Transcript Cell - Thomas A. Stewart Secondary School

MACROMOLECULES
Carbohydrates and Lipids
AKA … Sugars and Fats
Types of Carbohydrates
1.
2.
3.
Monosaccharides
Oligosaccharides (Di’s and Tri’s)
Polysaccharides
Carbs… Monosaccharides
“ONE”
 simple
“SUGAR”
sugar containing 3 to 7 carbons
 examples: glucose, fructose, galactose
 provides instant
energy
“STRAIGHT
CHAIN” FORM
“RING” FORM
(in water)
Carbs… Characteristics of Sugars
1) An –OH group is attached to each
carbon except one; this carbon is
double bonded to an oxygen (carbonyl
group
Start numbering the
carbons of your sugars
at the end closest to the
carbonyl group!!!
1
1
2
2
3
3
4
4
5
5
6
6
Carbs… Characteristics of Sugars
2) Size of carbon skeleton varies from
3 to 7 carbons.
Classification
Number of
Carbons
Example
Triose
3
Glyceraldehyde
Pentose
5
Ribose
Hexose
6
Glucose
Carbs… Characteristics of Sugars
3) Spatial arrangements may vary. For
example, glucose and galactose are
stereoisomers.
Can you spot the only
difference???
Notice how the –OH’s are on
different sides. This affects
the properties of these
molecules & makes them
chemically different
1
1
2
2
3
3
4
4
5
5
6
6
Carbs… Characteristics of Sugars
4) In aqueous solutions, many
monosaccharides form rings.
Equilibrium favours the ring structure.
The #5C –OH
reacts within the
molecule at the
terminal aldehyde
group, breaking
the double bond
and creates a
closed ring
6
5
1
2
4
2
3
4
5
6
3
1
Carbs… Dissaccharides
“TWO” “SUGARS”
made up of two monosaccharides
 common examples:
glucose + glucose = maltose (malt sugar)
glucose + fructose = sucrose (table sugar)
glucose + galactose = lactose (milk sugar)

MOO!!!
Dissaccharides… cont’d


the forming of a disaccharide creates water in the
process - this is known as dehydation synthesis or
condensation reaction
the connection between monosaccharides is called
a glycosidic linkage
Polysaccharides
“MANY” “SUGARS”
 a complex carbohydrate consisting of
many simple sugars linked together
Functions:
Energy Storage
Starch - in plants
Glycogen - in animals
Structural Support
Cellulose – component of
plant cell wall
Chitin – exoskeleton of
arthropods
•Glycogen is a
branched
polysaccharide.
This makes
glycogen more
loosely packed,
allowing
enzymes to
access it easily
to be broken
down into
glucose.
• Cellulose is tightly packed because of the lack of
branches. This allows the cellulose molecules to stack
themselves closer to each other, creating bonds
between molecules. This causes it to be rigid and
makes it difficult to break down.
Macromolecule #2
LIPIDS
Functions:
 Long-term energy storage (triglycerides)
 Form cell membrane (phospholipids)
 Messaging (steroids act as hormones)
 Insulation
 Cushioning of Internal Organs
Lipids
Why are lipids well suited for long term
energy storage?
 Contain
many high energy bonds
between carbon and hydrogen
 Contain twice as much energy per gram
than carbohydrates (very concentrated)
Types of Lipids
1.
2.
3.
4.
Fats (triglycerides)
Phospholipids
Steroids
Waxes
Fats
 Made up of glycerol and 3 fatty acids.
 There are many kinds of fatty acids. They
differ in two ways:
1. In length
2. In the # of hydrogen atoms attached to it
An Example of a Fat Molecule
(Triglyceride)
1
2
3
Glycerol
Fatty acids
Digestion of a Fat Molecule
+ 3 H2O
triglyceride
Fig 1.22
p. 29
+
glycerol
The above is a hydrolysis reaction.
What is the reverse of this reaction called?
3 fatty
acids
Types of Fatty Acids
SATURATED (palmitic acid)
 No double bonds between carbons
MONOUNSATURATED (oleic acid)
 1 double bond
POLYUNSATURATED (linoleic acid)
 More than 2 double bonds
Saturated
# of double bonds
between carbons
Orientation
State at Room
Temp.
Origin
Which are better
for you?
Example
Unsaturated
Polyunsaturated
Types of Fats
Poly Saturated Unsaturated
unsaturated
# of Double
Bonds
between
carbons
none
At least one
double bond
between
carbon
atoms
Several
double
bonds
Types of Fats… cont’d
Poly Saturated Unsaturated
unsaturated
Orientation
of
Fatty Acids
Straight
chains
Kinks /
Kinks /
bends at the bends at the
double
double
bonds
bonds
Types of Fats… cont’d
Poly Saturated Unsaturated
unsaturated
State at
Room Temp.
Solid
(tightly
packed)
Liquid
(less tightly
packed)
Liquid
(even less
tightly
packed)
Types of Fats… cont’d
Poly Saturated Unsaturated
unsaturated
Origin
Animals
(meat,
dairy)
Plants
Types of Fats… cont’d
Poly Saturated Unsaturated
unsaturated
Bad for
Which are
healthier?
Stored in
adipose
tissue
Healthier
Types of Fats… cont’d
Poly Saturated Unsaturated
unsaturated
Examples
Butter,
lard
Olive oil, vegetable oil,
peanut oil, canola oil
(genetically modified)
What up with TRANS-FATS?
NOT GOOD FOR YOU!!! (FRIES, PEANUT BUTTER)
 Created from oils (unsaturated) that are
hydrogenated (hydrogen added to double bonds)
 Done to increase shelf life, flavour, & workability (eg.
semi-solid for baking)
 Only partial hydrogenation occurs & get a change in
the orientation of hydrogens around some double
bonds
 This fat is packaged by your body as LDL (aka BAD
cholesterol) leaving you @ risk for heart disease,
artheriosclerosis, diabetes & obesity

