Cell Structure and Function The “ins and outs” of plant and animal cells
Learning Targets • Explain the history of gaining knowledge of the cell • Explain the three part of cell theory • Compare and Contrast prokaryotes and eukaryotes
0 The Cell • Smallest working unit of all living things.
Cell Beginnings • Robert Hooke • 1665 • Looked at cork • Publishes his book “Micrographia” which contains pictures of cork as seen through the first microscopes • Coined term “cell”
Cell Beginnings • Anton van Leeuwenhoek • 1674 • One of first to use microscope—first to see living things in a drop of water
Cell Beginnings • Brown • In 1833 Robert Brown discovered that cells had a dark structure in the middle of them • What do you think that was?????
Cell Beginnings • Matthias Schleiden • 1838 • Discovered that all plants are made of cells • Theodor Schwann • 1839 • Discovered that all animals are made of cells
Cell Beginnings • Rudolph Virchow • In 1855 Virchow added one more element to the cell theory • He discovered that all cells arise from the division of preexisting cells
Cell Beginnings • Janet Plowe • 1931 • Plowe demonstrates that the cell membrane is a physical structure and not an interface between two liquids
Cell Beginnings • Lynn Margulis • 1970 • She suggested that mitochondria and chloroplasts are actually the descendants of ancient prokaryotes. Her idea is that prokaryotic ancestors of these organelles formed relationships with early eukaryotic cells that benefited both cells
0 Endosymbiont Hypothesis Endo: Inside A close relationship between two organisms. Symbiont: • The endosymbiont hypothesis implies that eukaryotic cells arose as a combination of different prokaryotic cells.
The Cell Theory Together these scientists’ discoveries are called the Cell Theory. • The Cell Theory States… • That all living things are composed of cells • Cells are the basic units of structure and function in living things • New cells are produced from pre existing cells • THE CELL THEORY APPLIES TO ALL LIVING THINGS!!
STOP THINK!!!! • In your science journal answer the following questions: • What are the three parts of the cell theory? • Name two scientists who made important discoveries about the cell and describe the discoveries that they made.
Basic Cell Structures • Cells come in MANY different shapes and sizes • Some structures are common to most cells: • Cell Membrane • Cell Wall • Nucleus • Cytoplasm
Basic Cell Structures • Cell membrane —thin, flexible barrier around cell • Cell Wall -strong supporting layer around the cell membrane in plants, algae, and some bacteria • Cytoplasm —material inside cell membrane not including the nucleus —site of chemical reactions • Nucleus —(not in all types of cells) controls cell activities and contains most of the genetic information
0 Two types of cells: Prokaryotes and Eukaryotes
0 Prokaryote: = Before Pro = Nucleus Karyon Ex: Bacteria No Nucleus
0 Eukaryote: = True Eu Karyon = Nucleus Ex:Animal and Plant cells Has a nucleus
Prokaryotic Cells Do not have a nucleus Only have cell wall, cell membrane and ribosomes Missing all other organelles Eukaryotic Cells Contains a nucleus Membrane bound organelles Cell Comparison
Cell Comparison Eukaryotes Prokaryotes Nucleus and Membrane Bound Organelles No nucleus or membrane bound organelles Cell membrane Ribosomes Cell wall
Section 7-2 The Cell Learning Targets • Identify the basic cell structures • List Functions of Basic Cell Structures • Compare and Contrast Plant and Animal Cells
ORGANELLE • Smallest working unit within a cell • Means “little organ” • Organelle DNA • Chloroplasts and mitochondria have their own DNA • Endosymbiotic Hypothesis— Lynn Margulis suggested that these organelles used to be prokaryotic cells
Nucleus Nucleolus Smooth endoplasmic reticulum Cytoplasm Animal Cell Nuclear envelope Centrioles Ribosome Rough endoplasmic reticulum Ribosome (attached) Cell Membrane Lysosome Golgi Apparatus Mitochondria
Nucleolus Smooth endoplasmic reticulum Nucleus Plant Cell Cell Wall Nuclear envelope Rough endoplasmic reticulum Vacuole Ribosome Golgi Apparatus Chloroplast Mitochondria Cytoplasm Cell Membrane
0 Nucleus • JOB: The structure that controls the cell’s activities and contains DNA. • The control center or “brain” of the cell
Nucleus, cont’d • Only found in eukaryotes, not prokaryotes • Contains chromatin (DNA + protein) • During cell division, chromatin condenses to form chromosomes (packages of genetic info—DNA) • Contains nucleolus (RNA + protein) • Makes ribosomes • Surrounded by nuclear envelope, which has pores control what enters and exits the nucleus
0 Nucleolus • Found inside the nucleus • Composed of RNA and protein. • JOB: Ribosomes assembled here.
0 Nuclear Envelope • JOB: Controls what enters and exits the nucleus.
0 Chromatin • Found in the nucleus of a cell. • Contains DNA bound to proteins. • Known as Chromosomes when thicken and shortened
STOP! THINK!!! • Using your brain (only) See if you can name the organelles we just discussed. • What do they do? • Where are they found?
0 Cell Membrane • Outer boundary of the cell • Separates cell from its surroundings. • JOB: Regulates what enters/exits the cell. • Provides protection and support
Cell Membrane • Phospholipid Bilayer • Double layered sheet with hydrophilic (loves water) and hydrophobic (fears water) layers • Provides flexible but tough covering • Protein molecules • Act as channels and pumps • Carbohydrates • Act as ID card (are attached to lipid or protein)
0 Endoplasmic Reticulum • Jobs: Assembles cell membrane; modifies proteins. • Two types: • Rough ER • Smooth ER
ER, cont’d. • TWO TYPES • Rough ER • Covered with ribosomes • Helps with making/ modifying proteins • Smooth ER • No ribosomes • Synthesizes membrane lipids and fats • Has enzymes to do special tasks • Proteins and lipids produced in Rough and Smooth ER are sent to the Golgi Apparatus or Cell Membrane
0 Golgi Apparatus • Proteins from the Rough ER are sent here next for customization • JOB 1: Customizes and transports proteins and other macro-molecules. • JOB 2: Packages and ships to other parts of cell
Golgi Apparatus • Customize means: • Attaches carbohydrates and lipids to proteins then sends them to right place in the cell
0 Ribosomes • Tiny particles of RNA and proteins. • JOB: Where proteins are assembled.
Ribosomes, cont’d. • Make proteins • Made of RNA + protein • Found in two places: • Attached to endoplasmic reticulum (Rough E.R.) • Free floating in cytoplasm
STOP! THINK!!! • Can you trace the path of a protein in a cell?? • Where do the instructions start? • Where are they built? • Where are they modified? • Where are they sent??
Mitochondria 0 • “Powerhouse of the cell” • “MIGHTY MITOCHONDRIA” • JOB: Converts chemical energy found in food (sugars and starches) into usable energy for cell (ATP)
Mitochondria • Many reactions that produce ENERGY occur in the mitochondria • The cell cannot survive without energy • In plants-- converts the chemical energy produced in chloroplast by photosynthesis into ATP • “Inner membranes of mitochondria have many folds increasing surface area these reactions take place in the inner membranes” • Increased Surface Area= More reactions = more energy created • Where respiration occurs • C6H12O6 + O2 CO2 + H2O + ATP
0 0 Cytoplasm • Cyto = Cell • Plasm = Fluid
Vacuoles • Jobs: • Store water, salt, protein, carbohydrates • Central Vacuole—In plants • Allow them to support heavy structures such as leaves