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UNIT C Cycling of Matter in Living Systems (Bio) 1.1 A Window on a New World MICROSCOPES  Are anything that will magnify an object Make objects appear larger than they are Allow us to see objects that can’t be seen with our eyes  there are 2 basic types: 1. Simple...

UNIT C Cycling of Matter in Living Systems (Bio) 1.1 A Window on a New World MICROSCOPES  Are anything that will magnify an object Make objects appear larger than they are Allow us to see objects that can’t be seen with our eyes  there are 2 basic types: 1. Simple 2. Compound 1. SIMPLE MICROSCOPES  Are early microscopes Consist of a single lens 2. COMPOUND MICROSCOPES  contain more than one lens are parfocal : –still focused when objectives are switched There are 2 types: A. Research B. Dissecting A. RESEARCH MICROSCOPES  Have one ocular Ocular (eyepiece) Have a rotating nosepiece with 3 objectives  Use transmitted light (passes through specimen) Create an inverted image (upside down & backwards)  Are used to look at transparent specimens Can magnify up to 400 X B. DISSECTING MICROSCOPES  Have 2 eyepieces Ocular (eyepiece) ( biocular ) Have 1 rotating objective has 2 light sources top & bottom  Use incident light (light reflected off of specimen) Create a virtual image (same as it really is)  Are used to look at solid objects Magnify specimens up to 30 X  Comparison of Microscopes Feature Research Dissecting Type of Image inverted virtual Type of Light transmitted incident Number of Oculars 1 2 # of Objectives 3 1 Highest Magnification 400 x 30 x Type of Specimen transparent solid  PARTS OF A MICROSCOPE  Ocular (eye piece) Revolving Nose Arm Piece Objective Lenses Slide Holder Coarse Focus Stage Iris Diaphragm Fine Focus Condenser Light Source Power Switch Base  Ocular (eyepiece) – is the lens you look through – it magnifies the object 10X  Objective Lenses – Magnify the object; -low 4x -medium 10x -high 40x  Revolving Nosepiece – contains 1-4 objectives – Rotates enabling different lenses to be used  Course Focusing Knob – Is used to focus the object on LOW POWER – It moves the stage up and down  Fine focusing Knob – makes the image clearer  Iris diaphragm – regulates the amount of light reaching the slide  IMAGE MAGNIFICATION  Is the magnification you are using when viewing a specimen It is created by both the objective & ocular  Note: Each objective lens has a different power: – Low 4x – Med 10x – High 40x High power Low power Medium power  Formula: Image Magnification = ocular x objective x Example 1: A student is viewing a specimen on low power. What is the image magnification? Ocular = 10 Objective = 4 Image Magnification = Ocular x Objective Image Magnification = 10 x 4 = 40 40x or 40 times bigger Example 2: A student is viewing a specimen on high power. What is the image magnification? Ocular = 10 Objective = 40 Image Magnification = Ocular x Objective Image Magnification = 10 x 40 = 400 Example 3: A student is viewing a specimen on medium power. What is the image magnification? Ocular = 10 Objective = 10 Image Magnification = Ocular x Objective Image Magnification = 10 x 10 = 100 IMAGE  It is what you see Is created using light (transmitted or incident) There are two types: A. Virtual B. Inverted  Blue and red White light reflected (Transmitted) (Incident) A. VIRTUAL  The image is the same as it really is 🡪🡪🡪🡪 Produced by a dissecting microscope Created using incident light ; –reflects off the specimen B. INVERTED  The image is upside down & backwards 🡪🡪🡪🡪 Produced by a research microscope Created using transmitted light; –passes through the specimen FIELD OF VIEW  Is the amount of the specimen you see It is less with higher magnifications It is measured in microns  Low Medium High Power Power Power 4000 μ 1500 μ 400 μ  As you increase magnification, you are ‘zooming in’ on the specimen so you are able to see less of the overall organism. This is why the field of view gets smaller as magnification increases.  DRAWING MAGNIFICATION  Is how much bigger your drawing is then the actual specimen A formula is used to figure this out  Formula: D M = Drawing size Estimated size  Drawing Size Steps: 1. Draw the specimen 1. Measure the widest part in mm 1. Convert mm to microns (1000 μ = 1 mm) 45mm = 45000 μ  Estimating Size Steps: 1. Estimate how many specimens fit across the field 1. Divide the field of view by that number E.g. Low Power 1. About 4 will fit across 2. 