Robert Hooke: Mid 1600 s English scientist who looked at Cork under a microscope

Transcription

1 CELLS Robert Hooke: Mid 1600 s English scientist who looked at Cork under a microscope Early Compound Microscope 1

2 CORK He described what he saw as a CELL Another scientist: Anton van Leeuwenhoek Dutch Used a microscope and saw LIVING microscopic organisms. He called these Animicules He looked at pond water, and the plaque on his teeth 2

3 Cells: are the basic unit of life Schleiden: Schwann: German botanist ALL PLANTS ARE MADE OF CELLS German Biologist ALL ANIMALS ARE MADE OF CELLS Virchow: German Physician NEW CELLS COME FROM THE DIVISION OF EXISTING CELLS 3

4 CELL THEORY All living things are composed of cells. All cells come from other cells Cells are the basic unit of structure and function of all living things Model of a Simple Cell Cell Membrane Nucleus Cytoplasm 4

5 Cell size and shape varies with function Nerve cell: can transmit nerve signals quickly between distant parts of the animal s body Red blood Cells (RBC): Very Small so it can fit through the tiniest blood vessels. The dimple helps it to fold and bend. 5

6 Prokaryotic Cells Very small (2-8 µm) [µm = 10-6 m] NO NUCLEUS DNA is coiled in the Nucleoid Region EX: Bacteria Cell Wall: rigid & maintains shape sometimes surrounded by a STICKY capsule Further protects the cell surface Ribosomes: assemble Proteins Flagella: for movement Pili (pilus): attaches to surfaces 6

7 Eukaryotic Cells From the Greek: EU = True Karyon =Kernal NUCLEUS Much more complex cell Genetic material is separated from the rest of the cell This type of cell can be in : o Single celled organism Or o Multicellular organism This includes the following Kingdoms: Plants Animals fungi protists 7

8 Eukaryotic Cell Structure Organelles: Structures within the cell, each with a specific function 8

9 2 MAJOR CELL PARTS Cytoplasm Nucleus Portion of the cell outside the nucleus Control center of the cell Fluid filled region between the nucleus and the plasma (cell) membrane Contains : DNA & Instructions for protein synthesis Also surrounded by nuclear membrane/envelope Where are organelles found?? In the cytoplasm 9

10 NUCLEUS Nuclear Envelope 2 membranes with pores that control the flow of material in and out of the nucleus Chromatin Long fibers of nuclear DNA attached to protein 10

11 Nucleolus: Draguesku During Cell Division chromatin condenses to form CHROMOSOMES CHROMOSOMES carry genetic information A mass of fibers and granules in the nucleus Ribosomes assembly begins here Inside the nucleus there is DNA synthesis, RNA synthesis and the assembly of the ribosomes 11

12 Ribosomes: Small particles of RNA PROTEIN SYNTHESIS Rough Endoplasmic Reticulum (Rough ER) **Synthesis of MEMBRANE PROTEINS Transports proteins and other materials from one place in the cell to another Smooth Endoplasmic Reticulum (Smooth ER) **Lipid synthesis; detoxification in the liver Transports protein and other material through out the cell 12

13 Golgi Apparatus (Body) Draguesku Modify, sort and package proteins for storage or secretion out of the cell Lysosomes: Responsible for digestion: o Of nutrients, o damaged organelles, o destruction of certain cells during Embryonic development. Ex. Tay-Sachs disease results from lysosomes that don t work properly 13

14 Vacuoles: Storage of chemicals, products of digestion Water balance and storage o There is a large central vacuole in plants that keep the plant plump Turgor Chloroplasts: Found in plants and protists Convert light energy into chemical energy of SUGARS (Look for the poker chips ) 14

15 Mitochondria: Mighty Mitochondria Conversion of chemical energy stored in food to chemical energy of ATP POWER HOUSE OF THE CELL Fun Facts: Chloroplasts & Mitochondria have their own DNA Mitochondrial folds are called CRISTAE For more surface area Most of your mitochondria is inherited from your MOM! (this has genetic significance) 15

16 Cytoskeleton: Includes cilia, flagella, microfilaments, Microtubules*, and centrioles*, *Important in cell division Maintain cell shape, anchorage for organelles, movement of organelles in the cell Cell movement Cell walls (in Plants) 1. Made of CELLULOSE 16

17 The difference between Plant and Animal Cells Plant Animal Cell Wall Chloroplast X X Vacuole One giant Many small Cell Shape More square More circular Centriole Lysosome X X Kingdom Plantae Animalia 17

18 CELL MEMBRANE A thin flexible barrier that surrounds a cell. Made of a lipid bilayer PROTEIN CHANNEL In the membrane there are many proteins with carbohydrates attached o The cell membrane looks like a MOSAIC 18

19 CELL WALL Found in: Plants Algae Fungi Prokaryotes (many) Main function: Support the cell Protect the cell Made of CELLULOSE RIGID 19

