Cell Organelles What are some of the differences you see between these two cells? A. Cell Theory 1. All organisms are made up of one or more cells 2. Cells are the basic unit of organization in an organism Cells tissues organ organ system organism 3. All cells come from pre-existing cells B. Microscopes Microscopes allow us to see small organisms (Micro=small; scope=to see) 1. Compound Light Microscope a. 2 or more lenses b. Magnifies up to 1500x the actual size Compound Light Microscope Electron Microscope 2. Electron Microscope a. Sends beams of electrons b. Magnifies up to 500,000x the actual size c. Used to see cell parts Stereoscope 3. Stereoscope a. Dissecting (to see 3D image) Remember: Total magnification = lens (eyepiece) X objective Example: lens (eyepiece) = 10x ; objective = 4x Total magnification = 40x (specimen appears 40x bigger than it s actual size) **Carry a microscope by the arm and base!
C. Types of Cells 1. Prokaryotic cells (primitive, simpler): a. Example: bacteria b. Smallest cells: 1-10µm (in diameter) i. µ (micro)=10-6 c. NO membrane bound organelles d. Kingdoms: Archaebacteria, Eubacteria e. Structure: i. Cell wall: protective outer structure ii. Capsule: tough outer layer beyond the cell wall iii. Flagella: whiplike tail for locomotion iv. Plasma membrane: structure inside the cell wall that regulates homeostasis v. Cytoplasm: jelly-like substance inside the cell vi. Ribosomes: structures that make protein vii. Nucleoid region: where DNA/RNA is found viii. Plasmid: small, circular DNA aside from the nucleoid (useful in biotechnology) ix. Pili: structures that allow bacteria to stick to surfaces and to each other x. Drawing: 2. Eukaryotic cells (larger, more complex): a. Examples: protists, fungi, animals, plants b. Contain membrane bound organelles c. Rod-shaped chromosomes; double helix DNA
Cell Organelles 1) Plasma (cell) Membrane: a. allows materials in/out of the cell in order to maintain homeostasis b. structure of phospholipid bilayer with embedded proteins that determine what goes in/out of the cell c. Found in: plants, animals, bacteria, fungi, protists (all cells) 2) Cell Wall: a. rigid outer layer of protection b. gives structure to the cell c. made of cellulose d. Found in: plants, bacteria, fungi
3) Nucleus: a. control center of the cell b. where DNA is found i. nuclear membrane/envelope: porous to allow materials (not DNA) in/out of nucleus ii. chromatin: thread-like DNA; looks like spaghetti c. Found in: plants, animals, protists, fungi 4) Nucleolus: a. found inside the nucleus b. makes ribosomes c. Found in: plants, animals, protists, fungi 5) Cytoplasm: a. jelly-like substance surrounding the organelles i. some chemical reactions occur here b. Found in: plants, animals, bacteria, protists, fungi (all cells)
6) Ribosomes: a. where proteins are synthesized (made) b. free ribosomes: found in the cytoplasm c. bound ribosomes: found attached to the ER (endoplasmic reticulum) d. Found in: plants, animals, bacteria, fungi, protists (all cells) 7) ER (endoplasmic reticulum): a. Series of intracellular membranes responsible for transporting proteins within a cell i. Rough ER has ribosomes attached to it ii. Smooth ER no ribosomes attached to it b. Found in: plant, animals, fungi, protists 8) Golgi Apparatus (complex): a. Modifies, packages, ships proteins b. Receives protein-filled vesicles (membrane-bound sacs) from ER c. Vesicle fuses with Golgi where the protein is modified d. Vesicle will bud off the Golgi and is transported to another location e. Found in: plants, animals, fungi, protists
9) Mitochondria: a. Makes energy (ATP) for the cell b. Site of cellular respiration (using glucose to make ATP) c. Christae folded inner membrane; used to increase surface area to make more energy d. Found in: plants, animals, protists, fungi 10) Vacuole: a. Storage of excess waste, food and water b. Much larger in plants c. Found in: plants, animals, protists, fungi 11) Lysosome: a. Contains digestive enzymes b. Found in: plants, animals, protists, fungi 12) Chloroplast: a. Traps light energy for photosynthesis b. Photosynthesis process a plant uses to make food (glucose) c. Thylakoid where chlorophyll (green pigment is located) d. Found in: plants, some protists
13) Centriole: a. Aids in cell division b. Found in: animals 14) Cytoskeleton: a. Cell skeleton b. Network of connected filaments and tubules to maintain cell structure c. Found in: plants, animals, protists, fungi 15) Cilia: a. Short, hair-like projections b. Aid in movement c. Found in: some protists, some animals 16) Flagella: a. Long, whip-like tail b. Aids in movement c. Found in: sperm cells in animals, some protists and bacteria
17) Contractile Vacuole: a. Vacuole that collects water and contracts to squeeze it out b. Found in: protists 18) Eyespot: a. Structure that is sensitive to light b. Found in: protists 19) Pseudopod (Pseudo=false; pod=foot): a. false foot b. Extension of cytoplasm into membrane-enclosed area c. Used for movement d. Found in: protists D. Cell Size Why are cells small? 3 reasons: 1. Surface Area (provides) to Volume Ratio (needs): - Surface area is the outside of the cell that can be measured *Represents what the cell provides - Volume is the inside space of the cell *Represents what the cell needs -As the cell size increases, the volume (needs) increases at a faster rate than the surface area (provides) -Surface area is necessary for materials to enter and leave the cell 2. Diffusion: Movement of particles within a cell -Diffusion is not as efficient in larger cells because it takes longer to transport materials through the cell 3. DNA: Cells must have enough DNA to support protein production for the cell
E. Development of multicellular eukaryotes includes differentiation of cells into tissues and organs 1. Stem cells: undifferentiated cells that can become any kind of cell/tissue a. Embryonic stem cells found in embryonic tissue of developing fetuses and umbilical cords b. Adult stem cells found in bone marrow; limited cell differentiation 2. Chemical Signals: can be produced by cells to influence other cells development 3. Differentiation: Controlled by genes in a cell being turned on or turned off ; these instructions are in the DNA F. Comparison of Structure and Function (among various cell types): Note: As an embryo develops, it s cells become differentiated to do different jobs, but each cell has the same DNA 1. muscle cells: Have many mitochondria because they need energy to move 2. skin cells: Broad, flat cell structure allows for frequent replacement 3. nerve cells: Long, thin cells allow for conduction of electrical impulses 4. sperm cells: Male sex cells that will fertilize female egg cells; have flagella and mitochondria
5. Connective tissue cells: Specialized cells; fibrous in nature; form tendons and ligaments 6. Red blood cells: Structure allows for transport of oxygen through the bloodstream using hemoglobin 7. Xylem cells and Phloem cells (in plants): -Xylem-causes capillary action (cohesion and adhesion) of water to flow from roots to stems and leaves -Phloem allows for transport of sugar (glucose) made in the leaves to move to the rest of the plant