Download Biology Chapter 2 Organic Molecules 9-26

Organic Molecules
Carbon is very important to organic molecules. Look at the molecules below. In how many places can
carbon bond?
What about Hydrogen?
Oxygen?
Some molecules are very willing to interact with water. Based
on what you know about a water molecule, what characteristic
do these water-loving molecules have in common?
What is another name for water-loving?
(Hint: the prefix for water + the ending -philic)
Some molecules aren’t very willing to interact with water. Based
on what you know about a water molecule, what characteristic do
these water-fearing molecules have in common?
What is another name for water-fearing?
(Hint: the prefix for water + an ending that means
persistent fear)
Organic Molecules
Carbon can form 4 covalent bonds because it has 4 electrons
in its outer shell.
It can form the following number of bonds. Notice that in each
case below, there are a total of four bonds.

4 single bonds

two double bonds

one double bond and two single bonds

one triple and one single bond
Acetylene
Ethylene
Long chains of carbon atoms are common. The chains may be
branched or form rings.
Organic Molecules
Some molecules are hydrophobic (means "water fearing"). They
do not dissolve in water.
Nonpolar molecules and
functional groups are
hydrophobic.
Polar and ionic molecules and
functional groups are
hydrophilic.
Some molecules are hydrophilic (means "water loving"). They
dissolve in water.
Functional Groups
Functional Groups - Groups of atoms attached to carbon skeletons that
behave/react in known ways.
Methyl
Lipids
Monomers and Polymers
What does the prefix Mono- mean? ___________________ Poly-? _______________
Look at the pictures below. Based on your knowledge, circle the pictures that represent monomers.
Draw boxes around the polymers.
What is the relationship between monomer and polymers?
Building and Breaking Polymers
1. Is the product of the above reaction
more or less complex than the reactants?
1. Is the product of the above reaction more
or less complex than the reactants?
2. What molecule is released/produced
while forming the products?
2. What molecule is used to break the
reactant producing the products?
3. Why do you think this reaction is called
a dehydration synthesis reaction?
3. Why do you think this reaction is called
hydrolysis?
Building and Breaking Polymers
https://www.youtube.com/watch?v=b7TdWLNhMtM
https://www.youtube.com/watch?v=ZMTeqZLXBSo
Polymers like polysaccharides, proteins and nucleic acids are
made from different monomers, but they are all built and broken
in the same way.
Monomer – 1 unit
HO-
-OH
Dimer – 2 units
HO-
-O -
Polymer – 3+ units
HO-
-O-
-OH
-O-
-O-
-OH
Dehydration Synthesis Reaction
Dehydration synthesis is a chemical reaction that takes smaller,
simpler molecules and combines them to form larger, more
complex molecules with the removal of one WATER molecule.
Dehydration = taking water out
Synthesis = putting together
Is a Dehydration Synthesis Reaction happening below?
Hydrolysis
The opposite reaction of dehydration synthesis is called
hydrolysis. This involves adding water to break apart large
molecules into smaller ones.
hydro = water.......lysis = breaking apart
Review Dehydration Synthesis and Hydrolysis
Carbohydrates
1. Look at the monosaccharides (single sugars) below. How many different elements do they
contain?
What are they?
2. How would you describe the general shape of these monosaccharides?
3. Look at the polysaccharides below. What monosaccharide is used to build all of these big
sugars?
4. What atom is between each monosaccharide in the polysaccharides?
5. What reaction links two monsaccharides together? What molecule is released as a waste
product?
Macromolecules
A. Carbohydrates
Main function - provide energy for living things; also use
carbon skeleton to make organic molecules the body needs.
Elements: Carbon, Hydrogen and Oxygen
Simple sugars – Single sugar monomers and disaccharides
Complex sugars – Many sugar monomers bonded together
Monosaccharides (mono = single, saccharide = sugar)
Single sugar monomer
Most small sugars end in –ose
Most have the ratio: CH2O
Carbo (C) Hydrate (H2O)
 Glucose: C6H12O6
 Fructose: C6H12O6
 Galactose: C6H12O6
The structural differences give them their unique properties.
 Fructose sweeter than glucose
Some sugars have 3 to 7 carbon atoms
Disaccharides (Di = 2)
2 sugar monomers bonded together
Made by what type of reaction? Dehydration Synthesis Reaction
How many water molecules were released?
Examples:
Maltose – Glucose + Glucose – Malt sugar
1
Sucrose – Glucose + Fructose – Plant sugar
