02 24 2014 LECTURE 1 Plants Multicellular organisms Cellulose rich cell wall Chlorophyll photosynthetic Adapted to life on land Plant structure Shoot Specialized shoot where reproduction occurs fruit o Usually grows above o Stem leaves nodes internodes buds o Flowers seeds develop o Leaves Site of photosynthesis Blade petiole o Node o Stem Place in stem where leaf is attached Holds leaves transports water nutrients provides support above ground Root o Usually grows below ground o Anchors to soil absorbs water minerals o May serve as storage in some species o Branch roots root hairs root cap Shoot root apical meristems of the plant Variations in structure o Potatoes stems that grow underground o Celery overgrown leaf petiole o Radishes yams storage roots o Spines of cacti modified leaves o Region of embryonic tissue capable of developing new parts LECTURE 2 Cell macromolecules the molecules of life 4 molecules of life carbohydrates lipids proteins nucleic acids Carbohydrates o Sugars starches cellulose o Organic molecules composed of C H O 1 2 1 ratio o Most abundant of life s molecules o 3 types Monosaccharides one Simple sugars of 3 6 carbons CnH2nOn Glucose blood sugar Fructose fruit Ribose nucleic acids Disaccharides two Sucrose table sugar Maltose 2 glucose Lactose milk Polysaccharides many Starch energy storage Cellulose plant cell walls wood paper cloth o Functions Energy storage in the C H bonds glucose starch For structure in plants cellulose for cell wall Carbon sources to make other molecules nucleic acids amino acids Lipids o Diverse group of organic compounds o Usually composed of C O H sometimes P o 3 main types Fats oils waxes fatty acids Made from 2 building blocks glycerol molecule Fats oils are water insoluble Fats are solid lipids at room temperature Usually animal derived lard butter Oils are liquid lipids do not dissolve in water Usually plant derived corn oil peanut oil olive oil Phospholipids Similar to fats oils but contain phosphorous a Phosphate group makes head hydrophilic water phosphate group loving Fatty acid chain is hydrophobic water hating Membranes of cells are lipid bilayers Steroids Structurally different from other lipids Composed of 4 carbon rings side groups Sex hormones cortisol cholesterol others o Functions High energy food Part of cell membrane Waxes hormones vitamins pigments Energy storage of lipids Monoglycerides glycerol 1 fatty acid chain Diglycerides monoglyceride 2nd fatty acid chain Triglycerides diglyceride 3rd fatty acid chain Triglycerides highest neergy Proteins o Composed of amino acids There are 20 amino acids o Large complex molecules o Composed of C H O S N o Functions Building blocks of cells Transport they help control what passes through the plasma membrane Animal structure hair nails tendons muscles Enzymes to speed up chemical reactions Nucleic acids o DNA RNA o Large organic molecules o Composed of C H O P N o Basic unit is the nucleotide A sugar phosphate nitrogenous base Nucleic acids are long chains of nucleotides Deoxyribonucleic acid Carries information about the entire cell o DNA o RNA o ATP Ribonucleic acid Copy of DNA Nucleotide compound Energy transfer exchange o Functions Information storage DNA RNA are like a blueprint for the cell Energy carrier ATP Characteristics of life s molecules o Carbon based o Formed from a few elements C H O P N o Modular construction like bricks cheap easy to build small building blocks o Their function depends on structure structure shape determines function o We eat them every day o We are composed of fats carbohydrates proteins Cells Basic building blocks of living organisms Form tissues organs Each cell is functionally independent it can live on its own under the right conditions o Uses sugars to get energy stay alive o Contains all necessary info to replicate produce a multicellular organism o Can make a whole plant from a single cell Cell theory o Cell is the basic unit of life o Organisms are composed of cells o Cells arise from other cells 2 types of cells Prokaryotic o Simple cells lack organelles o 10 100 times smaller than animal or plant cells o Bacteria o Older organisms 3 5 billion years old Eukaryotic o Have organelles o Cells of plants animals fungi o Some unicellular organisms also algae amoeba o More recent 1 5 billion years old Plant cells vs animal cells Plant cells have 4 things animal cells do not o Cell walls o Chloroplasts o Plasmodesmata o Vacuoles Cells from animals other organisms have them but they are much smaller not as significant Outside of the plant cell Cell wall o Protects supports the cell o Made mostly of cellulose o Allows water other molecules to pass through like a cardboard box o Primary wall Formed early Located on outermost layer o Secondary wall Deposited on the inside between primary cell wall plasma membrane o Middle lamella What glues adjacent cells together Plasmodesmata o Cytoplasmic connections between adjacent cells o Allow for the movement of materials from cell to cell Plasma membrane plasma membrane o o Lipid bilayer Hydrophilic heads outer hydrophobic tails inner o Differentially permeable o Fluid mosaic model Lets water pass through but not other molecules Double layer of phospholipids with scattered proteins looks like protein icebergs in a sea of lipids Inside of the plant cell Cytosol Cytoplasm Protoplast o A matrix of water 90 proteins organic molecules ions o Cytosol organelles only except nucleus o All of the plant cell enclosed by the cell wall plasma membrane cytosol organelles Cytoskeleton o Microtubules microfilaments Make up the cytoskeleton A network of protein cables that provide structural support to the cell Help in cell division elongation o Important for mitosis cell division o Membrane bound sub compartments within the cell o See below Organelles Plant cell organelles Nucleus o Contains all genetic information DNA in chromosomes o Chromosomes DNA proteins o Nucleolus bodies where ribosomes are made Mitochondria o Provides energy to the cell by converting sugars into chemical energy respiration o Powerhouse of the cell Chloroplast o Site for photosynthesis o Produces sugars from carbon dioxide water sunlight o Contain chlorophyll makes the plant green other pigments Vacuole o Stores a watery solution of sugars salts acids proteins o Makes up to 90 of plant cell volume o Makes cells turgid water pressure in cell o Tonoplast vacuole s own membrane o Often acidic content sap what makes lemons limes tart