Molecules of Life posted

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Published on February 24, 2018

Author: acocil

Source: authorstream.com

Slide1: All living things have similar characteristics Require energy and nutrients Sense and respond to change Reproduce with the help of DNA Slide2: The building blocks (atoms) that make up all living things are the same ones that make up all nonliving things The unique properties of life emerge as certain kinds of molecules become organized into cells “Life is an emergent property” Levels of Organization: Levels of Organization Atom (not alive) the building block of all matter Molecule (not alive) An association of two or more atoms Cell (alive) Smallest unit of life (live emerges at the cellular level) Organism (alive) An individual; consists of one or more cells Slide4: Population Group of individuals of a species in a given area Community All populations of all species in a given area Ecosystem A community interacting with its environment Biosphere All regions of Earth that hold life Life’s Diversity: Three-Domain Classification System: Life’s Diversity: Three-Domain Classification System Prokaryotes Eukaryotes Slide6: archaea Bacteria Protist Fungi Plantae Animalia Prokaryotes: Prokaryotes Prokaryotes Single celled organisms in which DNA is not contained in a nucleus Bacterium A member of the prokaryotic domain Bacteria Archaeans A member of the prokaryotic domain Archaea Eukaryotes: Eukaryotes Eukaryotes Organisms whose cells typically have a nucleus Fungus Eukaryotic consumer that obtains nutrients by digestion and absorption outside the body Protists Eukaryotes that are not plants, animals, or fungi Eukaryotes: Eukaryotes Plant Typically a multicelled, photosynthetic producer Animal Multicelled consumer that develops through a series of embryonic stages and moves about during all or part of the life cycle Slide10: Scientists Slide11: Scientific Websites Scientific Reports and Science Divulgation Once upon a time in a library… Scientific meetings Publications: books, magazines, etc. Molecules of Life: Molecules of Life Slide18: Yes, we are what we eat and we must eat to survive! Cells, for example, use carbohydrates for energy and as structure materials. Slide19: The molecules of life – carbohydrates, proteins, lipids, and nucleic acids – are organic molecules Organic Type of molecule that consists primarily of carbon and hydrogen atoms Slide20: Carbon atoms bond covalently with up to four other atoms, often forming long chains or rings Enzyme-driven reactions construct large molecules from smaller subunits, and break large molecules into smaller ones Slide21: Cells assemble large polymers from smaller monomers , and break apart polymers into component monomers Metabolism All the enzyme-mediated chemical reactions by which cells acquire and use energy as they build and break down organic molecules Slide22: Monomers Molecules that are subunits of polymers Simple sugars, fatty acids, amino acids, nucleotides Polymers Molecules that consist of multiple monomers Carbohydrates, lipids, proteins, nucleic acids Slide23: Condensation (water forms) Process by which an enzyme builds large molecules from smaller subunits Hydrolysis (water is used) Process by which an enzyme breaks a molecule into smaller subunits by attaching a hydroxyl to one part and a hydrogen atom to the other Slide25: Lipids are greasy or oily nonpolar organic molecules, often with one or more fatty acid tails Slide26: Saturated fats pack more tightly than unsaturated fats, and tend to be more solid Saturated fat Fatty acid with no double bonds in its carbon tail Unsaturated fat Lipid with one or more double bonds in a fatty acid tail Slide27: Phospholipids are the main structural component of cell membranes Phospholipid A lipid with a phosphate group in its hydrophilic head, and two nonpolar fatty acid tails Phospholipids: Phospholipids Slide29: A protein’s function depends on its structure, which consists of chains of amino acids that twist and fold into functional domains Protein Organic compound that consists of one or more chains of amino acids Slide30: lysine glycine glycine arginine 1 2 3 4 5 Slide31: Changes in a protein’s structure may also alter its function Denature To unravel the shape of a protein or other large biological molecule Slide32: Nucleotide Monomer of nucleic acids Has a five-carbon sugar, a nitrogen-containing base, and phosphate groups Nucleic acids Polymers of nucleotide monomers joined by sugar-phosphate bonds (include DNA, RNA, coenzymes, energy carriers, messengers) Slide33: The nucleotide ATP can transfer a phosphate group and energy to other molecules, and is important in metabolism Adenosine triphosphate (ATP) Nucleotide that consists of an adenine base, five-carbon ribose sugar, and three phosphate groups Functions as an energy carrier Slide34: DNA encodes heritable information about a cell’s proteins and RNAs Different RNAs interact with DNA and with one another to carry out protein synthesis Slide35: Deoxyribonucleic acid (DNA) Nucleic acid that carries hereditary material Two nucleotide chains twisted in a double helix Ribonucleic acid (RNA) Typically single-stranded nucleic acid Functions in protein synthesis Small brake! 5 min : Small brake! 