Transcript Carbohydrates & Lipids - mvhs

Biomolecules:
Carbohydrates & Lipids
Images taken without permission from http://www.poster.net/marciali/marciali-fresh-pasta-2404234.jpg and
http://www.sciencemuseum.org.uk/exhibitions/lifecycle/images/1-2-6-2-1-0-0-0-0-0-0.jpg and
http://www.worldroom.com/pages/health/healthyoil_feature.jpg
Monomers and Polymers
• Monomer = single unit
– Examples: amino acids, monosaccharides
• Polymer = made up of monomers
– Examples: DNA, protein
Images taken without permission from http://www.greenspirit.org.uk/resources/glucose.gi and http://www.nmslab.com/images/dna.jpg
Dehydration Synthesis
• Building reaction
• H2O is removed in order to form a new
bond
Hydrolysis Reaction
• Breaking reaction
• H2O is required to break a bond
“Structure-Function” Theme
• Recurring theme on the AP
exam
• We will look at how the
physical structures in
biology support their
specific function
– Ex. How does the structure
of the cell membrane support
its function?
Carbohydrates
• Biological roles
– Energy
– Cell to cell recognition
– Etc.
• Monosaccharide = Monomer
• 1:2:1 ratio of C:H:O
– C6H12O6
Disaccharides
• 2 monosaccharides linked together
• Key disaccharides you need to know:
– Fructose + glucose  sucrose + H2O
– Glucose + galactose  lactose + H2O
– Glucose + glucose  maltose + H2O
Image taken without permission from http://www.pp3moo.com/ and
http://www.iktmc.edu.hk/subjects/hecon/milk.jpg
Glycosidic linkage
• The bond between
monosaccharides
• What type of reaction
would form this bond?
– Dehydration reaction
• What kind of bond is a
glycosidic linkage?
– Polar covalent
OH
OH
H2 C
H2C
O
OH
O
C
HO
OH
OH
OH
HO
HO
HO
OH
OH
H2C
H2C
O
OH
HO
O
C
OH
O
HO
HO
+ H2O
OH
Polysaccharides: Starch & Glycogen
• Both are used for energy storage
– Starch = energy storage in plants
– Glycogen = energy storage in animals
• When energy is needed, enzymes break the
bonds between monosaccharides
Image taken without permission from http://www.dpiw.tas.gov.au/inter.nsf/Images/TTAR-5P549Z/$File/faf_potato_variety.jpg
Structure of Starch & Glycogen
• Branched structure
– How does the branched
structure support the
function of these
molecules?
– branching allows for
more points of access for
enzymes to act (greater
surface area)
Image taken without permission from: http://wps.prenhall.com/wps/media/objects/724/741576/Instructor_Resources/Chapter_22/Text_Images/FG22_02.JPG
Polysaccharides: Cellulose + Chitin
• For structural support
– Cellulose = structural
support in plants
– Chitin = makes up the
hard exoskeleton of
insects
Structure of Cellulose & Chitin
• Long, unbranched chains
– Fibers form parallel chains
– How would the structure of cellulose & chitin
support their functions?
– Long, unbranched chains provide greater
strength
Lipids
• Biological roles: energy (storage),
structural, protection, insulation, pigments
• Mostly hydrocarbons (nonpolar,
hydrophobic)
– Lots of C-C and C-H bonds
– How would this property support its function of
energy storage?
– Nonpolar quality allows for them to be stored
without water– more compact
http://www.matthewklein.com/adm/photo/9_Bread_PeanutButter.jpg
Triglycerides: Fats & Oils
glycerol
• Made up of 1 glycerol
and 3 fatty acids
• What kind of reaction
forms a triglyceride?
– Dehydration reaction
H
O
H C O C
O
H C O C
O
H C O C
H
Fatty
acids
Types of Fatty Acids
• Fatty Acids can be saturated or unsaturated
• Saturated Fatty Acid
OH
H2C
– No double C-C bonds
– Molecules are more straight
– Fats: solid at room temperature
• Unsaturated Fatty Acid
H2C
H2C
H2C
H2C
H2C
H2C
CH2
H2C
CH2
H2C
CH2
H2C
CH2
HC
CH2
CH2
HC
H2C
H2C
H2C
H2C
CH2
CH2
CH2
CH2
OH
CH3
O C
– Contain at least 1 C-C double bond
– Causes “kinks” in molecule
– Liquid at room temperature
H2C
CH2
CH2
H2C
CH2
H2C
CH2
OH
H2C
CH2
H2C
CH2
CH3
O C
H2C
OH
O C
O C
CH2
H2C
CH2
H2C
CH2
H2C
CH2
CH2
CH2
CH2
CH3
HC
HC
CH2
CH2
CH2
CH2
CH2
CH2
H2C
CH2
H2C
CH2
H2C
CH2
CH3
Fatty Acid Structure
• Why would the type of fatty
acid determine its state at room
temperature?
– Double bonds create the kinks in
the structure can’t be packed
as closely together  less Van
der waals forces
– This makes them more fluid at
room temperature  lower
melting temperature
The peanut butter puzzle…
• Fats are usually found in animals
• Oils are usually found in plants
• So why is peanut butter solid?
– hydrogenation
Images taken without permission from http://www.theunderweardrawer.homestead.com/files/peanut_butter.JPG and
http://chinaproducts.supplierlist.com/manufacturers/36428/en_madeinchina.htm
Phospholipids
• Structurally and chemically
similar to triglycerides
• One fatty acid is replaced with
a phosphate group
• Phosphate group is hydrophilic
– “likes” water
• Fatty acids are hydrophobic
– “dislikes” water
Steroids
• Chemically and structurally
different from other lipid
categories
• Classified as a lipid because of
their nonpolar/hydrophobic
nature
• Can be recognized by 6 carbon
rings and 5 carbon rings
• Chemical messengers
(hormones)
• Structural components in cell
membranes
cholesterol