Download Biological Molecules

Chapter 3
Biological
Molecules
Chapter 3
Why Is Carbon So Important?
Organic vs. Inorganic in Chemistry
• Organic refers to molecules containing a
carbon skeleton
• Inorganic refers to carbon dioxide and all
molecules without carbon
2
Chapter 3
Why Is Carbon So Important?
Carbon atoms are versatile and can
form up to four bonds (single, double,
or triple) in rings and chains
Bonds are very high in energy
(strongest substance on Earth = pure
carbon = …?)
Functional groups in organic molecules
confer chemical reactivity and other
characteristics…
3
Chapter 3
Example Groups, I
•
•
Hydrogen
H
•
•
•
Hydroxyl
OH
•
Polar / Nonpolar
Dehyd. Synth /
Hydrolysis
Almost all
biochemicals
Polar
Dehyd. Synth /
Hydrolysis
Sugars
4
Chapter 3
Example Groups, II
Carboxyl
(Carboxylic
acid)
COOH
Amine
or Amino
NH2
•
Polar & acidic
•
Peptide bonds
•
Fats; amino acids
•
Polar & basic
•
Peptide bonds
•
Amino acids;
proteins
5
Example
Groups, III
Chapter 3
•
•
Phosphate
H2PO4
Methyl
CH4
•
Acidic & polar
Energetic bonds;
Links nucleotides
DNA; ATP;
Phospholipids
•
Nonpolar
•
Hydrophobic
•
Many, especially
lipids
6
Chapter 3
Joining Monomers Together
Builds bigger molecules
H from one joins OH from another
Forms water (condensation) – the molecule
loses water “DEHYDRATION”
Loose bonds of remaining molecules join
“SYNTHESIS” of starch
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Chapter 3
Splitting Polymers Apart
Opposite of condensation
"Splitting (lysis) with water (hydro-)"
Molecule broken in two
Water is split (“HYDROLYSIS”)
–H+ goes to one; –OH- goes to other
Digestion
8
Chapter 3
Dehydration / Hydrolysis
Dehydration Synthesis
Hydrolysis
9
1. Carbohydrates
10
Chapter 3
Monosaccharides
“Mono-” means “one”
Simple sugars — glucose, fructose
Usually with 5 or 6 carbons
• 5-carbon sugars are pentoses
• 6-carbon sugars are hexoses
• etc.
CH2OH
Soluble in water
Taste sweet
HO
H
H HO
H
O
H
H
HO
HO
O OH
H
OH H
HOCH2
H
OH
H
Deoxyribose
Galactose
1. Carbohydrates
Chapter 3
11
Oligosaccharides
“Oligo-” means “few”
Few monosaccharides joined together
Sucrose is disaccharide of glucose &
fructose
Often combined with other molecules
Sometimes used for cell I.D.
CH2OH
HOCH2 O H
OH
H
+
H
H HO
OH H
CH2OH
HO
OH HO
HO
H
H HO
Glucose + Fructose
CH2OH
H
HOCH2
O
OH
H
H HO
H
OH H
O
HO
CH2OH
H
H HO HOH HO
Sucrose & Water
1. Carbohydrates
Chapter 3
Plant Starch (Amylose)
Actually forms
a spiral
CH2OH
O
O
OH
Glucose
CH2OH
O
CH2OH
O
O
OH
CH2OH
O
O
OH
CH2OH
O
O
OH
CH2OH
O
O
OH
O
OH
Polymerization of glucose to form starch
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1. Carbohydrates
13
Chapter 3
Starch
CH2OH
O
CH2OH
O
CH2OH
O
O
O
OH
CH2OH
O
OH
CH2OH
O
O
OH
CH2OH
O
O
OH
OH
CH2
O
O
OH
O
OH
Cellulose
CH2OH
O O
OH
OH
CH2OH
O O
CH2OH
OH
CH2OH
O O
O O
OH
CH2OH
HO
O O
HO
O O
CH2OH
CH2OH
O O
CH2OH
O O
O O
HO
OH
CH2OH
OH
HO
CH2OH
O O
O O
OH
CH2OH
14
O O
CH2OH
O O
HO
OH
CH2OH
O O
HO
CH2OH
O O
Chapter 3
CH2OH
OH
1. Carbohydrates
Chapter 3
Cellulose Structure & Function
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1. Carbohydrates
Chapter 3
Chitin
Like cellulose, but with nitrogen
Arthropods’ exoskeletons, fungal cell walls
Strong, very resistant to digestion
O O
N H
O C
CH3
CH2OH
CH2OH
O O
N H
O C
CH3
CH3
O C
N H
O O
CH2OH
O O
CH3
O C
N H
CH2OH
CH2OH
O O
N H
O C
CH3
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1. Carbohydrates
Chitin
Chapter 3
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Lipids - 2nd of 4 Classes
of Organic Compounds
Slippery-oils
Chapter 3
Nonpolar; mostly C & H, little bit of O
Heterogeneous group
• Other classes more homogeneous
• Unified by insolubility in water
Fatty-acid types: Oils & waxes
Nonfatty-acid types: steroids
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2. Lipids
Fat Molecules
Chapter 3
Triglycerides from beef, vegetable oils
Three fatty acids and a glycerol
• Glycerol has 3 carbons
• Each with an –OH group
Each fatty acid has a COOH
These condense to form triglyceride and
H2O
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2. Lipids
Fatty Acids
Determines properties of fat
Hydrocarbon chain with a COOH
Most fats = 3 FAs + glycerol
• Glycerol: 3-carbon alcohol
• 3 OHs attract the COOH of FAs
Chapter 3
20
Components of Triglycerides Chapter 3 21
Triglyceride
(Fat) Formation
H
Glycerol
Remove
These
Waters
Add 3
Fatty
Acids
HC
OH
OH
C O
HCH
HCH
HCH
H
H
Chapter 3
22
Triglyceride
H
C
CH
OH
OH
OH
OH
C O C O
HCH HCH
HCH HCH
HCH HCH
H
H
H
H
H
HC
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
C
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
CH
O
C O
HCH
C O
HCH
HCH
HCH
HCH
H
HCH
H
HOH
3 Waters
2. Lipids
Fatty Acid Types
Saturated - No C=C double bonds
animal fat, solid @
room temp, “bad” fats
Unsaturated - One or more
C=C double bonds
plants & fish, liquids
oils, “good” fats
Chapter 3
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2. Lipids
Phospholipids
Chapter 3
Phospholipids - mostly in cell membranes
1 glycerol, 2 FAs, & 1 polar phosphate
group
• Like a triglyceride...
