1 / 102

Chemistry in Biology Chapter 6

Chemistry in Biology Chapter 6. 6.1 Atoms, Elements, and Compounds. Chemistry: the study of matter Atoms: the building blocks of matter. Atoms. They are soooo small but they are made up of even smaller particles: neutrons protons electrons. Atoms.

marshl
Download Presentation

Chemistry in Biology Chapter 6

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemistry in BiologyChapter 6

  2. 6.1 Atoms, Elements, and Compounds Chemistry: the study of matter Atoms: the building blocks of matter

  3. Atoms They are soooo small but they are made up of even smaller particles: neutrons protons electrons

  4. Atoms There is a nucleus at the center of an atom! In the nucleus you can find: protons: positive charge neutrons: no charge Outside the nucleus you find: electrons: negative charge

  5. Atoms continued Electrons orbit around the atoms nucleus. The attraction between protons and electrons are what cause the structure of an atom. There are equal numbers of electrons and protons in an atom: the overall charge of an atom is zero

  6. Atoms • The atomic number: the number of protons found in the nucleus of the atom (therefore, it is also the number of electrons found that orbit around the nucleus) • The atomic mass: the weight of the protons and the neutrons combined.

  7. Elements • Element: pure substance that can’t be broken down further by chemical or physical means. • They are made up of only one type of atom • There are over 100 known elements

  8. Elements • Each element has a unique symbol and name Groups: the vertical columns Periods: the horizontal rows

  9. Isotopes Isotopes: atoms of the same element that have different numbers of neutrons (so the atomic mass is different) Radioactive isotopes: less stable nucleus which may decay. When the nucleus breaks apart it gives off radiation Carbon-14 used to calculate the age of things (within 50,000 years)

  10. Compounds Compound: a pure substance formed when two or more different elements combine Each has a chemical formula Each formed from a specific combination of elements in a fixed ratio (like C6H12O6)

  11. compounds They are chemically and physically different than the elements that make them up for instance: H is a gas, O is a gas together they make H20 which is liquid They can’t be broken down into simpler compounds or elements by physical means but they can by chemical means

  12. Chemical Bonds • The force that holds substances together are chemical bonds. The first orbit can hold 2 electrons The next ring can hold 8 electrons The outermost ring can hold 2 electrons

  13. Chemical bonds • In order for an element to be stable you must have the outer most energy level either completely full or completely empty • Otherwise it isn’t stable • Atoms become stable by either losing electrons to something else or by attracting more electrons from something • Either way, there is energy stored in the bonds that are made and when bonds are broken they release energy

  14. Covalent Bonds Covalent Bond: the bond that forms when electrons are shared Most compounds in living organisms have covalent bonds holding them together.

  15. Molecule Molecule: a compound in which the atoms are held together by covalent bonds

  16. Ionic Bonds Ion: An atom that has lost or gained one or more electrons and carries an electric charge Ionic bond: an electrical attraction between two oppositely charged atoms or groups of atoms

  17. ions • Substances formed by ionic bonds are called ionic compounds • Ions: sodium, potassium, calcium, chloride and carbonate ions • Help to maintain homeostasis • Help to transmit signals among cells to see, taste, hear, feel and smell

  18. ions • Some atoms tend to donate or accept electrons more easily than other atoms • (and when given the opportunity to choose, will choose certain atoms over others)

  19. Van der Waals Forces When molecules are attracted to each other based on positive and negative regions. Not as strong as covalent or ionic bonds but determined by the size of the molecule, its shape, and its ability to attract electrons Important in water molecules

  20. 6.2 Chemical Reactants Chemical reaction: when two or more chemical substances mix together. They become new substances that are very different than the original substances.

  21. Chemical reactions Sometimes substances change without involving a chemical reaction (so they are still made up of the same atoms but just a physical change happens)

  22. Chemical Equations • Reactants and products • Reactants: The starting substances that go into a chemical reaction • Products: The substances formed at the end of a reaction (or as a middle step)

  23. This is a chemical equation! This shows what goes in and what comes out.

  24. Balanced equations Matter cannot be created or destroyed WHAT GOES IN MUST COME OUT (but it can be rearranged because the bonds can change and form something else) So, you must account for the atoms that go into a reaction and what comes out of a reaction

