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The Chemistry of Life Chapter 2.

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Presentation on theme: "The Chemistry of Life Chapter 2."— Presentation transcript:

1 The Chemistry of Life Chapter 2

2 vocabulary Atom the most basic and smallest unit of matter Nucleus
center of the atom holds protons and neutrons Contains subatomic particles called protons, electrons and neutrons Discuss next diagram

3 Atoms Nucleus; Protons; + charge; mass = 1AMU
Neutrons; no charge; mass = 1AMU Electrons: - charge; no mass

4 vocabulary Element specific atoms of one type form pure substances
Over 100 elements/pure substances exist Ca calcium H hydrogen O oxygen Na sodium C carbon

5 Periodic table Elements are organized in a table and assigned a number
Number atomic number Table periodic table This your new friend…at least for this next unit! Get use to it

6 Atomic Number Defines the element Is equal to the number of protons
Is equal to the number of electrons in a neutral atom Always the whole number

7 C 6 Carbon 12.011 Atomic Mass Atomic Number
An Element in the Periodic Table Section 2-1 Atomic Number 6 C Carbon 12.011 Atomic Mass Go to Section:


9 Atomic Mass Is equal to the number of protons and neutrons in the nucleus of the atom May not be a whole number on the periodic table In biology you may round up the mass number to a whole number

10 To find the number of Neutrons
Atomic mass – atomic number = Neutrons

11 Isotopes of Carbon Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 8 neutrons Isotopes have the same number of protons and electrons but have a different number of neutrons

12 Time to play… Candium isotope lab!!!

13 Energy Levels 1st 2e- 2nd 8e- 3rd 8e- 4th18e-

14 Valence Electrons Outer level Electrons Bonding Electrons

15 Image Source: SStevens 2002

16 Image Source: SStevens 2002

17 Image Source: SStevens 2002

18 Image Source: SStevens 2002

19 Image Source: SStevens 2002

20 Image Source: SStevens 2002

21 How are things kept together
Ionic Bonds Transferring of electrons Create ions Opposite charged particles are attracted to each other Electrons are gained/lost Covalent bonds Can create slightly different charges Strongest chemical bond Orbitals/shells overlap and electrons bounce back and forth Van der Waals forces Happens when molecules are super close together Hydrogen bonding-weak bonds

22 Drawing molecules showing Ionic Bonding
Draw all atoms showing protons, and electrons in their energy levels Decide which electrons must be transferred in order to fill all of the atoms outer level Draw the electrons being transferred Show the resulting charge on the Ions

23 Ionic Bonding Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+)
Chloride ion (Cl-) Transfer of electron Protons +11 Electrons -11 Charge Protons +17 Electrons -17 Charge Protons +11 Electrons -10 Charge Protons +17 Electrons -18 Charge

24 Ionic Bonding Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+)
Section 2-1 Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +11 Electrons -11 Charge Protons +17 Electrons -17 Charge Protons +11 Electrons -10 Charge Protons +17 Electrons -18 Charge

25 Draw the following molecules showing them form ionic bonds
KF MgCl2

26 Chemical formulas CO2 3 Atoms H2O 3 Atoms Ca(OH)2 5 Atoms
2C6H12O atoms

27 Covalent Bonding Sharing of electrons No ions are formed
Sharing of electrons holds it together.

28 Guided/independent practice
Chemistry worksheet…time to think!

29 Water Most abundant compound found in living things.
Water is a molecule (H2O) Water is a polar molecule. (unequal sharing of electrons) Hand out chemistry worksheet!

30 Water Facts It is a neutral molecule
Water is the single most abundant compound on earth It expands when it freezes It floats when frozen What advantage does this play in the survival of fish and plants 75% of earth is water The human body is 70% water Ph of 7.0

31 Properties of Water Its Polar High heat capacity
It has a negative end and a positive end Uneven sharing of electrons High heat capacity Absorb

32 Hydrogen bonds Because of the uneven charge water atoms can attract each other Cohesion: attraction between molecules of the same substance Insects walking on water Adhesion: attraction between molecules of different substances Water drawn up a plant (capillary action)

33 Hydrogen Bonding

34 Water demo Water lab

35 Acids, Bases, and the pH scale
Water is the universal solvent Most compounds will dissolve in water Remember 75% of most animals are water H20 → H+ + OH- Water → Hydrogen ion + Hydroxide ion Only about one water molecule in 55 million will form a hydrogen ion H+ = OH- , so water is always neutral

36 PH scale – measures the concentration of H+ and OH- ions.
Ranges from 0-14 At 7 the concentration of H+ and OH- is equal. (pure water) Acid – H+ ions, 0-6 Alkaline or base- OH- ions, 8-14 Each step represents a factor of 10

37 pH Scale Increasingly Basic Neutral Increasingly Acidic Oven cleaner
Bleach Ammonia solution Increasingly Basic Soap Sea water Human blood Neutral Pure water Milk Normal rainfall Acid rain Increasingly Acidic Tomato juice Lemon juice Stomach acid Go to Section:

