Presentation on theme: "Cell Discovery, Theory, & Organelles Direct Instruction Synthesize Notes on 26R."— Presentation transcript:
Cell Discovery, Theory, & Organelles Direct Instruction Synthesize Notes on 26R
Cell Diversity and Size
First Sightings of Cells Around 1590, the invention of the microscope made it possible for people to discover and learn about objects on the micro (µ) scale. Micro = 10 -6
One of the first people to observe cells was Robert Hooke. He looked at cork samples and named what he saw cells.
Robert Hooks composite microscope
Anton von Leeuwenhoek was the first person to observe what are now called bacteria. Matthias Schleiden found that all plants are made of cells.
Theodor Schwann, found that all animals are made up of cells. Rudolf Virchow proposed that new cells are formed only from existing cells
The Cell Theory One of the fundamental ideas of modern biology Includes 3 principles: 1. All living organisms are composed of one or more cells 2. Cells are the basic unit of structure and organization of all living organisms 3. Cells arise only from previously existing cells
Remember 2 major cell types Eukaryotes Prokaryotes
Prokaryotic cells Cells that do not contain a nucleus & membrane bound organelles Prokaryotes contain DNA, but only a single, circular molecule Which kingdoms contain living organisms with only prokaryotic cells?
PROKARYOTES UNICELLULAR ORGANISMS EXAMPLE= cyanobacteria Fossil 2 billion years old (left) and living (right). Note the similarities in appearance. Interspersed among the cyanobacteria colonies are chains of rod- shaped bacteria.
Eukaryotic cells Contain a nucleus and membrane- bound organelles More advanced – organelles allow specialized cell functions to take place in different parts of the cell at the same time Which kingdoms contain eukaryotic cells?
INTERNAL ORGANIZATION ORGANELLES: –CELL COMPONENT THAT PERFORMS SPECIFIC FUNCTIONS FOR THE CELL
Parts of the cell that both eukaryotes and prokaryotes have
Most cells have a: Cell Wall Cell wall Thick, rigid, mesh of fibers that surrounds the outside of the plasma membrane, protecting the cell and giving it support Which Kingdom does NOT have a cell wall?? Make sure you know what each kingdoms cell wall is composed of!!
All cells have a: Plasma membrane PLASMA MEMBRANE Plasma membrane – flexible boundary that controls the movement of substances into and out of the cell
Plasma Membrane The plasma membrane has selective permeability: Allows some substances to pass through while keeping others out
Structure of the plasma membrane The plasma membrane can have this selective permeability because it is composed of a phospholipid bilayer Phospholipid bilayer = two layers of phospholipid molecules arranged with polar heads facing outside and nonpolar tails facing inside
Plasma membrane – phospholipid bilayer
Plasma membrane continued… Proteins are embedded in the phospholipid bilayer Held in place by polar (charged)/non-polar attractions Help cells recognize each other Recognize & bind specific substances Move substances in and out of cell
The phospholipids create a sea in which other molecules can float, like apples floating in a barrel of water.
All Cells Have CYTOPLASM: –CELL GOO INSIDE CELL –WHERE THE ORGANELLES ARE LOCATED –ALSO CALLED CYTOSOL
Cytoplasm Cytoplasm= semifluid material inside the cells plasma membrane In prokaryotes, all of the cells functions take place directly in the cytoplasm In eukaryotes, all of the cells functions take place within organelles in their cytoplasm Cytoplasm
Cytoskeleton Supporting network of long, thin protein fibers that form a framework for the cell and provide an anchor for the organelles inside the cells
CYTOSKELETON NETWORK OF LONG PROTEIN STRANDS IN THE CYTOSOL NO MEMBRANE AIDS IN MOVEMENT OF ORGANELLES MICROFILAMENTS: –THREADS OF A PROTEIN CALLED ACTIN. –SMALLEST STRAND MAKES UP CYTOSKELETON
MICROTUBLES: LARGEST STRANDS HOLLOW TUBES WHEN CELL IS ABOUT TO DIVIDE BUNDLES COME TOGETHER AND EXTEND ACROSS THE CELL SPINDLE FIBERS: THICK BUNDLES ASSIST IN MOVEMENT OF CHROMOSOME DURING CELL DIVISION
All cells have: RIBOSOMES MAKES PROTEINS MOST NUMEROUS ORGANELLE IN THE CELL NO MEMBRANE 60% RNA AND 40% PROTEINS MAKE UP RIBOSOME'S
PRODUCED & ASSEMBLED IN THE NUCLEOLUS Many Proteins are produced by a specialized cell, e.g. antibodies –transported and used elsewhere in the organism WHEN RIBOSOMES ARE ATTACHED TO ER: –PROTEINS INSERTED TO MEMBRANES –PROTEINS EXPORTED FROM CELL Electron Micrograph of ribosomes. The ribosomes operate in chains when translating a mRNA.
