BSCI124 Introduction to Science What is Science 01 24 2013 o A body of knowledge about the natural world o Science is a technique a way of seeking principles about the natural world Science tries to verify these principles via experiments o Scientists use data to The Science Method o Observation observed o Hypothesis testable statement New observations are made and previous data input from various sources used to make a A tentative assumption Testable educated guess to explain something and to test it o Tests or experiments to obtain data The hypothesis is tested by experiments and or further observations Controls compare two different experiments one with a variable one controlled o Data interpretation the results are analyzed and hypothesis is either supported or rejected o Conclusions the results are analyzed and hypothesis is either Many experiments and observations supported or rejected Scientific Theory to support it Scientific Method 2 o Hypothesis tentative assumption Testable educated guess to explain something and to test it o Theory hypothesis that has survived many tests all competing hypothesis have been disproved o Law a theory that has been tested extensively based on lots of evidence and no data has been found in disagreement Biology the scientific study of life What is life o R D Laing Life is a sexually transmitted disease and the mortality rate is 100 All living things share these 8 features o Living things are highly organized Atoms molecules cells tissue etc o Maintain stable chemical composition Same chemicals found in living things proteins carbs fats nucleic acids salts water etc o Take energy from environment transform it use it Plants get energy from the sun o Respond to different stimuli Ex Trees and bears respond differently when kicked o Living things grow and develop True growth as opposed to expansion bubbles or stalactites Ex Redwood seed huge flipping tree o Reproduce Sexual v asexual o Show variations based on heredity Genes composed of DNA o Evolve and adapt to their environments and ways of life Plants are alive plants are always moving and checking out their environment Plants are essential to our lives Top 10 reasons Oxygen we breathe we would die Ozone layer we would fry Food we eat we d starve Clothing fibers Woods we d be without homes Paper Medicines and drugs Flavors spices and fragrances Decoration and beauty Life without plants would be impossible What is a plant Multicellular organism Cellulose rich cell wall Chlorophyll and are photosynthetic Adapted o life on land in case of ocean plants they descended from land plants Plant Structure Adapted to its needs Shoot usually grows above ground o Flowers leaves nodes stems Root usually below ground o Roots anchor the plant to the soil o Absorb water and mineral nutrients o May serve as storage in some species o Branch roots root hairs root cap Variations in plant structure Some stems grow underground potato Celery an overgrown leaf petiole Storage roots radish yams Modified leaves spines of cactus Plant growth Shoot and root apical meristems region of embryonic tissue Indeterminate growth totally different from animals capable of developing new parts of the plant The Cell 01 24 2013 Cell Macromolecules The Molecules of Life The cell is made of the following four biologically important molecules o Carbohydrates Sugars starches cellulouse o Lipids fats oils waxes phospholipids steroids o Proteins Composed of amino acids o Nucleic Acids DNA RNA Life s Molecules All life s molecules share the following four characteristics o Carbon based o Formed from a few elements C H O P N o Modular construction like bricks cheap and easy to build small building blocks Carbohydrates Lipids Proteins Nucleic Acids o Their function depends on structure or structure shape determines function THEIR SHAPE AND STRUCTURE DETERMINES THEIR FUNCTION Why should we learn about life s molecules Because we eat them every day We are composed of these bio molecules 1 Carbohydrates Organic molecules composed of C H O 1 2 1 ratio Most abundant of life s molecules Carbohydrate carbon water There are three types of carbohydrates o Mono saccharides one o Di saccharides two o Poly saccharides many Mono saccharides simple sugars of 3 to 6 carbons o Glucose C6H12O6 Blood sugar o Fructose C6H12o fruit o Ribose C5H10O5 nucleic acids Di saccharides o Composed of two monosaccharides o Sucrose table sugar C12H22O11 o Maltose two glucose o Lactose milk o Glucose Fructose Sucrose water Poly saccharides many o Long chains of monosacch o Starch energy storage varied structure o Cellulose plant cell walls wood paper cloth even structure nicely arranged Makes up outside of plant cell makes plant rigid Function of Carbohydrates o Energy storage in the C H bonds glucose starch o For structure in plants cellulose for cell wall o Carbon sources to make other molecules nucleic acids amino acids 2 Lipids Diverse group of organic compounds Composed of C O H atoms THREE MAIN TYPES o Fats oils waxes o Phospholipids o Steroids Fats and Oils o Fats are solid lipids at room temperature usually animal o Oils are liquid lipids usually plant derived corn oil peanut oil derived lard butter olive oil o Glycerol Molecule o Fatty Acids Lipids do NOT dissolve in water o Fats don t like water they don t mix This is due to chemical composition Phospholipids o Similar to fats oils but contain phosphorous a phosphate o Shaped like a bobby pin head is the closed part of the pin tail group is the separated part o Phosphate group makes head hydrophilic water loving fatty acid chain TAIL is hydrophobic water hating o The membranes of cells is a lipid bilayer when you combine tons of phospholipids the bilayer forms o Steroids o Steroids are structurally different from other lipids o They re composed of 4 carbon rings and side groups o Steroids include sex hormones cortisol cholesterol and others Function of Lipids o As a high energy food o As part of cell membrane o As waxes hormones vitamins pigments o Energy storage of lipids Mono glycerides glycerol 1 fatty acid chain Di glycerides monoglyceride 2nd fatty acid chain Tryglicerides diglycerides 3rd fatty acid chain o Triglycerides highest energy more fat more energy 3 Proteins Large complex molecules Composed of C H O S and N Building blocks are amino acids 20 Function follows form proteins do different things based on the different shapes they have Function of Proteins o Building blocks of cells o Transport they help
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