Chemistry of Life biochemistry CHS
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Transcript Chemistry of Life biochemistry CHS
Chemistry of
Life
What is Chemistry?
Study of composition of matter
What is matter?
anything that takes up space and has mass
Why mass? Not weight?
B/c weight changes but mass is constant
What is an element?
a substance consisting of only one type of
atom
On Earth, 92 elements occur naturally, and 25
of them are essential to living organisms
Ex: C, H, O, N, Ca, P, K, S, Na, Cl, Mg
What are 4 elements that make up
>96% of mass of a human?
Carbon, Hydrogen, Oxygen, Nitrogen
Trace elements
essential elements that present in living
things in very small amount (less than 0.01%)
What is an atom?
Nucleus (+ proton & 0 neutron) in center and
– electron cloud out side
Compounds
a substance that contains 2 or more
elements into a fixed ratio
ex: water (H2O), glucose (C6H12O6)
Compounds are made by bonding
elements
Ionic bond
by mutual attraction of 2 ions of opposite charge
ex: Sodium Chloride (Na+Cl-)
Covalent bond
by sharing electrons
ex: H2, CH4, H2O
Hydrogen bond
by attraction of opposite charge b/w Hydrogen
and Oxygen
It holds and stabilize many large biological
molecules such as proteins and DNA
How do the unique chemical
and physical properties of
water make life on earth
possible?
Water Structure
Held together by
covalent bond
Neutral in charge as
a whole
Polar
Unequal distribution
of charge
Is the basis for
hydrogen bond
Hydrogen Bond
Formed by
attraction of
opposite charge b/w
hydrogen and
oxygen
Important to
properties of water
and to DNA
replication
Properties of Water
Strong Cohesion
Tendency of molecules to stick together
High Surface Tension
A measure of how difficult it is to stretch or
break the surface of a liquid
High Specific Heat
Amount of heat that must be absorbed or lost to
change its temperature
High Heat of vaporization
Quantity of heat a liquid must absorb to be
converted from the liquid to the gaseous state
Universal solvent
Dissolving agent of a solution
Strong Cohesion (and adhesion)
High Surface Tension
Evaporative cooling
Density of Water
Ice less dense than
liquid water
Ocean and lakes don’t
freeze solid because ice
floats
Ice protects the liquid
water below from colder
air
If liquid water were less
dense tan ice
Ice will sink and all
ponds, lakes and ocean
would freeze solid
Life on Earth would not
be possible
pH
a measure of how
acidic or basic a
solution is.
Scale of pH is 0-14
Acids
any substances that
form hydrogen ion
(H+) in water
pH below 7
Bases
any substances that
form hydroxide ion
(OH-) in water
pH above 7
Buffers
substances that resist change in pH by
accepting or donating hydrogen ion
prevent sharp change in pH
controlling pH is important for maintaining
homeostasis
Acid Rain
rain or snow with a pH below 5.6
causes: air-pollutants; sulfur oxide and
nitrogen oxide from burning of fossil
fuel
Effects: damages forest, other lands,
lakes, and streams (kills trees and fish)
Biologically important
macromolecules
How do structure of
biologically important
molecules (Carbohydrates,
lipids, proteins, and Nucleic
Acids) account for their
functions?
PROPERTIES OF ORGANIC COMPOUNDS
Contains Carbon
4 electron in the outer shell of carbon allow
it to form complex structures
Hydrocarbon
compound composed of only carbon and
hydrogen Ex: methane, ethane, propane, etc.
Isomers
compounds that have same simple
(molecular) formula but different 3-d
structures
Ex: glucose & fructose (simple formula C6H12O6)
PROPERTIES OF ORGANIC COMPOUNDS
Macromolecules
Monomers
The fundamental molecular unit; building block
of polymers
Polymers
A large molecule formed by bonding many
smaller molecules ; usually in long chains
Therefore, cells build macromolecules by
forming a chain
Ex: DNA, RNA, Protein, Polysaccharides
HOW DO CELLS COMBINE
MONOMERS TO MAKE
POLYMERS?
By Dehydration Synthesis
Cells link monomers together to form
polymers by removing a water molecule
Ex: Glucose to Starch
Ex: Amino Acids to Proteins
HOW DO CELLS BREAK DOWN
POLYMERS INTO MONOMERS?
By Hydrolysis
“Breaking (lyse) apart with water (hydro-)”
Cells break down macromolecules into
monomers
ex: Starch to glucose
ex: ATP to ADP
4 organic compounds
Carbohydrates
Lipids
Proteins
Nucleic Acids
CARBOHYDRATES
Composed of Carbon, Hydrogen,
and Oxygen
Categorized by size
(A) Monosaccharides
(B) Disaccaharides
(C) polysaccharides
(A) MONOSACCHARIDES
Simple sugars
C:H:O::1:2:1
Glucose (plants)
Fructose (fruits)
Galactose (milk)
Functions
Readily available energy
(B) DISACCHARIDES
Double sugars
Maltose (glucose + glucose)
Sucrose (glucose + fructose)
Lactose (glucose + galactose)
Functions
Transport form of sugars in plants
Available to be break down for energy
How would we combine glucose
and fructose to make sucrose?
