Chapter 2- Basis of Life - Notes

Chapter 2- Basis of Life - Notes H2O is water. There is one oxygen and two hydrogens attached to the oxygen. This is all in the atom. The circles are known as orbits or shells, and the inner circle is the nucleus. First level: Atoms & Molecules The periodic table of elements consists of squares that are elements. Periodic table has chemical elements in it. Every element you look at has its own name. The first element of group one is hydrogen. Hydrogen has its own symbol “H.” H is for hydrogen, and every element on the table has its own chemical signal. ANother element is oxygen, the symbol is “O.” Another one is carbon “C.” Carbon is the backbone of compounds. Every element has its own name and symbol which come from Latin or Greek origin. Every element has atomic mass and its own atomic number. The most important thing from the periodic table is the electronegativity and the electro positivity. ● Hydrogen is electropositive element, oxygen is a electronegative element ● Cellular respiration is the process of your body making energy. Hydrogen and oxygen play important roles in that process. ● As we move from the left to right of the periodic table, the electronegativity of the elements increases ● One of the elements in the periodic table is oxygen (electronegative) ● Fluorine would be the most electronegative element of the periodic table ● Every element in the periodic table has its own atomic mass and its own number, as well as its own symbol. Example: Oxygen “O” ● Every element on the periodic table is made up of its own atoms. Example: Chlorine made up of chlorine atoms, oxygen made up of oxygen atoms ● The blue (group 8) of the periodic table are noble gases Matter: We and everything around us is matter. Matter is any substance that takes up space by having volume. Matter is found in 3 states, which are solid, liquid, and gas. Matter in its 3 forms example: cube of ice, liquid (water) from ice, and the water boiled evaporates, which is the gas. Matter & Atoms: An attom indevisbale which means undividable is the smallest unit of matter. Subatomic particles that make a atom are: ● Proton, has a positive charge ● Electron, has a negative charge ● Neutron, has no electric charge Protons and neutrons in nucleus. Electrons are in shells around the nucleus In a netruol atom, (no postiive or negative) the number of protons is equal to the number of electrons. Protons, neutrons, and electrons. Element: Lithium Nucleus has protons and neutrons 3 protons, 3 neutrons. Electrons are in shells or orbits around the nucleus. Every element in the periodic table has a specific number of protons, and that number doesn’t change. Lithium will always have that same number of protons. (3) The number of electrons and neutron changes, but number of protons does not change Atomic Number- Atomic Mass Atomic number- is the number of protons. This number is referred as the atomic number of that element Atomic Mass- sum of number of protons and neutrons. Atomic mass will always be a larger number compared to number of protons. Example: atomic number of carbon is 6, atomic mass of carbon is 12 The first closest to the nucleus will hold 2 electrons. The second shell can hold a maximum of 8 electrons. Outer most shell is known as “Valency Shell” - it determines the chemical property of the element. How many chemical bonds an element will be forming. Number of electrons in vallency shell determines how many bonds that element will be forming. The first shell of an atom can hold 2 electrons, second can hold maximum of 8 electrons The goal behind forming chemical bonds is to be stable. Stability is given in a rule callee octet rule Elements that have 8 electrons in the outer most shell are known stable elements. Oxygen is an unstable element because it has 6 electrons on the outside shell, not 8. Form a chemical bond by taking, giving or sharing the goal behind it is to become stable. All elements in group of periodic table have 8 electrons are stable. Those elements with less electrons, donate, accept or share electrons to acquire 8 electrons in valence shell. By formation of chemical bonds is how you give take or share. The 8 (blue) of periodic table already fulfill octet rule. Helium is one of the elements in the periodic table fulfills that octet rule. There are exceptions. Hydrogen has 1 proton and 1 electron. Hydrogen is another exception to that octet rule. Balance that needs to be created, negative outside and positive inside is what is going to hold atom in its place Matter & Elements: elements is a substance that cannot be further broken down. We and everything around us is made up of elements. An element is a substance made up of same kind of atoms ● 99% of our body is made up of 6 elements. Oxygen 65%, Carbon 18.5%, Hydrogen 9.5%, Nitrogen 3.5%, Calcium 1.5%, Phospahrus 1.0%, Potassium 0.4%, Salfur 0.3%, Sodium 0.2%, Chlorine 0.2%, Magnesium 0.1%, trace elements ,0.01% 118 elements have been identified 94 natural origin, 24 synthetic origin, human body requires 25 elements. Elements are identified by atomic symbols composed of one or two letters. Naturally occurring elements: O, C, H, He, Mg, CI… Synthetic elements- named by the person who made them: Am, Cm, Cf, No… Importance of trace elements- elements that are found in minute quantities in our body-less than 0.01% by weight of our body. Iodine, iron, fluorine Iodine- required for synthesis of thyroid hormones. iodine is absolutely essential for the correct working thyroid. Thyroid hormone requires iodine. Iron- essential for hemoglobin. Too much weight gain is a symptom of the correct fucntion fo the thyroid glan. (metabolism is slow) veggies and beans and fish have iodine in them, should be consumed to get enough of iodine. Second one- iron- essential for hemoglobin, red blood cells have hemoglobin in them. Hemoglobin is a folding of protein in a body or structure, cirdinary structure, with globin chains. Too much is not