Upload
franklin-wade
View
220
Download
3
Embed Size (px)
Citation preview
What’s so special about water?
It is a great solvent.
It holds heat very well.
It is the most importantinorganic molecule.
It is a polar compound
Water, pH and Biological Molecules
Water as a Solvent
Dissolving table salt (sodium chloride)
This means that ice forms an insulating blanket over water.
Water Is Lighter as Solid than as a Liquid
Water Has High Surface Tension
The attraction of one water molecule for another also accounts for its ability to hold huge amounts of heat.
Water is a Polar Compound
• Hydrogen ends holds slightly positive charges
• Oxygen end holds a slightly negative charge
p+ p+1H 1H(+) (+)
(--)
pH is a Big DealpH is a measure of proton (hydrogen ion or H+) concentration.
High pH (base) = few H+ ions ; more OH- ions
Low pH (acid) = lots of H+ ions
Acids and BasesAcid = H+ Donors Base = H+ Acceptors
ORGANIC COMPOUNDS
Making MoleculesBecause carbon contains 4 electrons in its outer shell, it can share electrons with many different atoms in an “attempt” to fill its outer shell.
Organic compounds are carbon compounds, made by living things
Carbon is the Central Atom of Life.
glucose
amino acids
fat
Some Useful
Nomenclature
In Biology, Shape Matters
Its not just chemical formula, it’s the shape of the molecule that lets it do its “job”.
Never forget the axiom – structure dictates function.
Some biological molecules.
Ah, That Smell!
Once again, shape matters. It’s the good fit between odorant and receptor molecule that lets us detect aromas.
Molecules of Life
Start with water, add lots of small carbon-containing molecules and …….
Four Major Classes of Biological Molecules
How do you build a cell?
Rules of the Game
Macromolecules are built by linking a set of building blocks (monomers) together into long chains (a polymer).
Each hexagon is this figure is a monomer, building blocks linked together to form a polymer.
Monomers – basic units that repeats over and over in organic compounds
Macromolecules Are Built By Linking a Set Of Building Blocks (Monomers) Together Into Long
Chains (A Polymer).
FOUR TYPES OF ORGANIC COMPOUNDS
• CARBOHYDRATES – SUGARS AND STARCHES
• LIPIDS– FATS
• PROTEINS– HAIR, FINGERNAILS, MUSCLES
• NUCLEIC ACIDS– DNA AND RNA (GENETIC MATERIAL)
CARBOHYDRATES• ELEMENTS – C, H AND O
• RATIO H:O = 2:1
• MONOMER = MONOSACCHARIDE
• EXAMPLES – SUGARS & STARCH
• MAIN FUNCTION – QUICK ENERGY
Glucose: A Simple Carbohydrate Used For Energy Production and as a Building Block
For Complex Carbohydrates
Linking Simple Sugars – the First Step to a Polymer and the Last Step to Some Familiar Compounds
MONOSACCHARIDES DISACCHARIDES
Some Familiar and Important Complex Carbohydrates
3 OR MORE REPEATING UNITS = POLYSACCHARIDE
Carbohydrates are Central Players in
Energy Production and Storage
LIPIDS
• ELEMENTS: C, H and O• RATIO OF H:O = More H than O• MONOMER = Glycerol and 3 Fatty Acids• EXAMPLES
– Fats, Oils and Waxes
• MAIN FUNCTION– Storage– Energy reserves– Cell membranes
Glycero
l
FA
FA
FA
Lipids are Hydrophobic Molecules That Exist In Three Primary Forms
Sterol
Fat
Phospholipid
Fats Are Made By Linking Fatty Acid Chains to Glycerol, a Three
Carbon Molecule
Space-filling model of a fat
A fatty acid
Fats are Used in Energy Storage and Production
The Degree Of Saturation In A Fat
Affects Its Physical
And Nutritional Properties
Where are the double bonds?
The Degree Of Saturation In A Fat Affects Its Physical And Nutritional Properties
Where are the double bonds?
saturated
monounsaturated
polyunsaturated
Sterols Are Part of Cellular Membranes and Act as Hormones
Note the four ring structure common to all sterols.
Sterols As HormonesEstrogen,
testosterone, progesterone,
and corticosteriods
(cortisol) are all steroid
hormones.
Sterols As Hormones
“Designer steroids” are major sporting news where they have been used illegally in track
and field, baseball, football and
countless other sports.
A heavily muscled Linford Christie who was disqualified from international competition after testing positive for a banned steroid.
Phospholipids are Building Blocks of Cellular Membranes
The hydrophilic head group and hydrophobic tails are the keys to phospholipid function.
Hydrophilic Head Group And Hydrophobic Tails Are The Keys To Phospholipid Function
Phospholipids have a Jekyll and Hyde personality.