Dehydration Synthesis
By removing a water molecule and
bonding them together
How do we digest or break down
lactose into glucose and
galactose?
Hydrolysis
To break down a disaccharide, add
the water back
(C) POLYSACCHARIDES
Many sugars
Glycogen
Starch
Cellulose
Chitin
Functions
Storage forms of energy
Structural molecules
LIPIDS
Composed of carbon, hydrogen, and oxygen
C:H:O::1:2:1
Subunits
triacylglycerol and 3 fatty acids
Triacylglycerol- 3 carbon alcohol
Fatty acids- chain of 16 or 18 carbons with a carboxyl group
Hydrophobic nature
due to nonpolar C-H bonds in the hydrocarbon chains of fatty
acids
BIOLOGICALLY IMPORTANT
LIPIDS
(A) Fats and oils
(B) Waxes
(C) Steroids
(D) Phospholipids
(A) FATS AND OILS
Saturated fatty acids
Animal fats
single bond between the carbon atoms of
hydrocarbon chain
Unsaturated fatty acids
Vegetable oils
one or more double bonds, formed by the removal of
hydrogen atoms from the carbon skeleton
(A) FATS AND OILS
Formed by which process?
Dehydration Synthesis
Functions
1. Storage form of energy
2. insulation (fat)
3. Cushioning (fat)
(B) WAXES
Where are they naturally found?
coats on leaves, fruits, animal skin,
feather, fur
Function
prevent water loss
(C) STEROIDS
Are based on cholesterol
Functions
1. Components of animal cell membrane and
myelin sheaths
2. metabolic regulation
(a) makes hormones
(b) sex hormones are steroids
(D) PHOSPHOLIPIDS
Function
1. A major component
of cell membrane
2. Affects transport
across the membrane
Characteristics
Hydrophilic heads
Hydrophobic tails
PROTEINS
Composed of carbon, hydrogen, oxygen,
nitrogen, and sulfur
Subunits
Amino Acids
Formed by peptide bond between amino
acids by dehydration synthesis
Involved in almost everything organisms
do
TYPES OF PROTEINS
1. Structural proteins- collagen
2. Storage proteins- albumin
3. Transport proteins- hemoglobin
4. Defensive proteins- antibodies
5. Contractile proteins- actin, myosin
6. Receptor proteins- neuro-receptors
7. Hormonal proteins- insulin
8. Enzyme/Biocatalysts- gastrin
PROTEINS
4 Levels of organization in proteins
1. Primary Structure
Linear sequence of amino acids
2. Secondary structure
Based on hydrogen bonding between
amino and carboxyl group
3. Tertiary structure
Based on bonding between R group
4. Quaternary structure
Results from intertwining 2 or more amino
acid chains
PROTEINS
What determines Protein Conformation?
The sequence of the polypeptide
Denaturaton
The loss of protein conformation
What causes the denaturation?
Physical & Environmental alteration such as
pH, temperature, salt concentration
How do enzymes regulate the
rate of chemical reactions?
Enzyme is a catalyst; a protein that speeds
up a chemical reaction
(without itself being changed into a different
molecules in the process) by lowering the
required activated energy
How does the specificity of an enzyme
depend on its structure?
Enzymes are
substrate-specific
(Key-lock
relationship)
How does the activity of an
enzyme regulated?
Temperature, pH, and some chemicals
Optimal condition for Enzyme activity
Temperature 35-40 °C (close to our normal body
temperature)
pH of 6-8
Cofactor and coenzyme
Cofactor: non-protein helper
ex: magnesium is a cofactor that is essential for the
proper functioning of chlorophyll
Coenzyme: organic cofactors (most Vitamins)
Inhibitors
Block substrate from entering active sites
Ex: Penicillin
NUCLEIC ACIDS
Composed of carbon, hydrogen, oxygen,
nitrogen, and phosphorus
Subunit: Nucleotide
3 components of nucleotide
Pentose (5-carbon sugar)
Phosphate group
Nitrogen base
2 types
DNA & RNA
DNA
RNA
Double Helix
Single Strand
Master copy of an organisms’s
information (gene) code
Process genetic instructions
to use in building proteins
DNA nucleotide
RNA nucleotide
1. Ribose
2. Phosphate group
3. Nitrogen base
1. Deoxyribose
2. Phosphate group
3. Nitrogen base
Purines
Adenine (A)
Guanine (G)
Pyrimidines
Cytosine (C)
Thymine (T)
Purines
Adenine (A)
Guanine (G)
Pyrimidines
Cytosine (C)
Uracil (U)