Transcript CP Biology Macromolecules

• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
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*Organic Compounds
• Compounds that contain CARBON
are called organic.
• Macromolecules are large organic
molecules.
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*Carbon (C)
• Carbon has 4 electrons in outer
shell.
Usually bonds with C, H, O or N.
• Example:
CH4(methane)
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*Macromolecules
• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller “building blocks”
called MONOMERS.
• Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleiccopyright
acids
(DNA and RNA)
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*Question:
How Are
Macromolecules
Formed?
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*Answer: Dehydration Synthesis
• Also called “condensation reaction”
• Forms polymers by combining
monomers by “removing water”.
HO
H
HO
H
H2O
HO
H
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*Question:
How are
Macromolecules
separated or
digested?
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*Answer: Hydrolysis
• Separates monomers by “adding
water”
HO
H
H2O
HO
H
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HO
H
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• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
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Carbohydrates
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*I. Carbohydrates
• Small sugar molecules to large
sugar molecules.
• Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
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*Carbohydrates
Monosaccharide: one sugar unit
Examples:
glucose
*glucose (C6H12O6)
deoxyribose
ribose
Fructose
Galactose
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*Carbohydrates
Disaccharide: two sugar unit
Examples:
– *Sucrose (glucose+fructose)
table sugar
– *Lactose (glucose+galactose)
– Maltose (glucose+glucose)
glucose
glucose
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*Carbohydrates
Polysaccharide: many sugar units
Examples: starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
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glucose
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• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
copyright cmassengale
15
*II. Proteins
• Amino acids (20 different kinds of aa)
bonded together by peptide bonds
(polypeptides). Essential and non-essential
• 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
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• Amino acids
– Are organic molecules possessing both carboxyl and
amino groups
– Differ in their properties due to differing side
chains, called R groups
Twenty Amino Acids
• 20 different amino acids make up CHproteins
CH
3
CH3
H
H3N+
C
CH3
O
H3N+
C
H
Glycine (Gly)
O–
C
H3N
C
H
+
O–
C
CH2
CH2
O
H 3N
C
H
Valine (Val)
Alanine (Ala)
CH
CH3
CH3
O
CH3
3
C
+
O–
O
C
H
Leucine (Leu)
H3C
H3N
+
O–
CH
C
O
C
H
Isoleucine (Ile)
O–
Nonpolar
CH3
CH2
S
NH
CH2
CH2
H3N+
C
H
H3N+
C
O–
Methionine (Met)
Figure 5.17
CH2
O
C
H
CH2
O
C
O–
Phenylalanine (Phe)
H3N+
C
H
O
C
H2C
CH2
H2
N
C
O
C
H
O–
Tryptophan (Trp)
Proline (Pro)
O–
OH
OH
Polar
H3N
+
CH2
C
O
C
H
CH
H3N
O–
Serine (Ser)
C
+
O
C
H3N
O–
H
+
CH2
C
H
O
C
CH2
H3N
O–
C
+
O
C
H
Electrically
charged
H3N
+
C
+
O–
O–
O
NH3+
NH2
C
CH2
C
CH2
CH2
CH2
CH2
CH2
CH2
O
H
O–
H3N
+
CH2
C
O
C
H
O–
H3N
+
CH2
C
H
Aspartic acid
(Asp)
O–
+
CH2
C
O
C
H
O–
Glutamine
(Gln)
Asparagine
(Asn)
C
C
C
H3N
Basic
O
C
CH2
O
H
Acidic
–O
CH2
H3N
Tyrosine
(Tyr)
Cysteine
(Cys)
Threonine (Thr)
C
NH2 O
C
SH
CH3
OH
NH2 O
Glutamic acid
(Glu)
O–
Lysine (Lys)
NH2+
H3N
+
CH2
O
C
NH+
H3N
+
CH2
C
H
NH
CH2
O
C C
O–
H
O
C
O–
Arginine (Arg)
Histidine (His)
*Primary Structure
Amino acids bonded together
by peptide bonds (straight
chains)
Amino Acids (aa)
aa1
aa2
aa3
aa4
aa5
aa6
Peptide Bonds
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Proteins (Polypeptides)
Four levels of protein structure:
A.Primary Structure
B. Secondary Structure
C. Tertiary Structure
D.Quaternary Structure
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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
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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
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Quaternary Structure
• Composed of 2 or more
“subunits”
• Globular in shape
• Form in Aqueous environments
• Example: enzymes (hemoglobin)
subunits
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• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
copyright cmassengale
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*
Proteins must be in a certain shape to
function. If you take it out of its
shape, you have denatured it and it
can not longer work. Heat and pH can
denature a protein.