4000 μ = 1000 μ 4  Formula: D M = Drawing size Estimated size D M = 45000 μ 1000 μ DM= 45 It is 45 times larger Example 1 A student measures their drawing of a protozoa on low power and it is 64 mm. The student is then asked to calculate her drawing magnification. Step(1) 64 mm = 64000μm Step(2) 4000μ = 666.66 μm 6 D M = drawing size = 64000 μ = 96 estimated size 666.66 μ Example 2 A student measures their drawing of a protozoa on low power and it is 24 mm. The student is then asked to calculate her drawing magnification. Step(1) 24 mm = 24000μ Step(2) 4000μ = 1333.33 μ 3 D M = drawing size = 24000 μ = 18 estimated size 1333.33 μ Example 3 A student measures their drawing of a protozoa on low power and it is 36 mm. The student is then asked to calculate her drawing magnification Step(1) 36 mm = 36000μ Step(2) 4000μ = 1000 μ 4 D M = drawing size = 36000 μ = 36 estimated size 1000 μ  Read pg. 247-251 1.2 Development of the Cell Theory Life From Nothing ✦ Early humans could not explain why life seemed to appear “out of nowhere” ✦ Early doctors and scientists had different theories or models of how this happened -In the mid 1600’s, it was believed that mice could be formed from placing sweaty underwear and husks of corn in a jar for a period of time (~21 days) SPONTANEOUS GENERATION  Is the idea that life can emerge (spontaneously) from non-living matter  It was an idea that continued to thrive from 1500s to the mid 1800s It was disproved by: 1. Francesco Redi 2. Louis Pasteur  VARIABLES IN EXPERIMENTS  Represent conditions that occur in an experiment There are 3: 1. Controlled variable 2. Manipulated variable 3. Responding variable  1.Controlled Variable Are the conditions in an experiment that remain the same for each trial E.g. the temperature in the room  2.Manipulated Variable Are the condition(s) in the experiment that are changed E.g. amount of light  3.Responding Variable Is the response (what happens) E.g. the plant with no light dies  1. Francesco Redi - 1668 Questioned the idea that maggots could appear spontaneously from raw meat Conducted an experiment with flies & meat  Redi’s Experiment Had 3 jars that contained raw meat: – 1 open to the air – 1 completely sealed – 1 covered with gauze (contains tiny holes) Redi’s Experiment The manipulated variable = cover The control variable = meat The responding variable = presence of flies Result = Maggots were only found in the flask that was open and accessible to flies Only the closed one did not have flies  Needlham’s Experiment ✦ Belief: boiling destroyed microorganisms ✦ Needham’s Experiment: put boiled chicken broth into a sealed flask ✦ In theory, no microorganisms should exist ✦ But …microorganisms still appeared?!? ✦ Spontaneous generation remained popular… they ignored contact with air  Spallanzani’s Work ✦ Spallanzani’s belief: microbes in the air inside the flask got into the broth ✦ The test: remove the air from the flask and then seal in the boiled chicken broth ✦ Result: nothing grew in the chicken broth! ✦ Why is Spontaneous generation still popular?!?  2.Louis Pasteur - 1864 Expanded on the work of Needlham & Spallanzani Conducted experiment using broth and S shaped flasks  Pasteur’s Experiment He boiled the broth & put it in an s-shaped flask  After some time he removed the s-shaped flask Result = Swan neck let in no air & there was no mould growth Removal of neck produced mould  Pastuer’s Experiment The manipulated variable = Exposure to dust The control variable = Amount of broth temperature & light The responding variable = Mould growth CELL THEORY  It applies to all living things (except prions & viruses) It is the cornerstone of biology  It has it’s beginning with: 1. Aristotle 2. Robert Hooke 3. Antoni van Leeuwenhoek  1. Aristotle 4 th century B.C. Was a Greek philosopher who made careful observations & records of 500 animals species His scientific approach was the method used by later scientists  2. Robert Hooke 1665 Looked at cork under a microscope He called the empty chambers he saw “cells”  3. Antoni van Leeuwenhoek Used a simple microscope (1 lens) to observe organisms He was the 1st to see the movement of bacteria, sperm, and protozoa He called them “ animalcules”  The Cell Theory States: 1. All living things are made of 1 or more cells and materials made by these cells 2. All life functions take place in the cell, making them the smallest