5 min Slide38: All living things consist of the same kinds of molecules. Slide39: Molecule Group of two or more atoms joined by chemical bonds Compound Type of molecule that has atoms of more than one element Common in Science: defining concepts with other concepts. Slide41: All substances (matter) consist of atoms Atom Fundamental building-block particle of matter Life’s unique characteristics start with the properties of different atoms Slide42: an atom Slide43: + - Slide44: Atoms consist of electrons moving around a nucleus of protons and neutrons Atoms differ in numbers of subatomic particles Charge Electrical property of some subatomic particles Opposite charges attract; like charges repel Electron (e - ) Negatively charged subatomic particle that occupies orbitals around the atomic nucleus Slide45: Proton (p + ) Positively charged subatomic particle found in the nucleus of all atoms Neutron Uncharged subatomic particle found in the atomic nucleus Nucleus Core of an atom, occupied by protons and neutrons How many elements do you know? Can you name them?: How many elements do you know? Can you name them? Hydrogen Lithium Beryllium Vanadium 118? Slide47: Are you?... Slide52: Element A pure substance that consists only of atoms with the same number of protons Slide53: The proportions of different elements differ between living and nonliving things Some atoms, such as carbon, are found in greater proportions in molecules made only by living things – the molecules of life Slide54: mass number element symbol atomic number element name elemental substance Carbon Number of protons in nucleus Number of protons and neutrons in nucleus Slide56: Electrons travel around the nucleus in different orbitals (shells) – atoms with vacancies in their outer shells tend to interact with other atoms Atoms get rid of vacancies by gaining or losing electrons, or sharing electrons with other atoms Shell model Model of electron distribution in an atom Slide57: 1 proton 1 2 1 electron first shell hydrogen (H) helium (He) 6 8 10 second shell carbon (C) oxygen (O) neon (Ne) 11 17 18 third shell sodium (Na) chlorine (Cl) argon (Ar) Slide58: The negative charge of an electron balances the positive charge of a proton in the nucleus Changing the number of electrons may fill its outer shell, but changes the charge of the atom Ion Atom that carries a charge because it has an unequal number of protons and electrons Slide59: electron loss Sodium atom 11 11p + 11e – charge: 0 Sodium ion 11p + 11 charge: +1 10e – electron gain Chlorine atom 17 17p + 17e – charge: 0 Chloride ion 18e – 17 17p + charge: –1 Slide60: Atoms can also fill their vacancies by sharing electrons with other atoms A chemical bond forms when the electrons of two atoms interact Chemical bond An attractive force that arises between two atoms when their electrons interact Slide61: Depending on the atoms, a chemical bond may be ionic or covalent Ionic bond A strong mutual attraction formed between ions of opposite charge Covalent bond Two atoms sharing a pair of electrons Slide62: ionic bond 11 17 sodium ion (Na + ) chloride ion (Cl – ) An Ionic Bond: Sodium Chloride Covalent Bonds: Covalent Bonds Molecular hydrogen (H—H) and molecular oxygen (O=O) Slide64: A covalent bond is nonpolar if electrons are shared equally, and polar if the sharing is unequal Polarity Any separation of charge into distinct positive and negative regions Slide65: Nonpolar Having an even distribution of charge When atoms in a covalent bond share electrons equally, the bond is nonpolar Polar Having an uneven distribution of charge When the atoms share electrons unequally, the bond is polar Slide66: A water molecule (H-O-H) has two polar covalent bonds – the oxygen is slightly negative and the hydrogens are slightly positive – which allows water to form hydrogen bonds Slide67: Hydrogen bond Attraction that forms between a covalently bonded hydrogen atom and another atom taking part in a separate covalent bond Slide68: Hydrogen bonds form and break more easily than covalent or ionic bonds – they do not form molecules Hydrogen bonds impart unique properties to substances such as water, and hold molecules such as DNA in their characteristic shapes Water: Water All living organisms are mostly water, and all chemical reactions of life are carried out in water Hydrogen bonds between water molecules give water unique properties that make life possible Capacity to dissolve many substances Cohesion (surface tension) Temperature stability Slide71: slight negative charge slight positive charge slight positive charge Slide73: Polar water molecules hydrogen-bond to other polar (hydrophilic) substances, and repel nonpolar (hydrophobic) substances Hydrophilic (water-loving) A substance that dissolves easily in water Hydrophobic (water-dreading) A substance that resists dissolving in water Slide74: Water is an excellent solvent Solvent Liquid that can dissolve other substances Solute A dissolved substance Slide75: Salts, sugars, and many polar molecules dissolve easily in water Salt Compound that dissolves easily in water and releases ions other than H + and OH - Example: sodium chloride (NaCl) Slide76: Water molecules surround the atoms of an ionic solid and pull them apart, dissolving it Slide77: Temperature stability is an important part of homeostasis Water absorbs more heat than other liquids before temperature rises Hydrogen bonds hold ice together in a rigid pattern that makes ice float Temperature Measure of molecular motion Slide78: Cohesion helps sustain multicelled bodies and resists evaporation Cohesion Tendency of water molecules to stick together Evaporation Transition of liquid to gas Absorbs heat energy (cooling effect) Break time: Break time 10 minutes almost…lunch break! Slide82: Water molecules separate into hydrogen ions (H + ) and hydroxide ions (OH - ) pH A measure of the number of hydrogen ions (H + ) in a solution The more hydrogen ions, the lower the pH Pure water has neutral pH (pH=7) Number of H + ions = OH - ions Slide83: Acid Substance that releases hydrogen ions in water pH less than 7 Base Substance that releases hydroxide ions (accepts hydrogen ions) in water pH greater than 7 Slide84: — 0 battery acid — 1 gastric fluid lemon juice — 2 acid rain cola — 3 vinegar more acidic tomatoes, wine orange juice — 4 bananas beer — 5 black coffee bread urine, tea, typical rain butter — 6 corn milk — 7 pure water — 8 seawater egg white blood, tears — 9 detergents baking soda Tums — 10 hand soap toothpaste milk of magnesia household ammonia — 11 more basic — 12 hair remover bleach — 13 — 14 drain cleaner oven cleaner A pH Scale Acid Rain: Acid Rain Sulfur dioxide and other airborne pollutants dissolve in water vapor to form acid rain Slide86: p32 Slide87: Most molecules of life work only within a narrow range of pH – essential for homeostasis Buffers keep solutions in cells and tissues within a consistent range of pH Buffer Set of chemicals that can keep the pH of a solution stable by alternately donating and accepting ions that contribute to pH

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