Macromolecules
AP Biology 2015 - 2016
Campbell Biology in Focus: Chapter 3
I. Macromolecules are polymers
Monomers
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Small organic
Used for building
blocks of polymers
Connects with
condensation
reaction
(dehydration
synthesis)
Polymers
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Macromolecules
Long molecules of
monomers
With many
identical or similar
blocks linked by
covalent bonds
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Giant molecules
2 or more polymers
bonded together
II. Biological polymers are primarily produced using dehydration synthesis and are broken down
using hydrolysis
Dehydration Synthesis
(Condensation Reaction)
Hydrolysis
Make polymers
Breakdown polymers
Monomers → Polymers
Polymers → Monomers
A + B → AB + H2O
AB + H2O → A + B
III. Dehydration Synthesis and Hydrolysis Reactions in Detail
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IV. Proteins
A. 50% dry weight of cells
B. Contains: C, H, O, N, S
C. Functions:
i. Enzymes (lactase)
ii. Defense (antibodies)
iii. Storage (milk protein = casein)
iv. Transport (hemoglobin)
v. Hormones (insulin)
vi. Receptors
vii. Movement (motor proteins)
viii. Structure (keratin)
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D. Levels of Protein Structure
i. Primary
a. Amino acid (AA) sequence
b. 20 different AA’s
c. peptide bonds link AA’s
d. Amino acid structure
1. R group = side chains
Properties: hydrophobic, hydrophilic, ionic (acids & bases),
large, small
2. “amino” : -NH2
3. “acid” : -COOH
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e. formation of peptide bonds
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ii. Secondary: 3D structures formed by hydrogen bonding
a. Gains 3-D shape (folds, coils) by H-bonding
b. Alpha (α) helix, Beta (β) pleated sheet
iii. Tertiary
a. Bonding between side chains (R groups) of amino acids
b. H bonds, ionic bonds, disulfide bridges, van der Waals interactions
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iv. Quaternary: two or more polypeptides bond together
v. Overview of the four levels of protein structure
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E. Protein folding is very complex
i. Chaperonins are proteins that assist in the folding of other proteins
ii. Strong acids/bases, hydrophobic solvents and temperature changes can all change
or denature a protein so that it is no functional.
iii. A change in the shape of a protein may create a change in function
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V. Nucleic acids
A. Functions:
1. stores hereditary information
2. contains the instructions for making proteins
3. assists in creating proteins
4. indicates when certain proteins are created
5. allows only certain proteins to be created in specialized cells
B. Differences between DNA and RNA
DNA
RNA
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Double-stranded helix
N-bases: A, G, C, Thymine
Stores hereditary info
Longer/larger
Sugar: deoxyribose
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Single-stranded
N-bases: A, G, C, Uracil
Carry info from DNA to
ribosomes
• tRNA, rRNA, mRNA, RNAi
• Sugar: ribose
C. Nucleotides - the monomers of nucleic acids
Nucleotide = Sugar + Phosphate + Nitrogen Base
1. Phosphate
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2. Sugar
Purines
3. Nitrogenous base
Pyrimidines
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Adenine
Guanine
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Cytosine
Thymine (DNA)
Uracil (RNA)
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Double ring
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Single ring
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D. Information flow in a cell
DNA → RNA → Proteins
VI. Carbohydrates
A. Fuel and building material
B. Include simple sugars (fructose) and polymers (starch)
C. Typical ratio of 1 carbon: 2 hydrogen: 1 oxygen or CH2O
D. monosaccharide → disaccharide → polysaccharide
E. monosaccharides = monomers (eg. glucose, ribose) and used for energy storage
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Glucose structure
F. Disaccharides (used for energy storage)
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G. Polysaccharides:
i. Functions: storage (plants-starch, animals-glycogen)
and structure (plant-cellulose, arthropod-chitin)
ii. Cellulose vs. Starch
a. There are two forms of glucose:
b. Starch uses α-glucose while cellulose uses β-glucose
(just know that starch has all the glucose molecules in the same orientation, which makes it
easy to digest while cellulose alternates orientation which makes it difficult to digest.)
c. Glycogen (animal starch) and plant starches are slightly different
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d. Cellulose is used as a structural polysaccharide in plants....
....while chitin is used in fungal cell walls and in exoskeletons of arthropods
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VII. Lipids
A. Fats (triglyceride): store energy
i. consist of glycerol and 3 fatty acids
ii. fatty acids come in saturated, unsaturated, polyunsaturated forms
Saturated
“saturated” with H
In animals
Solid at room
temp.
Eg. butter, lard
Unsaturated
Polyunsaturated
Have some C=C, result in kinks
In plants
Liquid at room temp.
Eg. corn oil, olive oil
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B. Steroids: cholesterol and hormones
C. Phospholipids: lipid bilayer of cell membrane and consist of
hydrophilic head, hydrophobic tails
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