unit of life 3. All cells are produced from pre-existing cells through cell division  Read pg. 253-264 1.3 Developments in Imaging Technology and Staining Techniques MICROSCOPE OBSERVATION  Is affected by 2 factors: 1. Contrast 2. Resolution You can see the structures and it is clear 1. CONTRAST  Is the ability to see differences between structures It is the result of a structures capacity to absorb light  It is increased by using stains  Staining/ Fixation Kills the cell The stain attaches to internal structures in the cell E.g. Iodine or methylene blue 2. RESOLUTION  Is the ability to distinguish between two structures that are close together (sharpness of the image)  0.2 μ is the standard for a light microscope High resolution = more clarity  TECHNOLOGY ADVANCEMENTS  Have allowed for advancements in research & medicine Have allowed us to see organisms that we can’t see with our eyes Have enhanced our ability to see & study cell structures  Examples are: 1. Fluorescence Microscopy 1. Confocal Technology 1. Electron Microscopes 1. FLUORESCENCE MICROSCOPY  Was first used in the 1940’s It uses ultraviolet light to make cells fluorescent 2. CONFOCAL TECHNOLOGY  Was first used in the 1980s uses laser beams & computers to produce 3D images  3. ELECTRON MICROSCOPES  Use a beam of electrons to produce an image (micrograph) There are 2 types: A. Transmission (TEM) B. Scanning (SEM) A. TRANSMISSION ELECTRON MICROSCOPES  Uses dead specimens Passes a beam of electrons through stained tissue imbedded in plastic  magnifies up to 100,000 times operates in a vacuum  A. SCANNING ELECTRON MICROSCOPES  Electrons bounce off of gold covered specimens (gold reflects) It produces a 3D image  It magnifies 300,000 times Human Eye lashes  1.4 Cell Research at the Molecular Level CELL RESEARCH  Is the result of new technology Has resulted in breakthroughs in medicine & industry  Examples: 1. Scanning Tunnelling Microscope (STM) & Atomic Force Microscope (AFM) 1. Gene Mapping 1. Fluorescent Antibody technique 1. X-ray crystallography 1. GFP technology 1. STM & AFM  Both have allowed scientists to produce images of molecules Improved understanding of the structure & function of molecules 2. GENE MAPPING  Geneticist showed the material in chromosomes was associated with inheritance  Biochemists & microbiologists showed that the material in chromosomes is DNA  DNA contains genes Genes direct all the activities that occur in the cell & code for your traits  The Human Genome Project: – Created a map of human chromosomes  It involved finding: 1. The location of the genes 1. What those genes do BENEFITS  It could allows scientists to treat diseases It could be used to make new varieties of plants E.g. a drought resistant plant 3. FLUORESCENT ANTIBODY TECHNIQUE  Allowed diagnosis of diseases Showed that cells are open systems: – Interacting & exchanging materials with its environment E.g. O2  Showed that messenger molecules target receptors & trigger reactions inside the cell  4. X-RAY CRYSTALLOGRAPHY  Was used to determine the structure of DNA (that it was a double helix)  5. GFP TECHNOLOGY  Is being used to study Alzheimer’s Disease Allows scientists to compare proteins in healthy tissue & unhealthy tissue Read pg. 267-273 2.1 The Cell as an Efficient, Open System CELLS  Are open systems; – Exchange matter and energy with the surroundings – Acquire nutrients & excrete waste  Are the basic units of life Maintain life processes within tiny organs called organelles Cheek Cell  Carry on all life processes: – Intake of nutrients – Movement – Growth – Response to stimuli – Exchange of gases – Waste removal – Reproduction  There are two types of cells: 1. Prokaryotic 2. Eukaryotic 1. PROKARYOTIC CELL  Lack a nucleus DNA floats in the cytoplasm E.g. Bacteria 2. EUKARYOTIC CELLS  Have a nucleus DNA is in the nucleus packaged as chromosomes E.g. Plant and Animals cells Animal Cell Plant Cell  CELL STRUCTURES  There are 5 main structures: 1. Cell wall 1. Cell membrane 1. Nucleus 1. Cytoplasm 1. Organelles 1. CELL WALL  Provides strength and support Are found only in plant cells, bacteria & protists Are made of cellulose  2. CELL MEMBRANE  It is a protective barrier found in both plant and animal cells It is semi-permeable – some particles can enter while others can’t  It maintains balance (equilibrium) inside the cell – Allowing some substances in & keeping others out  Fluid Mosaic Model – Describes the structure (Mosaic refers to different substances held together by a common material)  It has 2 parts: A.) Phospholipids bilayer (fluid like) B.) Proteins Each part plays a role in maintaining equilibrium A. PHOSPHOLIPID BILAYER  Has a lipid bilayer that consists of: - a phospholipid head - a fatty acid tail Please Draw and label the following: B. PROTEINS  Embedded to form a pattern in the lipid bilayer  Can be: – Receptors… (for hormones) – Channels or pumps …..