Transcript Biochemistry notes (updated 10/13)

Are you what you eat?
1. The important Characteristics of
Carbon
 Forms 4 covalent bonds
 Forms double and triple bonds
 Forms long chains and rings
 Can bind with many other elements
 Even electron distribution (nonpolar molecules)
2. Macromolecules, Monomers
and Polymers
(Hint: think of the meaning of the prefixes)
What do these words mean?
Polygons
Polyester
Polygamy
2. Macromolecules, Monomers
and Polymers
 Polymer – Smaller organic molecules join into long
chains.
 Monomer – the individual unit that builds up
polymers
 Macromolecules – Very large molecules
3. Dehydration synthesis and
Hydrolysis
 These two terms refer to the processes that forms
monomers and polymers:
 Dehydration synthesis – A reaction that removes
molecules of water to form polymers from monomers
 Hydrolysis – The reaction that adds water to polymers
to separate them to their individual monomers.
 (http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html or
http://www.youtube.com/watch?v=UyDnnD3fMaU )
 Isomers
 Molecules that have the same formula, but different
structures.
 Examples: Glucose and Fructose
4. What are the big four?
Three out of the 4 types of
biochemical macromolecules
can be found on food
nutrition labels…
Look at the label to the left. 3
of the 4 macromolecules can
be found in foods.
1____________________
(0 grams in this product)
(13 grams in this product)
2____________________
(9 grams in this product)
3____________________
4. What are the big four?
 Fats (we call them lipids)
 Carbohydrates
 Proteins
 Nucleic acids (DNA and RNA)
When studying these
biochemical molecules, we are
interested in finding out…..
 what they do for living things.
 what they generally look like.
 what their monomers are.
 and how they may help the body gain energy to
sustain life.
SO, LETS GET STARTED!
Great website for reference…
 http://biomodel.uah.es/en/model3/index.htm
5. Carbohydrates
 Molecules that form from atoms in C1:H2:O1 ratio
 Monomers: Monosaccharides (simple sugars)
 Monosaccharides are usually sweet, white powdery
substances (such as fructose, glucose) that form rings
of carbon atoms.
 Monosaccharides in general serve as direct, quick
sources of energy for living organisms during cellular
respiration, they are building blocks of many polymers
 Important monosaccharides:
 Glucose
 Fructose
 Disaccharides – two monosaccharide molecules
combine by dehydration synthesis to form
disaccharides
 Important disaccharides:
 Lactose – found in milk sugar
 Sucrose – table sugar
 Polysaccharides – many (tens to hundreds) units of
monosaccharides combine by dehydration synthesis
 Polysaccharides also separate to monosaccharides by
hydrolysis while taking in water.
Important polysaccharides:
 Starch – made up of many glucose units, it is an important
storage polysaccharide that is found in plant roots and
other tissues. It stores monosaccharides that can be
broken down later to release useful energy during cellular
respiration – ONLY IN PLANTS
 Glycogen – also made up of many glucose units, it is an
important storage polysaccharide in the liver and animal
muscles. It can also be broken down to monomers to
release energy during cellular respiration. ONLY IN
ANIMALS
 Cellulose – also made up of many glucose units. However,
in this case the molecule is not easily broken down to its
monomers. It is important for providing a rigid structure
in plant cell walls.
 Chitin – made up of some nitrogen containing
monosaccharides. It is an important polysaccharide
that provide the solid structure of arthropods and
fungi.
6. Lipids
 a diverse group of molecules that are nonpolar and
generally do not dissolve in water
 They mostly contain carbon, hydrogen, very few
oxygen atoms, but some also have phosphorous.
 There are three distinct groups of lipids:
 Simple lipids
 Phospholipids
 Sterols
6A. Simple Lipids
 Very large molecules that form from 2 different kinds
of monomers by dehydration synthesis:
 3 Fatty acids – are long chains of carbon with oxygen at
the end (can be saturated and unsaturated)
 1 Glycerol – smaller 3-carbon compound.
 Simple lipids are important as storage materials in all
living things. They can store twice as many calories as
polysaccharides can. Oils (mostly from plants)
contain more unsaturated fatty acids, while fats
(animals) contain more saturated fatty acids.
 Simple lipids also dissolve vitamins

