Download Molecules of Life

Organic Compounds
Hydrogen and other elements
covalently bonded to carbon
Four types of organic compounds:
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids
What’s so special about
Carbon?
Carbon wants to make 4 bonds
with other elements which leads
to a big molecule
***Remember Carbon has 4
valence electrons***
What’s so special about Carbon?
1) Straight
2)Branched
3)Ringed
What’s so special about Carbon?
 Single bonds
C-C-C-C
 Double bonds
C=C=C
 Triple bonds
 With other carbons or
other elements
Functional Groups
 Since most organic compounds are large molecules,
the entire molecule does not take part in the chemical
reaction
 Only a few atoms that are covalently bonded will take
part in the chemical reaction
 These are called functional groups (groups of atoms
that function in the molecule)
 Give organic compounds their different properties
Examples of Functional Groups
Hydroxyl group
- OH
Amino group
- NH3+
Carboxyl group
- COOH
Phosphate group
- PO3-
Sulfhydryl group
- SH
Types of Reactions
Two main types of reaction happen in a cell
Condensation/dehydration synthesis =
small molecules or monomers are joined
together or condensed to make a larger
molecule
Cleavage or hydrolysis = large molecules or
polymers are broken down or cleaved to
form smaller molecules
Condensation
Hydrolysis
 A type of cleavage reaction
 Breaks polymers into smaller units
 An -OH group and an H atom derived
from water are attached at exposed sites
Hydrolysis
Carbohydrates
Elements: C H2 O
Basic building blocks
or
MONOMERS:
Monosaccharides
(simple sugars)
Ex: Glucose, Fructose
DIMERS or
Disaccharides:
Ex Sucrose, Maltose
Function: Energy
Carbohydrates
POLYMERS:
Oligosaccharides
(short-chain
carbohydrates)
And
Polysaccharides
(long chain or complex
carbohydrates)
Cellulose and Starch
Cell walls component
Stores of carbs in potato
Glycogen
 Sugar storage form in animals
 Large stores in muscle and liver cells
 When blood sugar decreases, liver cells
degrade glycogen, release glucose
What is the function of
carbs?
A. Energy
B. Support
C. Energy storage
D. All of the above
E. A and B only
What is the function of
carbs?
A. Energy
B. Support
C. Energy storage
D. All of the above
E. A and B only
Which of these are monomers
of carbs?
A. Starch
B. Glycogen
C. Glucose
D. Cellulose
Which of these are monomers
of carbs?
A. Starch
B. Glycogen
C. Glucose
D. Cellulose
Common Characteristics of
Carbohydrates
1) Hydrophilic- many hydroxyl groups (OH)
2) Mono and disaccharides dissolve in water
= sugar solution
3) Cellulose and some starch do not
dissolve in water because they are too
big
Lipids
 Elements C, H, O
 Monomers are
 Fatty acids
 Glycerol
 Polymers are
 Fats
 Phospholipids
 Waxes
Fats
 Fatty acid(s) attached to glycerol
makes Triglycerides
Glycerol
Function:
Energy stores
Thermal Insulation
Fatty Acid
Fatty Acids
 Carboxyl group (COOH) at one
end
 Carbon backbone (up to 36 C
atoms)
 Saturated (bad fat)- Single
bonds between carbons
 Unsaturated (good fat)- One
or more double bonds
Phospholipids
 Main components of cell membranes
Waxes
 Long-chain fatty acids linked to long chain alcohols
or carbon rings
 Firm consistency, repel water
 Important in water-proofing
Steroids
 No fatty acids
 Rigid backbone of four
fused-together carbon
rings
 Cholesterol - most
common type in animals
 Estrogen, testosterone
Give two differences and two
similarities between a carb and
a lipid?
Give two differences and two
similarities between a carb and a
lipid?
 Lipids and carbs have CHO
 Lipids and carbs provide energy to the cell
 Both have OH functional group
 Carbs have CH2O, Lipids have no ratio
 Lipids are long term, carbs are short term
 Lipids have OH and COOH functional group, carbs
have OH
 Hormones are lipids
Proteins
 Elements C, H, O, N,
sometimes S
 Monomers: Amino
acids
 Polymers: Polypeptides
or proteins
 Examples: hair,
muscle.
carboxyl
group
amino
group
R group
20 types of R groups = 20 types of
amino acids
Polymer = two or more
monomers joined by  Covalent bonds
 Specifically peptide
bonds
 What is a dipeptide?
 Polypeptide?
Protein have Shapes
 Fibrous proteins
 Polypeptide chains arranged as strands or sheets
 Globular proteins
 Polypeptide chains folded into compact, rounded shapes
Primary Structure
 Sequence of amino acids
 Unique for each protein
one
peptide
group
Secondary Structure
 Hydrogen bonds form
between different parts
of polypeptide chain
 These bonds give rise to
coiled or extended
pattern
 Helix or pleated sheet
Tertiary Structure
heme group
Folding as a result
of interactions
between R groups
coiled and twisted polypeptide
chain of one globin molecule
Quaternary Structure
Some proteins are
made up of more
than one polypeptide
chain
Hemoglobin
Functions of Proteins
1. Enzymes which control and speed up all
chemical reactions in our bodies
3. Hormones which act as signals to tell the
body what to do and when
4. Antibodies help our bodies fight infection
5. Hemoglobin carries oxygen around our
bodies
Functions of Proteins
6. Storage – in Milk, eggs, seeds etc
7. Structure of cell and body – web, silk,
hair, skin, feathers
8. Motor – muscle proteins, cilia, flagella
9. Receptor proteins – recieves signals from
nerves that help in response to stimuli
Important protein: Enzyme
Structure and Function
Protein that coordinates all cell activity
• Enzymes are catalytic molecules
• They speed the rate of reactions
IMPORTANT:
• All enzymes are protein BUT all
proteins are not enzymes
Process of enzyme activity
How enzymes work
Substrate ( reactant) fits into the active site of the
enzyme
2) The enzyme breaks/forms bonds and releases the
products
3) The enzyme can then be used again with another
substrate
1)
Four Features of Enzymes
1. Enzymes do not make anything happen
that could not happen on its own. They
just make it happen much faster.
2. Reactions do not alter or use up
enzyme molecules.
3. The same enzyme usually works for
both the forward and reverse
reactions.
4. Each type of enzyme recognizes and
binds to only certain substrates.
Activation Energy
 For a reaction to occur,
an energy barrier must
be surmounted
activation energy
without enzyme
starting
substance
 Enzymes make the
activation energy
with enzyme
energy barrier smaller
energy
released
by the
reaction
products
Factors Influencing
Enzyme Activity
Temperature
pH
Salt concentration
Enzymes secondary, tertiary and
quaternary structures change but the
primary structure does not – why?