(molecules travel through) 3. NUCLEUS  Directs all cellular activities Is only found in Eukaryotes (plant & animal cells)  It contains: – DNA – a porous membrane – the nucleolus this stores RNA 4. CYTOPLASM  It is a gel-like substance (mostly water) in both plant & animal cells contains nutrients needed for cellular activities It has organelles suspended in it 5. ORGANELLES  Are tiny organs Are the working units within the cell (like the working parts of a machine) Are not visible with a light microscope  Examples: a) Mitochondria (both) a) Endoplasmic Reticulum (both) a) Ribosome (both) a) Golgi Apparatus (both) a) Lysosomes (animal) a) Vacuoles & Vesicles (both) a) Chloroplasts (plant) A. MITOCHONDRIA  Is the site of Cellular respiration C6H12O6(s) + 6O2(g) 🡪 6CO2(g) + 6H2O(l)  Converts the chemical energy in glucose into ATP (energy)  Muscles contain lots of these It is the “power house” of the cell (it generates energy) B. ENDOPLASMIC RETICULUM (ER)  Is a series of tubes used to transport proteins There is two types: 1. Smooth 1. Rough  Smooth ER – Is the site of fat/oil & steroid production Rough ER – Is the site of protein synthesis C. RIBOSOMES  Is the site of protein synthesis  Take amino acids & make proteins  D. GOLGI APPARATUS  Stores proteins which will be secreted for use outside the cell  Glands contain a lot of these E. LYSOSOMES  Digest bacteria or damaged proteins & found in animal cells only Contain strong Enzymes  Is called the suicide sac White blood cells have lots of these F. VACUOLES & VESICLES  Are found in both plants & animals Both store nutrients & water  Vesicles: – Transport substances throughout the cell  Vacuoles: – Swell in plants when water enters (turgor pressure) G. CHLOROPLASTS  Are found only in plant cells & some protists  Contain a green pigment called chlorophyll (this captures light rays)  Is the site of photosynthesis  Converts carbon dioxide & water to sugar  The Cell as a City Cell Part City Structure Cell membrane City Limits Nucleus City Hall Mitochondria Power Plant Ribosomes Bakery, Carpenter, Tailor Lysosomes Garbage Trucks, Recycling Golgi Bodies Oil Sands Plants Vacuoles Safeway, IGA, Brick, Malls Endoplasmic Reticulum Streets, Rivers Chloroplasts Solar Energy Plants DNA Original Blueprints of city Chromosomes Rolled up blueprints  COMPARING PLANT & ANIMAL CELLS  Both are made up of: – Carbon – Hydrogen – Oxygen – Nitrogen  In both element are combined to form organic compounds: – Lipids = (fats/ oils) – Carbohydrates = (sugar) – Protein = (muscle) – Nucleic acids = (DNA)  In both water makes up 85 % of the cell (solvent for reactions)  Both contain the following structures: – Cell Membrane – Vacuoles/ vesicles – Nucleus – Cytoplasm – Mitochondria – ER – Ribosomes – Golgi  What is different: – Only plant cells have chloroplasts & cell wall – Only animal cells have centrioles & lysosomes  Comparing Plant and Animal Cells Structure Plant Animal Vacuoles large small Cell membrane & Same Same cytoskeleton DNA structure Same Same Centrioles (for cell NONE Has them division) Cell wall Has it NONE Chloroplast Has it NONE Energy Storage Starch glycogen  Assignment Draw a proper plant cell diagram – A. Title at top center of page – B. Drawn in pencil – C. Drawn on white paper – C. Use straight edge for lines (ruler) – D. Must include all plant cell parts (page 270) – E. 2D – F. DO NOT colour – G. Name on back – DUE BY THE END OF CLASS TODAY  Rubric /11 - Parts (drawn and labelled - nucleus, cell wall, cell membrane, vacuole, cytoplasm, chloroplasts, mitochondria, golgi apparatus, smooth ER, rough ER, ribosome) /1 - Title at top of page /1 - Straight lines /1 - Pencil used /1 - White paper used /1 - Name on back /16 - Total points 2.2 The Role of the Cell Membrane in Read pg. 274-281 Transport  THE CELL MEMBRANE  Is selectively permeable controls the transport of particles into and out of the cell Is essential for the cell’s survival PARTICLE MODEL OF MATTER  It is used to understand the types of transport in cells  It states: 1. All matter is made of particles but the particles in different substances may be different in size and composition 2.The particles of matter are constantly moving or vibrating. They move the least in solids and the most in gases. Adding or removing energy will affect the movement of particles. 