Essential knowledge 2.A.3: Organisms must exchange matter with the environment to grow, reproduce and maintain organization.

Molecules and atoms from the environment are necessary to build new molecules. Carbon is at the base of all life Carbon-most versatile building block of molecules. Why? - 4 valence electrons Can form 4 single covalent bonds Capable of forming double and triple covalent bonds Can combine with atoms of many different elements

Carbon moves from the environment to organisms where it is used to build carbohydrates, proteins, lipids or nucleic acids.

Carbon moves from the environment to organisms where it is used to build carbohydrates, proteins, lipids or nucleic acids.

Nitrogen moves from the environment to organisms where it is used in building proteins and nucleic acids.

Nitrogen moves from the environment to organisms where it is used in building proteins and nucleic acids. Nucleotides – monomers of DNA and RNA

Phosphorus moves from the environment to organisms where it is used in nucleic acids and certain lipids. Phospholipid Phospates make up the backbone of DNA and RNA

Properties of Water With a partner, write a few sentences about the properties of water that were observed in the weird water activities. Compare and Contrast the following terms as they apply to the properties of water: Cohesion Adhesion High specific heat capacity Universal solvent supports reactions Heat of vaporization Heat of fusion Water’s thermal conductivity

What makes water so weird? Most properties of water emerge because water is polar and hydrogen bonds form between adjacent water molecules.

Cohesion and Adhesion Cohesion: Water is attracted to water Adhesion: Water is attracted to other substances

Surface Tension The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The cohesive forces between molecules in a liquid are shared with all neighboring molecules. Those on the surface have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their nearest neighbors on and below the surface.

High specific heat capacity This is why it takes so long to boil water!!

Universal solvent supports reactions

Heat of vaporization

Heat of fusion water has a high heat of fusion, or the heat you need to take out of water to get it to solidify (freeze). What all this means is that water can hold a lot of heat energy before it changes temperatures and states (solid to liquid to gas). This property of water is great if you are an organism that lives in the water. Why, you might ask? A high heat of fusion means that, even if the temperature of the air changes a lot, water will shelter you from those changes and provide a pretty stable environment.

Water’s thermal conductivity Even though only the bottom of the pot is heated, the temperature of all the water will quickly rise.

Lastly … Thanks Water!! I did not know how neat you were!

Macromolecules Bozeman Biology: https://www.youtube.com/watch?v=PYH63o10iTE&list= PL8GOEDwLwlIOiSrWJuCzUxJ_zMemyYDDZ&index=5 Other macromolecule video: https://www.youtube.com/watch?v=H8WJ2KENlK0&list =PL8GOEDwLwlIOiSrWJuCzUxJ_zMemyYDDZ

Polymers Covalent monomers Condensation reaction (dehydration reaction): One monomer provides a hydroxyl group while the other provides a hydrogen to form a water molecule Hydrolysis: bonds between monomers are broken by adding water (digestion)

Carbohydrates, I Monosaccharides √ CH2O formula; √ multiple hydroxyl (-OH) groups and 1 carbonyl (C=O) group: aldehyde (aldoses) sugar ketone sugar √ cellular respiration; √ raw material for amino acids and fatty acids

Carbohydrates, II Disaccharides glycosidic linkage (covalent bond) between 2 monosaccharides; covalent bond by dehydration reaction Sucrose (table sugar) most common disaccharide

Carbohydrates, III Polysaccharides Structural in function: Plants: Cellulose Animals:Chitin~exoskeleton; cell walls of fungi; Polysaccharides Energy Storage: Plants: starch (glucose monomers) Animals: glycogen

Lipids No polymers; glycerol and fatty acid Fats, phospholipids, steroids Hydrophobic; H bonds in water exclude fats Carboxyl group = fatty acid Non-polar C-H bonds in fatty acid ‘tails’ Ester linkage: 3 fatty acids to 1 glycerol (dehydration formation) Triacyglycerol (triglyceride) Saturated vs. unsaturated fats; single vs. double bonds

Phospholipids 2 fatty acids instead of 3 (phosphate group) ‘Tails’ hydrophobic; ‘heads’ hydrophilic Micelle (phospholipid droplet in water) Bilayer (double layer); cell membranes

Steroids Lipids with 4 fused carbon rings Ex: cholesterol: cell membranes; precursor for other steroids (sex hormones); atherosclerosis

Proteins Importance: instrumental in nearly everything organisms do; 50% dry weight of cells; most structurally sophisticated molecules known Monomer: amino acids (there are 20) ~ carboxyl (- COOH) group, amino group (NH2), H atom, variable group (R)…. Variable group characteristics: polar (hydrophilic), nonpolar (hydrophobic), acid or base Three-dimensional shape (conformation) Polypeptides (dehydration reaction): peptide bonds~ covalent bond; carboxyl group to amino group (polar)

Protein Structure Primary Secondary Tertiary Quaternary

Primary Structure Conformation: Linear structure Molecular Biology: each type of protein has a unique primary structure of amino acids Ex: lysozyme Amino acid substitution: hemoglobin; sickle-cell anemia

Secondary Structure Conformation: coils & folds (hydrogen bonds) Alpha Helix: coiling; keratin Pleated Sheet: parallel; silk

Tertiary Structure Conformation: irregular contortions from R group bonding √hydrophobic √disulfide bridges √hydrogen bonds √ionic bonds

Quaternary Structure Conformation: 2 or more polypeptide chains aggregated into 1 macromolecule √collagen (connective tissue) √hemoglobin

Types of Proteins Structural Protein Storage Proteins Transport Proteins Receptor Proteins Contractile Defensive Enzymes Signal Sensory Gene Regulator

Nucleic Acids, I Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) DNA->RNA->protein Polymers of nucleotides (polynucleotide): nitrogenous base pentose sugar phosphate group Nitrogenous bases: pyrimidines~cytosine, thymine, uracil purines~adenine, guanine

Nucleic Acids, II Pentoses: √ribose (RNA) √deoxyribose (DNA) √nucleoside (base + sugar) Polynucleotide: √phosphodiester linkages (covalent); phosphate + sugar

Nucleic Acids, III Inheritance based on DNA replication Double helix (Watson & Crick - 1953) H bonds~ between paired bases van der Waals~ between stacked bases A to T; C to G pairing Complementary

Surface area-to-volume ratios affect a biological system’s ability to obtain necessary resources or eliminate waste products

Why can’t cells be extremely large? As cells increase in volume, the relative surface area decreases and demand for material resources increases; more cellular structures are necessary to adequately exchange materials and energy with the environment. These limitations restrict cell size.

Examples of tissues and cells that increases their surface are to maximize absorptions of nutrients and the elimination of waste. Root hairs Root hairs Cells of the alveoli Cells of the villi Microvilli

What have we learned today about cells? The surface area of the plasma membrane must be large enough to adequately exchange materials; smaller cells have a more favorable surface area-to-volume ratio for exchange of materials with the environment