Bio 11 Lecture- Chemistry II - PowerPoint PPT Presentation

About This Presentation
Title:

Bio 11 Lecture- Chemistry II

Description:

Bio 11 Lecture- Chemistry II Chemical reactions, Ions, pH, functional groups, organic molecules – PowerPoint PPT presentation

Number of Views:157
Avg rating:3.0/5.0
Slides: 84
Provided by: ccsf151
Learn more at: https://fog.ccsf.edu
Category:

less

Transcript and Presenter's Notes

Title: Bio 11 Lecture- Chemistry II


1
Bio 11 Lecture- Chemistry II
  • Chemical reactions, Ions, pH, functional groups,
    organic molecules

2
What part(s) of an elements atoms determines
its mass?
  • A. Protons
  • B. Neutrons
  • C. Electrons
  • D. Protons Neutrons
  • E. Electrons/Protons

3
What part(s) of an elements atoms define the
element?
  • A. Protons
  • B. Neutrons
  • C. Electrons
  • D. Protons Neutrons
  • E. Electrons/Protons

4
What part(s) of an elements atoms differentiate
its isotopes?
  • A. Protons
  • B. Neutrons
  • C. Electrons
  • D. Protons Neutrons
  • E. Electrons/Protons

5
What part of atoms determine how they bond with
other atoms?
  • A. Protons
  • B. Neutrons
  • C. Electrons
  • D. Protons Neutrons
  • E. Electrons/Protons

6
Basic atomic structure- protons, neutrons, and
electrons
7
The periodic table logically arranges and
describes all matter
8
Molecules, compounds, chemical reactions, and
bonding
9
Elements combine in chemical reactions to form
compounds
  • Molecules- 2 or more atoms combined in a specific
    way
  • Compounds- different elements in a molecule, in
    exact, whole-number ratios, joined by a chemical
    bond
  • 2 major means of intramolecular chemical bonding
    Covalent (incl. polar and nonpolar) and Ionic

10
Valence electrons determine bonding
11
Atoms seek complete valence electron shells (the
octet rule)
12
In Ionic bonding, atoms strip valence electrons
from partners, forming ions
13
Atoms are stable when their outer shells are
filled with electrons
  • Shell 1 Holds 2 electrons
  • Shell 2 Holds 8
  • Shell 3 Holds 8
  • Hydrogen- 1p, 1e, seeks a second electron in its
    outermost shell
  • Carbon seeks 4
  • The electrons in the outermost shell are called
    valence electrons

14
Noble gases have a stable electron structure
  • Their outer orbitals have a full complement of
    electrons
  • Noble gases are very unreactive

15
In ionic bonding, an atom takes an electron from
another atom, forming 2 ions
LE 2-7
Transfer of electron
Na Sodium ion
Cl- Chloride ion
Sodium chloride (NaCl)
Na Sodium atom
Cl Chlorine atom
16
5. Ions
  • Ions- Charged atoms or molecules
  • Anion- negative ion
  • Cation- positive ion
  • Ionization- reaction producing ions
  • Salt- a neutral compound comprised of ions

17
LE 2-7a-2
Na Sodium ion
Cl- Chloride ion
Sodium chloride (NaCl)
18
LE 2-7b
Na
Cl-
19
Water dissolves many ionic compounds (like
dissolves like)
Individual soluble ions are not physically bound
to each other
20
In covalent bonding, pairs of valence electrons
are shared, and molecules are formed
21
LE 2-17a

2 H2
O2
2 H2O

22
LE 2-6b
Nitrogen (N) Atomic number 7
Oxygen (O) Atomic number 8
23
In neutral molecules, carbon always forms 4 bonds
Structural formula
Ball-and-stick model
Space-filling model
Methane
The 4 single bonds of carbon point to the corners
of a tetrahedron.
24
LE 3-1b
Ethane
Propane
Carbon skeletons vary in length.
25
LE 3-1c
Butane
Isobutane
Skeletons may be unbranched or branched.
Butane and Isobutane are _______________of each
other.
26
LE 3-1d
1-Butene
2-Butene
Skeletons may have double bonds, which can vary
in location.
27
LE 3-1e
Cyclohexane
Benzene
Skeletons may be arranged in rings.
28
Organic Chemistry
  • The chemistry of carbon
  • Hydrocarbons are the most basic example
  • Combustible
  • Can form rings