3. The particles of matter are attracted to one another or are bonded together. + + + + + + + + + + _ _ _ - - + + + + + - + + + _ _ 4. Particles have spaces between them. The smallest are in solids and greatest in gases (exception - ice). The spaces may be occupied by particles of other substances. CELL TRANSPORT  Involves moving molecules into and out of the cell H2O H2O CO2 CO2 C 6 H12O 6 CO2  The type of transport that is used is determined by the molecules: – size – charge – whether or not they are soluble in lipids (ex. water, salt, carbon dioxide and oxygen pass through, but starch is too large therefore does not)  It occurs by: 1. Passive Transport 1. Active Transport 1. Endocytosis 1. Exocytosis 1. Phagocytosis  1. PASSIVE TRANSPORT  Does not require energy It is used by small molecules  continues until equilibrium is reached (same amount on both sides) There are 3 types: – Diffusion – Osmosis – Facilitated diffusion A. DIFFUSION  Is the movement of particles from an area of high concentration to an area of low concentration  It is how plants get nutrients from the soil NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3 NO3H2O NO3  It is how DIALYSIS TUBING works  This is a synthetic semi-permeable cell membrane It allows water, salt and sugar to diffuse through it stops starch and protein from diffusing  The rate (how fast it occurs) is affected by: 1. Size of molecules (small = fast) 2. Temperature (high = fast) 3. Concentration (high = fast) 4. Medium through which it travels (liquid or gas = fast) (solids = slow) B. OSMOSIS  Is the diffusion of water molecules across the cell membrane The membrane is NOT soluble to the solute  H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O  It is how plants take in water (in the roots) H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O  Three situations can arise depending if the cell’s environment is: i. )Hypertonic ii) Hypotonic iii) Isotonic i) HYPERTONIC ENVIRONMENT net movement of water is out of the cell  There are more solute particles outside the cell Water diffuses out of the cell E.g. your hands get wrinkled after being in the bath  before after http://www.youtube.com/watch?v=gWkcFU-hHUk  In animal cells causes crenation BOTH CELLS ARE DEHYDRATED In plant cells it causes plasmolysis II.) HYPOTONIC ENVIRONMENT net movement of water is into the cell  There are less solute particles outside the cell Water moves into the cell & causes it to swell E.g. over watering a plant… extra water can cause cells to explode!  In animal cells it causes cytolysis BOTH CELLS Animal HAVE TOO cell MUCH WATER & WILL BURST!!!! Plant cell In plant cells it causes deplasmolysis III.) ISOTONIC ENVIRONMENT  Has the same amount of solutes on either side There is no net movement of solutes Animal cell Plant cell Example 1 What is going to happen the Amoeba in Salt Water ? Example 2 What is going to happen the Amoeba in Fresh Water? Example 3 Euglena, a zooplankton, (microscopic animal) is placed in a Hypertonic solution. What will happen to the cell? Example 4 Euglena, a zooplankton, (microscopic animal) is placed in a Hypotonic solution. What will happen to the cell? C. FACILITATED DIFFUSION  A type of passive transport used by small substances that are not soluble in lipids ( they are water soluble & can’t pass through the membrane)  Involves using: i) Channel proteins ii) Carrier proteins H2O H2O H2O i ) CHANNEL PROTEINS: - create pores through which particles can travel ii) CARRIER PROTEINS: - physically move the molecules across the membrane - Change shape when moving a molecule  2. ACTIVE TRANSPORT  requires energy (ATP) Particles move from an area of low concentration to high ‘pumps’ are used to move substances across Direction of movement 3. ENDOCYTOSIS  Use ATP & vesicles to move large molecules into the cell 4. EXOCYTOSIS  Use ATP & vesicles to move large molecules out of the cell Animation 5. PHAGOCYTOSIS Engulfs the bacteria using phagocytosis pseudopods  This is only done by certain types of cells & micro-organisms (E.g. Amoeba)  A pseudopod: – (false foot) is formed – It wraps around the item – It then forms a vesicle …..Engulfing the food Summary 2.3 Applications of Cellular Transport in Industry and Medicine  MEMBRANE TECHNOLOGY  Is used to study: 1. Recognition proteins 1. Receptor proteins 1. Synthetic membranes (mimic real membranes) 1. In medicine 1.RECOGNITION PROTEINS  Are embedded in membrane and some have a carbohydrate chain Are used by cells to recognize self from non -self 2. RECEPTOR PROTEINS  Are proteins that hormones bind to…..initiating a response by the cell  They are useful in the study of HIV and cancer Must recognize a virus in order to prevent it from entering the cell (focus of research)  3. MEMBRANE TECHNOLOGY IN MEDICINE  Use for : A. Creating liposomes A. Dialysis A. LIPOSOMES  Are synthetic membranes (man made) Are a safer method to deliver drugs Medication placed inside will not affect other tissues  B. DIALYSIS  Uses diffusion to remove waste from the blood… when kidneys fail Two types: i) Peritoneal dialysis ii) Hemodialysis I) PERITONEAL DIALYSIS  A catheter (tube) is inserted into the abdominal cavity A bag of sterile dialysate fluid (mixture of water, glucose, sodium, chloride, etc.) is pumped into the body cavity Toxins diffuse from the tissues into the fluid ……. which slowly drains into the bag. Peritoneal II) HEMODIALYSIS DIALYSIS  must be performed in a hospital Blood is pumped to a machine in a tube.. which acts as a semi-permeable membrane Small particles diffuse from the tube and collect in the machine The clean blood is pumped back to the body this cycle repeats… it takes hours and patients are unable to move around Hemodialysis  Scenario 1 Starch-Glucose Test ✦ A solution of starch and glucose is put in sealed dialysis tubing & placed in water ✦ Predict what will happen & why?  Scenario 2 Iodine-Starch Test ✦ A solution of starch and glucose is placed in dialysis tubing & placed in a beaker that contains an iodine solution which is yellow in color. ✦ If Iodine reacts with starch… it will turn black. ✦ Predict the color of the bag 2.4 Is Bigger Better? SURFACE AREA TO VOLUME RATIO  All cells need to transport nutrients into a cell and waste out of a cell  Cells: - Are small - Have a high surface area …. making it easier to get particles in & out - Often divide to maintain a high surface area to volume ratio More Waste can surface build up area & because it more takes too long efficient to transport Tissue Large cell  some organisms have specialized structures to help increase the overall surface area to volume ratio E.g. micro-villi lining the small intestine increases E.g. Alveoli n lungs – absorption during increase SA for O2(g) digestion and CO2(g) diffusion CALCULATING SURFACE AREA TO VOLUME 1. Calculate the surface area (area of all faces added together) 1. Calculate the volume (l x w x h) 1. Divide SA by Volume ratio = SA/V  Example 1 For the following “cell”, calculate the surface area, the volume and the surface area to volume ratio: SA = (l × w × 2) + (l × w × 2) + (l × w × 2) 2 mm = (4 mm × 2 mm × 2) + (4 mm × 10 mm × 2) + (2 mm × 10 mm × 2) = 16 mm2 + 80 mm2 + 40 mm2 = 136 mm2 10 mm V=l×w×h = 4 mm × 2 mm × 10 mm 4 mm = 80 mm3 SA/V = 136/80 = 1.7  Example 2 For the following “cell”, calculate the surface area, the volume and the surface area to volume ratio: SA = (l × w × 2) + (l × w × 2) + (l × w × 2) = (4 mm × 7 mm × 2) + (4 mm × 10 mm × 4 mm 2) + (7 mm × 10 mm × 2) = 56 mm2 + 80 mm2 + 140 mm2 = 276 mm2 10 mm V=l×w×h = 4 mm × 7 mm × 10 mm = 280 mm3 7 mm SA/V = 276/280 = 0.99 3.1 Cells, Tissues, and Systems Read pg. 296-302 ORGANISMS  Come in all different shape & sizes Can be: A. Unicellular B. Multicellular A. UNICELLULAR ORGANISMS  Live alone or in colonies Are made of one cell Are microscopic Perform all life processes  Once a single-celled organism reaches a certain size, it requires a multicellular level of organization to sustain life B. MULTICELLULAR ORGANISMS  Are made of many cells E.g. Plants Have specialization of cells …… which form tissues  There are advantages and disadvantages to having a large structure that depends on trillions of cells: – A. Division on labor – cell specialization allows specific functions to be carried out efficiently – B. Size – able to grow larger due to transport systems – C. Interdependence of cells – if one cell dies, the entire organism does not die  CELL SPECIALIZATION  