The Cell PDF

THE CELL THE MODERN CELL THEORY Smallest unit of life 1. The cell is the basic unit of life Can function independently 2. All organisms are made up of All organisms consist of one or one or more cells more microscopic...

THE CELL THE MODERN CELL THEORY Smallest unit of life 1. The cell is the basic unit of life Can function independently 2. All organisms are made up of All organisms consist of one or one or more cells more microscopic structures 3. All cells come from pre-existing cells PEOPLE WHO CONTRIBUTED THE EXPANDED VER. Zacharias Janssen 1. Cells carry genetic material - Late 1500s passed to daughter cells during - a spectacle maker from the cellular division Netherlands 2. All cells are essentially the - invented the microscope same in chemical composition Anton van Leeuwenhoek 3. Energy flow (metabolism and biochemistry) occurs within - 1600s cells - Dutch shopkeeper with great skills in crafting lenses PROKARYOTES VS. EUKARYOTES - observed the movements of Biologists have never found a cell protists and sperm and called it they can’t assign to just one of two “animalcules” basic types: prokaryotic or Robert Hooke eukaryotic. - 1665 A cell’s most obvious distinguishing - Publication called feature is the presence or absence of “Micrographia” a cell nucleus. - Coined the term “cellulae” for EUKARYOTIC CELLS the box-like structures when he viewed cork tissue - eu = true, karyo= nucleus - contain a prominent, roughly Matthias Schleiden (BOTANIST) and spherical, membrane-enclosed Theodor Schwann (ZOOLOGIST) body called “nucleus” - Late 1830s nucleus - which houses DNA - studying tissues and proposing the first postulates of the cell DNA - the cell’s hereditary material theory nucleus bound by membrane Rudolf Virchow fungi, protists, plants, and animals - made important contributions possess many organelles - unified cell theory has been presented - illuminated the cell’s significance to life 1|Page PROKARYOTIC CELLS PLASMA/CELL MEMBRANE - pro= before, karyo= nucleus - semi-permeable membrane - the DNA is loose in the cell’s - composed of a lipid bilayer and interior and not separated proteins from the rest of the cell’s - present in both animal and contents by a membrane plant cells. CYTOPLASM first cell type on Earth (bacteria and archaea) - where the cell’s internal no membrane-bound nucleus organelles are suspended. (nucleoid) NUCLEUS organelles not bound by - contains genetic information or membranes DNA in eukaryotic that controls thrive in the boiling waters of most of the cell’s activities hot springs (for some - the information in DNA is prokaryotes) copied into RNA SIMILARITIES - RNA then moves out of the have cell membrane nucleus into the cytoplasm, have cytoplasm and its information is used to make proteins have ribosomes - DNA > RNA > Protein have DNA ENDOPLASMIC RETICULUM (ER) CELL’S STRUCTURE AND FUNCTIONS - Endo = inside Plasmic = cell CYTOSKELETON Reticulum = network - structure of thin fibers forming - system that forms a lattice compartments within the - suspending the organelles and cytoplasm. allowing cell parts to move. - main function is in lipid CENTRIOLE synthesis and the manufacture of proteins - organize the cytoskeletal fibers called “microtubules” into ROUGH ER - membrane surface that scaffolds is studded with ribosomes making - maintain cell shape and move proteins that enter chromosome SMOOTH ER - synthesizes lipids and houses enzymes that detoxify drugs 2|Page MITOCHONDRIA PEROXISOMES - harvesters of energy - originates in Endoplasmic - powerhouse of the cell Reticulum - singular = Mitochondrion - contain several types of - harvest energy from food by enzymes that dispose of toxic breaking down ATP substances - provides chemical fuel for SPECIALIZED ORGANELLES cellular activities CELL WALL ATP - carbon-containing molecules that release energy packets - its porous wall allows water, gases, and some solid materials RIBOSOMES to pass through cell membrane - provides a site for protein PLASTIDS synthesis - may lie freely in the cell or - found in plants and some attach to the membranes of protozoa that harvests solar the endoplasmic reticulum energy, manufacture