Transcript chapter 5 the structure & function of macromolecules

CHAPTER 5
THE STRUCTURE &
FUNCTION OF
MACROMOLECULES
CARBOHYDRATES, LIPIDS,
PROTEINS, NUCLEIC ACIDS
Collins I
3 lines
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Explain pH
Objectives:
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Macromolecules are polymers
Sugars (smallest carbohydrate) are used for fuel and carbon
sources
Polysaccharides (polymers of sugar) have storage and structural
roles
Fats store large amounts of energy
Phospholipids are a part of the cell membrane
Steroids = cholesterol and hormones
Proteins' function depends on its shape
Nucleic Acids store and transmit hereditary info
RNA and DNA
Root Words:
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Con –
Di –
Glyco –
Hydro –
Macro –
Meros –
Mono –
Poly –
Tri –
MOLECULES TO
RECOGNIZE
Basic Protein Structure
Cellulose
Amino Acid Structure
Glycogen
Steroids
Glucose
Phospholipids
The
Synthesis
&
Breakdown
of
Polymers.
Fig. 5.2
Monosaccharides - Simple Sugars (Fig. 5.3)
Note: Asymmetric Carbons in Hexose Sugars:
Carbohydrates - “Carbon” “Hydrated”
( 1:2:1 ratio ) ( C )
( H2O )
Sugars - Major role - Energy. Fig. 5.4)
Disaccharide - Dehydration Synthesis &
Glycosidic Linkage. (Fig. 5.5)
Sucrose = Glucose & Fructose
Lactose = Glucose & Galactose
1-4 & 1-2
Linkage
Starch is in the
form of Amylose
& Amylopectin
(Fig. 5.7)
(in PLANTS)
GLYCOGEN
is also called
animal starch,
stored in muscles
& liver.
POLYSACCHARIDES -3 OR MORE
MONOSACCHARIDES.
1. Structural:
a. Cellulose - cell walls of plants.
b. Chitin - exoskeleton of
arthropods (insects; spiders etc.) and
exterior of mushrooms
2. Storage - Starch & Glycogen
LIPIDS - Diverse Hydrophobic
Molecules (Fig. 5.10)
FATS:
Made of 1
glycerol & 3
fatty acids
(16 to 18
carbons).
C-H on
fatty acids
make lipids
hydrophobic
Saturated Fatty Acids - have no
double bonds between the carbons in
the chain (solids at room temp)
Unsaturated Fatty Acids - have
double bonds between the carbons in
the chain. (Liquids at room temp due
to “kinks” in the fatty acid which
prevents it from solidifying)
Fat Molecules are storage for energy.
Second Type of Lipid: Phospholipid
Have 2 fatty acids NOT 3 like lipids
Major
components
of cell
membranes.
Hydrophilic
head
Hydrophobic
tail.
Kink in one
fatty acid
means it has
double bonds
(Fig. 5.12)
Phospholipid Bilayer is found in cell
membrane.
Fig. 5.13
Outside of
cell
Inside of
cell
3rd Type of Lipid - Steroids
Lipids with carbon skeleton of 4
interconnected rings.
Cholesterol - common component of
cell membranes. (Fig. 5.14).
Also precursor
for other
steroids such
as hormones
including sex
hormones.
Cholesterol
Sex Hormones:
What is the male sex hormone?
 What is the female sex hormone?
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Nucleic Acids:
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DNA
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RNA
Proteins
•Storage
•Structural
support
•Transport of substances
•Cell to cell signaling
•Movement
•Defense against foreign
substances
•Enzymes – speed up
chemical reactions
Amino Acids
Amino acids – contain carboxyl and
amine functional group
 Link together by peptide bonds to form
a polypeptide chain
 Only 20 amino acids
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Protein Structure
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4 levels
– Primary Structure: precise sequence of
amino acids
– Secondary Structure: coils or folds within
the sequence due to Hydrogen bonding.
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The H bonds are weak, but can support a
particular shape
Alpha (a) helix - coil
Beta (B) pleated sheet - fold
Protein Structure Cont.
– Tertiary Structure:
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Irregular looping and folding of the protein bc
of interactions of side groups
– Quaternary Structure
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The addition of one or more polypeptide chains
to the original structure
Changes in Protein
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Denature – when a protein unravels
due to changes in pH, salt
concentration, temperature and
environment