Lactose – Glucose + Galactose – Milk sugar
Polysaccharides (Poly = many)
3 or more sugar monomers bonded together
Made by what type of reaction? Dehydration Synthesis Reaction
Starch
Structure: Looping chain of glucose monomers
 Branch or unbranched
Function: Plant sugar storage
 How is the sugar released? Hydrolysis
Foods: Potatoes and grains (wheat, corn and rice)
Glycogen
Structure: Highly branching chains of glucose monomers
Function: Animal sugar storage
 How is the sugar released? Hydrolysis
Food: Liver and muscle cells
Cellulose
Structure: Unbranched rod of glucose monomers
 Hydrogen bonds hold rods together
Function: structural compounds (support and protection)
Food: Fruits, vegetables, grains
 How is the sugar released?
o Hydrolysis by some organisms. We can’t hydrolyze
these polysaccharides
Organic Molecules – Crash Course http://www.youtube.com/watch?v=H8WJ2KENlK0
Introduction and Carbohydrates - Start – 7:07
Lipids - 7:07 – 10:45
Proteins - 10:45 - End
Lipids
1. Look at the 2 different fatty acids below.
What is the main difference between them?
2. How does the difference affect their shape?
3. Look at the molecule of Fat below.
How many fatty acid molecules
make up this fat and of what
type(s)?
4. Look at the molecule of Oil below.
How many fatty acid molecules
make up this oil and of what
type(s)?
5. What is the main difference
between fats and oils?
B. Lipids
Very Diverse – All hydrophobic = water fearing
 Fats/Oils
o Main functions: Energy Storage, cushion organs,
insulate
o Building blocks: Glycerol and 3 Fatty Acids
 Triglyceride
Elements: Carbon, Hydrogen and Oxygen
How many
water molecules
produced?
3
Saturated fats:
 Carbon chains hold the maximum number of hydrogen
atoms. NO carbon = carbon double bonds
 Solid at room temperature
 Animal fats
 Not healthy
Unsaturated fats:
 Carbon chains don’t hold the maximum number of
hydrogen atoms. Carbon = Carbon double bonds (C=C)
 Liquid (liquid-like) at room temperature
 Fish, plant fat
 More
healthy
Hydrogenated – Hydrogen atoms have been added to molecules
to make them saturated.
 “Trans” fats are
linked to heart
disease.
 Phospholipids
o Main function: Structural component of the plasma
membrane
o Building blocks: Glycerol, 2 Fatty Acids and
Phosphate group
 Waxes
o Main function: Retain water
 Fruits and insects
o Building Blocks: Alcohol + Fatty Acid
 Steroids
o Main functions: Hormones, cell membrane
components
 Cholesterol
 Sex hormones (testosterone and estrogen)
o Structure: 4 fused carbon rings ( 3, 6-sided and
1, 5-sided)
Anabolic Steroids – synthetic variants of the male hormone
testosterone.
 Mimic effects: muscle buildup and bone mass
 Side effects – “steRoid rage”, depression, liver damage,
cancer, high blood pressure, shrunken testicles, reduced sex
drive, infertility and breast enlargement. Women –
menstrual cycle disruption and masculine characteristics.
Teens – stops bone growth, stunts growth
Proteins
Look at the three amino acids below. Each one has a “central” carbon. Besides this central carbon,
what else is shared by all three amino acids?
1. Look at the picture below. How many levels are there to protein structure?
2. What is the first level of protein structure?
3. What type of bond allows the secondary structure to fold into an alpha helix or pleated sheet?
4. What does the 4th level of protein structure consist of?
Enzymes
Look at the two graphs. Each contains two
lines, one with an enzyme and one without
an enzyme. Do the reactants or products
change depending on whether the reaction
includes an enzyme or not?
How do you know?
What is different about the reaction when
an enzyme is involved?
What letter from the graph at the left corresponds to the
energy released from the reaction with or without an enzyme?
C. Proteins
Main function: necessary for growth/repair of tissues, found in
cell membranes, enzymes, immune system
signals, communication and other functions.
 Protein structure determines its function
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur
(some)
Monomer Building Block: Amino Acids (20)
 Type, number and order make each protein different
o Like letters in the English language
Amino Acids
 Each amino acid has 4 parts around a central carbon atom:
R-Group or
Side Group
R-Group or Side group – A variable part of an amino acid
o Could be a Hydrogen atom
o Could be a collection of atoms
 Determines the specific properties of each amino acid
o Hydrophobic or Hydrophilic
Dipeptides and Polypeptides
The carboxyl group of one amino acid and the amino group of
the next amino acid can join together by dehydration synthesis
