Download Macromolecules Basic Facts: Most are polymers – large molecules

Macromolecules
Basic Facts:
1. Most are polymers – large molecules made up of many smaller
ones (monomers)
2. Constructed using dehydration synthesis or condensation
reactions (forms bond by losing water)
3. Broken apart by hydrolysis reactions (break bond by adding
water)
Carbohydrates
Subunit = sugars
Functions = energy usage/storage; structure
Names often end in “ose”
3 general classes:
1. Monosaccharides
C, H, O in 1:2:1 ratio
Can exist in linear form:
glucose
in water, they form rings
glucose
2. Oligosaccharides
Typically between 2 and 10 monosacs
Disaccharide – 2 monosacs joined together by a glycosidic
linkage (covalent bond that joins 2 sugars)
Ex. sucrose = glucose + fructose
3. Polysaccharide – long polymers (100s – 1000s) of monosacs
IMPORTANT DETAIL ABOUT BONDS BETWEEN GLUCOSE:
Secondary
structure shapes formed
by orientation of
hydrogen bonds
a. Starch – polymer of glucose, has α linkages, forms spirals,
energy storage in plants
2 types: amylose (straight chain) and amylopectin (short,
branched chains)
b. Glycogen – polymer of glucose, energy storage in animals (liver
and muscles), similar but more branched than amylopectin
c. Cellulose – polymer of glucose, has β linkages, forms straight,
unbranched chains, component of plant cell walls
Forms microfibrils – H bonds hold strands together =
dietary fiber, humans cannot digest β bonds (do not
have enzyme)
d. Chitin – polymer of modified glucose with nitrogen groups
attached; fungus cell walls and insect exoskeleton
Lipids
Not polymers
Many nonpolar C-H bonds
Hydrophobic
“subunit” of most: fatty acids:
Hydrocarbon chain of 10-50 carbons
3 types of fatty acids:
1.
saturated – no C-C double bonds, straight chains, solid
at room temp, most animal fats
2.
unsaturated – one or more double bonds, kinked, liquid
at room temp, plant and fish oils
3.
polyunsaturated – many double bonds
4.
hydrogenated vegetable oil – unsaturated fats that have
been converted to saturated fats; peanut butter and
margarine
5.
trans fats – made with trans double bonds
* saturated and trans fats contribute to atherosclerosis
(plaque deposits in veins)
Types of Lipids
1.
Fats = triglyceride = 1 glycerol + 3 fatty acids
Formed by dehydration synthesis
Function – energy storage, at least 2x amount of energy as
carbohydrates, mammals store it as adipose tissue
Also insulation and cushioning of organs
2.
Phospholipids – fat with one fatty acid replaced by a phosphate
group
Amphipathic – both polar and nonpolar
Phosphate “head” is polar (hydrophilic)
Hydrocarbon “tails” are nonpolar (hydrophobic)
Can vary with the addition of sugars, amines, or other groups
When added to water, hydrophobic tails will congregate toward
each other
Function – major component of cell membranes, arranged in
bilayer, forms a barrier between internal and external environment
3.
Steroids – four fused carbon rings + small carbon tail
Nonpolar
Varies by attached functional groups
Testosterone
Estradiol
Special steroid: cholersterol
2 types:
LDL – “bad” – cardiovascular disease
HDL – “good”
Function – precursor to all other steroids, found in cell
membranes
Synthesized in liver or obtained in diet (meat, eggs, cheese)
4.
waxes – fatty acids linked to alcohols or carbon rings
Function – protective waterproof covering (feathers, skin, leaves,
fruit)
Proteins
Subunit = amino acids
Central (alpha) carbon with carboxyl, amine, and R group
R group is variable; can be acidic, basic, polar, nonpolar,
ionic
20 common amino acids
9 “essential” – humans cannot synthesize them
Functions: determined by shape
1.
structural – hair, fingernails, etc
2.
storage – egg white, milk protein
3.
transport – hemoglobin/iron
4.
hormonal – insulin
5.
membrane proteins – receptors
6.
movement – muscle contraction
7.
defense – antibodies
8.
metabolism – enzymes
9.
toxins – botulism
polypeptide – polymer of a.a. subunits in a specific sequence joined by
peptide bonds; made by dehydration synthesis
**Levels of Protein Organization – leading up to the 3D structure:
1.
Primary Structure – sequence of amino acids, determined by
DNA; determines every other level of structure
2.
Secondary Structure – hydrogen bonds form between C=O and
N-H of backbone components; forms an alpha helix or beta
sheet
3.
Tertiary Structure – interactions between R groups; hydrogen
bonding, hydrophobic interactions, ionic bonds, disulfide
bridges; gives 3D shape
4. Quaternary Structure – protein made up of more than one amino
acid chain
Nucleic Acids
Basic Facts:
Nucleic acids store, transmit, and help express heredity information
Protein synthesis
Roles:
1. Deoxyribosenucleic acid (DNA) - provides directions for its own
replication
a. DNA directs RNA synthesis and through RNA, controls
protein synthesis
b. Genetic material that organisms inherit from their parents
c. Forms a double helix
2. Ribonucleic acid (RNA) – Replicates
DNA  RNA  Protein
Components:
1. Polynucleotides – polymers consist of monomers called
nucleotides
2. Nucleotides – composed of three parts
 Nitrogen- containing base (nitrogenous)
 Five-carbon sugar
 One or more phosphate groups
Pyrimidine – six-membered ring of carbon and nitrogen atoms
Members are Cytosine (C) and Thymine (T)
Uracil (U) – only for RNA
Purines – larger with a six-membered ring fused to a five-membered ring
Members are Adenine (A) and Guanine (G)
Pairs:
Adenine pairs with Thymine
Guanine pairs with Cytosine
Uracil replaces Thymine
- used in RNA only
5’ TAAGCCT 3’
3’ ATTCGGA 5’