Proteins (AA chains) being made by ribosomes from mRNA Once amino acids bond together to form a chain, it is now a protein, and can be used by the body. Simplified translation on the ribosome
JHK PROTEIN CHAIN JHK RIBOSOMES Allow PROTEIN CHAINS to be made correctly Translation = the language of nucleic acids translated to the language of proteins
Eukaryotes have organelles that prokaryotes do not have.
NUCLEUS: –LARGE –NEAR CENTER OF CELL –CONTAINS MOST OF CELLS GENETIC INFO –DIRECTS MOST ACTIVITIES OF CELL
Nucleus In eukaryotic cells, the central membrane- bound organelle that manages cellular functions and contains DNA Surrounded by a nuclear envelope – a double membrane that has nuclear pores to allow substances in and out of the nucleus
NUCLEAR MATRIX= PROTEIN SKELETON NUCLEAR ENVELOPE= DOUBLE MEMBRANE AROUND NUCLEUS CHROMOSOME= DENSELY PACKED (X) CHROMATIN CHROMATIN= COMBO OF DNA & PROTEIN (stretched out chromosome) NUCLEAR PORE= SMALL HOLES (Doors) NUCLEOLUS= RIBOSOME SYNTHESIS, PRODUCTION
nuclear pores nucleus
ENDOPLASMIC RETICULUM (ER) A SYSTEM OF MEMBRANE BOUND SACS AND TUBULES INTRACELLULAR HIGHWAY –MOLECULES MOVE FROM ONE PART OF CELL TO ANOTHER 2 TYPES OF ER: –SMOOTH ER= (no ribosomes) –ROUGH ER= (COVERED W/RIBOSOMES)
Endoplasmic reticulum Highly folded membrane system in eukaryotic cells that is the site for protein and lipid synthesis
ROUGH ER: MAKE PROTEINS USED FOR EXPORT OUT OF THE CELL ALSO TO BE INSERTED INTO THE CELL MEMBRANE SMOOTH ER: INVOLVED IN PRODUCTION (SYNTHESIS) OF STEROID GLAND CELLS REGULATION OF CALCIUM LEVELS BREAKDOWN OF TOXIC SUBSTANCES BY LIVER CELLS
SMOOTH ER ROUGH ER
Golgi apparatus UPS crew Flattened stacks or sacs of membranes that modifies, sorts, and packages proteins into sacs called vesicles Vesicles can fuse with the cells plasma membrane to release proteins to the environment outside of the cell
GOLGI APPARATUS PROCESSING PACKAGING SECRETING ORGANELLE SYSTEM OF MEMBRANESPANCAKES MODIFIES PROTEINS FOR EXPORT BY CELL
Vacuoles storage crew Membrane-bound vesicle for temporary storage of materials such as food, enzymes, and wastes
LYSOSOME clean up crew SMALL SPHERICAL ORGANELLE ENCLOSE ENZYMES in a SINGLE MEMBRANES DIGEST PROTEIN, CARBS., LIPIDS, DNA, RNA –When needed: OLD ORGANELLES, VIRUSES, BACTERIA THAT WERE INGESTED RARE IN PLANT CELLS
MITOCHONDRIA CONTAIN THEIR OWN DNA (circular) SURROUNDED BY A DOUBLE MEMBRANE
Mitochondria Power-house Mighty Mouse Converts fuel (sugars) into the energy molecule ATP for the rest of the cell
TRANSFER ENERGY FROM ORGANIC COMPOUNDS (pyruvate) TO ATP VIA CHEMICAL RXNS ATP = (AdenosineTriPhosphate) MOLECULE THAT MOST CELLS USE AS ENERGY CURRENCY CAR (MITOCHONDRIA) GASOLINE (CHEMICAL RXN) GAS + ENGINE = CAR STARTS (ATP MADE) CAR RUNS (ENERGY) MITOCHONDRIA IN HUMAN LIVER CELL
SURROUNDED BY: 2 MEMBRANES –OUTER & INNER CRISTAE: –THE LONG FOLDS OF THE INNER MEMBRANE ENLARGE SURFACE AREA WHERE CHEMICAL RXNS TAKE PLACE
HOW CELLS MOVE CELLS USE HAIRLIKE STRUCTURES THAT EXTEND FROM THE SURFACE OF THE CELL SHORT & IN LARGE QUANTITIES = CILIA LONG & LESS NUMEROUS = FLAGELLA
Cilia and Flagella Flagella Long, tail-like projection with a whiplike motion that helps a cell move through a watery environment Cilia Short, numerous projections that look like hair and function in cell movement
Plant cells have 3 structures that animal cell lack 1. Cell wall 2. Chloroplasts 3. Central vacuole
Chloroplast Double membrane organelle that captures light energy and converts it to chemical energy through photosynthesis
Central vacuole Membrane bound space that stores water; Aids in the rigidity of the cell