Transcript + Energy - StangBio

Chapter 3:
Biochemistry
Honors Biology 2011
What
are we
made of?
Why
do we
have to eat?
Elements of Life

96% of living
organisms is
made of:




carbon (C)
oxygen (O)
hydrogen (H)
nitrogen (N)
The Chemistry of Carbon


Living organisms are made of carbon based molecules
known as organic molecules.
Carbon’s versatility is the key to the structure of organic
molecules:

Carbon can bond with up to 4 other atoms at once.
 Carbon can form single, double or triple bonds.
 Carbon bonds easily with other carbon atoms to form the
backbone of large organic molecules.
 Carbon can bond with many different
elements such as H, O, P, S, N.
Macromolecules
Most molecules in cells are so large they
are macromolecules or “giant molecules”
made from thousands
of smaller molecules
 Polymerization: large molecules
are made from joining smaller
ones together

 Monomers:
small building blocks
 Polymers: long chains of monomers
Building large molecules of life

Chain together smaller molecules
 building

block molecules = monomers
Big molecules built from little molecules
 polymers
Building large organic molecules

Small molecules = building blocks = monomers

Bond them together = polymers
Making Polymers


Monomers link to form
polymers in a reaction
called a condensation
reaction
One small molecule
comes out each time
two monomers
form a bond.

When that molecule is water, it’s called dehydration
synthesis.
Monomer + Monomer  Polymer + Water
Example of synthesis
amino acids

protein
Proteins are synthesized by bonding amino acids
amino acids = building block
protein = polymer
How to take large molecules apart
Digestion
 Hydrolysis

 taking
big molecules apart
 getting raw materials

for synthesis & growth
 making

energy (ATP)
for synthesis, growth & everyday functions
+
Energy
Breaking Down Polymers



Polymers can be broken
down back into monomers
by a reaction called
hydrolysis.
Water is added to break a
bond between monomers.
Exergonic reaction
(energy comes out)
Polymer + Water  Monomer + Monomer
Example of digestion
Energy
Energy
Energy
Energy
Energy
starch
Energy
glucose
Energy

Starch is digested to glucose
Energy Currency
Life processes require energy
 Adenosine Triphosphate (ATP) is a
molecule that contains LOTS of energy
 When P is removed,
energy is released
and can be used by
the cell.

Section 3-3:
Molecules of Life
Molecules of Life
Put C, H, O, N together in different
ways to build living organisms
 What are bodies made of?

 carbohydrates

sugars & starches
 proteins
 fats
(lipids)
 nucleic acids

DNA, RNA
Why do we eat?

We eat to take in more of these chemicals
 Food
for building materials
to make more of us (cells)
 for growth
 for repair

 Food
to extract energy
Unit = calorie
 to make ATP

ATP
What do we need to eat?

Foods to give you more building blocks
& more energy

for building & running bodies
 carbohydrates
 proteins
 fats
 nucleic
acids
 vitamins
 minerals, salts
 water
Don’t forget water

Water
 65%
of your body is H2O
 water is inorganic


doesn’t contain carbon
Rest of you is made of carbon molecules
 organic
molecules
carbohydrates
 proteins
 fats
 nucleic acids

Carbohydrates


Elements: C, H, O
in a 1:2:1 ratio
Monomer = Building block molecules =
monosaccharide
or simple sugar (glucose, fructose, galactose)
sugar sugar sugar sugar sugar sugar sugar sugar
sugar - sugar - sugar - sugar - sugar
Carbohydrates

Function:
 quick
energy
 energy
glucose
C6H12O6
storage
 structure


cell wall in plants
sucrose
Examples
 sugars
 starches
 cellulose
(cell wall)
starch
Monosaccharides = Sugars = building blocks

Names for sugars usually end in -ose
CH2OH
 glucose
 fructose
 sucrose
 maltose
H
O
H
OH
H
H
OH
HO
H
OH
glucose
C6H12O6
sucrose
fructose
maltose
Building carbohydrates

Disaccharides = 2 monosaccharides put together by
dehydration synthesis.
Example: Maltose = glucose + glucose
monosaccharides
|
glucose
|
glucose
2 sugars =
disaccharide
|
maltose
Building carbohydrates

Dehydration Synthesis
monosaccharides
|
glucose
|
fructose
2 sugars =
disaccharide
|
sucrose
(table sugar)
BIG carbohydrates

Polysaccharides
 starch

energy storage in plants

potatoes
 glycogen

energy storage in animals

in liver & muscles
 cellulose

structure in plants

cell walls
 chitin

structure in arthropods & fungi

exoskeleton
Cellulose

Cell walls in plants


herbivores can digest cellulose well
Cross-linking between polysaccharide chains hard to digest,
most carnivores cannot digest cellulose


that’s why they
eat meat
to get their energy
& nutrients
cellulose = roughage


stays undigested
keeps material
moving in your
intestines
Lipids




Concentrated energy
molecules
Elements: C, H, O
Lipids are not polymers- only made of 4 parts, not a
long repeating chain
 Made of Glycerol & Fatty Acids (long, unbranched carbon
chains)
Lipids are large,
nonpolar organic
molecules that do
not dissolve in water.
Lipids

Function:
 energy
storage
very concentrated
 twice the energy as carbohydrates!

 cell
membrane
 cushions organs
 waterproofing
 insulates body

think whale blubber!
 some
hormones
Lipids

Examples
 fats
 oils
 waxes
 hormones

sex hormones

testosterone (male)

estrogen (female)
Molecular Structure of Fat
not a chain (polymer) = just a “big fat molecule”

Many C-H bonds that store more energy
than the C-O bonds common in other
organic compounds.
Saturated fats




Each carbon atom is
covalently bonded to four
atoms.
They are full or
saturated.
Contain LOTS of energy
Most animal fats
 solid
at room
temperature

Limit the amount in your
diet
 contributes
to heart
disease
 deposits in arteries
Unsaturated fats



Carbon atoms that are not
bonded to the maximum
number of atoms that they
can bond to, form double bonds
and are said to be
unsaturated, not full.
Contain less energy than
saturated fats.
Plant, vegetable & fish fats
 liquid
at room
temperature


the fat molecules
don’t stack tightly
together
Better choice in your
diet
Other lipids in biology

Cell membranes are made out of lipids
 phospholipids
 forms
a barrier
between the cell
& the outside
Other Types of Lipids

Wax - long fatty acid
joined to long alcohol chain.


Waterproof, form a protective coating on outer surfaces.
Steroids - four fused carbon
rings with various functional groups
attached.


Many animal hormones are steroids
Cholesterol is needed by the body for
nerve cells and other cells to
function normally.
Other lipids in biology

Cholesterol
 good
molecule in cell membranes
 make hormones from it

including sex hormones
 but
too much cholesterol in blood may lead to
heart disease