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Biology - Chp 3 - Cells - Notes
- 1. Chapter 3 Cells
- 2. Historical View ofthe Cell Theory • As science improves, so do improvements in scientific instruments, and improved scientific instruments lead to new discoveries 1590 – Zacharias Janssen • Dutch lens maker, built first __________________________________________ 1670’s – Anton Van Leeuwenhoek • Dutch naturalist and lens maker, made simple microscope that could magnify objects 270 times • Saw bacteria, protozoa, sperm cells, red blood cells and yeast cells 1665 – Robert Hooke • English physicist, combined two sets of lenses and produced a _______________________________________________ • Examined a thin piece of cork, saw hollow boxes and named them _______________________ 1831 – Robert Brown • Scottish botanist, saw central structure in plants cells, called this structure a ________________________ 1838 – Matthias Schleiden • German botanist, concluded that all plants are made of ________________ 1839 – Johannes Purkinje • Czech physiologist, studied “protoplasm” • Stated that _________________________________________________________ ________________________________________________________ _ 1858 – Rudolf Virchow • German scientist, “father of pathology” • Concluded that _____________________________________________________ _____________________________________________________ • These discoveries, confirmed by other scientists are summarized in the cell theory The Cell Theory 1. 2. 3. 2
- 3. The Compound Microscope:Parts and Functions Compound microscope - ___________________________________________________ Eyepiece or ocular lens - ___________________________________________________ Objective lens - __________________________________________________________ How to figure out magnification • Multiply eyepiece by the objective lens Eyepiece X objective = Magnification 10x X 10x X 10x X Nosepiece - ______________________________________________________________ Stage - _________________________________________________________________ Stage clips - _____________________________________________________________ Body tube - ______________________________________________________________ Light source - ____________________________________________________________ Diaphragm - _____________________________________________________________ Base - __________________________________________________________________ Arm - __________________________________________________________________ Coarse focusing knob - ____________________________________________________ Fine focusing knob - ______________________________________________________ • A microscope reverses and inverts the image of an object seen under it • Things moving under a microscope are actually moving in the opposite direction 3
- 4. Stereomicroscope • Binocular microscope • Object is seen in 3-D • Only used to see large objects • Does not reverse or invert images Transmission Electron Microscope • Uses a beam of electrons instead of light rays • 200,000x magnification • tissues have to be sliced really thin, dry and in a vacuum chamber • can’t be used with living material Scanning Electron Microscope • provides images with 3-D quality • can’t be used with living material • Knowledge of cells has been increased by manipulation and dissection of cells Micromanipulator – used to dissect cells, can remove nuclei High – Speed Centrifuge • Spin at high speeds • Cell components sort out in different layers according to density 4
- 5. Microscopic Measurements • Objects seen under the microscope are so small that they are measured in a special unit called the ______________________________ • A micrometer is 1/1000 of a millimeter Ex.) red blood cell = 8.5 micrometers Bacteria = 2 micrometers How to convert millimeters to micrometers • Multiply by one thousand or move the decimal point 3 places to the right Ex.) 4.56 mm = 0.0378mm = How to convert micrometers to millimeters • Divide by 1,000 or move the decimal point three places to the left Ex.) A tiny worm is 2,500 micrometers long. How long is this worm in millimeters? 2,500 micrometers = Ex.) Convert .15 micrometers to millimeters .15 micrometers = How to find the diameter of your field of view • Place a transparent plastic ruler in the field of view like this Ex.) 1.3 mm field of view - convert to micrometers 1.3mm = 5
- 6. Name _______________________________________ Date______________________ Homework 1. Explain the difference between a simple microscope and a compound microscope 2. What are the three concepts of the cell theory 3. What damage can result if you focus downward while looking through the eyepiece of a microscope? How can you prevent this? 4. If you were observing an organism in a microscope swimming up and to the right in your field of view, what direction is it really going? 5. Compare and contrast a compound microscope and a transmission electron microscope 6. Compare and contrast a stereomicroscope and a scanning electron microscope 6
- 7. Prokaryotes and Eukaryotes • cells fall into two broad categories depending on whether or not they have a nucleus and membrane covered organelles Eukaryotes - _____________________________________________________________ _______________________________________________________________________ _ Prokaryotes - ____________________________________________________________ _______________________________________________________________________ Prokaryotes • generally smaller • genetic material not in nucleus • simple • ex.) Eukaryotes • larger • genetic material is inside of a nucleus • complex • ex.) Eukaryotic Cell Structure Plasma Membrane (Cell Membrane) ____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________ • allows some materials but not others to pass through…this is called ___________________ ______________________________________ Endoplasmic Reticulum (ER) ____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________ 7
- 8. • some tubes join with the nuclear membrane Ribosomes ______________________________________________ • attached to the walls of the ER or move freely in the cytoplasm Golgi Bodies (Golgi Apparatus) ____________________________________________ ____________________________________________ ____________________________________________ • package protein molecules in a membrane and send the package to the cells surface Mitochondria ____________________________________________ ____________________________________________ Microtubules _____________________________________________ _____________________________________________ Microfilaments _____________________________________________ _____________________________________________ _____________________________________________ 8
- 9. Lysosomes _____________________________________________ _____________________________________________ _____________________________________________ • fuses with food vacuoles to digest food into smaller • digest old cell structures to dispose of them or even entire cells The Nucleus _____________________________________________ _____________________________________________ • separated by a double layered membrane • has pores in the membrane to permit certain chemicals to pass • holds the chromosomes • chromosomes - _____________________________ _________________________________________ _________________________________________ _________________________________________ The nucleus contains two types of nucleic acids: • DNA (deoxyribonucleic acid) • RNA (ribonucleic acid) Contains a smaller body called a ________________________________ • Composed of RNA • Involved in the passage of RNA to the cytoplasm Centrioles _______________________________________________ _______________________________________________ Cilia and Flagella • Outward projections from the cell membrane used for locomotion cilia – short, hair-like flagella – longer, whip-like 9
