Transcript Organic Compounds

Biology I Honors
“Life depends on
chemistry.”
The Nature of Matter
What is the basic unit of matter?
Atoms!
Elements are made of like atoms.
Compounds are formed when two or more
elements combine.
Compound are held together by bonds.
2 Main Groups of Chemical
Compounds
Organic
 Inorganic

Organic Compounds
 Contain carbon
 Large molecules (made
up of lots of atoms)
 Complex
 Lots of carbon and
hydrogen atoms bound
covalently (sharing
electrons)
 primary
compounds that
make up the working
structures of living
things!
Inorganic Compounds

Generally do NOT contain
carbon
 CO2 is an exception

Also tend to be
 Small
 Simple

While NOT the major
building blocks of life,
they are absolutely
necessary for life
 Think WATER and Carbon
Dioxide!
What’s so special about CARBON?

It’s a great
Tinker Toy!
 4 outer
(valence)
electrons
 Can bind with
4 different
atoms
What’s so special about CARBON?

Readily forms
COVALENT bonds
with other atoms that
are strong and stable
What’s so special about CARBON?
Can form chains
of almost
unlimited length
by bonding with
other carbon
atoms
 These long
chains can then
FOLD to make
many complex
shapes

THE BOTTOM LINE about CARBON

It has HUGE potential for making a
WIDE VARIETY of different types of
molecules!
How to BUILD (and take apart)
Organic Molecules
Polymer – a large
molecule made up of
many smaller
subunits
 Monomer – a small
subunit (building
block) that can be
joined with other
subunits to make a
polymer

FOUR MAJOR GROUPS of Organic
Compounds
Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

Carbohydrates

Functions
 Quick ENERGY
 Energy STORAGE in PLANTS
 Energy STORAGE in ANIMALS
 Structural compounds for SUPPORT
GENERAL CARB STRUCTURE:
Monomers and Polymers

Monomers
 Monosaccharides
 i.e. Individual car in the train

Polymers
 Polysaccharides
 i.e. The whole train
Monosaccharides



Simple/single sugars
Basic formula CH2O
Example:
 GLUCOSE; C6H12O6
 Sugar made by plants in
photosynthesis
 Others: galactose (milk
sugar); fructose (fruit)
Why monosaccharides are important

Energy in them can be made QUICKLY
available to living things
 Energy is stored in the chemical bonds of the
sugar molecules
○ In particular, bonds between CARBON and
HYDROGEN atoms store lots of energy
 When these bonds are broken, energy is released
 This energy is then available to use
○ Cellular respiration converts this energy to a
usable form!
Monosaccharide - Glucose
Note that there are
lots of these C-H
bonds in a sugar
molecule
 Each has lots of
potential energy
stored in it

Disaccharides



DOUBLE sugars
Two monosaccharides
joined
Examples:
 Sucrose (table sugar)
○ Glucose + fructose (corn,
beets, sugar cane)
 Lactose (milk)
○ Galactose (dairy, beets) +
glucose
Why are Disaccharides useful?
Not quite so easily
broken down as
monosaccharides
 Can by used by plants /
animals for safe
temporary storage of
sugars

 Used in transport in plants
○ Sugar not consumed on its
way from leaves to roots
 Makes milk harder to
digest in animals
○ MOST adult animals cannot
digest milk
○ Keeps it for YOUNG ONLY
Polysaccharides
Made by joining MANY
monosaccharides
 Sugar (thus energy) is STORED in this
form

TYPES of Polysaccharides

STARCH
 PLANTS store energy in this form
 LOTS of GLUCOSE molecules linked in
LONG CHAINS
 Animals CANNOT store energy in this form,
but they CAN digest and USE it!
Starch
TYPES of Polysaccharides

GLYCOGEN
 Energy storage carbohydrate in ANIMALS
 Found in the liver, mostly.
 ALSO made of lots of glucose linked together
 As you consume sugar, your liver converts it to
glycogen and stores it.
○ Through the day as you need energy, the liver
breaks off sugars from the glycogen molecules for
you to us
Glycogen
Cellulose
STRUCTURAL
carbohydrate in PLANTS
 ALSO lots of glucose
linked together
 CELL WALLS in plant
cells
 SUPPORT and
PROTECTION
 UNDIGESTABLE BY
ANIMALS
 WOOD

Chitin
STRUCTURAL
carbohydrate
 Cell walls of fungi
 Exoskeleton of
arthropods

Carbohydrate Review
 Are we addicted to sugar??

