Name: __________________________________
Notes: Biochemistry
Date: _________________________
RB- ____________
The Basics:
All things are made up of tiny particles called atoms.
There are only about 100 different types, called elements
The most common elements in biology are:
C = carbon
H = hydrogen
O = oxygen
N = nitrogen
P = phosphorus
Organic Molecules:
The evil Regents Exam writers use the words “organic molecules” when they mean FOOD.
Organic means the molecule contains the elements, carbon and hydrogen.
If something does NOT contain those 2 elements, we say it is inorganic.
The most abundant (common) inorganic compound in your body (& on the planet) is water.
The Big Three Organic Molecules:
There are 3 big groups of organic molecules that you must know – carbos, proteins, and lipids
1. Carbohydrates:
What are they? sugars and starches.
What is their use in the body?
energy
What elements do they contain? Carbon, hydrogen, and oxgen
The smallest carbos are called simple sugars, or monosaccharides
(mono = one saccharide = sugar)
The monosaccharide you need to know is named glucose
Glucose’s chemical formula is C6H12O6
Is it organic? Yes How do you know? Has both carbon and hydrogen
The image to the right is a structural diagram of glucose. It shows how the
C, H, & O are arranged in the molecule.
Draw a schematic image to show the general shape of a
glucose molecule:
Carbohydrates continued:
If you hook 2 simple sugars (2 monosaccharides) together, you get a disaccharide
An example of a disaccharide is table sugar, or sucrose
If you hook MANY simple sugars together, you get a
polysaccharide
An example of a polysaccharide is starch
Sketch diagrams of a disaccharide and a polysaccharide:
How does the body join molecules together and take them apart? Dehydration Synthesis
There are 2 simple processes used over and over in the body.
Dehydration synthesis: making more complex, larger molecules by removing water.
Hydrolysis: breaking up large molecules into smaller molecules with the addition of water.
Draw a sketch showing the dehydration synthesis of 2 simple sugars into a disaccharide.
How many water molecules got squeezed out, to form the new bond? 2
Draw a sketch showing the hydrolysis of a polysaccharide into several monosaccharides.
How many waters did we add? 2
DEHYDRATION SYNTHESIS to make a disaccharide; additional water removal would
result in a polysaccharide.
Plants use photosynthesis to combine carbon dioxide (CO2) and water (H2O) to make glucose (the
monosaccharide you need to know). They capture the energy from the sun and it is stored in the
bonds of the glucose.
Plants either use the glucose for energy (by doing cellular respiration) or they can store it in chains
(a polysaccharide) called starch (hint: what do we call foods that are made from plants—like
spaghetti, bread, or cereal?)
Plants also use their glucose to make their cell wall. It is composed of “sheets” of glucose chains,
called cellulose making it a very rigid structure! You can probably imagine that with EVERY plant
having cellulose around EVERY cell—it’s the most abundant organic compound!
When animals eat plants, the starch is digested (by hydrolysis) into individual glucose molecules
(yup, that monosaccharide again!)
The animals can either use the glucose for energy (by doing cellular respiration) or they can store
it in their liver or muscle cells in long chains called glycogen (sometimes referred to as “animal
starch”).
Of course, some animals use polysaccharides for structure, too! Arthropods (like insects and
crustaceans) have exoskeletons made out of chitin That’s what makes the “crunch” when you step
on a beetle or break into your lobster dinner!
2. Proteins:
What types of things are made of protein? Meat (muscle), milk, eggs, beans, lentils, seeds, nuts
What is their use in the body? Repair and Growth
What elements do they contain? Carbon, hydrogen, oxygen, nitrogen
Proteins are long chains of amino acids
Draw a diagram of an amino acid:
There are 20 different things that could go where you see that “R”, so there are only 20 different
amino acids. Are there only 20 different proteins? no
Proteins are chains that can be thousands of amino acids long. The R Group of the amino acids
determines what protein it is. Having amino acids in the wrong order, or substituting the wrong one,
or skipping one will usually result in a defective protein. Sometimes this is not really a big deal, but
sometimes these mistakes can result in diseases like diabetes or
Cystic fibrosis
What process would your body use to join up all those amino acids into a protein chain?
Dehydration Synthesis What would you have to remove to do it? Water
The bond that holds 2 amino acids together is called a peptide bond, so proteins (chains of many
amino acids) are sometimes called polypeptide
Actually, a protein is really 1 or more polypeptides bent and twisted into a 3-D shape. The shape of
the protein determines its job or function
If you chemically added water to a long protein chain, what would you end up with? Amino acids
what type of reaction did you do? hydrolysis
Quick Review:
What element in proteins is NOT in carbos?___________________
Are proteins small molecules or large?_________ Another name for a protein?_________________
DEHYDRATION SYNTHESIS to make a dipeptide; additional water removal would result in
a polypeptide:
The image to the right shows the formation of a complex
protein molecule.
The primary protein structure is a sequence of a chain
of amino acids
The secondary protein structure occurs when the
sequence of amino acids are linked by special bonds
called hydrogen bonds, causing the chain to curl up
(alpha helices) at some locations and form pleats (beta
sheets) at other locations.
The tertiary protein structure occurs when certain
attractions are present between the segments of the
secondary structure, causing the molecule to form folds and kinks.
The quaternary protein structure is a protein consisting of more than one polypeptide (chains of
amino acids). It is the functional protein that is the right shape to do a certain job!
The image to the right shows the quarternary
structure of hemoglobin. It is a protein found in
red blood cells. It gives red blood cells their red
color.
Hemoglobin is the right shape to bind to oxygen
molecules to transport them throughout the body!
What determines hemoglobin’s shape?
Notes – Lipids pp. 98-99 Green Biology Book
What is an important characteristic of all lipids? Tend to be insoluble in water
What are they? fats, waxes and oils.
What are they used for, in the body? Insulation, long term energy storage, some hormones, cell
membranes (phospholipids)
What elements do they contain? Carbon, hydrogen, and oxygen
What process do you think is used to connect the fatty acids to the glycerol? Dehydration synthesis
What are the products of the hydrolysis of a lipid? Glycerol and three fatty acids
In the image on the right, a triglyceride
(a fat molecule) is “flipped” onto its
side. See how it kind-of looks like the
letter ______ with the glycerol
molecule making up the vertical side of
the “E” and the 3 fatty acids making up
the horizontal lines of the “E”.
Notice how BIG this molecule is! Look
at all of those carbons, all hooked together in chains! Now think back (or look back in your notes) to
glucose. In glucose, the energy is stored in its bonds, but it does not have nearly as many as this
molecule. Small surprise that we use this molecule for our Energy (fat) reserves (stored)!