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Goal 2 The learner will develop an understanding of the physical, chemical, and cellular basis of life Main Topics • • • • • • • Organic Compounds Structure and Function of Cells Organelles Cell Specialization and Communication Cell Transport Enzymes Cellular Respiration and Photosynthesis Organic Compounds • 4 organic compounds – “organic” = contains carbon = all living things have organic compounds in them – Carbohydrates – Lipids – Proteins – Nucleic Acids Carbohydrates (Polysaccharides) • Subunit (made of) = monosaccharides • Function = immediate energy • Examples: – Starch = energy storage for plants – Cellulose = makes up cell walls – Glycogen = energy storage for animals – Glucose = a simple sugar Carbs Cont’ • Tests = – Starch is tested with iodine – Monosaccharides are tested with Benedicts Solution Lipids • Subunits = glycerol and fatty acids • Function = long term energy storage • Examples: – Fats – Waxes on plants (cuticle) • Tests = brown paper bag test Proteins • Subunits = amino acids • Function = structure of tissues, transport for cells • Examples: – Insulin (hormones) – Hemoglobin (red blood cells) – Enzymes – Antigens/Antibodies • Test = Biuret’s Reagent Enzymes • Speed up chemical reactions = catalysts • Can be affected by pH or temperature = enzymes are very specific! • Enzymes are reusable! Lock and Key Nucleic Acids • Subunits = nucleotides • Function = stores cellular information for cells • Examples: – DNA and RNA • Tests = NONE… all living things have DNA and RNA Cell Organelles • Nucleus = controls cell activity “brain” • Plasma Membrane (aka cell membrane) = controls what enters and exits cell “gate keeper” • Cell Wall = protects and supports some cells • Mitochondria = provides energy (ATP) to cells “powerhouse” Organelles, cont’ • Vacuoles = stores water, waste, food • Chloroplast = site of photosynthesis, makes food for plant cells • Ribosome = site of protein synthesis – where proteins are made Microscope • Total Magnification: – Ocular lens x objective lens – Ex: • The microscope you are using has an ocular lens of 10x. The objective lens is on 60x. What is the total magnification? Organization • Unicellular = made of 1 cell (bacteria) • Multicellular = made of many cells (us, plants, animals) • Cells Tissues Organs Organ Systems Organism Plant Cells Animal Cells • Have cell walls made of cellulose outside of cell membrane • Have chloroplasts and mitochondria • Boxy shape • Green • 1 big vacuole • No cell walls; just a cell membrane • Mitochondria only • Round shape, more flexible • Centrioles • Many small vacuoles Cell Communication • Chemical signals can be released by one cell to influence another cell – Ex: Hormones • Chemicals attach to receptor proteins on cells and pass the message along Cell Transport • Cells must maintain homeostasis • Homeostasis = maintaining a stable internal environment – Regulate temperature = shiver or sweat – Blood glucose = insulin is released after eating – Water = mouth becomes dry when thirsty, eliminate water by urine Cell Membrane • The cell membrane maintains homeostasis in a cell by allowing only certain things in and certain things out! – Semi-Permeable or Selectively Permeable • Structure = phospholipid bilayer Two Types of Transport • Passive Transport – NO ENERGY NEEDED – Goes from HIGH concentrations to LOW concentrations – Ex: Diffusion and Osmosis, Faciliated Diffusion • Active Transport – ENERGY is NEEDED!! – Goes from LOW concentrations to HIGH concentrations Diffusion - PASSIVE • Diffusion = the movement of PARTICLES (solutes) from an area of high concentration to low concentration • Concentration Gradient = when the sides are not equal Osmosis - PASSIVE • Osmosis = the movement of WATER from an area of high concentration to an area of low concentration Water Cells and Osmosis • Water goes into cell = causes swelling • Water leaves cell = causes shrinking Osmosis Examples • A cell is placed in a solution where there is 20% water outside and 80% water inside. Where does the water go? What happens to the cell? • A cell has 40% glucose outside and 60% glucose inside. What happens? Facilitated Diffusion - PASSIVE • Facilitated Diffusion = diffusion through transport proteins • Two proteins – Channel = does not change shape – Carrier = changes shape ACTIVE Transport • Active Transport = requires ENERGY! • Can use carrier proteins Active Transport, Cont’ • Endocytosis and Exocytosis are examples of active transport = require ENERGY – Endo- = taking IN of large molecules – Exo- = EXPELLING of large molecules Cell Energy • ATP is the source of energy for cells – ATP = A-P-P-P – ADP = A-P-P • ATP becomes ADP by: losing a P = releases energy • ADP becomes ATP by: gaining a P = stores energy Cell Energy Photosynthesis - Occurs in chloroplast - Occurs in plants - Makes food for plants CO2 + H2O + light C6H12O6 + O2 ** after plants make food in photosynthesis, the food is turned into energy during cellular respiration! Cellular Respiration - Occurs in mitochondria - Occurs in plants AND animals - Turns food into energy (ATP) C6H12O6 + O2 CO2 + H2O+ ATP Cellular Respiration Aerobic - Occurs in mitochondria when oxygen is available - Makes 36 ATPs Anaerobic - Occurs in mitochondria when oxygen is NOT available - Makes 2 ATP - AKA Fermentation - 2 types: Alcoholic (makes Alcohol and CO2 – bread, beer) and Lactic Acid (makes lactic acid in your muscles) A student tested different foods to determine which organic compounds were present. She based her results on the following information: All four tests were performed on skim milk. The observations were that Benedict’s solution changed color and Biuret’s changed color. All other tests had a negative result. Which organic compounds were present in skim milk? A. B. C. D. Sugar and Protein Fat and Sugar Sugar and Starch Starch and Protein Test Positive Reaction Organic Compound Indicated Brown paper Shiny spot fat Benedict’s Solution Color change Sugar iodine Color change starch Biuret’s solution Color change protein