Download Amino acids - Workforce3One

The Chemical Building Blocks of
Life
Chapter 3
How Carbon forms the framework
of Biological Molecules?
• Biological molecules consist
primarily of Carbon
-carbon bonded to carbon,
or
-carbon bonded to other
molecules.
• Carbon can form up to 4
covalent bonds.
• Carbon may be bonded to
functional groups with
specific properties
2
Biological Molecules
• Large molecules constructed from smaller
subunits.
• Monomer: single subunit
(mono = 1; -mer = unit)
• Polymer: many units
(poly = many)
• Carbohydrates (sugars), nucleic acids
(nucleotides), proteins (amino acids) and fats
(fatty acids)
3
Making and Breaking Macromolecules
Dehydration synthesis: formation of large molecules by the
removal of water
-monomers are joined to form polymers
Hydrolysis: breakdown of large molecules by the addition of
water
-polymers are broken down to monomers
4
What are Isomers?
Isomers are molecules
with the same structural
formula and exist in
different forms.
-Structural isomers
-Stereoisomers
Chiral molecules are
mirror-images of each
other.
5
What are Carbohydrates?
Molecules with a 1:2:1 ratio of carbon,
hydrogen, oxygen
- empirical formula: (CH2O)n
- examples: sugars, starch, glucose
C – H covalent bonds hold much energy
Carbohydrates are good energy storage
molecules.
6
Carbohydrates-Monosaccharide
Glucose
-a monosaccharide –
simple/single sugar
-contains 6 carbons
-very important in
energy storage
-fructose is a structural
isomer of glucose
-galactose is a
stereoisomer of glucose
7
Carbohydrates-Disaccharide
-2 monosaccharides linked together by
dehydration synthesis
-used for sugar transport or energy storage
-examples: sucrose, lactose, maltose
8
Carbohydrates-Polysaccharide
Polysaccharides
-long chains of sugars linked by dehydration
synthesis
-plants use starch; animals use glycogen (for
energy purposes)
-plants use cellulose; animals use chitin (for
structural purposes)
9
What are Nucleic Acids?
Nucleic acids are polymers of
nucleotides.
-nucleotides:
sugar + phosphate +
nitrogenous base
-sugar is deoxyribose in DNA
or ribose in RNA
-Nitrogenous bases include
-purines: adenine and
guanine
-pyrimidines: thymine,
cytosine, uracil
10
Nucleic Acids
11
Nucleic Acids
12
Ribonucleic Acids
RNA
-contains ribose instead of deoxyribose
-contains uracil instead of thymine
-single polynucleotide strand
-functions:
-read the genetic information in DNA
-direct the synthesis of proteins
13
Other Nucleic Acids
Other nucleotides
-ATP: adenosine triphosphate
-primary energy currency of the cell
-NAD+ and FAD: electron carriers for many
cellular reactions
14
Proteins
Proteins are polymers of amino
acids.
Amino acids
-20 different amino acids
-joined by dehydration
synthesis
-peptide bonds form
between adjacent amino
acids
15
Proteins
Amino acid structure
-central carbon atom surrounded by
-amino group
-carboxyl group
-single hydrogen
-variable R group
16
Proteins
The structure of the R group dictates the chemical
properties of the amino acid.
Amino acids can be classified as:
1. nonpolar- CH2 or CH3 in their R group
2. polar- O or OH in R group
3. charged-Capable of undergoing ionization
4. aromatic-ring structures with double/single bonds
5. special function- chemical properties to form links
17
Functions of Proteins
Protein functions include:
1. Enzyme are biological catalysts that lead chemical reactions
2. Defense are proteins are present in immune and endocrine
systems
3. Transport molecules and ions. Example: Haemoglobin
4. Support - structural proteins like keratin in hair, fibrin in
blood cloths
5. Motion proteins are actin and mysosin which help the
muscles to contract
6. Regulation – Hormones serve as intercellular messengers
7. Storage- Calcium and iron bind to storage proteins as ions
18
Structure of Proteins
The shape of a protein determines its function.
-Primary structure – sequence of amino acids
-Secondary structure – interaction of groups in the
peptide backbone
-a helix
-b sheet
19
Proteins
20
Structure of Proteins
Protein structure (continued)
-Tertiary structure – folded shape of the
polypeptide chain
-Quaternary structure – interactions between
multiple polypeptide subunits
Protein folding is aided by chaperone proteins.
21
Additional structural units
Motifs are common
elements of secondary
structure seen in many
polypeptides.
Domains are functional
regions of a
polypeptide.
22
Denaturation of Proteins
• Denaturation is a change in
the shape of a protein.
- caused by changes in the
protein’s environment
-pH
-temperature
-salt concentration
- causing loss of function.
- may involve complete
unfolding
- Renaturation is refolding
into natural shape
23
What are lipids?
Lipids are a group of molecules that are
insoluble in water.
A high proportion of nonpolar C – H bonds
causes the molecule to be hydrophobic.
Two main categories:
-fats (triglycerides)
-phospholipids
24
Types of lipids
Triglycerides (fats)
-composed of 1 glycerol + 3 fatty acids
Fatty acids are long hydrocarbon chains which
may be
-saturated
-unsaturated
-polyunsaturated
25
Saturated and Unsaturated fats
Saturated fatty acids
without double bond
Unsaturated fatty acid with
one or more double bond 26
Triglycerides
Triglycerides
-an excellent molecule for energy storage
-store twice as much energy as
carbohydrates
-animal fats are usually saturated fats and
are solid at room temperature
-plant fats (oils) are usually unsaturated and
are liquid at room temperature
27
Phospholipids
Phospholipids composed of:
-1 glycerol
-2 fatty acids
-a phosphate group
Phospholipids contain
polar “heads” and
nonpolar “tails”.
28
Phospholipids
Phospholipids spontaneously form micelles or lipid bilayers.
These structures cluster the hydrophobic regions of the
phospholipid toward the inside and leave the hydrophilic regions
exposed to the water environment
29
Carbohydrates
30
Carbohydrates
31
Deoxyribonucleic Acid
DNA
-nucleotides connected
by phosphodiester
bonds
- double helix: 2
polynucleotide strands
connected by hydrogen
bonds
-polynucleotide strands
are complementary
-genetic information is
carried in the sequence of
nucleotides
32
Proteins
33
This project is funded by a grant awarded under the President’s Community Based Job Training Grant as implemented
by the U.S. Department of Labor’s Employment and Training Administration (CB-15-162-06-60). NCC is an equal
opportunity employer and does not discriminate on the following basis: against any individual in the United States, on
the basis of race, color, religion, sex, national origin, age disability, political affiliation or belief; and against any
beneficiary of programs financially assisted under Title I of the Workforce Investment Act of 1998 (WIA), on the basis of
the beneficiary’s citizenship/status as a lawfully admitted immigrant authorized to work in the United States, or his or
her participation in any WIA Title I-financially assisted program or activity.
“This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants
as implemented by the U.S. Department of Labor’s Employment and Training Administration. The solution was created
by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of
Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such
information, including any information on linked sites and including, but not limited to, accuracy of the information or its
completeness, timeliness, usefulness, adequacy, continued availability, or ownership. This solution is copyrighted by
the institution that created it. Internal use by an organization and/or personal use by an individual for non-commercial
purposes is permissible. All other uses require the prior authorization of the copyright owner.”
34