38 Acids Any compound that gives off a hydrogen ion (H+) in a solution. HCl Stomach acid Lemon juice Tomato juice

39 Bases Any compound that will produce hydroxide ions (OH-) in a solution. Human blood Sea water Oven cleaner Bleach soap

40 Time to play… Ph lab

41 Buffers Facts Most cells in animals must generally be kept at a pH level between 6.5 and 7.5 Human blood has a pH of 7.4 If the body’s pH level goes to high or too low then cells do not work Maintaining pH levels is important for homeostasis Large changes in pH are controlled by substances called buffers

42 Examples of buffer in the body’s cells
Carbonic Acid (H2CO3) (H2CO3) → HCO3- + H+ Carbonic acid dissociates in water to form bicarbonate ion and H ions

43 Chemical Reactions Everything that happens in an organism is based on chemical reactions Definition: a chemical reaction is a process that changes one set of chemicals into another set of chemicals Cellular respiration Formation of Carbonic Acid from carbon dioxide and water

44 Mixture 2 or more elements or compounds that are physically mixed together but not chemically combined. Salt & pepper Earth’s atmosphere Salad soil

45 Solutions Evenly distributed throughout. Solvent; does the dissolving
Solute; gets dissolved Water is the greatest solvent.

46 NaCI Solution Cl- Cl- Na+ Na+ Water Water

47 NaCI Solution Cl- Cl- Na+ Na+ Water Water

48 Suspension Unevenly distributed throughout. (settle out) Water & gas
Water & oil Blood

49 4 Organic Compounds Carbon Compounds Carbohydrates Lipids
include Carbohydrates Lipids Nucleic acids Proteins that consist of that consist of that consist of that consist of Sugars and starches Fats and oils Nucleotides Amino Acids which contain which contain which contain which contain Carbon, hydrogen, oxygen Carbon,hydrogen, oxygen, nitrogen, phosphorus hydrogen,oxygen, nitrogen,

50 Organic Compounds Organic compounds contains Carbon, Hydrogen and Oxygen

51 Carbohydrates Main source of energy Monosaccharide (simple sugar)
Glucose – produced by green plants. Fructose – fruits, vegetables, honey. Disaccharides (double sugar) Lactose – mammals milk. Sucrose – table sugar. Polysaccharides (complex sugar) Cellulose (plants) Starch (plants) Glycogen (animals)


53 Plants store carbohydrates as Starch
Glucose Go to Section:

54 Animals store carbohydrates as Glycogen in the liver and muscles

55 Lipids Stored energy Fatty acids Saturated fatty acids – meat & dairy.
Unsaturated fatty acids – plants. Phospholipids Waxes Oils Steroids

56 Lipids What is it? Functions Fat, oils, and waxes
Lipid cells together are know as adipose tissue, hey look at that spare tire! Adipose tissue acts to cushion vital organs Once your body creates a fat cell, it is yours for life, you can never get rid of it! Functions Stores a huge amount of energy, even more than that carbohydrates But it is used for emergency situations when you run out of carbohydrates

57 Types of lipids found in animals
HDL Known as the “good” lipid Found in vegetables, oils, and some nuts Helps clear out LDL of you system Exercise will increase the levels of HDL in an animals system LDL Triglycerides

58 Proteins Made up of Amino acids 20 different amino acids
Structural- cell, muscle, skin, organs. Movement Enzymes

59 Proteins Examples of proteins Facts Muscle, insulin, hair
Accounts for %50 of cells weight Used for support, storage, transport defense, signaling other cells Humans have 10s of thousands of different proteins Are made of monomers called amino acids There are 20 different amino acids

60 What makes a protein function
The order of the amino acids Each protein has a specific order The shape of a protein determines its function Homeostasis: too much acid-proteins unfold. To high a temperature: proteins unfold, to cold: proteins cant function






66 3-D Protein

67 Nucleic Acids Deoxyribonucleic Acid (DNA) Ribonucleic Acid (RNA)
Contains genetic information Controls the production of proteins Nucleotides Phosphate Sugar base




71 Enzymes Some reactions that are needed in life are too slow to happen by themselves. To speed up these reactions cell in plants and animals produce catalysts. A substance that speeds up chemical reactions They work by lowering the activation energy Enzymes are proteins that act as biological catalysts Always end in ase Lactase, carbonic anhydrase Very specific

72 Catalyst Substance that reduces the amount of energy for a reaction to occur. Catalyst in cells are proteins called Enzymes. The substance that the enzyme works on are called a substrate. Enzymes are very selective.

73 Enzyme animation

74 Effect of Enzymes Reaction pathway without enzyme Activation energy
Section 2-4 Reaction pathway without enzyme Activation energy without enzyme Reactants Activation energy with enzyme Reaction pathway with enzyme Products Go to Section:

75 Time to play… Enzyme lab Organic compounds lab

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