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Ch2 notes 2013

Ch2 notes 2013






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    Ch2 notes 2013 Ch2 notes 2013 Presentation Transcript

    • Chapter 2
    • Organisms are chemical machines  All organisms consist of atoms – Subatomic particles  Electron (e-) – located in electron cloud  Proton (p+) – located in the nucleus  Neutron (no) – located in the nucleus Oxygen atom (O) Nucleus: 8 protons (+) 8 neutrons outermost energy level: 6 electrons (-) inner energy level: 2 electrons (-)
    • – Differ in the number of protons in the nucleus. – Number of protons = Number of electrons  Elements are neutral on the periodic table – Atomic Number = Number of protons – Atomic Mass = Number of protons + Number of neutrons http://www.privatehand.com/flash/elements.html
    • Name Symbol # p+ # e- #no Tin 25 N 15 12
    • Differ in the number of neutrons they contain in the nucleus – Example:  Carbon 12 – 6p+, 6e-, 6no  Carbon 13 – 6p+, 6e-, 7no  Carbon 14 – 6p+, 6e-, 8no
    •  Chemical Bonding – Compounds are made of joined atoms of two or more different elements.  Valence shell – outermost electron shell – Atoms with a full valence shell are inert (unreactive) – Atoms without a full valence shell can form bonds (reactive).
    • Name Symbol # p+ # e- #no Oxygen 6 K 53 - Why do all isotopes of an element have the same chemical properties? (Use your book to help you answer this)
    •  The first electron shell of every atom can hold a maximum of 2 electrons.  Each additional shell can hold a maximum of 8 electrons.
    • 1. Fluorine 2. Boron 3. Sodium
    •  Covalent bonds – atoms share electrons – Ex: H2, O2, CO2 covalent bonds Oxygen atom (O) Carbon atom (C) Oxygen atom (O) Carbon dioxide (CO2 )
    •  Ionic Bonds – atoms gain or loose electrons – Atoms form ions  + charge – cation  - charge – anion  Ex: NaCl
    •  Hydrogen Bonds – weak chemical attraction between polar molecules – Water is a polar molecule because the electrons of O and H are shared unequally.
    • • 70% of your body is made of water. • The remaining 30% is made up mostly of organic compounds (Carbon-based molecules). – Carbon is a unique element because it forms four covalent bonds and can form a lot of different structures.
    • Many carbon-based molecules are made of many small subunits bonded together. – Monomers are the individual subunits. – Polymers are made of many monomers.
    •  Key source of energy found in most foods  Fruits, vegetables, and grains  Made up of single sugars called monosaccharides.  Glucose, fructose  Disaccharides - two monosaccharides are joined  Sucrose (table sugar)  Polysaccharides – chains of three or more monosaccharides  Starch, cellulose, glycogen
    • Polymer (starch) Starch is a polymer of glucose monomers that often has a branched structure. Polymer (cellulose) Cellulose is a polymer of glucose monomers that has a straight, rigid structure monomer
    •  Nonpolar molecules not soluble in water  Fats, phospholipids (make up the cell membrane), steroids (cholesterol), waxes  Saturated fatty acids  Solid at room temperature  Butter, lard, grease  Unsaturated fatty acids  Liquid at room temperature  Olive oil, fish oil
    •  Formed by chains of linked amino acids  Many functions including:  Enzymes  Structural (imbedded in the cell membrane)  Antibodies
    •  Formed by chains of nucleotides  Two types :  DNA (deoxyribonucleic acid)  Double strand of nucleotides  Stores hereditary information  RNA (ribonucleic acid)  Single strand of nucleotides  Plays a key role in making proteins Nucleotide
    • Another important biological molecule  ATP (adenosine triphosphate) – Consists of a single nucleotide with 2 extra phosphate groups. – ATP stores energy temporarily. – All cells require ATP to function.
    • Chemistry allows life to function! Everything living things do is possible due to chemical reactions The chemistry of breathing
    • Activation energy is the amount of energy that needs to be put in to start a chemical reaction.
    • Exothermic reactions release more energy than they absorb. – Excess energy is released by the reaction as heat.
    • Endothermic reactions absorb more energy than they release. – Energy is absorbed by the reaction.
    • – Proteins that increases the speed of a chemical reactions in cells – Act as a catalyst (reduces the activation energy needed in a reaction)
    •  Any factor that changes the shape of an enzyme can affect the enzyme’s activity. – An enzyme’s function depends on its structure. – Denaturing (changing the structure) the protein by changes in temperature or pH – Example: pepsin