biochemistry chapter 3. water section 2.3 structure of water most abundant molecule held together...
TRANSCRIPT
Water
Section 2.3
Structure of Water
Most abundant molecule Held together by covalent bonds 2 atoms of H, 1 atom of O
Water is a Polar Molecule
Definition: a molecule with an uneven distribution of charge but a net charge of zero
Water bonds at an angle
Water’s ability to dissolve
“Like Dissolves Like”
Polar substances can dissolve polar substances, nonpolar substances can dissolve nonpolar substances
“Universal solvent”
Questions:
Why don’t oil and water mix?
Why can water dissolve sugar or salt?
How does water dissolve a polar substance?
Answer:
The + end of water attracts to the – ion of the substance
The – end of water attracts to the + ion of the substance
This breaks the ionic bond of the substance thus dissolving it
Water’s special bond:
Hydrogen Bond: a weak chemical bond that exists between the H atoms and a – charged part of a different molecule
Water’s special properties:
Due to H-bonds:1. Water can cling to itself and other
substances
2. Water is able to absorb large amounts of energy without changing temperatures quickly
(high boiling point)
Cohesion: When like molecules are attracted
to each other Ex) surface tension in water
Adhesion:
Definition: the attractive forces between unlike substances
Capillarity:
Definition: cohesion and adhesion working together to move water molecules up a narrow tube against the force of gravity
Homeostasis?
1. The H-bonds in water are the first bonds to break when an increase in energy (temp) is applied
2. It takes a LARGE amount of energy to break/move water molecules
3. Thus, the temperature of water stays fairly constant in a cell even though there might be a drastic temperature change outside
Carbon Compounds
SECTION 3.1
Organic Compounds
Organic compounds contain carbon atoms
Form covalent bonds with other C atoms or to other elements - N, H, and O.
Carbon Bonding
C readily covalently bonds (a bond forms when electrons are shared)
Each C forms 4 covalent bonds
Large Carbon Molecules
Polymers are made up of many small, repeating molecules called monomers.
Macromolecules- large polymers
Condensation Reaction A chemical reaction that links
monomers to form polymers One water molecule is produced A.k.a. dehydration synthesis
Ex) Glucose and Fructose combine to make Sucrose, table sugar
Condensation Reaction:
The formation of larger molecules by removing a H+ from one monomer and a OH- from the other monomer.
The H+ and the OH- combine to form the bi-product H2O.
Hydrolysis
A chemical reaction that breaks down polymers
Reversal of condensation reaction
Usually done by adding water
ATP – Adenosine Triphosphate
All of life’s functions require energy Energy compounds found in cells
Biochemistry
The stuff life is made of!
Section 3.3
The Four Molecules of Life
1. Carbohydrates 2. Proteins 3. Lipids 4. Nucleic Acids
All of your body is made up of these four types of molecules!
The Building Blocks
Each type of molecules is made up of smaller parts called monomers.
When 3 or more monomers are linked together, they form a polymer.
How to make a macromolecule.
How do you make a polymer from many monomers?
CONDENSATION REACTION!
What will break up a large molecule?
The opposite reaction of condensation……
HYDROLYSIS REACTION!
The use of water to break apart polymers back into monomers.
Monomers of the 4 Life Molecules
1. Carbohydrates - Monosaccharide 2. Proteins – Amino Acids 3. Lipids – Fatty Acids 4. Nucleic Acids - Nucleotides
How do you make macromolecules of each monomer?
CONDENSATION REACTION
1. Carbohydrates Used for “fuel” and structural material Monosaccharide = monomer, simple
sugar, ex) fructose, galactose, & glucose C6H12O6
Disaccharide = 2 monomers, double sugarex) sucrose (table sugar)
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Examples)
Polysaccharide = too many to countex) starch & cellulose (in plants)
glycogen (in animals)
2. Protein Amino Acid = monomer, 20
different types
Peptide bond holds amino acids together
Polypeptide = chains of amino acids Protein = the final functional form, 1
or more polypeptides
Most DIVERSE group of molecules:• structures such as antibodies, hormones, muscles,
skin, hair, and biological catalysts (enzymes) are made of proteins.
Enzymes Protein molecules that catalyze
(increase the rate of) biochemical reactions
How Do Enzymes Work? Animation: How Enzymes Work
3. Lipids
Fatty Acids = monomer
• Hydrophilic carboxyl head - polar
• Hydrophobic fatty acid tail – nonpolar, not soluble in water
Ex) saturated (solid) and unsaturated (liquid)
Complex Lipids Triglycerides (fats)
Ex) butter Phospholipids
Ex) cell membrane Waxes
Ex) earwax Steroids
Ex) testosterone, cholesterol
4. Nucleic Acids
Nucleotide = monomer
Found in the genetic material DNA & RNA
carries out all of the functions of the cell