Ch 3, Sec 3 Chemical Compounds in Cells Target: To define elements & compounds, explain how water is important to the function of cells, and identify the functions of carbs, lipids, proteins, & nucleic acids We are surrounded by trillions of tiny particles, some are made up of elements, others are made of compounds Air is made up of gases, both elements & compounds. Three gases in air: - oxygen -nitrogen - carbon dioxide

Elements - any substance that CANNOT be broken down into a simpler substance - ex: oxygen (O 2 ), nitrogen (N 2 ) - made up of only one kinds of atom Atom - smallest unit of an element Elements found in living things - carbon- oxygen - hydrogen- nitrogen - phosphorus- sulfur

Compound - two or elements chemically combined together - ex: carbon dioxide (CO 2 ) - most elements in living things occur in compound form Molecule - smallest unit of many compounds - a molecule of CO 2 is one carbon atom & two oxygen atoms

Water is compound - H 2 O (how many hydrogen atoms & how many oxygen atoms are in each molecule of water?) - makes up 2/3 of your body - dissolves chemicals that cells need -most chemical reactions within cells wouldn’t take place without it - plants couldn’t convert energy from chloroplasts into food - helps cells keep their shape & size - helps cells keep their temperature regulated

Inorganic compound - does not contain the element carbon - ex: H 2 O, no carbon in it NaCl 2 (Sodium Chloride, table salt) Organic compound - contains the carbon element - ex: carbohydrates, lipids, proteins, nucleic acids Carbohydrate - energy-rich organic compound made of carbon, hydrogen, & oxygen - ex: sugars & starches

- sugars are produced during food-making process in plants - fruits & vegies have high sugar content - sugar molecules combine, form starches or complex carbohydrates (large molecules) - plant cells store the starch - when we eat potatoes, pasta, rice, the body breaks down the starch into glucose for energy - also important components of cell parts - cellulose in the cell wall - in cell membrane

Lipids - fats, oils, waxes - energy rich organic compounds made of C 2, H 2, O 2 - have more energy than carbs - cells stores energy here for later use - make up most of the cell membrane Proteins - large organic molecules made of - carbon- hydrogen - nitrogen- oxygen - sometimes sulfur - foods high in protein: eggs, fish, meat, nuts, beans

- Structure of proteins - made of smaller molecules called amino acids Amino acids - a small molecule linked chemically to other amino acids to form proteins - like letters of the alphabet, they can be combined together to make different proteins - ex: lysine, tyrosine, leucine (put these together and it makes different) - 20 amino acids

- Function of proteins - most of cell structure is made of proteins (parts of cell membrane, many organelles) Enzyme - type of protein that SPEEDS up chemical reactions in living things - without enzymes, chemical reactions would take too long for cells to do their job or not happen at all - ex: saliva has enzymes in it to help break down food & aid in digestion

Nucleic Acids - long organic molecules - contain instructions for cells to carry out their functions of life - made of - carbon - oxygen - hydrogen- nitrogen - phosphorous - two types - DNA (deoxyribonucleic acid) - genetic material passed on from parent to offspring - directs all cell’s functions - mostly contained in chromatin in nucleus

- RNA (ribonucleic acid) - aids in production of proteins - found in cytoplasm of cell, & nucleus