29
The variety of carbon compounds is limitless
inorganic - lack carbon atoms organic - with
carbon (plus hydrogen) biochemical - organic
molecule in life carbohydrates proteins
lipids nucleic acids
30
Covalent bonds hold together the macromolecules
of life
  • Living things create macromolecular products for
    structure
  • 6CO2(g) 6H2O(l) h? ? C6H12O6(s) 6O2(g)
  • Macromolecules as reactants are broken down for
    energy
  • C6H12O6(s) 6O2(g) ? 6CO2(g) 6H2O(l)
  • All the reactions of a living thing are called
    its metabolism

31
Electronegativity determines properties of
covalently bonded molecules
32
Electronegativity electron greediness
  • Atoms in covalently bonded molecules do not
    always share electrons equally
  • This creates polar molecules
  • Polar regions of water molecules interact to form
    hydrogen bonds
  • Hydrogen bonds weak/temporary intermolecular
    forces

33
Some electronegativity values
  • Hydrogen 2.20
  • Oxygen 3.44
  • Carbon 2.55
  • Chlorine 3.16
  • Sodium 0.93
  • Difference between
  • H and O 1.22
  • H and C 0.35

34
Hydrogen bonding in water determine many of
waters unique properties
  • H-bonds can form a lattice (ice)
  • H-bonds require much energy to break
  • H-bonds give water surface tension

Hydrogen bond
35
Water dissolves many ionic compounds (like
dissolves like)
36
Intermolecular Hydrogen bonds give water its
surface tension
0
37
Intermolecular Hydrogen bonds require much heat
in order to be broken
38
Water also forms ions sometimes
  • H2O ? H OH-
  • Spontaneously happens to water molecules
  • 1/ 107 water molecules are ionized in distilled
    water
  • In dH2O, H OH-
  • salt - neutral molecule releases ions
  • acid releases hydrogen H, burns
  • base releases hydroxide OH, slimy

39
pH is a measure of acidity/basicity
  • pH -log H (logarithmic scale)
  • pH 1? 6.9 acid
  • pH 7.1?14 base
  • pH 7? neutral
  • buffers - absorb excess H or OH
  • - stomach 2, urine 5-7.8, blood 7.4
  • Acids donate H to water
  • Bases remove H from water (or donate OH- to
    water)
  • Proteins are very sensitive to small changes in pH

40
LE 2-15
pH scale
H
H
H
OH?
H
Lemon juice, gastric juice
H
OH?
H
H
H
Grapefruit juice, soft drink
Increasingly ACIDIC (Higher concentration of H)
Acidic solution
Tomato juice
Human urine
OH?
OH?
NEUTRAL H??????-
Pure water
OH?
H
H
Human blood
OH?
OH?
H
H
H
Seawater
Neutral solution
Increasingly BASIC (Lower concentration of H)
Milk of magnesia
Household ammonia
OH?
OH?
OH?
OH?
H
Household bleach
OH?
OH?
H
Oven cleaner
Basic solution
41
7. FUNCTIONAL GROUPS
  • hydroxide group OH amino group
    NH2 carboxyl group COOH phosphate group
    PO4 methyl group CH3

42
The physical/ chemical properties of carbon
skeletons can be modified by functional groups
43
2.20 Part 2
figure 02-20b.jpg
  • Figure 2.20 Part 2

