crew”. • have hydrolytic enzymes which breakdown larger substances and garbage (worn out organelles) http://highered.mcgrawhill.com/sites/0072437316/student_view0/c hapter5/animations.html Lesson Overview Life Is Cellular The Cytoskeleton Eukaryotic cells are given their shape and internal organization by a network of protein filaments known as the cytoskeleton. Microfilaments and microtubules are two of the principal protein filaments that make up the cytoskeleton. ****Used for structure and movement (internal and external) Lesson Overview Life Is Cellular Microtubules Microtubules are hollow structures made up of proteins known as tubulins. Important in cell division, where they form a structure known as the mitotic spindle, which helps to separate chromosomes. In animal cells, structures known as centrioles are also formed from tubulins Microtubules help to build cilia and flagella, which enable cells to swim rapidly through liquids. Lesson Overview Life Is Cellular Organelles That Build Proteins REVIEW: Why are proteins so important? Organelles that help build proteins: ribosomes ER Golgi apparatus vesicles Lesson Overview Life Is Cellular Ribosomes Ribosomes - small particles of RNA and protein found throughout the cytoplasm (in both prokayotes and eukaryotes) Ribosomes produce proteins by following coded instructions that come from DNA in process called translation Lesson Overview Life Is Cellular Endoplasmic Reticulum Endoplasmic reticulum, or ER – an internal membrane system; “highway” Two kinds: rough ER and smooth ER http://bcs.whfreeman .com/thelifewire/defa ult.asp - Chapter 4, Tutorial 4.2 Lesson Overview Life Is Cellular Endoplasmic Reticulum rough endoplasmic reticulum - take newly formed proteins from ribosomes and modified and transported Lesson Overview Life Is Cellular Endoplasmic Reticulum Smooth ER - contains collections of enzymes that perform specialized tasks, including the synthesis of membrane lipids and the detoxification of drugs. Lesson Overview Life Is Cellular Golgi Apparatus The proteins are bundled into tiny vesicles that bud from the ER and carry them to the Golgi apparatus The Golgi apparatus modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or release outside the cell Lesson Overview Life Is Cellular Organelles That Capture and Release Energy Chloroplasts (mostly found in plants) Mitochondria (found in mostly all cells) Lesson Overview Life Is Cellular Chloroplasts Chloroplasts - capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis. Two membranes surround chloroplasts. Inside the organelle are large stacks of other membranes (grana), which contain the green pigment chlorophyll. Lesson Overview Life Is Cellular Mitochondria Mitochondria - power plants of the cell; convert the chemical energy stored in food into compounds that are more convenient for the cell to use Two membranes—an outer membrane and an inner membrane— enclose mitochondria. The inner membrane is folded up inside the organelle (cristae) Lesson Overview Life Is Cellular Mitochondria Chloroplasts and mitochondria contain their own genetic information in the form of small DNA molecules. The endosymbiotic theory suggests that chloroplasts and mitochondria may have descended from independent microorganisms http://www.sumanasinc.com/webcontent/animations/content/organelles.html Lesson Overview Life Is Cellular Cellular Boundaries cell membrane – found in all cells; regulates what goes in and out of cell cell wall – not found in animal cells; provides support and protection for the cell Lesson Overview Life Is Cellular Cell Membranes Cell membranes made up of a lipid bilayer, which gives cell membranes a flexible structure and forms a strong barrier Phospholipid bilayer: hydrophobic, or “water-hating” fatty acid chains (TAILS) hydrophilic, or “water-loving,” (HEADS) Lesson Overview Life Is Cellular The Fluid Mosaic Model Most cell membranes contain protein molecules that are embedded in the lipid bilayer. Carbohydrate molecules are attached to many of these proteins. Proteins used as channels Carbohydrates used as ID markers Lesson Overview Life Is Cellular The Fluid Mosaic Model Most biological membranes are selectively permeable Selectively Permeable/Semipermeable: some substances can pass across them and others cannot Lesson Overview 7.3 Cell Transport Lesson Overview Life Is Cellular Passive Transport • The movement of materials across the cell membrane without using