• 1 FA swapped for polar, phosphate group
Soap-like properties
Likes to get between polar and nonpolar
materials
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2. Lipids
Phospholipids
Polar
Head
Glycerol
Hydrophilic
Chapter 3
Fatty Acid Tails
Hydrophobic
25
2. Lipids
Steroids
Chapter 3
Complex ring forms
Some hormones
Cholesterol
• Natural substance
• Found in membranes
• Gives membranes natural flexibility
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2. Lipids
Steroids
Cholesterol
Chapter 3
Estradiol
Testosterone
27
Proteins - 3rd of 4 Classes
of Organic Compounds
Proteins are amino acid polymers
Many roles in the cell…
• Enzymes
• Hormones
• Structure (muscle, hair, nails)
• Cell membrane pumps and channels
Chapter 3
28
3. Proteins
Amino Acids
Chapter 3
Small molecules — 20 kinds
• 1 amino group
• 1 carboxyl group
• 1 "R" group
Joined by peptide bonds to form
polypeptide
Different sequence makes different protein
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Chapter 3 30
Generic Amino
Acid: 20 Different “R” Groups
Carboxylic Acid
Group
Amine
Group
R
“Alpha”
Carbon
The “R” Group
Placeholder
Amino Acids:
Glutamic Acid Structure
Amine
Group
Chapter 3
Carboxylic Acid
Group
“Alpha”
Carbon
Glutamic Acid
“R” Group
31
Chapter 3 32
3. Proteins
Amino Acids: Leucine Structure
Amine
Group
Carboxylic Acid
Group
Leucine “R”
Group
Chapter 3 33
3. Proteins
Amino Acids: Cysteine Structure
Amine
Group
Carboxylic Acid
Group
Cysteine “R”
Group
3. Proteins
Structural Proteins
Chapter 3
34
Horn
Hair
Spiderweb
3. Proteins
Peptide Bond Formation
Phenylalanine
Chapter 3
Leucine
By Condensation
between COOH & NH2
35
Chapter 3 36
Peptide Bond:
Phenylalanine-Leucine Dipeptide
The Peptide Bond
Water
3. Proteins
Levels of Protein Structure
Chapter 3
37
Like describing a knot by starting with the
strands of the rope
• Primary: The amino acid sequence
• Secondary: Coiling or folding
• Tertiary: folding, kinking, twisting entire structure
• Quaternary: Two or more chains together
Illustration of
Protein Structure
Primary
(Sequence)
Chapter 3
Tertiary
(Bending)
Quaternary
(Layering)
Secondary
(Coiling)
38
3. Proteins
Pleated Sheets
Hydrogen
Bonds
Chapter 3
“Right-side up” AAs
“Flipped” AAs
39
Nucleic Acids: 4th Class
of Organic Compound
Chapter 3
Nucleic acids are nucleotide polymers
Genetics & cell control
DNA: Genes
RNA: Manages protein synthesis
40
4. Nucleic Acids
Nucleotides
Chapter 3
5-carbon sugar, a PO3, and a nitrogenous
base
Not only serve to make RNA & DNA
Some are energy carriers (ATP, NAD)
Some are chemical messengers (cAMP)
41
Chapter 3 42
4. Nucleic Acids
Nucleotide Structure: 3 Parts NH
2
Phosphate Group
OH
HO
P
O
HC
O
N C
C
N
CH
C
N
CH2 O
N
Deoxyribose
Nitrogenous
H or H
Base
(1
of
5)
Ribose
H
H
OH
H
Pentose Sugar
4. Nucleic Acids
Nucleic Acid Molecule
Nucleotides can be joined
together into a chain
Result is a nucleic acid
Nucleotide polymer
DNA, RNA
Connected by “sugarphosphate” backbone
Chapter 3
43
Chapter 3 44
Cyclic AMP:
(Adenosine Monophosphate) NH2
Used for intracellular
communication
O
CH2
H
P
OH
O
Ribose
O
N
CH
C
N
N
H
H
H
O
HC
N C
C
OH
Chapter 3 45
4. Nucleic Acids
ATP: (Adenosine Triphosphate)
Used for energy transfer
from one molecule to another
OH
OH
OH
HC
HO P O P O P O CH2
O
O
NH2
O
H
O
Deoxyribose
H or H
Ribose
OH
H
N C
C
N
CH
C
N
N
H
4. Nucleic Acids
Coenzyme Structure
OH
HO
P
Chapter 3
NH2
HC
O
CH2
O
H
O
Deoxyribose
H or H
Ribose
OH
H
N C C N
CH
C
N
N
H
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Chapter 3
The End