20 REGULATING MOVEMENT ACROSS THE CELL MEMBRANE Draguesku Some definitions: Solution: A mixture of 2 or more substances Example: Kool-aide and H 2 O Solute: The substances dissolved in the solutions Example: the Kool-aide powder Concentration (of a solutions): The mass of a solute in a given volume Example: 12 g NaCl in 3 L of H 2 O= 12g/3L 4g/L 20

21 How do you think the food you eat gets to the cells in your body? (answer in the space below) Molecule demonstration Write your observations of what happened after Dr. D. released the molecules Why do you think your observations happened? 21

22 DIFFUSION: The movement of molecules from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION across a SELECTIVELY PERMEABLE MEMBRANE Molecules move down the Concentration Gradient The difference in concentration of molecules ***Molecules continue to move until EQUILIBRIUM is reached What is the concentration of the molecules on each side of the membrane? 22

23 How much energy is needed to reach EQUALIBRIUM? Works by random particle movement!! Osmosis: The diffusion of H 2 O molecules through a selectively permeable membrane Definition: membrane that only allows certain substances through. Also called semipermeable 23

24 Solute molecules Water molecules move in the direction where there are fewer (lower concentration) of water molecules ***Be careful to look at the number of molecules of H 2 0** Definitions to know Isotonic: The concentration of solutes is the same inside and outside of the cell Hypertonic: Solution has a higher solute concentration than the cell. (number of molecules of solute is higher in the solution) 24

25 Hypotonic: Solution has a lower solute concentration than the cell. (number of molecules of solute is lower in the solution) Here s what happens in the animal cell in solution Isotonic Solution: water in water out NO change In the cell Hypertonic Solution: water out Cell shrinks Hypotonic Solution: water in Cell Bursts 25

26 PLANT CELL: Hypertonic: VACUOLE COLLAPSES Hypotonic: VACUOLE SWELLS Isotonic: NO CHANGE IN VACUOLE 26

27 Facilitated Diffusion Diffusion using Protein channels Fast and specific but still Diffusion PASSIVE TRANSPORT = NO ENERGY 27

28 ACTIVE TRANSPORT Requires ENERGY Usually uses pumps Molecules can be located in cells Move against the CONCENTRATION GRADIENT (Moving from LOW to HIGH) (ACTIVE TRANSPORT VIDEO) ansport--whole.htm web code: cbe

29 PHAGOCYTOSIS ENDOCYTOSIS ACTIVE TRANSPORT PINOCYTOSIS EXOCYTOSIS Endocytosis: Take material into the cell by folding and engulfing Vacuole formed inside the cell Two types: 1. Phagocytosis= cell eating Cytoplasm surrounds the particle and engulfs it 29

30 2. Pinocytosis = cell drinking Draguesku Liquid filled pockets along the membrane pinch off inside to form vacuoles inside the cell Exocytosis Membrane of the vacuole fuses with the cell membrane and forces its contents out of the cell (video) 30

31 So how large is a cell? The Levels of Cell Organization: Single Cell - smallest structural unit of an organism that is capable of independent function. Example - White Blood Cell 31

32 Tissue A group of cells that all do the same work Example - Muscle Organs: A group of tissues that work together to perform a function Example: Heart, lungs, kidneys A g r o u p o f E 32

33 Organ System A group of organs that do a certain job. Examples - Circulatory System, Digestion System, Lymphatic System (immune System) Important Point: Cells in an organism may differ in appearance and function, but they all work together to keep the organism alive Unicellular = Single cell These organisms out number multicellular organisms 33

34 Multicellular = Many cells Cell specialization: Cells can develop to do different tasks CELL DIVISION 2 MAIN STAGES MITOSIS CYTOKINESIS CELLULAR DIVISION OF BODY CELLS SIMILAR TO ASEXUAL REPRODUCTION DIVISION OF THE CYTOPLASM 34

35 REPLICATES Draguesku The nuclear material =DNA Starts as chromatin= Thread like coils Chromatin CONDENSES (THICKENS) CHROMOSOME Sister Chromatids 35

36 The human body cell has 46 chromosomes each with 2 Sister Chromatids 36

37 2HRs 1 HR 10 HRS 9 HRS. Interphase: G 1, S, G 2 Chromosomes copied DNA & Centrioles Replicate(copied) 37

38 Begins. PROPHASE Chromatin Chromosome Centrioles separate Spindles begin to form ***Nuclear membrane breaks down*** 38

39 METAPHASE Draguesku Chromosomes line up across the MIDDLE of the cell (equatorial plate) Chromosome connected to spindle fiber at its CENTROMERE 39

40 ANAPHASE Centromeres SPLIT Chromatids SEPARATE each becomes a NEW CHROMOSOME New chromosomes move to the ends Cell stretches SHORTEST PHASE!! LASTS ONLY A FEW MINUTES 40

41 TELOPHASE Nuclear membrane REFORMS Chromosomes lose distinct shape LAST PHASE OF MITOSIS CYTOKINESIS 2 DAUGHTER CELLS are formed Cell membrane pinches off completely 41

42 Mitosis in Plant Cells A CELL PLATE develops and begins by being fused with the cell membrane Then later it will separate from the cell membrane and fuse with the parental cell wall. Now there are 2 daughter cells 42

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