Biomolecules

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Biomolecules

• Biologically important molecules
• Organic Compounds- made mostly of carbon,
  hydrogen and oxygen
• Make incredible shapes
• Polymers- large molecules made up of repeated
  units of smaller molecules called monomers

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Structural formula
Ball-and-stick model
Space-filling model
Models of Methane
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Lifes diversity is based on the properties of
carbon

• A carbon atom forms four covalent bonds
• It can join with other carbon atoms to make
  chains or rings

Structuralformula
Ball-and-stickmodel
Space-fillingmodel
Methane
The 4 single bonds of carbon point to the corners
of a tetrahedron.
Figure 3.1, top part
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• Carbon skeletons vary in many ways

Ethane
Propane
Carbon skeletons vary in length.
Butane
Isobutane
Skeletons may be unbranched or branched.
1-Butene
2-Butene
Skeletons may have double bonds, which can vary
in location.
Cyclohexane
Benzene
Figure 3.1, bottom part
Skeletons may be arranged in rings.
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Table 3.2
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• Cells link monomers to form polymers by
  dehydration synthesis

1
2
3
Unlinked monomer
Short polymer
Removal ofwater molecule
1
2
3
4
Longer polymer
Figure 3.3A
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• Polymers are broken down to monomers by the
  reverse process, hydrolysis

1
2
3
4
Addition ofwater molecule
1
2
3
Coating of capture strand
Figure 3.3B
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Carbohydrates

• Sugars
• (CH2O)n
• Monomer Monosaccharide
• Names end in -ose
• Examples Glucose, Sucrose, Cellulose
• Energy storage and structure

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• Many monosaccharides form rings, as shown here
  for glucose

Abbreviatedstructure
Figure 3.4C
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fructose
glucose
H2O
sucrose
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cellulose
glycogen
amylose (a starch)
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Lipids

• Hydrocarbons, CH2
• Fats and oils
• Not true polymers
• Fats 1,2 or 3 fatty acids attached to glycerol
• Used for waterproofing, insulation, cell
  membranes and energy storage

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Phospholipids, Waxes and Steroids

• Phospholipids- Used in cell membranes
• Waxes- Used in waterproofing
• Steroids- Used as hormones and cellular
• signals

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Phospholipids
hydrophilic head
hydrophobic tails
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hydrophilic head
two hydrophobic tails
cell membrane section
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Figure 2.21cPage 29
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Sterols
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Steroids are often hormones
Figure 3.9
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Proteins

• Most Diverse Group of Biomolecules
• Monomer Amino Acid
• Enzymes- Catalyze metabolic reactions
• Transport proteins- move things across membranes
• Structural proteins-keep the structure of cells

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Amino group (basic)
Carboxyl group (acidic)
R group (20 kinds with distinct properties)
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alanine (ala)
valine (val)
tryptophan (trp)
methionine (met)
proline (pro)
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Amino acids are linked by peptide bonds

• Dehydration synthesis
• The bonds between amino acid monomers are called
  peptide bonds

Carboxylgroup
Aminogroup
PEPTIDEBOND
Dehydrationsynthesis
Amino acid
Amino acid
Dipeptide
Figure 3.13
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A proteins specific shape determines its function

• A protein, such as lysozyme, consists of
  polypeptide chains folded into a unique shape
• The shape determines the proteins function
• A protein loses its specific function when its
  polypeptides unravel

Figure 3.14A
Figure 3.14B
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3.15 A proteins primary structure is its amino
acid sequence
3.16 Secondary structure is polypeptide coiling
or folding produced by hydrogen bonding
Primarystructure
Amino acid
Hydrogen bond
Secondarystructure
Pleated sheet
Alpha helix
Figure 3.15, 16
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3.17 Tertiary structure is the overall shape of
a polypeptide
3.18 Quaternary structure is the relationship
among multiple polypeptides of a protein
Tertiarystructure
Polypeptide(single subunitof transthyretin)
Quarternarystructure
Transthyretin, with fouridentical polypeptide
subunits
Figure 3.17, 18
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one peptide group
Linear primary structure
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Tertiary structure
Secondary structure
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Secondary structure
Tertiary structure
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Quarternary Structure
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Nucleic Acids

• Monomer Nucleotide
• ATP is a Nucleotide
• Molecules of inheritance hold the code for how
  to make proteins
• Deoxyribose Nucleic Acid- DNA
• Double-Stranded
• Ribose Nucleic Acid- RNA
• Single-Stranded

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nitrogen- containing base
Ball-and-stick model of ATP
sugar
3 phosphate groups
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Adenine (a base)
Thymine
phosphate group
sugar (deoxyribose)
Guanine
Cytosine
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Single strand of DNA or RNA
base
phosphate
connected by covalent bond
sugar
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covalent bonding in carbon backbone
hydrogen bonding between bases