  25. Balancing equations All chemical equations must show this balance of mass. This means that the number of atoms of each element ON THE REACTANT SIDE (the left side of the equation) must equal the number of atoms of the same element ON THE PRODUCT SIDE (the right side of the equation)

  26. Balancing Equations • The coefficient (the number in front) is used to make the number of atoms on each side of the arrow equal (you do not use the subscript for this

  27. Energy of Reactions There is a minimum amount of energy needed to make a reaction occur. This is called ACTIVATION ENERGY. The point: allowing the reactants create products

  28. Energy Change in Chemical Reactions When the reaction releases energy (in the form of heat) the reaction is EXOTHERMIC this means there is more energy in the bonds of the reactant (the stuff on the left side of the arrow) compared to the products(the stuff on the right side of the arrow).

  29. Energy Change in Chemical Reactions When the reaction requires more energy to happen than what is released the reaction is ENDOTHERMIC this means there is more energy in the bonds of the product (the stuff on the right side of the arrow) compared to the reactants (the stuff on the left side of the arrow).

  30. Enzymes All living things are “chemical factories” driven by chemical reactions There has to be an input of energy in order for reactions to occur. Some reactions would occur incredibly slow if allowed to occur on their own.

  31. Enzymes • In order to reduce the activation energy (reduce the amount of energy needed for a reaction to occur) ADDITIONAL substances are required. • This allows the reaction to happen more quickly.

  32. Enzymes • These things are biological catalysts: • A CATALYST is a substance that lowers the activation energy needed to start a chemical reaction. • It doesn’t change what is made, or how much is made…only how fast it is made

  33. Enzymes • A biological catalyst is an ENZYME • It is used to speed up a chemical reaction • It is usually specific to one reaction • Can be used over and over

  34. Enzymes • An enzymes name describes what it does: • Such as: • Amylase breaks down amylose • Maltase breaks down maltose • Lactase breaks down lactose (lactose intolerance is when lactose isn’t broken down by lactase: causing bloating, gas, diarhea)

  35. How enzymes work • The reactants that bind to the enzyme are called SUBSTRATES • Where the SUBSTRATE and the ENZYME bind together is called the ACTIVE SITE • The enzyme/active site fit together like puzzle pieces. Once together the active site changes shape.

  36. How enzymes work • Enzymes help chemical reactions happen by breaking bonds and allowing new ones to form. • It increases the speed at which reactions occur.

  37. 6.3 Water and Solutions • The properties of water make it well suited to maintain homeostasis in an organism HOMEOSTASIS: the body’s ability to regulate its internal condition by adjusting cellular processes

  38. Recall the structure of water

  39. Water is Polar Meaning- one side of the molecule has a slightly positive charge while the other side has a slightly negative charge Water molecules bond to each other with hydrogen bonds (shown above in the animation). The hydrogen is attracted to the oxygen.

  40. More Properties of Water It is the universal solvent because many substances dissolve in it

  41. Water is cohesive It has a strong attraction to other water molecules. Because of this it has high surface tension. This also causes droplets to form.

  42. Water is Adhesive It forms hydrogen bonds with other molecules on other surfaces. (think of tape) This causes capillary action.

  43. Acids and Bases Remember that water is a universal solvent because a lot of things dissolve in it. Your body is about 70% water. When a substance that contains hydrogen is dissolved in water it may release hydrogen (H+)

  44. Acids • Substances that release hydrogen ions when dissolved in water are called ACIDS. • The more hydrogen released the more acidic the solution becomes

  45. Bases • Substances that release hydroxide ions (OH-) when dissolved in water are called BASES. • The more hydroxide released the more basic the solution becomes

  46. pH Scale The measure of the concentration Of hydrogen in a solution is the pH. The more hydrogen something Releases the more acidic it is. HOWEVER, the more acidic it Is the lower the pH number on The pH scale. The more hydroxide (OH-) that Is released the more basic Something is. The higher the number is on the pH scale.

  47. Pure water is neutral and has a pH value of 7.0. • Acids have a pH number lower than 7 • Bases have a pH number higher than 7

  48. pH Scale Acids and bases are key substances in biology. All the chemical reactions in the body happen in certain ideal temperatures, environments and pHs Most chemical reactions occur between the pH of 6.5 and 7.5

  49. Maintaining the proper pH is important for chemical reactions to occur. • This is called HOMEOSTASIS-maintaining the internal environment.

More Related