Chapter 2: The Chemistry of Life

1
Chapter 2The Chemistry of Life
2
Lesson 2.1

• The Nature of Matter

3
Elements and Isotopes

• Element substance that consists entirely of one
  type of atom
• Represented by chemical symbol
• of protonsatomic

4
Atoms

• Atom the basic unit of matter

5
Nucleus
Neutrons

• center of the atom
• Contains protons and neutrons

6
Subatomic Particles

• Atoms are made up of smaller particles
• Electrons (negatively (- ) charged particles)-
  located outside the nucleus
• Protons (positively ( ) charged particles)
• Neutrons (particles with no charge, neutral)

7
(No Transcript)
8
Isotope

• atoms of the same element that differ in the
  number of neutrons

9
Radioactive Isotopes

• nuclei are unstable and break down at a constant
  rate over time
• Dangerous, but useful
• Using radiation from certain isotopes
• Geologists find out rock and fossil ages
• Treat cancer and kill food-spoiling bacteria
• Labels or tracers that follow movements of
  substances within organisms

10
Chemical Compounds

• Compound substance formed by the chemical
  combination of two or more elements in definite
  proportions

• Composition of compounds shown in chemical
  formula- water is H2O since there are 2 Hydrogen
  (H) atoms, and one Oxygen (O) atom

11
Chemical Bonds

• Hold atoms in compounds together
• Two types
• 1. Ionic Bond
• Formed when one or more electrons are transferred
  from one atom to another
• Ion an atom that gains or loses and electron to
  have a positive or negative charge

Cl
12
Chemical Bonds

• 2. Covalent Bond
• Formed when electrons are shared between atoms
• Form a structure called a molecule
• Molecule the smallest unit of most compounds
• Energy is stored in a molecules chemical bonds

13
Covalent bonds
Single bond
Oxygen
Hydrogen
Hydrogen
In the water molecule, each of the two hydrogen
atoms is sharing two electrons with the oxygen
atom.
14
(No Transcript)
15
(No Transcript)
16
Lesson 2

• Properties of Water

17
Water

• One of few compounds that is a liquid at most
  Earth surfaces
• The most abundant compound in living things

18
Hydrogen Bonds

• H2O molecules can attract each other
• Strongest of bonds that can form between
  molecules (not as strong as ionic or covalent)

19
Cohesion

• an attraction between molecules of the same
  substance

20
Adhesion

• an attraction between molecules of different
  substances
• Capillary action the attraction of the surface
  of a liquid to the surface of a solid

21
Solutions and Suspensions

• Mixture a material composed of two or more
  elements or compounds that are physically mixed
  together but not chemically combined
• e.g.
• Earths atmosphere
• Salt pepper
• Sugar sand
• 2 types of mixtures that can be made w/water are
  solutions and suspensions

22
Solutions

• a mixture of two or more substances

23
Solvent

• Solvent the dissolving agent
• Ex. water

24
Solute

• Solute the substance that is dissolved
• Ex. NaCl

25

• Ionic compounds and other polar molecules are
  able to be dissolved in water since it is polar

26
Suspensions

• Definition a mixture in which fine particles are
  suspended in a fluid where they are supported by
  buoyancy
• Example blood

27
The pH Scale

• Definition a measurement of H ions in a
  solution
• Ranges from 0-14
• 7 is neutral (same amt. of H ions and OH- ions)
• Below 7 is acidic (more H ions than OH- ions)
• Above 7 is basic (more OH- ions than H ions)

28
Acids and Bases

• Acid any compound that forms H ions is solution
  (1- 7 on scale)
• The stronger the acid, the lower the pH scale

29
Acids and Bases

• Base (aka alkaline) a compound that produces OH-
  ions in a solution ( 7 -14 on scale)
• The stronger the base, the higher the pH scale

30
Buffers

• weak acids or bases that can react with strong
  acids or bases to prevent sudden changes in pH
• Help to maintain homeostasis in substance
• Homeostasis metabolic equilibrium actively
  maintained by several complex biological
  mechanisms that operate via the autonomic nervous
  system to offset disrupting changes
• If pH is lower or higher, it will affect chemical
  reactions within cells

31

• H2O ? H OH-
• Water ? Hydrogen ion Hydroxide ion
• The concentration of H and OH- are equal in pure
  water