to form a peptide bond.
 Additional amino acids added = Polypeptide
Peptide Bond
A protein’s shape determines its function
 If you change the shape, you change (possibly lose)
function.
o This could lead to a protein that
doesn’t function properly and
the death of the organism.
Protein Structure
Primary Structure (1o) – unique sequence of the amino acids.
Second Structure (2o) – Hydrogen bonding causes the primary
structure to fold onto itself
 Alpha helix – spiral
 Pleated sheet – folds
Denaturation – unraveling the specific shape of a polypeptide
and changing its function
 Break the hydrogen bonds in the Secondary Structure
o pH, high temperatures, salt concentration
Tertiary Structure (3o) – the protein takes on 3-D shape
because of the hydrophobic and hydrophilic R-groups.
Quaternary Structure (4o) – 2 or more tertiary structures
bonded together.
 Collagen – fibrous protein
 Hemoglobin
Denaturation – unraveling the specific shape of a polypeptide
and changing its function
 Break the hydrogen bonds in the Secondary Structure
o pH, high temperatures, salt concentration
Enzymes and Chemical Reactions
Cells must invest energy to start chemical reactions.
 Energy of Activation (EA) or Activation Energy - the
energy that must be absorbed to start a chemical reaction.
o What does the energy do?
 Contorts or weaken bonds before the reaction
forms new bonds.
If cells need certain chemical reactions to happen quickly,
why not increase kinetic energy (heat)?
 Speed up all chemical reactions (not good)
 Denature proteins
Why use enzymes (special enzyme catalysts)?
 Speed up specific chemical reactions by lowering
the Energy of Activation.
o How do they work?
 Position molecules for bonding or
weaken bonds before breaking.
Enzymes are proteins. Remember protein shape is important to
function.
Enzymes generally end in –ase and are named after the substrate
they bind.
Enzymes Are Specific
Enzymes are proteins whose 3-D shape determines their
function/role in a chemical reaction.
The reactant(s) that a specific enzymes acts upon is called the
substrate.
The specific region on the enzyme where the substrate binds is
called the active site.
 Enzymes catalyze specific reactions because only certain
substrate molecules fit into the active site.
o When the substrate binds to the active site, the shape
changes to weaken bonds for breaking or positions
molecules close together for bonding.
Enzyme hydrolysis of sucrose
Enzymes and Environmental Conditions
An enzyme’s shape determines its function, and the shape can
be affected by the environment.
Enzymes are most effective under specific conditions.
Temperature – close to normal cell/body temperature
Salinity – high salt ions interfere with chemical bonds
pH – close to neutral, H+ interfere with bonding
http://www.youtube.com/watch?v=PILzvT3spCQ
Nucleic Acids
1. Is DNA single stranded or double stranded?
2. Is RNA single stranded or double stranded?
3. What is the monomer used to build Nucleic
Acids?
4. How many parts are needed to build a
nucleotide? What are the parts?
5. What is different about the sugar found in DNA
and RNA?
6. What four bases (letters) are found in DNA?
7. What four bases (letters) are found in RNA?
8. What letters pair together in DNA?
9. What kk
two parts of a nucleotide make up the “backbone” of DNA and RNA?
10. What holds the two strands of DNA to each other?
D. Nucleic Acids (DNA/RNA)
Observations – Similarities : Differences
Nucleic Acids
Main function:
Information storage
 DNA – Long-term all genes
 RNA – Short-term 1 gene
 Gene – a specific portion of a DNA molecule that
codes for the production of a specific amino acid
sequence (protein).
DNA
RNA
Primary sequence of a protein
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and
Phosphorous
Monomer Building Block: Nucleotide
Nucleotide – Made of 3 subparts
A. Five–Carbon sugar
a. Deoxyribose for DNA
b. Ribose for RNA
B. Phosphate Group
C. Nitrogenous Base
a. Adenine (A) – DNA and RNA
b. Guanine (G) – DNA and RNA
c. Cytosine (C) – DNA and RNA
d. Thymine (T) – DNA
e. Uracil (U) –
Purines
Pyrimidines
RNA
Polynucleotides are formed by Dehydration Synthesis Reactions
 The phosphate group of one nucleotide bonds to the sugar
of the next monomer to form a sugar-phosphate backbone.
RNA usually has a single sugar-phosphate backbone.
DNA is a double helix – two polynucleotide strands wrapped
around each other.
 Backbone on the outside
 Nitrogenous bases protrude inward and pair together
oA T
oG
C
 What do the lines represent?
Hydrogen Bonds
http://www.goldiesroom.org/Note%20Packets/04%20Biochemis
try/00%20Biochemistry--WHOLE.htm