energy is called passive transport • Diffusion & Osmosis Lesson Overview Life Is Cellular Diffusion • The process by which particles move from an area of higher concentration to an area of lower concentration Equilibrium • Particles continuously move but NO NET CHANGE http://programs.northlandcollege.edu/biology/Biology1111/animations/transp ort1.html Lesson Overview Life Is Cellular Facilitated Diffusion • Molecules that cannot directly diffuse across the membrane pass through special protein channels • The movement of molecules by facilitated diffusion does not require energy AND molecules move from high to low concentration SO it is DIFFUSION. Lesson Overview Life Is Cellular Osmosis: An Example of Facilitated Diffusion • Many cells contain water channel proteins, known as aquaporins, that allow water to pass right through them. (faster than usual) Lesson Overview Life Is Cellular Osmosis: An Example of Facilitated Diffusion • Osmosis involves the movement of water molecules from an area of higher concentration to an area of lower concentration. http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP11003 Lesson Overview Life Is Cellular How Osmosis Works In the experimental setup below, the barrier is permeable to water but not to sugar. This means that water molecules can pass through the barrier, but the solute, sugar, cannot. Lesson Overview Life Is Cellular How Osmosis Works • More sugar molecules on the right side than on the left • Concentration of water is lower on the right than left • Water moves from high to low concentration Lesson Overview Life Is Cellular How Osmosis Works • When the concentration is the same on both sides of the membrane, the two solutions will be isotonic (“equal”) Lesson Overview Life Is Cellular How Osmosis Works • The more concentrated sugar solution at the start of the experiment was hypertonic (more solutes/less water) • The dilute sugar solution was hypotonic (less solutes/more water) Lesson Overview Life Is Cellular Osmotic Pressure Lesson Overview Life Is Cellular Active Transport • The movement of materials against a concentration gradient (low to high) • requires energy (ATP) http://programs.northlandcollege.edu/biology/Biology1111/animations/transport 1.html Lesson Overview Life Is Cellular Active Transport Lesson Overview Life Is Cellular Active Transport 1. ENDOCYTOSIS - phagocytosis (“eating”) - pinocytosis (“drinking”) 2. EXOCYTOSIS 7-3 QUIZ TIME!! Unlike a cell wall, a cell membrane a. is composed of a lipid bilayer. b. provides rigid support for the surrounding cell. c. is found only in plants, fungi, algae, and many prokaryotes. Copyright Pearson Prentice Hall 7-3 QUIZ TIME!! Unlike a cell wall, a cell membrane a. is composed of a lipid bilayer. b. provides rigid support for the surrounding cell. c. is found only in plants, fungi, algae, and many prokaryotes. Copyright Pearson Prentice Hall 7-3 If a substance is more highly concentrated outside the cell than inside the cell and the substance can move through the cell membrane, the substance will a. move by diffusion from inside the cell to outside. b. remain in high concentration outside the cell. c. move by diffusion from outside to inside the cell. d. cause water to enter the cell by osmosis. Copyright Pearson Prentice Hall 7-3 If a substance is more highly concentrated outside the cell than inside the cell and the substance can move through the cell membrane, the substance will a. move by diffusion from inside the cell to outside. b. remain in high concentration outside the cell. c. move by diffusion from outside to inside the cell. d. cause water to enter the cell by osmosis. Copyright Pearson Prentice Hall 7-3 The movement of materials in a cell against a concentration gradient is called a. facilitated diffusion. b. active transport. c. osmosis. d. diffusion. Copyright Pearson Prentice Hall 7-3 The movement of materials in a cell against a concentration gradient is called a. facilitated diffusion. b. active transport. c. osmosis. d. diffusion. Copyright Pearson Prentice Hall 7-3 The process by which molecules diffuse across a membrane through protein channels is called a. active transport. b. endocytosis. c. facilitated diffusion. d. osmosis. Copyright Pearson Prentice Hall 7-3 The process by which molecules diffuse across a membrane through protein channels is called a. active transport. b. endocytosis. c. facilitated diffusion. d. osmosis. Copyright Pearson Prentice Hall