Download Molecules of life

Chemical Building blocks of
life Raven Chp 3
Biochemistry
Biological molecules


Molecules that are only made by living
things
Most are macromolecules

Types
Bio molecules all based on CARBON
Carbon has 4 unpaired electrons,
makes 4 covalent bonds
Hydrocarbon chain
carbon-hydrogen chains
Shorthand for Carbon hydrogen
chain
Functional groups attach to carbon
chain
Determine
specific functions

Isomers


Organic molecules exist in different forms
but have same chemical formula
Stereo isomers are mirror images
Chiral molecules




Mirror image isomers of carbon
D form – Dextrorotary (right handed)
L form – Levorotary (left handed)
Biological molecules usually only are one
or other L- Amino acids D - sugars
2 forms for all biomolecules


Polymer form – chains
Monomer form – single unit
Types of biomolecules


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Carbohydrates – starch, glycogen,
cellulose
Nucleic acids – DNA and RNA
Proteins – structure, function
Lipids – fats, phospholipids, steroids
Carbohydrates

Carbohydrates
Monomer = monosaccharide

Sugars and Starches and cellulose
Function - Store energy and cell structure

Easily available energy

Made of
Carbon, Hydrogen and Oxygen

Monosaccharides = One

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
Simple sugars
C6H12O6 (ratio 1:2:1)
Ex. Glucose, fructose and galactose
Each type sugar has formula
C6H12O6 1:2:1 ratio
Sugars are found in RING shape in
nature
Structural Isomers

Have same formula, but different
molecular structure
Other sugars

Alcohol sugars – sugar substitute
Contain calories, but metabolized differently
 Ex. Xylitol
Other alcohol sugars
Ingredient
Sweetness GI
Cal/g
Sucrose (sugar)
100%
60
4
Maltitol Syrup
75%
52
3
Hydrogenated Starch
Hydrolysate
33%
39
2.8
Maltitol
75%
36
2.7
Xylitol
100%
13
2.5
Isomalt
55%
9
2.1
Sorbitol
60%
9
2.5
Lactitol
35%
6
2
Mannitol
60%
0
1.5
Erythritol
70%
0
0.2
Disaccharides = two



Double sugar
Ex. Sucrose = glucose + fructose
Dehydration synthesis – Water
byproduct during bond formation
Other disaccharides

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
Glucose + Glucose = maltose
Glucose + Fructose = Sucrose (table sugar)
Glucose + galactose = Lactose (milk sugar)
Polysaccharide = many



Chain of simple sugars
Fiber = polysaccharides
Ex. Starch, cellulose, glycogen
Starch

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
In plants
Straight chains of glucose
digestible
Starch types


Amylose – long chains w/ no branches
Amylopectin – Starch with branches
Glycogen = “animal starch”

(Liver cells) glucose Branches
Cellulose



Glucose bonds in opposite directions.
Forms fiber, cell walls
Human indigestible
Structure compare
Chitin

Forms shells in arthropods
Nucleic Acids = DNA and RNA

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Very large complex organic
molecules that store and carry
information in a cell.
NOT required nutrient
DNA – contains Genetic code
RNA – copies code and makes
proteins
Nucleic acids are made of
Nucleotides linked together

Nucleotide = monomer
Nucleotides contain

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1 – Sugar
2 – Phosphate
3 – Nitrogen Base
DNA backbone

Made of sugar and phosphates
DNA has 4 nitrogen bases

A = Adenine
T = Thymine
G = Guanine
C = Cytosine

This is the 4 letter alphabet for DNA


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DNA (DeoxyRibonucleic Acid)
Forms Double helix
 Contains all the information a cell
needs to reproduce and grow
 Contained in nucleus
 Must be replicated
prior to cell division

RNA (RiboNucleic Acid)




3 different types.
Has uracil instead of thymine
Has ribose instead of deoxyribose
RNA reads the DNA and then builds proteins for
the body
Proteins
Proteins



Building blocks of cells.
Contain Nitrogen as well as
Carbon, Hydrogen and Oxygen
C
+H+O+N
Protein functions
1)
2)
3)
4)
5)
6)
Enzymes – catalyze reactions
Defense – antibodies , toxins (venom)
Transport – membrane transport and
hemoglobin
Support – fibers such as hair keratin
Motion – muscles and contraction of cell
Regulation – hormones
Proteins are made of chains of
Amino Acids


There are 20 different Amino Acids
Each have:
- Amino group (-NH2)
- Carboxyl (-COOH)
- R group (other)
Peptide bonds


link amino acids
Also Dehydration synthesis. Water is
formed at each bond
Hydrolysis is the breaking of a
peptide bond
Water added
Shape of protein determines
function




Primary structure – sequence of amino
acids
Secondary structure – alpha helix, beta
pleated sheets
Tertiary structure – Hydrogen bonds
hydrophobic interactions, ionic bonds
Quaternary structure – 2 or more poly
peptides together
H bonds form secondary structure
Tertiary structure forms from other
bonds

Denaturing proteins

Heat etc. will break bonds of protein
tertiary structure. reversible
Lipids (Fats)
Lipids (Fats)



Store energy, Form cell membranes.
Hydrophobic -Do not dissolve in water.
Lipids have much more Carbon and
Hydrogen than Oxygen
C
+H
>
O
Fats are made of fatty acids


Have a Hydrocarbon chain
Hydrocarbons are hydrophobic
Triglycerides = fats

Fatty acids attach to glycerol
Saturated fats


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Are filled up with hydrogen and tend
to be solid
Ex: butter
Animal fats
Unsaturated fats


Are not filled up with hydrogen
(double bonds) and tend to be liquid
Ex. Plant fats, corn oil, olive oil
Saturated vs. Unsaturated


Saturated = straight, fit tight together
Unsaturated = bent, fit loose together
TRANS FATS =Unsaturated but
act like saturated

Should they be banned?
Trans fats
Saturated
Unsaturated
Has no double bonds
Straight
Has one Cis double
bond. Hydrogens on
same side of bond.
bends
Unsaturated
Trans fat
has one Trans double
bond. Hydrogens on
opposite sides.
Acts like saturated
Phospholipids



Main building blocks of cell membrane
Heads (glycerol and phosphate groups)
hydrophilic (polar)
2 Fatty acid tails hydrophobic
Steroids

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Hydrophobic hormones and cholesterol
Have 4 carbon rings
vitamin D
• Sunlight turns cholesterol to vitamin D
Terpenes
• Pigment lipids
• Chlorophyll in plants
• Retinol in eye retina