Transcript amino acids - El Camino College

Macromolecules
Macromolecules
• form the living organisms
• have:
– a carbon core base
– the core has attached groups of atoms called functional groups which confer
specific chemical properties
• very large
• assembled from many small components, called monomers;
the assembled chain of monomers is known as a polymer
• polymers/monomers are dynamic structures depending on
the needs of the cells by two reversible processes
• There are four types of macromolecules:
1.Carbohydrates
2.Lipids
3.Proteins
4.Nucleic acids
Carbohydrates
•
a carbohydrate is any molecule that contains
the elements C, H, and O in a 1:2:1 ratio
•
Important role in:
1. making up the structural framework of cells
2. energy storage
•
the sizes of carbohydrates varies


simple carbohydrates – made up of one or two
monomers
complex carbohydrates – made up of polymers
•
Simple carbohydrates are small molecules
made up of one or two monomers
1. monosaccharides consist of only one monomer
•
an example is the sugar glucose (C6H12O6)
2. disaccharides consist of two monosaccharides
•
•
an example is the sugar sucrose, which is formed by
joining together two monosaccharides, glucose and
fructose
the lactose is made up of two glucose molecules
• Complex carbohydrates are long
polymer chains and called
polysaccharides
• Plants and animals store energy in
polysaccharide chains formed from
glucose
• plants form starch
• animals form glycogen
• Some polysaccharides are structural and
resistant to digestion by enzymes
 plants form cellulose cell walls
 some animals form chitin for exoskeletons
Lipids
 molecules are not soluble in water
 lipids are non-polar molecules
 lipids have many different types
•
•
•
•
•
•
•
fats
oils
Steroids
cholesterol
rubber
waxes
pigments
Oleic acid: olive oil
Fats are converted from glucose for longterm energy storage

have two subunits
1. fatty acids
2. glycerol

fatty acids are chains of C and H atoms,
known as hydrocarbons
Because
there are
3 fatty acids
attached to a
glycerol,
another name
for a fat is
triglyceride
• Fatty acids have different chemical properties
due to the number of hydrogens attached
 maximum number of hydrogens are attached, fat is
saturated (bad fat for your body), they are solid at
room temperature
 there are fewer than the maximum attached, fat is
unsaturated (the less number of hydrogens the
better for your body), they are liquid at room
temperature
Saturated and
un-saturated
fats
• cell membranes contain lipids
 phospholipids make up the two layers of the membrane
 cholesterol is embedded within the membrane
Fats are divided into three groups —
 monounsaturated,
 polyunsaturated
 saturated.
Monounsaturated Fats:
• in foods that come from plants.
• liquid at room temperature
• can reduce blood cholesterol levels, but less than polyunsaturated
fats do.
• can raise HDL cholesterol (the "good" kind of cholesterol) levels.
Polyunsaturated Fats:
• mainly from plants.
• liquid at room temperature.
• can reduce blood cholesterol levels.
Saturated Fats:
• animal origin food and some vegetables
• in processed bakery goods, nondairy milk, cream
substitutes.
– Coconut Oil
– Cocoa Butter (Chocolate)
– Palm Kernel Oil, Palm Oil
• As a rule of thumb when shopping, saturated fats are
solid at room temperature.
• When you have a lot of saturated fat in your diet, your
liver responds by making more cholesterol. This raises
your blood cholesterol level. It is the most harmful type of
fat you can eat.
Hydrogenation / Trans Fats
 hydrogen is bubbled through polyunsaturated and
monounsaturated fats and oils to change from liquid to solid form
 make vegetable margarines have a butter-like texture, and
prolong the shelf life of packaged foods.
 The effects: cause blood cholesterol levels to increase.
 limit your use
 manufacturers are not required to list how much trans fats are
included in a product: Read the list of ingredients carefully
Saturated
• Beef
• Brazil Nuts,
Macadamia Nuts
• Butter
• Cheese
• Chocolate
• Coconut, Coconut
Oil
• Lard
• Milk
• Palm Oil
• Pistachios
• Poultry
Monounsaturated
• Avocado
• OIL: Canola Oil, olive
oil, sesame oil
• Cashews
• Olives
• Peanuts, Peanut
Butter, Peanut Oil
Polyunsaturated
• Almonds, pecans,
Walnuts
• Corn Oil,
Cottonseed Oil,
Soybean Oil
• Fish
• Margarine
• Mayonnaise
• Sesame Seeds,
Sesame Oil
• Sunflower Oil,
Sunflower Seeds
Proteins
• are complex macromolecules/polymers made up
by subunits called amino acids
• the assembled polymer is called a polypeptide
Amino acids
• are small molecules
• 20 different types of amino acids
•the covalent bond linking two amino acids
together is called a peptide bond
Protein structure is complex
1. order or sequence of the amino acids affects
how the protein folds together,

