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Biochemistry
Bio 300
What does Organic Mean?
Atomic Number
# of protons
(and also # of
electrons)
Chemical
symbol
6
C
Name of
Element
Carbon
12.011
What’s so special
about Carbon??
Atomic Mass
The weight
Of carbon
atom or
average
weight of
all isotopes
Biochemistry Topics
• 4 major macromolecules of life
– Structure
– Function
• Why are they important?
• Energy and Reactions
– Hydrolysis vs. condensation/dehydration synthesis
Why Carbon?
• Carbon can form 4 covalent bonds
– Leads to many different molecules
– forming large chains or rings
• Linking of carbons can form very large
molecules called Macromolecules
• Each individual unit is called a monomer.
When they are linked together they are called
a polymer.
• 4 macromolecules necessary for life:
carbohydrates, lipids, protein, nucleic acids
“Elements of Life”
Organic = carbon-based molecules
Examples: C6H12O6, CH4
Inorganic = molecules without carbon–carbon
or carbon–hydrogen bonds
Examples: NaCl, NH4, H2SO4 , CO, CO2
Polymerization
Synthesis of organic molecules
Small subunits called MONOMERS are joined to
form POLYMERS
Polymers are MACROMOLECULES
Monomers
Polymer
MONOMERS
POLYMERS
Simple or Single Sugars
Carbohydrates or
Complex Sugars
Amino Acids
Proteins
Fatty Acids and Glycerol
Fats or Lipids
Nitrogenous Bases
Phosphoric Acid
5-Carbon Sugar
Nucleic Acids:
RNA or DNA
Carbohydrates
• Fxn: Primary source of Energy
• Structure: Made of C, H, and O
– Ratio of C:H:O is 1:2:1
– General formula: Cn(H2O)n-1 ie. C12H22O11
• n = the # of C’s in the molecule : usually 3 - 7
– Rings are usually formed as opposed to the linear structure
• Small carbs. are water soluble because of -OH groups
GLUCOSE: key to life
Energy is stored in the bonds between atoms.
This is what our bodies break down when we eat
to obtain energy!
Types of Carbohydrates
• Monomer = Monosaccharide
– Simple sugars: glucose, galactose, fructose
– 6-C sugar molecule = “hexose”
• Disaccharides = 2 sugars linked together
– Sucrose = glucose + fructose
– Lactose = glucose + galactose
– Maltose = glucose + glucose
• Polymer = Polysaccharide = many monosacc.s joined
– Longterm energy storage
– Plants = starch, cellulose
– Animals = glycogen
ISOMERS
Same molecular formula different structural formula
Glucose
Fructose
Galactose
What is the molecular formula for each? What are the structural differences?
Why does this matter?
Polysaccharides in Plants vs. Animals
POLYSACCHARIDES
Structural Materials & Energy Storage
1. Plant Cell walls: Cellulose (not digestable)
2. Plant tissue: Starch (yummy!)
3. Arthropod Exoskeleton: Chitin
4. Cell Walls of Fungi: Chitin
5. Cell Walls of Bacteria: Peptidoglycan
6. Animals: Glycogen (liver & muscles)
Insulin
Glycogen
Glucose
Glucagon
Recap…
• What is the main function of a carbohydrate?
• What is the general name of the monomer for
a carbohydrate?
• What is the most important, specific
monomer of carbohydrates?
• What is an isomer? Give an example.
• Challenge Q: Why do isomers matter?
LIPIDS  Fats, Oils, Waxes
• Fxn: Long-term energy storage
& Cell membrane structure
• Structure: Made of C, H, O
– No definite ratios
• Nonpolar – not soluble in water; hydrophobic
• Examples: triglycerides - saturated &
unsaturated fats, phospholipids, sterols
(steroids &cholesterol, hormones and vitamins
Lipid Properties
• MONOMER: 1 glycerol and 1-3 fatty acids
• POLYMER: Lipid
• Properties of lipid depends on fatty acids
– (saturated vs. unsaturated)
Triglyceride
Fatty acid
Saturated
Fatty acid
Saturated
Fatty acid
Unsaturated
Glycerol
Saturated vs. Unsaturated
•
•
•
•
All single bonds connect C
Solid at room temp
Ex: butter, lard
“Straight, stackable”
•
•
•
•
Contain double bonds
Liquid at room temp
Ex: olive oil, corn oil
Typically plant-based
What are trans-fats?
• “Trans” double bonds are not naturally found in
biological systems
• When unsat. fats are “hydrogenated” to become
sat. fat (easier to store, ship,use), the H’s can
rearrange and ‘straighten out’ the molecule
• Trans fat is bad (?) b/c it is not recognized by our
body’s enzymes (?)
