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CHAPTER 3 CELL PROCESSES SECTION 1 - CHEMISTRY OF LIFE All things are made up of matter and energy Matter is anything that takes up space and has mass Energy is anything that brings about a change Energy can hold matter together or break it up ATOMS Matter is made of atoms At center of atom is the nucleus which contains protons (+ charge) and neutrons (no charge Outside nucleus are electrons that are negative ELEMENTS Something made up of only one kind of atom is an element An atom can not be broken down into simpler forms Everything is made up of elements Most things are made of a combination of elements COMPOUNDS AND MOLECULES Compounds are made up of two or more elements in exact proportions Example – pure water is always 2 atoms of hydrogen and one oxygen Compounds have properties different than the elements they are made of MOLECULAR COMPUNDS A molecule is a group of atoms held together When chem. Reactions occur, new molecules are produced that are different from original IONS Atoms are usually neutral, but sometimes gain or lose an electron, making them + or – Electrically charged atoms are called ions Mixtures Can be solids, liquids or gases When substances combine,the individual substances retain their own properties In a solution, two or more substances are mixed evenly Suspensions – formed when a liquid or gas has another substance evenly spread throughout it. Substances in a suspension eventually sink to the bottom Organic compounds All living things are made up of organic compounds They always contain carbon and hydrogen Associated with living things Organic compounds in all living things Carbohydrates, lipids, proteins, and nucleic acids Carbohydrates Supply energy for cell processes Ex. Sugar and starches Cellulose carbohydrate is important in plant cells Lipids Do not mix with water Fats and oils – release larger amounts of energy than carbs. Proteins Made up of amino acids Building blocks of many structures inside organism Enzyme proteins regulate nearly all chemical reactions in cells Nucleic acids Store important coded information – dna Carries info. That directs cells activities Inorganic compounds Made from elements other than carbon Source of elements needed by living things Many foods we eat contain inorganic compounds Water is one of the most important inorganic compounds Importance of water Living things are composed of more than 50% water Can live for only days without water Seeds, spores, fungi, bacteria need water to grow and reproduce All chemical reactions in living things need water Organisms need water to transport materials through their body Blood is mostly water Plants use water to move materials thru the plant Characteristics of water 2/3 of your body’s water is contained in cells Water helps maintain cell shape and size 1/3 of body’s water is found outside of the cell