Is when a cell is designed to perform a specific task/function It occurs when cells begin to form organs & organ systems (E.g. during embryonic development) TISSUES  Are groups of cells performing the same function (E.g. red blood cells, dermal tissue) ORGANS  Are groups of tissues performing the same function (E.g. heart)  ORGAN SYSTEMS  Are organs contributing to the same function (E.g. circulatory system)  PLANT STRUCTURE  Plants are: – Multicellular organisms – They have organ systems & specialized cells  PLANT ORGAN SYSTEMS  There are 2: 1. Shoot System 1. Root System 1. SHOOT SYSTEM  Function is reproduction & photosynthesis Includes everything that is above ground Leaves, stems, buds, flowers and fruits  It is involved in: – gas exchange – photosynthesis – reproduction  Also includes tubers (E.g. potatoes) – This is where plants store their extra food (sugar) 2. ROOT SYSTEM  Function is to obtain nutrients and water Everything underground  Is involved in H2O & mineral uptake from soil PLANT GROWTH  It occurs at the tips of leaves in the Meristem region Is the result of mitosis Cells build up on each other and act as building blocks Example 1 If a person cuts the meristem region of a plant, will the leaf grow?  PLANT PROTECTION  Herbaceous plants (non-woody) are covered by dermal tissue (epidermis) In woody plants, epidermis is replaced by cork and bark PLANT TISSUE  There are three types: 1. Dermal 2. Vascular 3. Ground 1. DERMAL TISSUE  Is one cell-layer thick It protects the plant from disease It is on the outside of the plant E.g. Cuticle  Cuticle Is a waxy substance secreted by cells in the leaves & stems It coats the leaf and reduces H2O loss and protects it 2. VASCULAR TISSUE  Is responsible for transport in plants (between the roots & shoots) It consists of: A. Xylem B. Phloem  A. Xylem moves H2O & dissolved minerals from roots up the stem to the leaves  Thick-walled tubes (E.g. stacking paper towel tubes together)  B. Phloem Transports dissolved sugars produced in the leaves to other parts of the plant  Formed from sieve tube cells & companion cells  Sieve tube cells – Is a cylindrical cells lacking nuclei – allow the movement of phloem sap between cells (Stacked like paper towel rolls with holes in them)  Companion cells – Connect to the sieve tube – Control sugar transport in phloem 3. GROUND TISSUE  Is Layer of cells found beneath the epidermis (top layer of cells) It is the bulk of the plant  In stem: provides strength & support In roots: provides food and water storage In leaves: where photosynthesis occurs  PLANT SPECIALIZATION  Cells and structures that have specialization Examples: – Root hairs – Guard cells – Stomata  Root Hairs – are tiny hair-like projections that absorb water and minerals from soil  Guard Cells: – are on the underside of leaf – swell and contract to control gas exchange through a stomata in a leaf  Stomata: – Are pores formed by guard cells allow gases to pass through  The leaves Main purpose is to carry out photosynthesis  Palisade Cells cells that contain chloroplasts (organelle) which contains a green pigment = chlorophyll – Note: these are in all the green parts of plants E.g. leaves; sometimes in stems  Chloroplasts Are the organelles that carry out photosynthesis  Photosynthesis - ‘photo’ = light – ‘synthesis’ = putting together It is a process that converts CO2 (from air) and H2O (from soil) to produce glucose and O2  Occurs in the palisade cells It needs light  The Equation water + carbon dioxide + energy 🡪 glucose + oxygen 6 H2O + 6 CO2 + energy 🡪 C6H12O6 + 6 O2 Light energy → chemical energy *Glucose stores chemical energy in its bonds*  Cellular Respiration Is a process that breaks down chemical energy (glucose) & makes ATP Occurs in all organisms (plant and animal) Occurs in the mitochondria (of all cells) Converts sugar and oxygen to water and carbon dioxide Is the complete opposite of photosynthesis  The Reaction glucose + oxygen 🡪 water + carbon dioxide C6H12O6 + 6 O2 🡪 6 H2O + 6 CO2 cells take in O2 & break down glucose (for energy) and release H2O and CO2 3.3 Tissues and Gas Exchange  Plants have specialized tissues for gas exchange, water & nutrients distribution  Gas Exchange in Plants Involves the: Taking in of carbon dioxide (photosynthesis) Releasing oxygen (photosynthesis) It involves three tissues: 1. Dermal 2. Ground 3. Vascular  1. Dermal Tissue Is tissue that is on the outside