- 10. Chloroplasts _______________________________________________ _______________________________________________ Vacuoles _______________________________________________ _______________________________________________ • Plant cells have very large vacuoles compared to animal cells Cell Wall ________________________________________________ ________________________________________________ • Made of cellulose • Permits most things to pass through Cell Wall 10
- 11. Name ___________________________________________ Date__________________ Homework 1. Lysosomes are often referred to as “suicide sacs”. What reason can you give for this? 2. Could a cell live without a nucleus? 3. Of what materials are chromosomes composed of? What is the function of chromosomes? 4. Describe the difference between a typical plant cell and a typical animal cell 5. Describe the difference between the cell membrane and the cell wall 11
- 12. Cell Boundaries 1. Cell membrane - ____________________________________________________ _________________________________________________________________ _ Outside of cell Carbohydrate chains Proteins Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer • Made of a double layered sheet called a ______________________________ o Gives it its flexible structure o Also contains protein molecules and carbohydrates embedded in the bilayer o Proteins form channels and pumps that help move material across the membrane o Carbohydrates act as ID cards 2. Cell Walls - ________________________________________________________ • Found in plants, algae, fungi and many prokaryotes • Allow many molecules to pass through easily (not selectively permeable) Diffusion Through Cell Boundaries • One of the most important functions of the cell membrane is to regulate the movement of dissolved molecules from one side of a membrane to the other. Measuring concentration Concentration - ___________________________________________________________ Ex.) What is the concentration of 12 grams of salt in 3 liters of water? 12
- 13. Ex.) What isthe concentration of 12 grams of salt in 6 liters of water? Which is more concentrated? • In a solution, particles move constantly. They collide with one another and tend to spread out randomly Diffusion - ______________________________________________________________ _______________________________________________________________________ _ Equilibrium - ____________________________________________________________ _______________________________________________________________________ _ • Because diffusion depends on random particle movements, substances diffuse across membranes without ____________________ being used • Even during equilibrium, particles still move, but there is no net change in concentration Osmosis - _______________________________________________________________ How Osmosis Works 13
- 14. Osmosis Terminology Isotonic -_______________________________________________________________ _______________________________________________________________________ Hypertonic - _____________________________________________________________ _______________________________________________________________________ _ Hypotonic - _____________________________________________________________ _______________________________________________________________________ 14
- 15. Facilitated diffusion -______________________________________________________ _______________________________________________________________________ _ ex.) glucose passing into cells • Only go from high concentration to low concentration • Does not require energy Types of Active transport • Sometimes cells must move materials in the opposite direction – low concentrations to high concentrations Active transport - _________________________________________________________ _______________________________________________________________________ _ Molecular transport - ______________________________________________________ Carrier proteins - _________________________________________________________ • Requires a lot of energy to keep working • Moves substances against a concentration gradient Endocytosis and Exocytosis • Some molecules are too large to be moved by carrier proteins 15
- 16. Endocytosis - ____________________________________________________________ _______________________________________________________________________ _ • Forms a vacuole • Large molecules, clumps of food and even whole cells can be taken in this way Examples of Endocytosis Phagocytosis – extensions of cytoplasm surround a particle and package it within a food vacuole. • We can give this the nickname __________________________ Pinocytosis – tiny particles form along the cell membrane, fill with liquid, and pinch off to form vacuoles within the cell • We can give this the nickname __________________________ Exocytosis - _____________________________________________________________ _______________________________________________________________________ _ 16
- 17. Name __________________________________________ Date___________________ Homework 1. Describe the functions of cell membrane and cell walls 2. What happens during diffusion? 3. Describe how water moves during osmosis 17
- 18. 4. What isthe basic structure of a cell membrane 5. What is the difference between phagocytosis and pinocytosis? 6. What is the main way that active transport differs from diffusion? 7-4 The Diversity of Cellular Life Unicellular organisms - ___________________________ • Do everything a living organism does Ex.) yeast, protests, bacteria Multicellular Organisms - __________________________ • Depend on communication and cooperation among specialized cells Specialization - ________________________________________________________ ____________________________________________________________________ _ Specialized Animal Cells • Red blood cells – • Pancreatic cells – • Skeletal muscle – Specialized Plant Cells • Stomata – exchanges gases with the atmosphere • Guard cells - ____________________________________________________ Level of Organization 18
- 19. Tissues - ________________________________________________________________ Ex.) Organ- _________________________________________________________________ Ex.) Organ System - __________________________________________________________ Ex.) • This organization creates a division of labor that makes multicellular life possible Muscle cell Smooth muscle tissue Stomach Digestive system Homework 1. In what kinds of organisms is cell specialization a characteristic 2. List the levels of biological organization in multicellular organisms from most simple to most complex 3. How are unicellular organisms similar to multicellular organisms 19
- 20. 4. Using whatyou know about the ways muscles move, predict which organelles would be most common in muscle cells 20