http://biomodel.uah.es/en/model3/index.htm
6B. Phospholipids
 Phospholipids – phosphate containing lipids.
 Their monomers: 1 glycerol + 2 fatty acids (saturated
or unsaturated) + phosphate. These monomers
combine by dehydration synthesis
 Phospholipids have both polar and nonpolar sections.
As a result, they are able to dissolve in both type of
solvents as well.
 They are important for living things because they form
the borders of all cells (cell membranes) and also
participate in forming many cell organelles.
6C. STEROLS
 Sterols are a highly nonpolar (hydrophobic) group of
molecules.
 They occur naturally in plants, animals, and fungi, with
the most familiar type of animal sterol being
cholesterol.
 Cholesterol is vital to cellular function, and a precursor
to fat-soluble vitamins and steroid hormones.
 3-six sided rings and one 5-sided ring + alcohol
7. Proteins
 Protein- Polymer constructed from amino acid
monomers.
 Only 20 amino acids, but make 1,000s of proteins
 Some are 100 a.a. in length; some are thousands
3-D Protein
7A. Protein Functions
 Each of our 1,000s of proteins has a unique 3-D shape
that corresponds to a specific function:
 Defensive proteins

Antibodies in your immune system
 Signal proteins

Hormones and other messengers
 Hemoglobin

Delivers 02 to working muscles
 Transport proteins

Move sugar molecules into cells for energy (insulin)
 Storage proteins

Ovalbumin (found in egg white) used as a source of amino acid for developing
embryos
 Most important roles is as enzymes


Chemical catalysts that speed and regulate virtually all chemical reactions in
cells
Example, lactase
7B. Amino Acid structure
 Proteins diversity is based on differing arrangements of 20
amino acids.
 Amino acids all have an amino group and a carboxyl group.
 R group is the variable part of the amino acid; determine the
specific properties of the 20 amino acids.
 Two main types:
 Hydrophobic
 Example: Leucine
 R group is nonpolar and hydrophobic
 Hydrophilic
 Polar and charged a.a.’s help proteins dissolve in aqueous solutions
inside cells.
 Example: Serine
 R group is a hydroxl group
7C. Amino Acid Dehydration
 Cells join amino acids together in a dehydration
reaction:
 Links the carboxyl group of one amino acid to the amino
group of the next amino acid as a water molecule is
removed.
 Form a covalent linkage called a peptide bond making a
polypeptide.
7D. Protein Structure
 Primary Structure
 Unique sequence of amino acids
 For any protein to perform its specific function, it must
have the correct collection of amino acids arranged in a
precise order.

Example: a single amino acid change in hemoglobin causes
sickle-cell disease
 Determined by inherited genetic information.
7D. Protein Structure
 Secondary Structure
 Parts of the polypeptide coil or fold into local patterns.

Patterns are maintained by regularly spaced hydrogen bonds
between the hydrogens of the amino group and the oxygen of
the carboxyl groups.
 Coiling results in an alpha helix.


Many fibrous proteins have the alpha structure over most of
their length
Example: structural protein of hair
 Folding leads to a pleated sheet.


Make up the core of many globular proteins
Dominate some fibrous proteins, including the silk proteins of
a spider’s web
7D. Protein Structure
7D. Protein Structure
 Tertiary Structure
 Overall, three-dimensional shape of a polypeptide.
 Roughly describe as either globular or fibrous
 Generally results from interactions among the R groups
of amino acids making up the polypeptide.
7D. Protein Structure
 Quaternary Structure
 Results from association of subunits between two or more
polypeptide chains.
 Does not form in every protein.
 Example, Hemoglobin
8. Nucleic Acids
 DNA and RNA
 Deoxyribonucleic Acid (DNA)
 Monomers made up of nucleotides:

Nucleotides consist of:
 A five carbon sugar, deoxyribose
 Phosphate group
 Nitrogenous base (Adenine, Guanine, Cytosine, Thymine)
 Double helix consists of:


Sugar-phosphate backbone held by covalent bonds
Nitrogen bases are hydrogen bonded together; A pairs with T
and C pairs with G
8A. Nucleotides of DNA
8B. DNA
 Genetic material that organisms inherit from their
parents.
 Genes

Specific stretches of DNA that program amino acid sequences
of proteins.
8C. RNA
 Ribonucleic Acid (RNA)
 Intermediary for making proteins
 Single-stranded
 Also made up of monomers of nucleotides

Nucleotide of RNA:
 Sugar is ribose (not deoxyribose)
 Phosphate group
 Nitrogen bases (Adenine, Uracil (instead of Thymine,
Guanine, and Cytosine)
Enzymes