of the plant In the leaf is involved in gas exchange… through the stomata  Stomata: – are tiny pores on the underside of leaves that allow CO2 diffuse in and O2 diffuse out – The size is controlled by the swelling and shrinking of guard cells that surround them  2. Ground Tissues Is found beneath the epidermis (dermal tissue) A. Consists of Palisade tissue B. Spongy Mesophyll Tissue  A. Palisade Tissue It contains rectangular cells Site of photosynthesis B. Spongy Mesophyll Tissue Is in the middle of the leaf Moves O2 towards the stomata Moves CO2 towards the palisade cells  3. Vascular Tissue Transports sugar to other parts of the plant Transports water from the roots It consists of the vascular bundle  The vascular bundles is made of: – Xylem: It transports water and salts to leaves – Phloem: It transports sugar (made in the leaves) to the rest of the plant  Read pg. 315-320 3.4 Transport in Plants  Transport in Plants It is the movement of water, minerals and C6H12 O6 Occur as a result of: – Adhesion – Cohesion – Root pressure – Transpiration pull  Adhesion The attraction of water molecules to other types of substances (i.e. xylem wall)  Cohesion The attraction of water molecules to other water molecules Occurs because water is a polar molecule Positive end of one molecule attracted to negative end of another  Root Pressure A high concentration of dissolved minerals are inside the root cells  It forces fluid up the xylem Water is drawn in by osmosis..causing root cells to swell & this forces fluid up the xylem  Water Transport Begins at the roots Water is drawn from the roots, up the stem to the leaf (high to low pressure) Once in the leaf it is used in photosynthesis or evaporates from the stomata  Transpiration pull draws water up the stem  Evaporation of water: – occurs in the stomata – Is called transpiration  As each water molecule evaporates, it pulls on an adjacent water.. forcing more up the xylem  Turgidity Allows the plant to hold itself up to the sunlight for photosynthesis It is caused by water entering vacuoles, making the cells turgid. 3.5 Control Systems Read pg. 323-328  Control Systems A stimulus is a change in the environment that causes an organism to react Tropism is a response plants have to stimulus  Types of Stimulus Temperature Chemicals Water Touch Length Light Gravity  Brief History of Phototropism ✦ Darwin (1880) asked: “Which part of the plant detects a light stimulus?” ✦ Five identical plants set up: 1) did nothing to it (control) 🡪 normal growth 2) chopped growth tip off 🡪 elongation stops 3) Covered tip with black cap 🡪 elongation stops 4) Covered tip with clear cap 🡪 normal growth 5) Covered base with dark tube 🡪 normal growth ✦ Conclusion: only the plant tip is stimulated! ✦ Boysen and Jensen (1913) asked: “How does the tip signal the area of elongation?” ✦ Three identical plants set up: 1) did nothing to it (control) 🡪 normal growth 2) slice off the tip and put it back on with a layer of conductive gel in between 🡪 normal growth 3) slice off the tip and put it back on with a layer of mica rock in between 🡪 stops growth! ✦ Conclusion: a communication chemical must diffuse from the tip to area of elongation! ✦ Went (1926) asked: “What chemical is sent by the tip to the area of elongation?” ✦ He analyzed the chemicals that were transported ✦ Discovered “Auxin,” the plant hormone responsible for communication from the tip to the area of elongation  Phototropism Is a plant’s response to light There are two types: – Positive – Negative  Positive Phototropism Plant grows towards the light E.g. leaves, stem, flowers  Why it Occurs The tip of the plant: – detects light – It sends out auxin to the meristem region (growth region of the plant....mitosis occurs)  the effect is the plant bends toward the light auxin is a hormone that promotes cell growth or elongation of cells facing away from the light, causing the leaf or stem to bend toward the light  Negative Phototropism Growth away from the light E.g. roots  Gravitropism Is a plant’s response to gravity There are two types: – Positive – negative  Positive Gravitropism Growth in the same direction as gravity E.g. roots  Negative Gravitropism Is growth in the direction opposite to gravity E.g. stem http://www-users.york.ac.uk/~drf1/tropism/jcf_1.htm  Other Control Mechanisms Temperature Chemicals Water Touch (if the plant has tendrils {e.g. ivy} ) Length of daylight hours