example the insulin molecule
2. the way that a polypeptide folds to form the
protein determines the protein’s function
– some proteins are comprised of more than one
polypeptide
•
There are four general levels to protein
structure
1. Primary
2. Secondary
3. Tertiary
4. Quaternary
• Primary structure –
 is the sequence of the amino acids in the polypeptide
chain
 This affects all other levels of protein structure
•
Secondary structure

•
forms because regions of
the polypeptide that are
non-polar are forced
together
The folded structure may
resemble
1. Coils
2. Helices
3. sheets
• Tertiary structure –
• final 3-D shape of the
protein
• The final twists and
folds that lead to this
shape are the result
of polarity differences
in regions of the
polypeptide
• Quaternary
structure –
• the spatial
arrangement of
proteins
• comprised of
more than one
polypeptide
chain
The shape of a protein affects its function:
• changes to the environment of the protein
may cause it to unfold or denature:
• increased temperature or lower pH affects
hydrogen bonding, which is involved in the folding
process
• a denatured protein is inactive
Enzymes
• are globular proteins that have a special 3D shape that fits precisely with another
chemical
• they cause the chemical that they fit with
to undergo a reaction
• this process of enhancing a chemical
reaction is called catalysis
Nucleic Acids
•
are very long polymers that store
information
•
There are two types of nucleic acids


Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Nucleid acids are comprised of monomers
called nucleotides (A, T, U, G, C)
• each nucleotide has 3 parts
1.a five-carbon sugar
2.a phosphate group
3.a nitrogen-containing base
• there are five different types of nucleotides whose
sequence encodes genetic information
RNA is similar to DNA except that
 it uses uracil instead of thymine
 it is comprised of just one strand
 it has a ribose sugar
DNA
is a double helix with
• two base pairs
– Adenosine (A) pairs with thymine (T)
– Cytosine (C) pairs with Guanine (G)
• A hydrogen bond between the base pairs
• a sugar-phosphate backbone comprised of
phosphodiester bonds gives support
The DNA
double
helix
The structure of DNA helps it to function
 the hydrogen bonds of the base pairs can be easily
broken to unzip the DNA so that information can be
copied
• each strand of DNA is a mirror image so the DNA contains
two copies of the information
 having two copies means that the information can be
accurately copied and passed to the next generation
Review questions
1. The four kinds of organic macromolecules are:
A)hydroxyls, carboxyls, aminos, and phosphates.
B)proteins, carbohydrates, lipids, and nucleic acids.
C)ATP, ADP, DNA, and RNA.
D)carbon, hydrogen, oxygen, and nitrogen.
2. Organic molecules are made up of monomers.
Which of the following is not considered a
monomer of organic molecules?
A)amino acids
B. simple sugars
B)Polypeptides
D. Nucleotides
3. Your body is filled with many types of proteins.
Each type has a distinctive sequence of amino
acids which determines both its specialized
___________ and its unique ___________.
• number, weight
B) length, mass
C) structure, function
D) charge, pH
4. Nucleic acids:
A) are the energy source for our bodies.
B) act on other molecules, breaking them apart or
building new ones, to help us function.
C) are only found in a few, specialized locations within
the body.
D) are information storage devices found in every cell in
the body.
5. The two strands of a DNA molecule are held
together through hydrogen bonds between
nucleotide bases. Which of the following best
describes this base pairing?
A)Adenine forms hydrogen bonds with thymine.
B)Adenine forms hydrogen bonds with uracil.
C)Cytosine forms hydrogen bonds with thymine.
D)Guanine forms hydrogen bonds with adenine.
6. Carbohydrates are used for:
A)structure and for energy.B) information storage.
C) fat storage and for hair. D) hormones and enzymes.
7. Which carbohydrate is not found in plants? _____
8. A characteristic common to all lipids is:
A)that they contain long chains of C-H bonds.
B)that they are insoluble in water.
C)that they have a glycerol backbone.
D)All of these are characteristics of all lipids.
9. Lipids are used for:
A)motion and defense.
B)information storage.
C)energy storage and for some hormones.
D)enzymes and for some hormones.