good Floride- prevention of tooth decay. Iron deficiency- related anemia. When fluorine gets electron, it becomes floride. We find floride in tooth paste, too much fluoride is not good either. Red blood cells which are all over the body are found in iron blood cells All 3 elements are required in a small amount. IsotopesSome atoms of an element may different in atomic mass number (number of protons and neutrons) such atoms are referred to as isotopes. Electrons stay the same number, but neutrons change. atoms of the same element that differ in the number of neutron. Radiation is the factor that has the ability to damage genetic material If there is a cell in our body thats damaged or has damaged dna, that one cell will make copies of itself. From 1 damage cell, you have 100 damage cells. This condition is cancer. A bit of radiation use is good, it’s used a lot in agriculture, biomedical frields, hospitals. One form of iodine 141 we use it in a small amount to detect the working of an organ in our body, which is thyroid. We take a small amount of isootpes inject it into a persons body and we take a picture and check the thyroid glan. Chemistry of Life: Molecules A molecule is an electrically neutral group of 2 or more atoms held together by chemical bonds. “Molecule”= (Latin word) small unit of mass or “mole” Micromolecule- (SMALL) amino acids, monosaccharide (glucose), and nucleotide, small blocks of legos are micro. Mono means one, saccaridhe means sugar. Monosaccharides are single sugar. One example of monosaccaride is glucose. Glucose- C6H12O6. Building block of carbohydrate. Dysacchride means 2, polysacchride means many, polysacrides are made of many glucose coming together. Example of polysaccride is starch. Macromolecule- (BIG) proteins, polysaccharide (starch), DNA, big structure of lego is macro. Small legos make up a big lego. 3 categories: Carbohydrates, proteins, nucelic acids Macromolecule are the building blocks of carbohydrates Building blocks of Proteins: Amino acids are the building blocks of Proteins. Example of protein in our body: keratin in our hair, nails, hemoglobine, enzymes Third category of Macocolecules: Nucleic Acids- examples of nucelic acidsDNA & RNA- nucelotides are building blocks of DNA & RNA Compound: Substance consisting of 2 or more different elements in a fixed ratio. A compound is made up of molecules. Example: Pure sodium is a metal and pure chlorine is a poisonous gas- both combined together in equal purporting form table salt (sodium chloride) Molecules and Compounds: Hydrogen is a gas and oxygen is a gas combined together in the ratio of 2:1 forms water the most abundant on this planet. A molecule of water is made up of 2 atoms of hydrogen and 1 atom of oxygen Chemical Bonds: A carbon atom has 4 electrons in its outer shell. To complete its outer shell (under the octet rule) it will need 4 more electrons A hydrogen atom has 1 electron in its outer shell and will need one more electron to complete its vallency shell First type of chemical bond is Covalent bond: sharing, a covalent bond is described as sharing of electrons. Example: 2 hydrogen atoms come together and each atom completes its outer shell by sharing each other electrons Consists of 2 things: non-polar covalent and polar covalent. Difference between the 2: for non-polar covalent, equal sharing of electrons takes place. For polar covalent, unequal sharing of electrons take place Example of non-polar covalent bond: hydrogen. Hydrogen only has 1 electron, to become stable it needs 1 more electron. Each hydrogen brings its electron and they share their electrons. The electrons spend the same amount of time on both sides for both hydrogens. Second type of covalent bond which is polar covalent bond is Water Molecule aka H2o. Sharing of electrons in a covalent bond is not always equal. The negatively charged electrons are drawn more closely to the more electronegative element In a water molecule, (H2o) electrons of hydrogen (H) are drawn towards Oxygen (O) Oxygen is partially negative, Hydrogen is partially positive. Electronegative elements are the elements that pull the electrons towards themselves. Electrons will spend majority of the time towards electronegative elements. In a water molecule oxygen will pull oxygen because they are electronegative. Because of that, oxygen will become partially negative and hydrogen will be partially positive. When we have electronegativity we have unequal distribution of charges. Water - Polarity Water is polar because it is coming from that unequal distribution of charges. Positively charged H (in 1 molecule) is attracted yo negatively charged O (in the water molecule) of water. This gives rise to water polarity. Ionic bond- Transfer of electrons. Transfer of electrons from one atom to another forms an ionic bond. Sodium has 1 electron in its outer most shell and chlorine has 7 electrons in its outer shell. Positively charged ions (sodium) negatively charged ions (carbon) Atoms with electric charge are called ions. Chlorine will become negative 1 and sodium will become positive 1. sodium got 1 electron from chlroine, so chlorine is -1. Ions are charged atoms. Postively charged ion is sodium, are known as cat ions. Negatively charged ions are known an ion. Negatively charged ions, so chlroine is now chlroide. Negatively charged ions end in “ide.” Water & Hydrogen Bonds: Between 2 hydrogen and 1 oxygen, the bond is polar covalent bond. 1 water can hydrogen bond with 4 other water molecules. In the picture wer are looking at polar covalent and hydrogen bond. Hydrogen bond- it is a weak bond0 hydrogen bonds hold water molecules together. It is the property of these weak bonds, that is crucial for cellular functioning and sustenance of life All the life-supportung properties of water are because of the weak hydrogen bonds and the structure of its molecule The v shaped structure of water meolcule results in unequal distribution of charges and makes it a polar molecule