Chemistry Of Cells

Chemistry Science that studies the elements, their compounds, the chemical reactions that occur between them and the molecular structure of all matter

Matter Anything that takes up space and has mass Everything we touch is matter Three forms Solid Liquid Gas

Elements Substances that can’t be broken down into another substance by ordinary chemical means All matter, living and non-living composed of elements 92% naturally occurring elements Differ by properties

Our Elements Six elements special to us Make up 98% of our body weight C- carbon H- hydrogen N- nitrogen O- oxygen P- phosphorus S- sulfur Make up 98% of our body weight

Atomic Theory Elements consist of tiny particles called atoms- smallest particle of an element that displays the properties of the element

Atomic Structure Three types of subatomic particles Neutrons- no electrical charge Protons- positive charge Electrons- negatively charge Nucleus- center of the atom Protons and neutrons located within Electrons (e-) move about nucleus

Periodic Table Developed as a way to display elements according to their characteristics

Understanding Chemical Bonds Atoms most stable when outer shell is full Octet rule- outer shell containing 8 electrons

Compounds Substance composed of atoms of two or more elements that are chemically combined Example: NaCl (table salt) Compounds form when elements try to comply to the octet rule

Types of Bonds Ionic- forms when 2 atoms are held together by attraction between opposite charges Ions- charged atoms Often form salts Example: Na+ Cl-

Types of Bonds Covalent- two atoms share electrons in order to have completed outer shell Example: oxygen gas (O2) Molecule- group of atoms held together by covalent bonds

Bonds Single bond- when two atoms share a single electron Double bond- when each atom shares two electrons Triple bond- when each atom shares three electrons

Chemical Reactions Occur when bonds are formed or broken causing substances to recombine into different substances Metabolism- all chemical reactions occurring in the cells of organisms Written as follows:

Mixtures and solutions Mixture- combination of substances in which individual components retain their own properties Example: mixing sand and sugar Solution- mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent) Example: adding sugar to ice tea

Acids and Bases Acids- substances that dissociate in water Release hydrogen ions (H+) Example: HCl-hydrochloric acid (stomach) Base- substances that take up hydrogen (H+) ions or release hydroxide (OH-) ions Example: NaOH- sodium hydroxide

pH and Its Scale pH- way of indicating the number of hydrogen ions in solutions pH scale- used to indicate acidity or basicity of solutions Ranges from 0 to 14 7 is neutral pH < 7= acid pH > 7= base Buffer- chemical that keeps pH within normal limits (example- Tums and Rolaids)

Water’s Importance to Life Life began in water Single most important molecule on Earth Cells are 60-80% water Polar molecule- molecule with an unequal distribution of charge Each molecule has a positive end and negative end Unique properties

Another Type of Bond Hydrogen (H)- weak bond, arises between slightly positive hydrogen atom of one molecule and slightly negative atoms of another molecule Example: H2O Water molecules attract other water molecules

Properties of Water Because of H-bonds Properties Can engage in 4 H-bonds Properties Solvency Cohesion and adhesion High surface tension High heat capacity High heat of vaporization

Life Substances Carbon has 4 electrons available for bonding To be stable it forms 4 covalent bonds Can bond with other carbons or with many other elements Form straight chains, branched chains, or rings Can have almost any number of carbons Can form different structure (shapes) Isomer- compounds with same chemical formula but different 3-d structures

Carbohydrates Biomolecule composed of carbon, hydrogen and oxygen (1:2:1 ratio) Monosaccharide- simplest type of carb (sugar) Glucose and fructose Disaccharide- combining of two monosaccharides Glucose and fructose link together to form sucrose

Carbohydrate cont’d Polysaccharide- largest, composed of many monosaccharides Starch- branched, energy storage Glycogen- highly branched, stores energy in liver Cellulose- long chains (like chain link fenece), forms cell walls of plants and gives them support

Carbohydrates cont’d Five- and six-carbon simple sugars are smallest Five-carbon: deoxyribose and ribose Six-carbon: glucose and fructose Functions: energy storage and cell structure

Lipids Insoluble in water 95% of fats in body are triacylglycerols Saturated fat: fatty acids have single covalent bonds Unsaturated fat: fatty acids have one or more double covalent bonds Functions: energy, insulation and protection

Proteins Contain carbon, oxygen, hydrogen, nitrogen and sulfur Amino acids are building blocks of proteins Functions: energy and structure Enzymes: protein catalysts for chemical reactions

Proteins Structure Primary: amino acid sequence Secondary: determined by hydrogen bonds Tertiary: folding caused by interactions within peptide bonds and sulfur atoms Quaternary: determined by spatial relationships between units

Nucleic Acids Deoxyribonucleic acid: genetic material of the cell (DNA) Ribonucleic acid: protein synthesis Messenger RNA Transfer RNA Structure DNA: double helical chain RNA: single chain

Nucleic Acids Nucleic acids are made up of chains of nucleotides Nucleotide: nitrogen base, sugar and phosphate group Nitrogen bases: purines (two) and pyrimidines (three)

Adenosine Triphosphate ATP Fuel for cell function and maintenance Molecule consists of sugar, adenine, and three phosphates Energy is stored in the second and third phosphates Breakdown of glucose provides energy to make ATP

Enzyme Protein that changes rate of chemical reactions Involved in nearly all metabolic processes Speed reactions in digestion of food Activities of enzymes depend on temp, ionic conditions, and pH of surroundings