1. Chapter 6 – Chemistry in Biology
UNIT 2 – THE CELL

2. Section 1 – Atoms, Elements & Compounds
Everything we see, are and experience comes from stardust

3. Atoms Chemistry is the study of matter
Atoms are building blocks of matter
Although discussion began in the 5th century B.C., evidence was not in place until the 1800’s for the existence of the “atom”

4. Atoms are made up of even smaller particles
Nucleus (made up of p+’s and n0’s
Protons (+)
Neutrons (0)
Electrons (-)
Move around the nucleus
Atom is a result of attraction between particles
Overall charge on an atom is zero

5. Examples of “H” and “O” Atoms

6. Elements
Pure substance that cannot be broken down by physical or chemical means
Collected in the periodic table
Atomic mass
Chemical & physical behavior/characteristics
State
92 naturally occurring
Horizontal rows called periods & vertical columns called groups/families

8. Isotopes When atoms have different # of neutrons
Isotopes will have the same chemical characteristics

9. Radioactive Isotopes
Changing the number of neutrons can affect the stability of the nucleus
Radiation can be given off as a result
Ages can be taken by measuring the rate of decay in these radioactive isotope

10. Compounds Two or more different elements combined
i.e. water, sodium chloride, methane
Must be in a fixed ratio
Are chemically & physically different from the elements that make them up
Cannot be broken down by physical means
Can be separated by chemical means (i.e. electrolysis

11. Chemical Bonds Force that holds substances together
Energy levels & electrons control bonding
Forming chemical bonds stores energy while breaking them provides energy for life processes
There are two types
Covalent
ionic

12. Covalent Bonds Share electrons in the outer shell
Majority of compounds in a living organism
Called a molecule
Can have single, double or triple bonds

13. Covalent Bond Example

14. Ionic Bond Higher melting points Give or take an electron
Electrical attraction
Most dissolve in water
Called ions most solid at room temperature
Helps maintain homeostasis in organisms
Transmits signals

15. Ionic Bond Example

17. Van de Waal Forces Attraction between molecules
Dutch physicist named Johannes
Depends on the size, shape & ability to attract electrons
Not as strong as covalent or ionic
Key role in biological processes
This is why water droplets form

18. HOMEWORK 6-1
Find a covalent (molecule) & ionic (ion) example not mentioned in the text or in class. Give the formula and explain the bond in picture form or words
Write a poem about the difference between ionic & covalent. Have at least one line dedicated to Van de Waals forces (no examples from class or text)

19. Section 2 – Chemical Reactions
This is why we grow, develop, reproduce & adapt
Reactant & products
Chemical reactions (i.e. rust)
Creates a new substance (change in color, production of heat or light, formation of new gas, liquid or solid)

20. Chemical equation reactants on the left → products on the right
“→” meaning yields or reacts to form
Balanced equations – conservation of mass – use of coefficients
Unbalanced
Balanced

21. Energy of Reactions
Most compounds cannot undergoes chemical reactions without energy
Activation energy – the minimum amount of energy that it takes for reactions to occur (high or low)
Example: a candle will not light without a flame

22. Energy change in chemical reactions
Exothermic – releases energy in the form of heat (i.e. candle)
Endothermic – it absorbs heat energy (i.e. internal body homeostasis)

23. Enzymes All living functions require numerous chemical reactions
Catalyst – a substance that lowers the activation energy & does NOT get used up in the reaction

24. Enzymes or biological catalysts will speed up biological processes, are essential to life & can be reused.
i.e. amylase that is found in saliva
Most enzymes are specific to one reaction
Substrates (reactants that bind to enzyme)
Active site is where the substrates attach themselves (like puzzle pieces)
Once binding occurs, active site changes to an enzyme-substrate complex
pH, temperature & other substances can affect the enzyme

25. Example of Enzyme as catalyst

26. Substrate at Active Site of Enzyme

28. 6-2 Homework
Apple Lab pg. 159 at home. Create a table to record findings and take photographs (possible groups of 2)
Give an example of enzyme not mentioned in book or class and tell me name and function of said enzyme
Balance equations on the handout and list products and reactants
Other than book or class topics, let me know a specific example (real world please) of an endothermic and exothermic reaction.

29. Section 3 – Water and Solutions

30. Water’s Polarity Is water covalent or ionic?
Unequal distribution of electrons in the water molecule
Polar molecules (i.e. tug o war)
Opposites attract (electrostatic attraction) – in water this is called a hydrogen bond (F,O,N) – Van de Waal force
So what is the formula for water? What is it made of? What is the formula for ice? For water vapor?

31. Mixtures Combo of two or more substance Homogeneous (solution)
Solvent & solute
Heterogeneous
Suspension
colloid

32. Acids & Bases Acids (release H+ ions when dissolved in H₂O)
Bases (release OH- ions when dissolved in H₂O)

33. pH & Buffers
Biological processes carried out in pH range of 6.5 to 7.5
Buffers are mixtures that react with acid & bases to keep pH in that safe range

34. 6-3 Homework Paragraph on H₂O importance in the body
Examples (that were not mentioned in class or text) of a solution, a colloid, a suspension and a homogenous mixture with the reasons why.

35. Section 6-4 The Building Blocks of Life (Carbon based)

36. Organic Chemistry Study of organic compounds (containing C)
Can be a straight, branched or
ringed molecule – which leads to diversity of life on the planet

37. Macromolecules
Large molecules formed by joining smaller organic molecules together
Also called polymers which are large molecules made up of repeated molecules called monomers
There are 4 types of macromolecules/polymers
Carbohydrates
Lipids
Proteins
Nucleic acids

38. Carbohydrates (see pg. 168)

39. Carbohydrates Stores energy, provides structure
Made up of 1 C, 2 H’s, 1 O (CH₂O) n
Where “n” is 3 – 7 then the carb. is a simple sugar ( see glucose illustration)
When 2 monosaccharides are put together (ex. Sucrose or lactose) it is called a disaccharide
Even longer chained monosaccharides are called polysaccharides
Makes up plants mass, exoskeletons, ect.

40. Lipids Store energy, provide barriers Fats, oils & waxes
Fatty acids, glycerol & other compounds
Prevents water loss from plants
Needed to carry out body functions
Saturated (will not accept H’s) & unsaturated (will accept H’s)
Polyunsaturated can accept more H’s
Phospholipids – responsible for structure and function of cell membrane since lipids are hydrophobic they create wonderful barriers between cells
Steroids
Cholesterol & hormones

41. Proteins
Transport substances, speed reactions, structural support, hormones
Made up of amino acids (C,N,O,H and sometimes S)
Bonds covalently with H, amino group (-NH₂), carboxyl (-COOH) & variable(-R)
There are 20 variables
Peptide bonds amino acids together forming proteins
Makes up 15% of body mass

42. Amino Acids Making a Protein

43. Protein Shapes

45. Nucleic acids Store and transmit genetic information
Made up of nucleotides (C, N, O, P, H)
6 major nucleotides (all have)
A phosphate
A nitrogenous base
A ribose sugar
DNA & RNA (deoxyribonucleic acid & ribonucleic acid)
ATP (Adenosine triphosphate)

46. Nucleic Acids

47. 6-4 Homework Comprehension Sentences Handout Tutorials
Awesome grade on test