nutrient - no functional ribosomes inside molecules, and store materials the nucleus, so protein building CHLOROPLASTS occurs only in the cytoplasm. - type of plastid that traps the GOLGI APPARATUS energy of sunlight in a chemical - collection of flat sacs that form – generally, sugar process proteins for export molecules in photosynthesis. - known as the processing center FLAGELLUM - modifies, sorts, tags, packages, and distributes lipids and - either propels the cell, acting proteins. as a locomotory device, or moves fluids past the cell, LYSOSOMES becoming a feeding apparatus - cell’s recyclers CILIUM or CILIA - containing enzymes that dismantle and recycle food - small hair-like protuberances particles and captured bacteria on the outside of the eukaryotic VACUOLES - primarily responsible for - large fluid-filled sac inside cells locomotion surrounded by a single membrane - Plant cells: important for maintaining cell shape 3|Page MICROSCOPE PARTS AND FUNCTION Albert Crewe MICROSCOPE - designed the first scanning transmission electron - an important tool used by microscope biologists in their experimental - could magnify the image of tiny analysis. organisms to 7.5 million times - can easily view the structure of bacteria and other CLASSIFICATION OF MICROSCOPE microorganisms SIMPLE - like a magnifying glass, - could be optical and electronic consists of one double convex lens Ernst Ruska and has a short focal length - discovered that a magnetic coil COMPOUND - made up of a system could be used as a lens for of lenses (ocular and objective lenses) electron beams that can invert images. - developed the first electron OPTICAL – used for special purpose microscope in 1933 PARTS OF MICROSCOPE MECHANICAL, ILLUMINATING, AND MAGNIFYING 4|Page MECHANICAL PARTS – framework of Coarse Adjustment Knob microscope - large wheel used along with Stand or Base LPO for rough focus of the specimen - horse-shoe shaped iron portion that supports the entire Revolving Nosepiece microscope - below the draw tube for Pillar attachment and shifting of objectives - short connection between the base and the microscope Dust Shield Inclination Joint - black metallic disk above the revolving nosepiece to prevent - located between the pillar and dust entering the objectives the arm for tilting the upper part of the microscope to a Body Tube desired position - supports the objectives and the Substage ocular - located immediately below the Draw Tube stage containing the iris - a place where the eyepiece or diaphragm and condenser ocular is inserted Stage ILLUMINATING PARTS – regulation of - platform with an opening to let light the light pass and where the Mirror slide with the specimen is placed - used to focus the rays of the light source from the sun Arm toward the object - connects the base with the Light Bulb body tube - used to further control or Stage Clip concentrate the light from the - keep the glass slide in place source Fine Adjustment Knob Abbe Condenser - smaller wheel to see the finer - used to further control or detail of the object for precise concentrate the light from the focusing source Iris Diaphragm - regulates the amount of light passing through the condenser 5|Page MAGNIFYING PARTS – enlargement ANIMAL CELL VS PLANT CELL of objects PLANT CELL Eyepiece large and fixed rectangular- - fits into the draw tube shaped OBJECTIVES cell wall is present nucleus lies on one side - small tubes containing lenses mitochondria are present in attached to the nosepiece fewer numbers which magnify the object or plastids are present the specimen centrosomes are present 3 MAGNIFYING POWER: one large central is present LOW POWER OBJECTIVE (LPO) ANIMAL CELL - shorter tube; marked 10X small and irregular or round which is the lowest ocular shape magnification cell wall is absent HIGH POWER OBJECTIVE (HPO) nucleus lies in the center mitochondria are present in - longer tube; marked 45X or large numbers 43X & 40X sometimes plastids are absent OIL IMMERSION OBJECTIVE centrosomes are present many small vacuoles are - same length as the HPO; present marked 97 or 100X a special oil is placed on an object being studied 6|Page 7|Page