Cell Notes 2024 PDF

Lesson Overview Life Is Cellular THINK ABOUT IT What’s the smallest part of any living thing that still counts as being “alive?” Can we just keep dividing living things into smaller and smaller parts, or is there a point at which what’s left is no longer al...

Lesson Overview Life Is Cellular THINK ABOUT IT What’s the smallest part of any living thing that still counts as being “alive?” Can we just keep dividing living things into smaller and smaller parts, or is there a point at which what’s left is no longer alive? As you will see, there is such a limit. The smallest living unit of any organism is the cell.  HISTORY OF CELL DISCOVERIES -1665 – ROBERT HOOKE – First discovered and named cells (in non-living cork) -1673 – Anton Van Leeuwenhoek - “Father of MICROSCOPY”. – Examined pond water and sample from a human mouth Drew organisms in the mouth…we later call bacteria The CELL THEORY: 1800s 1. ALL LIVING THINGS ARE MADE OF CELLS. (Schleiden and Schwann) 2. CELLS ARE THE BASIC UNIT OF LIFE 3. CELLS COME ONLY FROM OTHER CELLS (Virchow)…Confirming a suggestion from Lorenz Oken 50 years earlier  Microscopes Light Microscope: allows light to pass through the specimen to form image – Stains are sometimes used to help reveal important structures  Microscopes Electron Microscope: uses a beam of electrons that are focused by magnetic fields – Only used to study nonliving organisms – Higher resolution than light microscope CELLS CAN BE DIVIDED INTO 2 DIFFERENT GROUPS PROKARYOTES EUKARYOTES -Lack ORGANELLES and -Have organelles and a NUCLEUS a nucleus -Always unicellular -Usually multicellular -Cells are not -Cells can be specialized – specialized have a specific function (i.e. nerve cell, muscle cell) -The only examples -Examples include: are BACTERIA ANIMALS, PLANTS, FUNGI and PROTISTS Prokaryotes vs. Eukaryotes  Two Types of Cells: Prokaryotic and Eukaryotic Cells Prokaryotic (before nucleus) – Small and most primitive – All have cell walls and cell membranes – Contain DNA (have nucleoid and plasmid), ribosomes and cytoplasm, but no true nucleus or Bacterium (colored SEM; magnification 8800x) membrane bound organelles – Divide by binary fission – Ex. bacteria  Two Types of Cells: Prokaryotic and Eukaryotic Cells Eukaryote (true nucleus) – Have a true nucleus – Have membrane bound organelles – All have cell membranes – May have cell walls – Can be unicellular or multicellular – More evolved cells – Some have cilia – Divide by mitosis or meiosis – Ex. Plants, animals, fungi, protists (no bacteria)  II. CYTOPLASM_ – Includes A. CYTOPLASM/ CYTOSOL – fluid portion of the cell outside the nucleus B. ORGANELLES – little organs (see chart below) ORGANELLE FUNCTION NUCLEUS CONTROLS Cell Activities; Contains DNA and coded instructions for building proteins 1. Structure a. Nuclear envelope – 2 membranes (each are lipid bilayers) i. Outer layer continuous with rough ER) ii. Nuclear pores: Control movement of proteins, RNA, and molecules in and out of the nucleus b. Nucleolus –where ribosomes are made Nucleus ORGANELLE FUNCTION ENDOPLASMIC ROUGH ER – With RETICULUM ribosomes (ER) Produce products for export SMOOTH ER – No ribosomes Synthesis of membrane lipids Detoxification of drugs (found in the liver) ORGANELLE FUNCTION RIBOSOMES Produce proteins by following coded instructions from DNA; can be attached to ER or free in cytoplasm ORGANELLE FUNCTION GOLGI BODIES Responsible for PACKAGING and TRANSPORT OF cell products out of the cell produce lysosomes ORGANELLE FUNCTION MITOCHONDRIA Site of ENERGY production (ATP -can self replicate -contains its own DNA ORGANELLE FUNCTION LYSOSOMES Filled with enzymes that remove “junk” from the cell Autolysis: Self destruction Autophagy: Recycle cell parts ORGANELLE FUNCTION PEROXISOMES Site of FILTERING toxic materials contains catalase Found naturally in liver ORGANELLE FUNCTION CYTOSKELETON Involved in support, transport, and reproduction of cell  Cytoskeleton – Includes 3 different protein filaments Microfilaments – Thinnest – Threadlike structures made up of a protein called actin – Help cells move Intermediate filament – Middle size; – Holds organelles in place Microtubules – Largest component; – Long, hollow tubes – Maintain cell shape – Important in cell division ORGANELLE FUNCTION VACUOLES Sac-like structure STORAGE of extra sugar, water, salt, and waste Plant cell Known as a central vacuole to hold water and increase rigidity Unicellular Organism Known as a contractile vacuole to pump excess water out of the cell  PLANTS ONLY ORGANELLE FUNCTION CHLOROPLASTS Conversion of SOLAR energy and CO2 into CHEMICAL energy (glucose) ORGANELLE FUNCTION NUCLEUS CONTROLS Cell Activities; Contains genetic information ENDOPLASMIC ROUGH ER – With ribosomes; Produce products for export RETICULUM SMOOTH ER – No ribosomes; System of channels (ER) RIBOSOMES Site of PROTEIN synthesis; Can be attached to ER or free in cytoplasm GOLGI BODIES Responsible for PACKAGING and TRANSPORT OF cell products MITOCHONDRIA Site of ENERGY production (ATP) LYSOSOMES Site of DIGESTION, DISPOSAL, and LYSIS of cells PEROXISOMES Site of FILTERING toxic materials CYTOSKELETON Involved in support, transport, and reproduction of cell VACUOLES STORAGE of extra sugar and water PLANTS/ALGAE ONLY CHLOROPLASTS CONVERT SOLAR ENERGY AND CO2 🡪 GLUCOSE AND O2 Prokaryotic Cell Review  III. The Cell WALL – Tough, outer layer outside of cell membrane Found in PLANTS (Cellulose), FUNGI (Chitin), and some BACTERIA (Peptidoglycan) For support and protection Not found in ANIMAL cells  Cell Structures I. The Cell Membrane (The LIPID Bilayer)…aka: Plasma Membrane…a thin, flexible barrier A. Separates (Boundary) B. Regulates (what comes in and out) 1. Semi-permeable: (aka: selectively permeable)- Controls what enters and leaves C. Communicates  Cell Membrane AKA: Lipid Bilayer or Plasma Membrane  B. Structure – Composed mainly of TWO organic compounds B. Structure – Composed mainly of TWO organic compounds 1. PHOSPHOLIPID- lipids – 2 layers a. HYDROPHILIC heads – Face towards water b. HYDROPHOBIC_ tails – Face inwards, away from water 2. PROTEINS – a. INTEGRAL Proteins – All the way through Cell Membrane i. CHANNEL Proteins – Open all the time ii. CARRIER Proteins – Open and close; Carry large molecules in and out (i.e.glucose) b. PERIPHERAL Proteins – On periphery – Inside and out i. Act as RECEPTORS and cell MARKERS C. Fluid Mosaic Model: Cell membrane acts as a fluid and is made of multiple components  Draw, color, and label this! Label: phospholipids, hydrophobic tails, hydrophilic heads, lipid bilayer, integral protein, peripheral protein, carbohydrate chains, inside of cell, outside of cell