44
Functional groups can radically change the
function of a molecule
Estradiol
Female lion
Testosterone
Male lion
45
  • The six functional groups that are most important
    in the chemistry of life
  • Hydroxyl group (alcohols)
  • Carbonyl group
  • Carboxyl group (carboxylic acids)
  • Amino group
  • Sulfhydryl group
  • Phosphate group
  • Methyl group

46
LE 4-10aa
STRUCTURE
(may be written HO)
Ethanol, the alcohol present in alcoholic
beverages
NAME OF COMPOUNDS
FUNCTIONAL PROPERTIES
Is polar as a result of the electronegative
oxygen atom drawing electrons toward itself.
Alcohols (their specific names usually end in -ol)
Attracts water molecules, helping dissolve
organic compounds such as sugars (see Figure 5.3).
47
LE 4-10ab
Acetone, the simplest ketone
EXAMPLE
STRUCTURE
Acetone, the simplest ketone
Propanal, an aldehyde
NAME OF COMPOUNDS
Ketones if the carbonyl group is within a carbon
skeleton
FUNCTIONAL PROPERTIES
Aldehydes if the carbonyl group is at the end of
the carbon skeleton
A ketone and an aldehyde may be structural
isomers with different properties, as is the
case for acetone and propanal.
48
LE 4-10ac
EXAMPLE
STRUCTURE
Acetic acid, which gives vinegar its sour taste
FUNCTIONAL PROPERTIES
NAME OF COMPOUNDS
Has acidic properties because it is a source of
hydrogen ions.
Carboxylic acids, or organic acids
The covalent bond between oxygen and hydrogen is
so polar that hydrogen ions (H) tend
to dissociate reversibly for example,
Acetic acid
Acetate ion
In cells, found in the ionic form, which is
called a carboxylate group.
49
LE 4-10ba
EXAMPLE
STRUCTURE
Glycine
Because it also has a carboxyl group, glycine is
both an amine and a carboxylic acid compounds
with both groups are called amino acids.
FUNCTIONAL PROPERTIES
NAME OF COMPOUNDS
Acts as a base can pick up a proton from the
surrounding solution
Amine
(nonionized)
(ionized)
Ionized, with a charge of 1, under cellular
conditions
50
LE 4-10bb
EXAMPLE
STRUCTURE
(may be written HS)
Ethanethiol
NAME OF COMPOUNDS
FUNCTIONAL PROPERTIES
Two sulfhydryl groups can interact to help
stabilize protein structure (see Figure 5.20).
Thiols
51
LE 4-10bc
EXAMPLE
STRUCTURE
Glycerol phosphate
NAME OF COMPOUNDS
FUNCTIONAL PROPERTIES
Makes the molecule of which it is a part an anion
(negatively charged ion).
Organic phosphates
Can transfer energy between organic
molecules.





52
Organic molecules are good energy sources
Energy is required to form covalent bonds energy
is released when bonds are broken
53
Most molecules in living things fall into four
categories
  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids

These all exhibit modular construction
54
Modular housing
Made of interchangeable parts
55
Freight trains have modular assembly
56
Modular assembly allows a wide variety of
products from a few pieces
57
Most biopolymers of life are formed by
dehydration synthesis
58
Hydrolysis is the reverse reaction (Catabolic)
59
4. CHEMICAL REACTIONS 
  • metabolism - all chemical reactions in body -
    reactants products  synthesis - build larger
    molecule CH3-OH H-CH3 CH3-CH3
    H2O  hydrolysis - break down molecule  CH3-CH3
    H2O CH3-OH H-CH3 exchange reaction -
    example AB CD AD CB

60
Carbohydrates
  • Carbon Hydro
  • Formula (CH2O)n
  • Different from hydrocarbons
  • Soluble in water
  • Includes table sugar, honey, starch, glycogen,
    cellulose, high fructose corn syrup
  • Glucose is the monomer

