Transcript Biochemicals TT

Chemistry of
Living Systems
Chemistry of Atoms
Atom: smallest unit of
matter
Three components of
an atom are…
 Electrons -1
Found outside the nucleus

Protons +1
Found in the nucleus

Neutrons 0
Found in the nucleus
Atomic Number=
# of Protons
11Na
Ions=
Different # of
p+ and e-
ATOMS
ISOTOPES=
Same # of p+ and eDifferent # of
n0
Atomic
Weight =
p+ + n0
Count the electrons!
# of electrons in the outer shell are clues!
 Greater than 4 in the outer shell will take
from other atoms
 Less than 4 in the outer shell will give to
other atoms
 Provides hints on how and what types of
bonds form

Elements Essential to Life
 About
25 elements are essential to
living organisms
CHNOPS:
Make up 97% of
living matter
Natural Elements in the Human Body
ELEMENTS
Oxygen (O)
Carbon (C)
ATOMIC #
8
6
% in HUMANS
65.0
18.5
Hydrogen (H)
Nitrogen (N)
Calcium (Ca)
1
7
20
9.5
3.3
1.5
Phosphorus (P)
Potassium (K)
Sulfur (S)
Sodium (Na)
15
19
16
11
1.0
0.4
0.3
0.2
Magnesium (Mg) 12
Chlorine (Cl)
17
0.2
0.1
Chemical Bonds
Chemical Bonds are the attractive force
that hold atoms together in a molecule
Bonds form when electrons are shared
OR transferred between atoms



Covalent bonds – sharing electrons (“co-”
means to share as in cooperate)
Ionic Bonds – give and take electrons
Hydrogen Bonds – weak attractions between
molecules
Stronger atoms try to “steal” the H’s electron,
but it keeps a tiny hold on it.
Nonpolar Covalent Bonds
Electrons
shared
equally
are
Polar Covalent Bonds

Share electrons as
in other covalent
bonds, but the
nucleus of one
atom attracts the
electrons more
strongly so it is not
equal.
Ionic Bonding

One atom gets extra electron(s) (becomes
a negative ion) and one gives extra
electron(s) (becomes a positive ion) the
two ions attract each other.
CARBON
Why is carbon so important in
biological molecules?
Carbon is easy to synthesize (break down
and be used).
Molecules with carbon are called
ORGANIC
Molecules without carbon are called
INORGANIC
What are the
important
molecules of life?
The Structure of Water
 “V”
shaped molecule
 Unequal
sharing of
electrons causes oxygen
to have a slightly
negative charge

called a polar molecule
Properties of Water
 Cohesion
is the
tendency of
molecules of the
same kind to stick
to one another.
 Water
has stronger
cohesion than most
liquids
 Water
molecules are
also attracted to
certain other
molecules
 Attraction
between
unlike molecules is
called adhesion
Cohesion
pulls molecules at
the surface tightly together,
forming a film-like boundary
This
is surface
tension
Carbohydrates
(C,H, and O molecules in a ratio of 1:2:1)
Carbohydrates
are an
important
energy source
for cells.
TYPES OF CARBOHYDRATES
Monosaccharide – simple sugars made of
one sugar molecule. (ex. Glucose)
TYPES OF CARBOHYDRATES
– (ex. Sucrose)
2 monosaccharides linked
together
 Disaccharides
TYPES OF CARBOHYDRATES

Polysaccharides – ex. Starch, Cellulose)
More than two sugars linked together.
Did you notice how the
sugars all sound the
same?
 They
all end in “-ose” (-ose =
sugar)
 Ex.
Sucrose, Glucose, Fructose,
Lactose
TYPES OF CARBOHYDRATES
Simple Carbs ~ mono and disaccahrides
 Complex carbs ~ starches, polysaccharides

LIPIDS
Made up of two parts:


A head (it is hydrophillic)
A tail made of a
hydrocarbon chain (it is
hydrophobic).
This lets the lipids form
bilayers creating waterproof
barriers like in a cell’s
membrane.
LIPIDS
 Fatty
acids, waxes, fats, steroids
and oils are formed by lipids (all
are insoluble in water)
Proteins
Molecules
made up of
one or more chains of
amino acids. They
are used for many
functions…
Proteins are used for…
– they make
collagen in skin and
keratin in hair/nails/horn
Structure
Proteins are used for…
 Movement
~
actin and
myosin in
muscle
stimulate the
muscle to move
Proteins are used for…
Defense
~
antibodies in
bloodstream
Proteins are used for…
Storage ~
corn seeds
are
predominately
made of
protein
Proteins are used for…
Signals ~
growth
hormones in
your blood
stream
Proteins are used for…

Nucleic Acids (used in
DNA or RNA) – long
chains of pieces called
nucleotides. A nucleotide
has 3 parts…
1. five carbon sugar (ribose
or deoxyribose)
2. phosphate group
3. Nitrogen base (A,T,C or G)
Proteins are used for…
 Catalysis
~ enzymes which
speed up processes in the body
So what is an
Enzyme?
An enzyme is used to
speed things up or help
break things down in
your body.
Words You Should Know
 Enzyme
(E): protein catalyst
 Catalysts:
speed up reactions without
being changed by the reaction
 Substrate
(S): reactant(s) in the
enzyme-catalyzed reaction
 Active
site: area of enzyme where
substrate(s) bind(s)
Enzymes
Enzymes are proteins with a SPECIFIC
SHAPE
 The active site is a part of the protein
which recognizes and binds to the
substrate


Cofactors (e.g. Zn 2+, Cu 2+, B vitamins)
some enzymes won’t hook-up to a
substrates without these
Specificity

‘Lock and Key Model’ – says there is a
perfect fit between active site and substrate

Modified to ‘Induced Fit Model’ - active site
can expand or contract to “fit” the substrate
shape

The induced fit model allows for small
differences (possibility of letting several
different kinds of substrates hook up)
How do enzymes speed up reactions?
Enzymes lower the
activation energy
(EA=amount of energy that
reactant molecules require
to start a reaction)
Enzymes

Are involved in every biochemical reaction
and thereby control metabolism

Are named according to the reaction that
they facilitate
Examples: Sucrase breaks down sucrose
into glucose and fructose

DNA Polymerase helps build DNA polymers
Did you notice that enzyme all
sound the same?
All
enzymes end in “-ase”
DNA
Polymerase
Sucrase
Factors affecting enzyme activity
1. TEMPERATURE
2. Concentration of Enzyme
3. Concentration of Substrate
4. pH
5. Inhibitors
Types of Inhibition

Competitive inhibition - molecules bind
to the active site and prevent the
substrate from binding

Non-competitive inhibition - molecules
that bind to a site other than the active site
but change the shape of the active site so
that it cannot bind the substrate
Enzymes in
Biotechnology
How does pectinase
work?
 Pectin
is the cement
that holds plant cells
together. Pectinase
helps farmers break
down the plant cells
faster. For example it
might help a farmer
release the juice from
apples faster to make
lots of Apple Juice.
Other enzymes in
biotechnology…
Biological
washing powder
Meat tenderizer
Production of glucose syrup