1. The Chemistry of Life

2. Matter Life depends on chemistry
Eat food, Breathe in oxygen – chemical reactions allow your body to use these substances

3. Matter
Just as an architect needs to understand the materials used to build a skyscraper
…biologists need to understand the chemical building blocks of life.

4. Matter Matter – anything that takes up space and has mass
Mass – the amount of matter a substance contains
This is NOT the same as weight!

5. Mass The international unit of measure for mass is the kilogram
1kg is equal to the mass of a single cylinder of platinum kept by the international committee of weights and measure

6. Democritus A Greek philosopher
If you break and object in half, are both halves still the same thing?
If you break a piece of chalk, are the two pieces still chalk?

7. The Atom Atom – the basic unit of matter Everything is made of atoms
An atom cannot be broken and still be the same thing

8. Subatomic Particles Atoms are made up of even smaller parts
Protons, Neutrons, Electrons
Protons are positively charged particles
Neutrons have no charge
Electrons are negatively charged particles

9. Element
Element – a pure chemical substance that consists entirely of one type of atom
We know of over 100 different elements
Only about 2 dozen are commonly found in living things

11. Element Elements are represented by letter symbols H = hydrogen
C = carbon
O = oxygen
Na = sodium
He = helium

12. Element
Elements are determined by the combination of protons, neutrons, and electrons in their atoms
Ex.
Hydrogen is the first element on the periodic table
H has 1 proton and 1 electron

13. Isotope
Isotope – atoms of an element that have a different number of neutrons
A change in the number of neutrons alters the atomic mass
Isotopes are important to many chemical processes in life
We’ve already learned they are useful when using radioactive dating

14. Radiocarbon Dating
Carbon dating is one of the most accurate ways to determine the age of organic material
C has an atomic mass of 12
C14 has an atomic mass of 14 - it is an isotope

15. Chemical Compounds
Elements are usually found combined with other elements
Chemical Compound – substance formed by the combination of chemical elements in defined proportions
H2O, NaCl, C6H12O6

16. Chemical Compounds
Physical and chemical properties of compounds are usually very different from the individual elements
Take Sodium (Na) and Chlorine (Cl) for example…

17. Chemical Compounds
Compounds are formed when elements are chemically bonded
The sole of your shoe is bonded to the upper
A book cover is bonded to the pages
A reaction has occurred and the two types of atoms are now chemically linked together

18. Chemical Bonds
Ionic bond – one or more electrons are transferred from one atom to another
Covalent Bond - electrons are shared between atoms

19. Chemical Bonds http://youtu.be/QqjcCvzWwww
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20. Van der Waals
Van der Waals forces – weak attraction between oppositely charged atoms
Electrons are not shared or transferred
Kind of like magnets!

21. Water!
H2O
2 hydrogen and 1 oxygen

22. Water is Polar Polarity – having poles or a positive and negative side
Water is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms

23. Hydrogen bonds Polar molecules can attract each other
Hydrogen bond – the attraction between water molecules

24. Adhesion and Cohesion
Cohesion – attraction between molecules of the same substance
Water is the best example! It sticks together!
Adhesion – attraction between molecules of different substances

25. Why can this spider walk on top of the water?!

26. Solutions and Suspensions
You can mix things without chemically bonding them!
Mixture – material made of two or more elements physically mixed together
NOT chemically combined!

27. Solutions
Solution – a mixture of two or more substances that are evenly distributed
Ex. Salt dissolved in water!
2 components of a solution
The Solute
The Solvent

28. Solute Solute – what is being dissolved
Solvent – what is doing the dissolving (most of the time this is water)

29. Ions
When NaCl dissolves the Na and the Cl atoms are pulled apart by the water molecules forming ions
Ion - an atom or molecule with a net electric charge due to the loss or gain of electrons

30. Suspension When a substances does not dissolve in water
Instead it separates into pieces so small they do not settle
Suspension – mixture of water and materials that do not dissolve
Ex. Dirt/sand in water