61
Glucose can cyclize to form a ring structure
Atoms in bonds are free to rotate around the bonds
62
Glucose Glucose Maltose (A Sugar
dimer)
63
Chain can be extended to thousands
64
9. Carbohydrates
  • functions
  • - principle source of energy (4 kcal/g)
  • - structure energy storage in plants
  •  atoms - C H O
  • structure - ring or chain of 5-6 Cs
  •  monosaccharide
  • - single sugars (example glucose)
  •  disaccharide
  • - double sugars (example sucrose)
  •  polysaccharide
  • - polymer or chain of 100s sugars
  • - starch cellulose (mostly plants)
  • - glycogen (animals, esp. liver)

65
Proteins are polymers made of 20 different kinds
of amino acid monomers
66
Table 3.2 Part 2
table 03-02bc.jpg
  • Table 3.2 Part 2

67
Table 3.2 Part 3
table 03-02d.jpg
  • Table 3.2 Part 3

68
Proteins Polymers of Amino Acids
  • Amino acids are covalently bonded together by
    peptide linkages. Review Figure 3.4

69
3.4
figure 03-04.jpg
  • Modular assembly of amino acids through
    dehydration synthesis

70
Proteins have an incredible variety of structures
71
Proteins have an incredible variety of functions
Hair, skin, fingernails, muscles, eye pigments,
are all made of protein
72
11. Proteins
  • functions - energy (4 kcal/g)
  • - structure in animals (meat)
  • - enzymes (speed up reg chem rxs) 
  • atoms - C H O N
  • amino acid
  • - central C, hydrogen H
  • - amino group NH2
  • - carboxyl group COOH
  • - R-group (20 different)
  • polypeptide - polymer of amino acids
  •  protein - 1 or more polypeptides
  • 4 levels of structure - necessary
  • for protein function, esp. enzymes
  • I primary structure - sequence of
  • amino acids in polypeptide chain
  • II secondary structure
  • - coiling or folding of chain
  • - hydrogen bonds between regions
  • III tertiary structure
  • - folding of coiled-folded chain
  • IV quaternary structure
  • - linkage to other polypeptides

73
Lipids
  • Non-polar
  • High-energy molecules
  • For energy storage
  • Forms cell membranes
  • Hormones
  • Members of family include oils, fats, waxes, and
    cholesterol (steroids)

74
Lipids are non-polar
  • Therefore, they are hydrophobic

75
Triglycerides are a primary lipid structure
76
Dehydration synthesis links fatty acids to
glycerol
77
Fatty acids can be saturated and unsaturated (cis
and trans)
78
10. Lipids
  • functions
  • - energy storage (9 kcal/g)
  • - also animal structure (blubber)
  •  
  • atoms - C H O
  •  
  • structure - glycerol 3 fatty acids
  •  
  • oil - liquid, unsaturated (missing Hs)
  •  
  • fat - solid, saturated (maximum Hs)
  • - promotes heart disease
  •  
  • others
  • - steroids, phospholipids, waxes

79
Nucleic acids
  • Informational molecules in cells
  • Include DNA, RNA, and ATP/ADP
  • Have other functions

80
Nulceotides are the subunits of nucleic acids
  • Consist of a sugar, a phosphate, and a
    nitrogen-containing base
  • Sugar can be deoxygenated

81
12. Nucleic Acids
  • function - not energy
  • - genetics (genes chromosomes)
  •  
  • atoms - C H O N P S
  •  
  • structure - chain of 100s nucleotides
  •  
  • examples - DNA, RNA, ATP
  •  
  •  

82
Review
  • Atomic structure- protons, neutrons electrons
  • Valence electrons
  • Carbon
  • Functional groups
  • Carbohydrate structure
  • Protein structure
  • Lipid structure

83
Things left unsaid
  • Isotopes of all elements exist (some of these are
    radioactive)
  • Electronegativity determines polarity of covalent
    bonds, and thus solubility
  • Water has important physical properties essential
    to life on earth
  • Isomers have the same molecular formula but not
    the same shape in space
  • Nucleic acids are comprised of nucleotide
    monomers
Write a Comment
User Comments (0)
About PowerShow.com