Type of Lipids #2
PHOSPHOLIPIDS
 are
fat derivatives in which one fatty
acid has been replaced by a phosphate
group and one of several nitrogencontaining molecules.
 an important part of the cell membrane
(phospholipid bilayer)
Phospholipid
Figure 1.23 p. 29
Phospholipid
• The phospholipid can also be represented as:
Polar Head – hydrophilic (water-loving)
Non-Polar Tails (fatty acids) - hydrophobic
(water-hating)
Type of Lipids #3
STEROIDS
Steroids consist of 4 fused carbon rings
Cholesterol
Testosterone
•Precursor for other steroids
•Component of animal cell membranes
•Contributes to arteriosclerosis
MACROMOLECULES
Proteins
Proteins
FUNCTIONS
 Act as enzymes (to control chemical
reactions)
 Provide support and help shape cells
 Act as transporters (hemoglobin)
 Act as hormones
 Make up structures (hair, cartilage)
 Act as antibodies (immunoglobulins)
Proteins
are polymers of…
20
Amino Acids
8 Essential
Need to obtain via diet
12 Non-Essential
Body can make
Amino Acid Structure
R – Side Chain
Amino Group
Carboxyl
Group
Central Carbon
 R – Side Chain  20 possibilities; different R-groups
give the amino acid different biological properties
Proteins
Are often very large polymers of many amino
acids (monomers) linked together to form
POLYPEPTIDES
 Proteins are built by condensation reactions
forming peptide bonds.

aa1 – aa2
aa1 – aa2 -- aa3
aa1 – aa2 -- aa3 – aan

dipeptide
tripeptide
polypeptide
Proteins are broken down through hydrolysis
reactions
Polypeptides
Polypeptide Chain
Amino Acid
Amino Acid
Amino Acid
Peptide Bonds
(Amide Linkage)
This polypeptide will begin to fold over on itself until it has
reached its 3-dimensional shape
The folding will be determined by the R-group interactions of the
specific amino acid sequence
It is only the final shape that will determine the protein’s specific
function
Peptide Bonds
+ H2O
This is a … DEHYDRATION REACTION!
Text: Appendix 5 p. 559-561
Levels of Protein Structure
Primary Structure
 Amino acid linear sequence
Secondary Structure
 Folding into a helix or pleated sheet
Levels of Protein Structure
p. 559-562: Appendix 5
Tertiary Structure
 Folding of secondary structures into a 3-D
shape
Quarternary Structure
 2 or more polypeptide chains assembling
together
Hemoglobin – A Complex Protein
 Found in RBCs, is responsible for oxygen
transport to your cells for respiration
 Scientists believe the protein dates back 4
billion years to the start of life
 A quarternary protein consisting of 4
polypeptides
 2 of the polypeptides (α subunits) contain
141 amino acids while the other 2 (β
subunits) contain 146 amino acids
Hemoglobin – A Complex Protein
Heme
 Heme groups contain iron (II), acting as
sites where oxygen molecules can bind
Hemoglobin – At the Heme of it all
DID YOU
KNOW?
These molecular cages are called porphyrins and
are thought to have predated oxygen (2 billion years
ago) back when single celled living things used
sulfur in its metabolism