2Ethylene gas ( hormone) stimulates the production of several enzymes The enzyme that makes bananas sweet is called amylase. Amylase breaks down the starch in the banana fruit. When the starch is broken into its smaller sugar components, called glucose, the banana tastes sweet.
3Prolong life by keeping warm temperatures - This is best explained by the banana’s slowed metabolic functions at a lower rate due to lower
4I. Atoms Definition: smallest particle of an element BOTH FOR LIVING AND NON LIVINGDefinition: smallest particle of an element
6B. Composition C. If Neutral Atom: # protons = # electrons Proton +1 1 Subatomic ParticleChargeMassLocationProton+11NucleusNeutronElectron-11/1840 the mass of a protonOrbiting nucleusC. If Neutral Atom: # protons = # electrons
7II. Elements Definition: substance that cannot be broken down into other substancesB. Biologically important elementsi. Major: C H O Nii. Minor: Ca Fe Mg I Se P K Na ClSymbol: usually from first letter or two of fullname
9Elements Con’t. Atomic Number: # of protons in nucleus Mass NumberAtomic Mass amuAtomic Number: # of protons innucleusBackbone of life- 4 valence electrons make it easy to bond
10E. Atomic Mass / Mass Number Atomic mass: count of the total number of protons and neutrons in an atom's nucleus
11F. Isotopes i. Definition: forms of the same element have same # of protons but different # ofneutronsMass Numberii. Radioactive isotopes: An isotope having an unstablenucleus that decomposesspontaneously
12G. Chemical Compoundsi. Molecules definition: two or more atoms held together by COVALENT bonds
13Compound definition: a substance containing two or more elements in a fixed ratioEx: H2O, NaCl
14Decoding Chemical Formulas?? C6H12O6Elementsubscript is the NUMBER of ATOMSSo in this molecule, there are 6 carbon atoms, 12 hydrogen, and 6 oxygen
152H2O The number in front of H2O means two entire molecules of H2O Think of it like 2 x (H20)Sooooo… how many total atomsof H are there?Of oxygen?
16III. Bonding happy Atoms want to fill their outer energy levels to be In order to do this, they will meet up with other atoms and either share or exchange electronshappy
17A. Covalent BondsAtoms share electrons so that both atoms fill their outer energy level
18B. Ionic Bonds: gimme that electron! Atoms transfer electrons, becoming (+) or (-) chargedThis attraction brings them togetherEx: Na and Cl
22IV. Water Human Composition: 65–90% water Plant Composition: 80-90% Formula: H2OBonds:i. Hydrogen bonds: the slightly (+) H atomsare attracted to nearby (-) O atoms, anddevelop a weak bond.ii. Covalent bonds: are shared between oxygenand hydrogen in a single molecule.
23V. Water (con.’t) Water is a polar molecule: i. Definition of polarity: moleculethat has opposite electricalcharges on opposite endsii. Why? Oxygen does not shareelectrons equally- pulls them closerto itself, making it more negativeand Hydrogen more positive
24V. Water (con.’t)F. Unique molecule: i. Cohesion: 1. Definition: molecules of same kind stick to one another 2. Example: Surface tension; trees transporting water from roots to leaves
25Adhesion:1. Definition: attraction that occursbetween unlike molecules2. Example: Water molecules andcotton string.
26Solutions:1. Water is able to dissolve other polar and ionic compounds when mixed by causing the ions to break away and surround them.Ex.: Salt Water
27Suspensionsa. Definition: A heterogeneous mixture inwhich particles settle out of solvent-likephase some time after their introductionb. Example: oil & wateriv. Boiling Point: water will boil at 100C or 212F
28Acids and Basesi. A water molecule can react to form ionsii. An ion is when a molecule breaks downand the atoms get a charge1. Example: H+ and OH-
29iii. pH Scale 1. How? Scale of 0-14; each pH unit represents a tenfold change in the concentration of H+ ions 2. Acid definition: pH Base definition: pH 8-14
304. Buffer definition: substances that cause a solution to resist changes in pH.; works by accepting H+ ions when levels rise and donating H+ ions when levels fall, maintaining a constant pH a. Weak acid or base