SBI4U RHSA
Water: A Special Molecule (V2c)
The solvent in cell, tissues and organs is water. Four special properties of water are:
1. Hydrogen bonding
Effects: cohesion, adhesion, surface tension. More energy is needed to break hydrogen bonds than other
intermolecular bonds, which gives water a high specific heat capacity.
2. Density
Effects: Ice is the only solid that floats in its liquid! This insulates water under ice.
3. Polar nature of the bond
Effects: as a solvent, water allows polar molecules and ionic compounds to dissolve due to water’s polarity.
4. Dissociation of intramolecular bonds
Effects: 1 in 107 water molecules dissociates to form H+ and OH- ions. This is a pH of 7 = NEUTRAL.
Functional Groups
Functional groups are parts of larger molecules.
They greatly influence biological reactivity because they have negative or positive regions that react to form
bonds.
SBI4U RHSA
Biochemical Reactions that Make and Break Molecules
Macromolecules are large organic molecules. Macromolecules are also called polymers. The four main types of
macromolecules are
1. Carbohydrates – sugars and starches
2. Lipids – fats and hormones
3. Proteins – enzymes and structures
4. Nucleic acids – DNA and RNA
Monomers and Polymers
• “mono” means “one”
• “mer” means “unit”
• So a single unit of a large molecule is a monomer
• “poly” means “many”,
• So a polymer is a large molecule made of many monomers
• For example:
sugar + sugar  starch
amino acid + amino acid  protein
Five Major Biochemical Reactions
Making and breaking bonds is important to forming polymers from monomers.
1. Condensation or dehydration synthesis
2. Hydrolysis or decomposition with water
3. Neutralization of acids and bases
4. Redox or electron trading
5. Phosphorylation or adding a phosphate group
1. Condensation Reactions
• A condensation reaction joins monomers to form polymers.
• When a bond is formed between two monomers a water molecule is also produced.
• This reaction is also called dehydration synthesis.
Example:
glucose + fructose  sucrose + H20
2. Hydrolysis Reactions
• A hydrolysis reaction breaks a polymer into monomers.
• Water is added to a molecule which causes a bond to break.
• The H+ is added to one monomer and the OH- to the other monomer.
Example:
sucrose + H20  glucose + fructose
3. Neutralization Reactions
• Acids have a -COOH or H+ group.
• Bases have a –OH or –NH2 group.
• A neutralization reaction occurs when acids and bases react to produce a salt and water.
• Buffers are molecules that react to minimize pH changes in a cell.
• Buffers absorb excess H+ (acids) or OH- (bases)
4. Redox Reactions
• Redox stands for reduction – oxidation reactions
SBI4U RHSA
• “LEO goes GER”
• Loss of Electrons is Oxidation
• Gain of Electrons is Reduction
Common in metabolic reactions like photosynthesis and cellular respiration.
The electrons are carrying energy.
5. Phosphorylation Reactions
5a. Substrate-Level Phosphorylation
ATP, adenosine triphosphate, is the energy molecule of all cells. The bond formed by adding a 3rd phosphate
group to adenosine diphosphate (ADP) is an important energy storage location.
Substrate-level phosphorylation uses the energy released from breaking a phosphate group off another
molecule to attach the phosphate to ADP to form ATP.
5b. Oxidative Phosphorylation
Oxidative phosphorylation is a metabolic reaction that uses energy released by the oxidation of glucose to
produce ATP in cellular respiration.
5c. Photophosphorylation
Photophosphorylation is the production of ATP using the energy of sunlight during photosynthesis.
SBI4U RHSA
Water: A Special Molecule
The solvent in cell, tissues and organs is water. Four special properties of water are:
1. Hydrogen bonding
Effects: cohesion, adhesion, surface tension. More ______________________________________________
than other intermolecular bonds, which gives water a ______________________________.
2. Density
Effects: Ice is the only solid that floats in its liquid! This ________________________________________.
3. Polar nature of the bond
Effects: as a solvent, water allows polar ______________________________________ due to water’s polarity.
4. Dissociation of intramolecular bonds
Effects: 1 in 107 water molecules _______________________________________. This is a pH of 7 = NEUTRAL.
Functional Groups
Functional groups are parts of larger molecules. They greatly influence biological reactivity because they have
___________________________________________________________.
SBI4U RHSA
Biochemical Reactions that Make and Break Molecules
Macromolecules are _________________________________ molecules. Macromolecules are also called
______________. The four main types of macromolecules are :
1. Carbohydrates – ____________________________
2. Lipids – ______________________________
3. Proteins – ______________________________
4. Nucleic acids – ______________________________
Monomers and Polymers
• “mono” means ____________
• “mer” means ____________
• So a single unit of a large molecule is a ____________
• “poly” means ____________
• So a polymer is a large molecule _____________________________________
• For example:
________________ + ______________  starch
amino acid + amino acid  ___________________
Five Major Biochemical Reactions
Making and breaking bonds is important to forming polymers from monomers.
1. Condensation or ____________________________
2. Hydrolysis or ____________________________
3. Neutralization ____________________________
4. Redox or ____________________________
5. Phosphorylation or ____________________________
1. Condensation Reactions
• A condensation reaction ____________________________
• When a bond is formed between two monomers a
__________________ molecule is also produced.
• This reaction is also called ____________________________
Example:
glucose + fructose  _______________ + ___________
SBI4U RHSA
2. Hydrolysis Reactions
• A hydrolysis reaction ____________________________
• Water is ___________________ to a molecule which
causes a ________________________.
• The H+ is added to one monomer and the OH- to the
other monomer.
Example:
sucrose + H20  ______________ + ________________
3. Neutralization Reactions
• Acids have a -COOH or ________ group.
• Bases have a _________ or –NH2 group.
• A neutralization reaction occurs when
___________________ react to produce ________________.
• Buffers are molecules that react to _______________________________________________.
• Buffers absorb excess H+ (acids) or OH- (bases)
4. Redox Reactions
• Redox stands for___________________________
__________________________reactions
• “LEO goes GER”
• _________ of Electrons is Oxidation
• _________ of Electrons is Reduction
Common in metabolic reactions like photosynthesis and
cellular respiration. The electrons are __________
5. Phosphorylation Reactions
5a. Substrate-Level Phosphorylation
ATP, adenosine triphosphate, is the _________
___________________________. The bond formed by
adding a 3rd phosphate group to adenosine diphosphate
(ADP) is an important ______________________
__________________. Substrate-level phosphorylation
uses the _______________________________ from
________________ a phosphate group off another molecule to ______________________________________.
5b. Oxidative Phosphorylation
Oxidative phosphorylation is a metabolic reaction that uses energy released by the oxidation of glucose to
_______________________________________________________________________.
5c. Photophosphorylation
Photophosphorylation is the production of ATP using the _________________________________________.