Download Ch 2 3- Carbon-Based Molecules

Do Now:
• Name the properties of water that make it
important to life.
Grapple Time…
• Car manufacturers often build several types of
cars from the same internal frame. The size
and style of the cars might differ on the
outside, but they have the same structure
underneath.
• Carbon-based molecules are similar…but much
more varied.
Mini-Lesson: Carbon- Based
Molecules
Carbon atoms have unique bonding
properties
I. Carbon is Often Called The Building Block of
Life
a. Carbon atoms are the basis of most molecules
that make up living things.
b. Carbon is so important because its atomic
structure gives it bonding properties that
unique among elements.
i.
Carbon has four unpaired electrons in its outer shell,
so it can bond with up to four other atoms, including
other atoms. It acts like an “intersection”.
ii. Because of carbon’s ability to form four covalent
bonds, it can have three basic structures- straight
chains, branched chains, and rings.
c. Small molecules are subunits of an entire
molecule, like links in a chain. Each sub unit is
called a monomer.
d. When monomers are linked, they form a
polymer (chain). A polymer is a large molecule,
or macromolecule, made of many monomers
bonded together.
Four main types of carbon-based
molecules are found in living things
I.
Carbohydrates
a.
These are molecules composed of carbon,
hydrogen, and oxygen, and they include sugars
and starches.
b. Main function- Can be broken down to provide
a source of usable energy for cells.
c. Function- Can be used to give structure to plant
cells, fungal cells, and the exoskeletons of some
invertebrate animals.
d. Monomer: Simple sugars. Fructose and
glucose are both 6-carbon simple sugars.
These are also known as monosaccharides.
e.
Polymer:
i.
ii.
Polysaccharides such as starch (stored by plants which can
then be broken down as a source of energy) and glycogen
(known as “animal starch” which is stored in the liver of animals
and broken down for energy as well).
Cellulose is a polymer of glucose monomers that has a straight,
rigid structure and gives support to plant cells. The long,
stringy fibers in celery are cellulose fibers.
Polymer (starch)
Starch is a polymer of
glucose monomers
that often has a
branched structure.
Polymer (cellulose)
monomer
Cellulose is a polymer
of glucose monomers
that has a straight,
rigid structure
II.
Lipids
a.
b.
These are nonpolar molecules that are made up
of chains of carbon atoms bonded to oxygen
and hydrogen atoms.
Fats, oils, cholesterol, and waxes are examples.
c. Main function: Broken down as a source of
usable energy for cells.
d. Function: Part of a cell’s structure.
e. Function: Insulation.
f. Monomer: Three fatty acids bonded to
glycerol, called triglycerides.
Triglyceride
g. All cell membranes are made mostly of a type
of lipid called a phospholipid.
h. Cholesterol is a lipid that has a ring structure,
and although you hear about the dangers of
eating foods that contain a lot of cholesterol,
your body actually needs a certain amount of it
to function.
i. Makes up cell membranes.
ii. Your body uses it to make steroid hormones such
as testosterone and estrogen.
III. Proteins
a.
These are the most varied carbon-based
molecules in organisms.
b. Main Functions: Many! Speed up reactions,
function in the immune system, carry
oxygen, build structures of the body.
c. Monomer- Amino acids. These are molecules
that contain carbon, hydrogen, oxygen, nitrogen,
and sometimes sulfur.
d. Organisms use 20 different amino acids to build
proteins. Your body can make 12 of the amino
acids, and you can get the others from foods you
eat such as meat, beans, and nuts.
e. Proteins differ in the number and order of
amino acids. The specific sequence
determines a protein’s structure and
function.
f.
Hemoglobin in red blood cells transports oxygen.
The structure of hemoglobin depends on
hydrogen bonds between specific amino acids.
Just one amino acid change causes red blood cells
to have the curved shape of sickle-cell anemia.
Hemoglo
bin
hydrogen bond
IV. Nucleic Acids
DNA
a.
Main function: Store and transmit
hereditary information, which makes proteins.
b.
Monomers- Nucleotides, which are made up
of a sugar, a phosphate group, and a nitrogen
containing base.
c.
Examples of nucleic acids: DNA and RNA.
RNA
Independent Practice
• Fill in the macromolecule chart using the
info from this powerpoint and your notes!
• With your group, decide which
macromolecule you feel is THE most
important and why.
Debrief
• If you had to argue for one of these
macromolecules to be THE most
important, which would it be and WHY?
Next Steps/Homework
• STUDY…macromolecule quiz on Monday.