31. Acids vs. Bases

32. Carbon Compounds We already know carbon is an important element
Carbon is found in each and every living thing
There is an entire branch of chemistry for just Carbon called Organic Chemistry

33. Carbon Compounds Carbon can bond to other carbon atoms
Carbon can link into long chains
…or form rings!
Carbon can form millions of different complex structures

34. Organic vs. Inorganic
Organic compound must have BOTH carbon and hydrogen
Ex.
CH4; C6H12O6

35. Macromolecules
Many molecules in living things are so large we call them macromolecules
Macro = large
Monomers – small unit that can join together with other units
Polymer – large compound formed from many smaller monomers

36. Macromolecules Carbohydrates Lipids Nucleic Acids Proteins
We can group organic compounds found in living things into 4 categories
Carbohydrates
Lipids
Nucleic Acids
Proteins

37. Carbohydrates
Carbohydrate – compound made of C, H, and O atoms; major source of energy for living things
Carbohydrates are polymers
The monomers that make up carbohydrate molecules are sugars

38. Carbohydrates
Carbohydrates are broken down into glucose molecules in living things
Glucose is the source of energy for all your body cells

39. Lipids
Lipid – macromolecule made of mainly C and H Fats, oils, and waxes Lipids are used to store energy Important parts of membranes and waterproof coverings

40. Lipids Lipids are long carbon hydrogen chains
Saturated and unsaturated fats
You may have seen these terms on food labels

41. Saturated vs. Unsaturated

42. Nucleic Acids
Nucleic Acid – macromolecule containing C, H, O, N, and P
Store and transmit genetic info
Two kinds:
DNA
RNA

43. Nucleic Acids Nucleic acids are polymers of nucleotides
Nucleic Acid – a sugar, a phosphate, nitrogenous base

44. Proteins Proteins – macromolecule made of C, H, O, and N
Needed for growth and repair
Made of amino acids

45. Proteins Proteins can have up to 4 levels of organization Primary
Secondary
Tertiary
Quaternary

46. Primary Level
Primary protein organization = the initial chain of amino acids
Peptide bond – the bond between amino acids to form the long chain we call a protein

47. Secondary Level Secondary structure consists of two shapes
Alpha helix
Beta sheets
Caused by hydrogen bonding

48. Tertiary Level
Three dimensional structure of a single protein molecule
Caused by hydrophobic interactions

49. Quaternary Structure 3D structure with multiple protein subunits
Held together by disulfide bonds

50. Proteins Some proteins help to control reactions and cell processes
Enzyme – protein that can speed up reactions
Other proteins build bone and muscle
Some help with transport

51. Chemical Bonds There are two main types of chemical bonds
Ionic Bonds
Covalent Bonds
Ionic bonds transfer electrons
Covalent bonds share electrons

52. Ions When a molecule with an ionic bond dissolves in water…
The molecule breaks into a positive and negative ion
NaCl  Na+ and Cl-

54. Chemical Reactions Living things are all made of chemical compounds
Chemistry is also how life works and what it does!
Growth, reproduction, movement

55. Chemical Reaction
Chemical Reaction – process that changes, or transforms one set of chemicals into another
Chemical reactions drive life processes!
Some reactions are slow
Some reactions are fast

56. *chemical reactions always involve changes in the chemical bonds
Reactants – the chemicals that enter into a chemical reaction
Products – the chemicals that are produced by the chemical reaction
Reactants  Products
*chemical reactions always involve changes in the chemical bonds

57. Chemical Reaction
H2O + CO2 + sunlight  C6H12O6 + O2 K2CO3 + 2HCl --> 2KCl + H2O + CO2

58. Energy in Reactions
Energy can be either released or absorbed whenever chemical bonds form or are broken
Living things carry out chemical reactions that require energy
Organisms need a source of energy
Plants have the sun
Animals eat food

59. Energy in Reactions
Activation energy – the energy needed to start a chemical reaction

60. Energy in Reactions Remember!
Some reactions give off energy…and some absorb energy!