32
Lesson 3

• Carbon Compounds

33
Organic Chemistry

• The study of all compounds that contain bonds
  between carbon atoms

34
The Chemistry of Carbon

• Carbon has 4 valence electrons
• Can bond with other elements to form covalent
  bonds
• Can bond with hydrogen, oxygen, phosphorus,
  sulfur, nitrogen, other carbon atoms, and more
• Carbon-carbon bonds can for chains with single,
  double, and triple bonds

35
Macromolecules

• Giant molecules made from thousands or even
  hundreds of thousands of smaller molecules
• Monomers smaller units
• Polymers groups of monomers joined together

36
NOTE 4 groups of organic compounds found in
living things

• 1. carbohydrates
• 2. lipids
• 3. nucleic acids
• 4. proteins

37
Carbohydrates

• Compounds made up of carbon, hydrogen, and oxygen
  atoms
• Main source of energy for living things
• Sugars and starches

38
Carbohydrates

• Monosaccharides single sugar molecules

• Polysaccharides large macromolecules formed from
  3 or more monosaccharides

39
Lipids

• Large and varied group of biological molecules
  that are generally not soluble in water
• Made mostly from carbon and hydrogen atoms
• Fats, oils, and waxes (also steroids)
• Used to store energy

40
Nucleic Acids

• Macromolecules containing hydrogen, oxygen,
  nitrogen, carbon, and phosphorus
• Made of nucleotides
• Store and transmit hereditary (genetic) info
• 2 kinds DNA and RNA

41
Proteins

• Macromolecules that contain nitrogen as well as
  carbon, hydrogen, and oxygen
• Polymers of molecules called amino acids
  (monomers)
• Over 20 found in nature

42
Protein Function

• 1. Help to fight disease
• 2. Control the rate of reactions and regulate
  cell processes
• Build tissues such as bone and muscle

43
Lesson 4

• Chemical Reactions and Enzymes

44
Chemical Reactions

• A process that changes one set of chemicals into
  another set of chemicals
• Atoms are rearranged
• Can occur slowly (ironoxygen?rust) or quickly

• Reactants elements of compounds that enter into
  a chemical reaction
• Products the elements or compounds produced by a
  chemical reaction

45
Chemical Reactions

• Rusting of iron
• Fe O2 ?Fe2O3
• Iron and oxygen are called reactants
• Iron Oxide is the product

46
Subscripts Coefficients

• 4Fe 3O2 ? 2Fe2O3
• Subscripts small numbers to the right of each
  element
• Coefficients large numbers to the left of each
  element or compound

47
Energy Changes

• Some chemical reactions release energy
  (spontaneously) and some absorb it (wont occur
  w/o source of energy)
• Energy releasing hydrogen gas burning w/oxygen
  to produce water vapor (energy is released in
  heat)
• Chemical Equation 2H2O2?2H2O
• Needs electrical current through water to reverse
  it (does absorb energy, but releases it too)

48
Reactions

• If a reaction in one direction releases energy,
  the reaction in the opposite direction absorbs
  energy

49
Reactions

• 1. EXOTHERMIC REACTIONS
• Chemical processes that release
• heat to the surroundings.

EN E R G Y
TIME
50
Reactions

• 2. ENDOTHERMIC REACTIONS
• Chemical processes that absorb or
• take in heat.

E N E R G Y
TIME
51
Types of Energy

• 1. Potential Energy
• energy that is stored in a molecule
• energy related to the position of an
• object

52
Types of Energy

• 2. Kinetic Energy
• energy of motion

53
Activation Energy

• The energy that is needed to get a reaction
  started
• occurs in non-spontaneous chemical reactions
• It is a factor in whether the overall chemical
  reaction releases energy or absorbs energy

54
(No Transcript)
55
Catalyst

• substance that speeds up the rate of a chemical
  reaction

56
Enzymes

• Proteins that act as biological catalysts
• Act by lowering a reactions activation energy
• Very specific
• Only catalyze one chemical reaction

57
All enzymes work at a

• 1. optimum temperature
• 2. optimum pH

According to Figure 2-2, which enzyme would you
expect to find in a bacterium growing in a hot
spring? According to Figure 2-2, at what
temperature do the two enzymes have the same
amount of activity? Based on Figure 2-2, which
enzyme is active over the largest temperature
range?
58
(No Transcript)
59
The End!!