• Component of cell
membrane
• Two fatty acids + glycerol +
phosphate group
• Amphipathic
– Polar head: hydrophilic
• Phosphate group attached to
glycerol
– Non-Polar Tail: Hydrophobic
• Two fatty acid chains attached to
glycerol
• Required to build and maintain
cell membranes
•
•
•
•
Regulates membrane fluidity
May act as an antioxidant
Aids in the manufacture of bile
Important for the metabolism of
fat-soluble vitamins (A, D, E, & K)
• Synthesis in hormones: cortisol,
aldosterone & sex hormones
Recap
• What are 2 functions of lipids?
• What atoms are in a lipid?
• What is the difference between saturated and
unsaturated fat?
– Which one is being banned by cities &
manufacturers for the health of the nation?
• What does amphipathic mean? What lipid fits
this description?
Proteins
• Fxn: control reactions (enzymes), regulate cell
processes, structure (tissues, bones, muscles),
transport & help fight disease
• Structure: contain N, C, H, O
– Have an amino group (-NH2)
– Have a carboxyl group (-COOH)
– Have an “R” group (“other”)
• there are 20 different R groups
• Three major groups: Polar, Ionic, and Nonpolar
20 Possible R groups (red)
Proteins
• MONOMER: amino acid
• POLYMER: Polypeptide or Protein
– 2 amino acids are joined by a peptide bond
– 4 levels of protein structure
Protein Structure
• Primary structure
– Amino acids bond forming polypeptide chain
• Secondary structure
– folds or twists & held by H bonds
• Tertiary Structure
– More complex folding: globular (“blobby”)
– Usually b/c of hydrophobicity
• Quaternary Structure
– Multiple structures folded together
• This is important because the funky shapes create
enzyme ‘pockets’ that are specific to a job
Causes of Denaturation
Change in protein conformation/shape
1. Temperature:
– Increase will cause bonds to twist too much (lose
shape); decrease slows everything down
2. pH
– Not enough “hydrogens” in surrounding messes
up the ionic attractions and repulsions that make
structure
3. Salt Concentration
- Same as pH – too many ions (+ or - ) will change the
folded shape
Recap…
• What is the monomer of a protein?
• What element is in a protein that is not in a
sugar or a fat?
• Describe the 4 levels of folding.
• Name 3 things that can change protein shape.
– What is the name for that?
Nucleic Acids
• Fxn: Store or transmit genetic information
• Structure: contains N, C, H, O, P
– Monomer made of three parts:
• 5-carbon sugar (ribose or deoxyribose)
• Phosphate
• Nitrogen base (adenine, thymine, uracil, cytosine,
guanine)
• MONOMER: Nucleotide
• POLYMER: DNA (deoxyribonucleic acid)
or RNA (ribonucleic acid)
Nucleotides:
Connect with Hydrogen Bonds
Recap…
• What are the two types of nucleic acids?
• What are the atoms in a nucleotide?
• We’ll study nucleic acids more in the future,
when we study genetics.
So why do these macromolecules
matter to life?
Studying Reactions
Chemical Reactions
 Process that changes one set of chemicals
into another set of chemicals
• Reactant + Reactant = Product + Product
• Always involve changes in the chemical bonds
that join atoms in compounds
REARRANGING!
What are two very famous biological equations?
Types of Reactions
• Hydrolysis
– Break apart monomers
– by the addition of water.
– An H is added to one monomer & an OH is added to the
other monomer.
• Dehydration Synthesis ( or Condensation)
–
–
–
–
Join monomers
One monomer loses a H+ and the other loses an OHWater is removed
Covalent bond is formed
Dehydration Synthesis
Energy in reactions
• Bonds are the storage place of energy in
molecules / compounds
– Break a bond  RELEASE energy
– Make a bond  REQUIRES energy
• Technical note: This is truest for biological complex molecules
Energy in Reactions
• EXERGONIC (E exiting)
• Chemical reactions that release energy
• Often spontaneous (occur on their own)
– But often need a “push” to get started
• ENDERGONIC (E needing)
• Chemical reactions that absorb energy
• Need energy input to occur
• ACTIVATION ENERGY  the energy needed to get a
reaction started. Enzymes (proteins) do this.
 The “push”
CATABOLISM
DIGESTION
EXOTHERMIC
RELEASE E
BREAK BONDS
CELL RESPIRATION
Big
Molecules
METABOLISM
ANABOLISM
DEHYDRATION
SYNTHESIS
ENDOTHERMIC
STORE E
MAKE BONDS
REDUCTION
Small
Molecules
Condensation Reaction
Recap…
• Do Hydrolysis reactions make polymers or
monomers?
• What is a condensation reaction?
• What’s the difference between endergonic
and exergonic?
Are these Organic? Why/why not?
Match the Elements (Left)
with Molecules (Right)
•
•
•
•
•
•
Nitrogen
Carbon
Hydrogen
Oxygen
Phosphorus
Sulfur
a. Glucose
b. Proteins
c. Starch
d. Fats
e. Nucleic acids
f. All of the above