Chapter 3: Chemistry of Life. Word Everyday Meaning Science Meaning Compound

Transcription

1 Everyday Words in Science: Chapter 3: Chemistry of Life Word Everyday Meaning Science Meaning Compound Solution Energy Section 1: Matter and Substances Matter: Atom: Element: substance made up of atoms that have the same number of protons Valence Electron: electrons in the outer most energy level or shell Compound: substance made up of the bonded atoms of 2 or more different elements Molecule: group of atoms held together by chemical bond Ion: atom or group of atoms with a chemical charge I. Atoms A. B. Atomic Structure 3 types of particles protons b. electrons c. neutrons

2 d. protons = electrons therefore atom has C. Elements isotopes atoms of the same element that have different numbers of neutrons II. Chemical Bonds A. form between groups of atoms because most atoms become stable when their valance shell is full (has 8 electrons) B. Covalent Bonding atoms bonding by electrons 2. molecule has covalent bonds 3. examples: C. Ionic Bonding atoms bonding by or electrons 2. results in a positive or negative charge 3. example: III. Polarity A. when shared electrons are more strongly attracted to one atom than another B. one end or pole has a slight negative charge and one end or pole has a slight positive charge C. example: D. Solubility partially charged ends of polar molecules attract opposite charges 2. water can dissolve other polar molecules (sugar) and ionic compounds (salt) 3. non-polar molecules (oil, grease, wax) do not dissolve in water 4. water molecules are attracted to each other (surface tension) E. Hydrogen Bonds weak bond between 2 hydrogen atoms 2. 2 strands of DNA are hydrogen bonded together between the bases

3 Section 2: Water and Solutions Cohesion: attraction of particles of the SAME substance Adhesion: attraction between particles of DIFFERENT substances Solution: Acid: Base: ph: Buffer: I. Properties of Water A. unique properties because water molecules form hydrogen bonds with each other B. C. D. E. water is less dense as a solid than as a liquid 2. prevents rivers, lakes, streams, oceans from freezing solid so life can survive under ice hydrogen bonds constantly breaking and forming 2. takes along time to cool/heat 3. large bodies of water help earth maintain temperature 4. helps body temperature remain relatively constant hydrogen bonds form a cohesive property 2. water is liquid at ordinary temperatures because of cohesion Adhesion helps water move up a stem to a leaf of a plant

4 II. Solutions A. Acids and Bases Acid examples b. c. 2. Base examples b. c. 3. Mix acids (H + ) and bases (OH - ) to form water (H 2 0) and salt B. ph and Buffers ph scale = = 3. 7 = ph of pure water = = 6. ph of living things must be stable 7. ph of human blood is averaged at 8. buffers help to keep ph stable

5 Section 3: Carbon Compounds Carbohydrate: molecules made of sugars, starches and fiber; contains carbon, hydrogen and oxygen in 1:2:1 ratio Lipid: Protein: Amino Acid: simple organic compound contains carbol and amino group that combines to form proteins Nucleic Acid: organic compound, DNA or RNA, made of 1 or 2 chains of nucleotides and carry genetic information Nucleotide: organic compound that consists of a sugar, phosphate and nitrogen base DNA: RNA: ATP: Adenosine Triphosphate; organic molecule that acts as the main energy source for cell processes I. Building Blocks of Cells A. Parts of a cell are made up of large, complex molecules called B. Large, complex biomolecules are built from a few smaller, simpler, repeating units arranged in an extremely precise way C. Carbon Compounds Basic units of most biomolecules contain carbon atoms II. Carbohydrates A. Found in foods like grains, fruits, vegetables Glucose

6 2. Sucrose table sugar b. lactose 3. Starch glycogen 4. Cells use carbohydrates for B. Energy Supply 2. plants store sun s energy by making glucose and converting it to starch 3. C. Structural Support Chitin and cellulose are complex carbohydrates that provide support 2. Chitin b. cell walls of mushrooms and molds 3. Cellulose D. Cell Recognition short branched chains of sugars on outside of cells 2.

7 3. carbohydrates on the outside of invading cells allow the body to recognize them as not normal so they can be destroyed III. Lipids A. Chains of carbon atoms bonded to each other and hydrogen atoms B. Main function of lipids include storing energy and controlling water movement C. Energy Stores D. 2. animals can survive without steady diet because of fat storage 3. animal converts excess food into fat molecules Cell s boundary made of phospholipids 2. Stems and leaves of plants covered by wax to prevent evaporation 3. Wax also found on feather on duck s back IV. Proteins A. Perform many types of functions

8 B. Amino Acids 2. Structure amino group b. carboxyl group c. variable group 3. Carboxyl groups linked by peptide bonds 4. Side group gives protein unique properties 5. Order of amino acids specific for protein V. Nucleic Acids A. Hereditary Information DNA instructions for the processes of an organism s life b. c. store and transmit hereditary information B. Energy Carriers Energy released in reaction breaks off 3 rd nucleotide Section 4: Energy and Metabolism Enzyme: Active Site: on an enzyme, site that attaches to substrate Substrate: reactant in a reaction catalyzed by enzyme I. Biological Reactions A. Living things have reactions that maintain a stable internal environment B. Enzymes

9 2. Enzyme activity substrates bind to an enzymes active site; b. binding causes enzyme shape to change slightly c. chemical reaction is complete when product, new substance, is formed C. Metabolism Food is digested, enters blood stream, delivered to cells 2.