Phospholipids Form Biological Membranes
THE CELL MEMBRANE
PROTEINS
• Basic building blocks of living material• ELEMENTS: C, H, O and N• MONOMER: Amino Acids
– 20 different amino acids
• USES– Hair, Muscles, Fingernails
– Enzymes – carry out chemical reactions
– Transport in cells
• FORMS PEPTIDE BONDS BETWEEN A.A.
Protein
Proteins are THE key elements of life. Forget DNA, proteins rule.
Remember the principle - Structure determines Function.
Since proteins are the key players of the cell, it follows that protein structure determines cell
function.
Some of the Diverse Functions of Proteins
Strands of the Protein Keratin Create Hair
Proteins are Linear Chains of Linked Amino Acids
A Common Thread and a
Unique Identity
R – Residual Group *side chain changes
Amino Group – NH2
Single Hydrogen - H
Acid or Carboxyl Group –C=O, OH
(Side chain)
PEPTIDE BONDS
• 1 amino acid
• 2 amino acids linked together – dipeptide
• 3 or more amino acids linked together - polypeptide
Peptide bonds
Amino Acids, Peptide Bonds, Polypeptides, Protein
Peptide bonds
Proteins are linear chains of 20 different building blocks called amino acids.
Amino acids are linked by peptide bonds – a form of covalent bond.
Proteins are Folded
Structures Whose Shape (and therefore
function) Depends on Amino Acid
Sequence
Nucleic AcidsThere are two kinds
of nucleic acids, DNA and RNA. Both are
involved in the storage and flow of information from
gene to gene product.
DNA
NUCLEIC ACIDS• ELEMENTS: C, H,
O, N P and S• MONOMER:
Nucleotides• USES: DNA and
RNA– Genetic material– Controls the cells
activities
NUCLEOTIDES
•SUGAR GROUP•DEOXYRIBOSE•RIBOSE (RNA)
•PHOSPHATE GROUP
•NITROGENOUS BASE•ADENINE•GUANINE•CYTOSINE•THYMINE•URACIL (RNA)
Nucleotides fuel the cell and
coordinate its metabolism.
Nucleotides are Important in Their Own Right
ATP, the cell’s primary energy
currency.
REACTIONS OF BIOLOGICAL COMPOUNDS• HYDROLYSIS REACTIONS
– Water is added to break apart molecules
• C12H22O11 + H2O C6H12O6 + C6H12O6
MALTOSE WATER GLUCOSE GLUCOSE
CONDENSATION / DEHYDRATION REACTIONS• CONDENSATION REACTIONS
(DEHYDRATION SYNTHESIS REACTIONS)– Joining molecules together by
removing water (-H and –OH are removed to make a water molecule)
• C6H12O6 + C6H12O6 C12H22O11 + H2O
GLUCOSE + GLUCOSE MALTOSE + WATER
CATALYST• SPEEDS UP THE NATURAL
RATE OF REACTIONS
• CAN BE ORGANIC OR INORGANIC
ENZYMES• A PROTEIN CATALYST
THAT CONTROLS THE RATE OF A REACTION
ENZYMES
• LOWER THE ACTIVATION ENERGY NEEDED TO CARRY OUT A REACTION
• INCREASES THE RATE OF REACTIONS
• ENZYME NAMES END IN –ase
• NAME IDENTIFIES A REACTING SUBSTANCE– LIPASE – REACTS WITH LIPIDS– SUCRASE – REACTS WITH SUCROSE
• NAME CAN IDENTIFY FUNCTION– OXIDASE – CATALYZES OXIDATION– HYDROLASE – CATALYZES HYDROLYSIS
SUBSTRATES
• Substance acted upon by an enzyme
ENZYME ACTION: LOCK & KEY MODEL
• AN ENZYME BINDS A SUBSTRATE IN A REGION CALLED THE ACTIVE SITE
• ONLY CERTAIN SUBSTANCES CAN FIT IN THE ACTIVE SITE
• ENZYME-SUBSTRATE COMPLEX FORMS
• SUBSTRATE REACTS TO FORM PRODUCT
• PRODUCT IS RELEASED
LOCK & KEY METHOD
ENZYME-SUBSTRATE COMPLEX
ACTIVE SITE
ENZYME FUNCTION
FACTORS AFFECTING ENZYME ACTION
• TEMPERATURE
– LITTLE ACTIVITY AT LOW TEMPS
– RATE INCREASES WITH TEMPERATURE
– MOST ACTIVE TEMP IN HUMANS (37ºC)
– ACTIVITY LOST WITH DENATURATION AT HIGH TEMPERATURE
TEMPERATURE AFFECTING ENZYME ACTION
RATE OF REACTION
TEMPERATURELOW HIGH
OPTIMUM TEMPERATURE
SUBSTRATE CONCENTRATION
AFFECTING ENZYME ACTION
RATE OF REACTION
SUBSTRATE CONCENTRATIONLOW HIGH
MAXIMUM ACTIVITY
pH AFFECTING ENZYME ACTION
RATE OF REACTION
pHLOW HIGH
OPTIMUM Ph
* Most enzymes lose activity in low or high pH