Proteins often change colors when they
are denatured. Cooking egg white is an
example.
•Denaturation is when a protein
unravels and loses its native
conformation
(shape)
Denaturation
Normal protein
Figure 5.22
Denatured protein
Renaturation
*2 types of amino acids
• Non-essential amino acids are those
your body can make. There are 12.
• Essential amino acids are those you must
get in your diet because your body
cannot make them. There are 8.
• If you don’t get the essential aa, you
develop kwashiorkor.
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Review of Protein
Structure
+H
3N
Amino end
Amino acid
subunits
helix
• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
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Enzyme reactions
enzyme + substrate
enzyme-substrate complex
*Enzymes -- Are defined as a BIOLOGICAL
catalyst i.e. something that speeds up a
reaction. Up to 1012 fold
– *Usually end in ‘…ase’ and named for
what they do or act on (sucrase breaks
down sucrose)
– Discovered in 1900 in yeasts. Some
40,000 in human cells
– *Control almost every metabolic reaction
in living organisms
– Are globular proteins coiled into a very
precise 3-dimentional shape with
hydrophilic side chains making them
soluble
– Possess an active site into which other
substrate molecules can bind to form an
enzyme-substrate complex
– *Once the substrate has been either
synthesised or split, enzymes can be reused.
– Do not ‘create’ reactions
– Widely used in industrial cleaning
– Often require co-factors (co-enzymes)
to function – metal ions, or vitamins
SUCROSE IS SUBSTRATE – SUCRASE IS ENZYME
Enzyme reactions
enzyme + substrate
E +S
enzyme-substrate complex
ES
Enzyme reactions
enzyme + substrate
enzyme-substrate complex
E +S
ES
enzyme-substrate complex
ES
enzyme + product
E +P
*Enzyme activity
How fast an enzyme is working
Rate of Reaction
Rate of Reaction = Amount of
substrate changed (or amount
product formed) in a given period of
time.
Rate of Reaction
Enzyme activity
Variable you are looking at
*Enzyme activity
Four Variables
*Enzyme activity
Four
Variables
Temperature
pH
Enzyme Concentration
Substrate Concentration
Rate of Reaction
Temperature
Rate of Reaction
Temperature
0
10
20 30 40 50 60
Temperature
Rate of Reaction
5- 40oC
Increase in Activity
0
<5oC - inactive
10
40oC - denatures
20 30 40 50 60
*Effect of heat on enzyme activty
If you heat the protein above its optimal
temperature, bonds break and the protein loses
it secondary and tertiary structure.
Cooking an egg denatures the proteins and it goes white.
Cooking meat denatures the proteins and it turns brown.
Effect of heat on enzyme activty
Denaturing the protein
Effect of heat on enzyme activty
Denaturing the protein
ACTIVE SITE CHANGES SHAPE
SO SUBSTRATE NO LONGER FITS
Rate of Reaction
pH
1
2 3 4 5 6 7 8 9
pH
Rate of Reaction
Narrow pH optima
1
2 3 4 5 6 7 8 9
pH
Rate of Reaction
Narrow pH optima
WHY?
1
2 3 4 5 6 7 8 9
pH
Rate of Reaction
Narrow pH optima
Disrupt Ionic bonds - Structure
Effect charged residues at active
site
1
2 3 4 5 6 7 8 9
• SCI.9-12.B-3.4 - [Indicator] - Summarize how
the structures of organic molecules (including
proteins, carbohydrates, and fats) are related
to their relative caloric values.
• SCI.9-12.B-3.5 - [Indicator] - Summarize the
functions of proteins, carbohydrates, and fats
in the human body.
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*III. 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
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*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)
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*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
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*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
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*Steroid
Steroids are
always four
fused rings.
Cholesterol is
the precursor
for all steroid
hormones.
•Testosterone
•Estrogen
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*IV. 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.
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*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)
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Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Nitrogenous base
(A, G, C, or T)
Sugar
(deoxyribose)
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C2
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*Nucleotides are bonded to each
other by the process of
dehydration synthesis, forming
phosphodiester bonds.
The arrows in the next slide are pointing to
these bonds.
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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
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P
60
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