Lipids
Waxes
 Oils
 Fats
 Steroids

Functions of Lipids
Energy Storage animals and plants
 Insulation

 Keeps animals warm
 blubber
Functions of Lipids

Waterproofing
 Duck feathers are kept dry
by a layer of oil
 Mammal fur (beaver, otter,
etc.), too.
 Plant leaves
Functions of Lipids



shockabsorption/protection of
organs
formation of membranes
in cells and organelles
make important
compounds called
steroids - cholesterol and
hormones (estrogen and
testosterone, for
example)
Structure of Lipids

Glycerol + 3 fatty
acids
 Glycerol is just a
“connector”
 3 fatty acids are the
most important part
Why are Fatty Acids the “important
part”?



fatty acids are LONG
chains of carbon and
hydrogen atoms
remember: bonds
between carbon and
hydrogen atoms STORE
ENERGY!
So fats (with their 3 fatty
acids) are PACKED with
energy and are GREAT
at energy storage
EFFICIENT energy storage

Because there are SO MANY C-H
bonds in fatty acids, lipids are VERY
efficient ways of storing energy.
 Fats produce more energy per gram than
carbohydrates do!

more efficient means better for animals lots of energy without much "baggage“
for animals that need to move.
Efficient energy storage

Some plants do use oils for energy
storage
 Corn oil, peanut oil, etc.

Efficiency is just not as important for
plants since they don’t have to move
around - so starch is still often the
primary energy storage molecule for
them
Saturated vs. Unsaturated Fats

saturated fat - when each carbon in a fatty
acid shares a single covalent bond with as
many hydrogen atoms as possible
 Solid at room temperature
Saturated vs. Unsaturated Fats

unsaturated fat - a fatty acid that has at least two
carbons double bonded to each other instead of to
hydrogen atoms –

liquid at room temperature
 oils
Saturated vs. Nonsaturated Fats
Protein

Functions
 Structural – build structures in organisms
 muscle contraction
 communication between cells
 movement of cell parts
 MOST IMORTANT: ENZYMES!!!
Structure of Proteins
 Monomers
of
Proteins are
AMINO ACIDS
○ 20 different types
○ All have different
characteristics
Protein Structure
A protein is a polymer of amino acids
 Amino acid monomers link together by
covalent bonds called PEPTIDE BONDS.
= Proteins are long chains of amino acids

 sometimes called polypeptides in reference to
their peptide bonds.

Peptide bonds are formed by
DEHYDRATION reactions.
Making Proteins from Amino Acids
Nucleic Acids

Functions
 tell the cell how to function
 transmit genetic information to offspring
Nucleic Acids

Structure
 Monomers of nucleic
acids are nucleotides
○ Sugar
○ Phosphate
○ Base
 Many nucleotides
linked together give a
nucleic acid - RNA and
DNA are the two main
examples
Chemical Reactions

The process that changes or transforms
one set of chemicals into another
 Mass and energy conserved
 Speed varies
 Some release energy, others absorb energy
Chemical Reactions
The elements or compounds that enter into a
chemical reaction are known as reactants.
The elements or compounds produced by a
chemical reaction are known as products.
Copyright Pearson Prentice Hall

All living things require energy to stay
alive!
 Energy is conserved
 Energy is required
 That’s why we eat and plants need the sun!

Activation energy-energy required to
get a reaction started (some rxns to
occur spontaneously)
 Living systems require catalysts to speed up
rxns because they occur too slowly
 Enzymes are catalysts-they speed up
reactions!
Enzymes


Enzymes have unique
shapes designed to fit the
chemicals that they are to
"speed up" (the
SUBSTRATES of the
REACTION)
The region of the enzyme
that FITS the substrate
specifically is called the
enzyme's ACTIVE SITE.
 The substrate BINDS with the
enzyme at the enzyme's
ACTIVE SITE.
Enzymes

Enzymes can either:
 bring two (or more) reactants together more
quickly and force them to react
 stress bonds in a single substrate and cause
it to break apart more easily
Enzymes
An enzyme itself is NOT CHANGED by
the chemical reaction it catalyzes
 A single enzyme can repeat its catalytic
activity with many, many substrate
molecules - that is, it can be used over
and over again.

Enzyme catalyzed reaction
Enzymes

ENZYMES ARE VERY SPECIFIC!
 If the shape of the enzyme's active site
becomes damaged, it will be unable to bind
with its substrate so I will be unable to
function.
 If an enzyme loses its shape it is said to be
DENATURED.
○ enzymes can be denatured by HEAT
○ or by extremes in pH.
 Cells regulate enzyme activity
Enzymes cont….
regulate chemical pathways
 Make essential chemical compounds
 Involved in energy transfer
 communication
