Download CH 2 -CH 2 -CH 2 -CH 2 -CH 2

Macromolecules
1
Organic Compounds
• Compounds that contain CARBON
are called organic.
• Macromolecules are large organic
molecules.
2
Carbon (C)
• Carbon has 4 electrons in outer
shell.
• Carbon can form covalent bonds
with as many as 4 other atoms
(elements).
• Usually with C, H, O or N.
• Example:
CH4(methane)
3
Macromolecules
• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller “building blocks”
called MONOMERS.
• Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids (DNA and RNA)
4
Question:
How Are
Macromolecules
Formed?
5
Answer: Dehydration Synthesis
• Also called “condensation reaction”
• Forms polymers by combining
monomers by “removing water”.
HO
H
HO
H
H2O
HO
H
6
Dehydration Synthesis
• Combining simple molecules to form a
more complex one with the removal of
water
– ex. monosaccharide + monosaccharide ---->
disaccharide + water
– (C6H12O6 + C6H12O6 ----> C12H22O11 +
H2O
• Polysaccharides are formed from
repeated dehydration syntheses of
water
– They are the stored extra sugars known as
starch
7
Question:
How are
Macromolecules
separated or
digested?
8
Answer: Hydrolysis
• Separates monomers by “adding
water”
HO
H
H2O
HO
H
HO
H
9
Carbohydrates
used as a source of energy; short term
and long term energy also some animals
and organisms use carbs for structural
purposes.
10
Carbohydrates
• Small sugar molecules to large
sugar molecules.
• Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
11
Carbohydrates
Monosaccharide: one sugar unit
Examples:
glucose
glucose (C6H12O6)
deoxyribose
ribose
Fructose
Galactose
12
Carbohydrates
Disaccharide: two sugar unit
Examples: (C12H22O11)
– Sucrose (glucose+fructose)
– Lactose (glucose+galactose)
– Maltose (glucose+glucose)
glucose
glucose
13
Carbohydrates
Polysaccharide: many sugar units
Examples: starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
14
Lipids
some store energy, some lipids form
important parts of biological membranes
& waterproof coverings.
15
Lipids
• General term for compounds which are
not soluble in water.
• Lipids are soluble in hydrophobic
solvents.
• Remember: “stores the most energy”
• Examples: 1. Fats
2. Phospholipids
3. Oils
4. Waxes
5. Steroid hormones
6. Triglycerides
16
Lipids
Six functions of lipids:
1. Long term energy storage
2. Protection against heat loss
(insulation)
3. Protection against physical shock
4. Protection against water loss
5. Chemical messengers (hormones)
6. Major component of membranes
(phospholipids)
17
Lipids
Triglycerides:
composed of 1 glycerol and 3
fatty acids.
H
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
fatty acids
H-C----O C-CH -CH -CH -CH
2
2
2
H
glycerol
18
Fatty Acids
There are two kinds of fatty acids you may see
these on food labels:
1. Saturated fatty acids: no double bonds
(bad)
O
saturated C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
2. Unsaturated fatty acids: double bonds
(good)
O
unsaturated C-CH2-CH2-CH2-CH
19
Proteins
20
Proteins (Polypeptides)
• Amino acids (20 different kinds of aa)
bonded together by peptide bonds
(polypeptides).
• Six functions of proteins:
1. Storage:
albumin (egg white)
2. Transport:
hemoglobin
3. Regulatory:
hormones
4. Movement:
muscles
5. Structural:
membranes, hair, nails
6. Enzymes:
cellular reactions
21
Major Protein Functions
•
•
•
Growth and repair
Energy
Buffer -- helps keep body pH constant
referred to as maintaining
homeostasis
22
Proteins (Polypeptides)
Four levels of protein structure:
A.Primary Structure
B. Secondary Structure
C. Tertiary Structure
D.Quaternary Structure
23
Primary Structure
Amino acids bonded together
by peptide bonds (straight
chains)
Amino Acids (aa)
aa1
aa2
aa3
aa4
aa5
aa6
Peptide Bonds
24
Secondary Structure
• 3-dimensional folding arrangement of a
primary structure into coils and pleats
held together by hydrogen bonds.
• Two examples:
Alpha Helix
Beta Pleated Sheet
Hydrogen Bonds
25
Tertiary Structure
• Secondary structures bent and folded
into a more complex 3-D arrangement
of linked polypeptides
• Bonds: H-bonds, ionic, disulfide
bridges (S-S)
• Call a “subunit”.
Alpha Helix
Beta Pleated Sheet
26
Quaternary Structure
• Composed of 2 or more
“subunits”
• Globular in shape
• Form in Aqueous environments
• Example: enzymes (hemoglobin)
subunits
27
Nucleic
Acids
28
Nucleic acids
• Two types:
a. Deoxyribonucleic acid (DNAdouble helix)
b. Ribonucleic acid (RNA-single
strand)
• Nucleic acids are composed of long
chains of nucleotides linked by
dehydration synthesis.
29
Nucleic acids
• Nucleotides include:
phosphate group
pentose sugar (5-carbon)
nitrogenous bases:
adenine (A)
thymine (T) DNA only
uracil (U) RNA only
cytosine (C)
guanine (G)
30
DNA Nitrogenous bases
31
DNA Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Nitrogenous base
(A, G, C, or T)
Sugar
(deoxyribose)
C3
C2
32
RNA Nucleotide
• directs cellular protein synthesis
• found in ribosomes & nucleoli
33
5
DNA
double
helix
O
3
3
O
P
5
O
C
G
1
P
5
3
2
4
4
2
3
1
P
T
5
A
P
3
O
O
P
5
O
3
5
P
34
Enzymes and Enzyme Action
• Catalyst : inorganic or organic substance
which speeds up the rate of a chemical
reaction without entering the reaction itself
• enzymes: organic catalysts made of protein
• most enzyme names end in -ase
• enzymes lower the energy needed to start a
chemical reaction. (activation energy)
• begin to be destroyed above 45øC. (above this
temperature all proteins begin to be
destroyed)
35
It is thought that, in order for an enzyme to affect the
rate of a reaction, the following events must take
place.
1. The enzyme must form a temporary association with
the substance or substances whose reaction rate it
affects. These substances are known as substrates.
2. The association between enzyme and substrate is
thought to form a close physical association between
the molecules and is called the enzyme-substrate
complex.
3. While the enzyme-substrate complex is formed,
enzyme action takes place.
4. Upon completion of the reaction, the enzyme and
product(s) separate. The enzyme molecule is now
available to form additional complexes.
36
How do enzymes work?
• substrate: molecules upon which an enzyme
acts
• the enzyme is shaped so that it can only lock
up with a specific substrate molecule
enzyme
substrate -------------> product
37
Factors Influencing Rate of Enzyme
Action
1. pH - the optimum (best) in most living things
is close to 7 (neutral)
• high or low pH levels usually slow enzyme
activity
• A few enzymes (such as gastric protease) work
best at a pH of about 2.0
38
39
. 2-Temperature
- strongly influences enzyme
activity
optimum temperature for maximum enzyme
function is usually about 35-40 C.
reactions proceed slowly below optimal
temperatures above 45 C most enzymes are
denatured (change in their shape so the
enzyme active site no longer fits with the
substrate and the enzyme can't function)
40
41
3-Concentration
Concentrations of Enzyme and Substrate
• ** When there is a fixed amount of enzyme
and an excess of substrate molecules -- the
rate of reaction will increase to a point and
then level off.
42