Download Lecture 4 POWERPOINT here

Lecture 4
Basic Chemistry refresher &
Macromolecules of all sorts
Latest model of an atom
02_01_atom.jpg
Hydrogen -the simplest
and smallest of all atoms
02_02_atomic number.jpg
Atomic number is the number of proton found in the nucleus
02_03_mole.jpg
The most
abundant
element in the
human body is
hydrogen
Why?
The most
abundant
element making
the planet is
oxygen
Why?
02_04_element abundance.jpg
02_05_chemical reactivity.jpg
02_06_stable arrangement.jpg
Sharing bond
Giving bond
Periodic Table of universal elements
02_07_periodic table.jpg
Ionic bond between two elements
02_08_ionic bond.jpg
The stability of a
covalent bond.
02_09_covalent bond.jpg
Remember that one
needs to supply
energy to get the two
atoms close together
in the first place
Properties of the most common bioelements
02_10_geometries.jpg
Hydrogen
Just one
A single bond allows rotation of the atoms either side,
whereas a double bond does not
02_11_C-C double bonds.jpg
The angle of the bond is very important
02_12_polar covalent.jpg
It may make a molecule polar, or…
…non-polar
Proteins rely very heavily on this molecular polarity (as well as other
Forces) to function correctly
02_13_Proteins bind.jpg
Atoms can be on the move constantly…
02_14_Protons on move.jpg
What is life made of…
ATOMS
MOLECULES
SPECIAL MOLECULES
02_15_organic molecules.jpg
These are the four organic classes of molecules
Glucose has this structure
02_16_glucose structure.jpg
Life systems are constantly making and breaking bonds
02_17_disaccharide.jpg
Macromolecules
•
•
•
•
Macro = huge
Amino acids can build into huge molecules
So can carbohydrates
So may nucleic acids
• There is theoretical limit to the size of these
There are three major types of biological macromolecules in
mammalian systems.
1. Carbohydrates
2. Nucleic acids
3. Proteins
Our tasty friends, fats, do not make the grade because they
do not form these immense complexes
FATS
• Here are some important facts about fats…
Saturated & Unsaturated Fats
Fact: we all need fats.
•Fats helps nutrient absorption, nerve
transmission, maintaining cell membrane integrity
etc.
•However, when consumed in excess amount, fats
contribute to weight gain, heart disease and
certain types of cancer.
•Fats are not created equal.
•Some fats promote our health positively while
some increase our risks of heart disease and other
ailments.
Bad Fats
•Saturated Fats
Saturated fats raise total blood cholesterol as well as LDL
cholesterol (the bad cholesterol). Saturated fats are
mainly found in animal products such as meat, dairy,
eggs and seafood. Some plant foods are also high in
saturated fats such as coconut oil, palm oil and palm
kernel oil.
Bad Fats 2
•Trans Fats
Trans fats are invented as scientists began to
"hydrogenate" liquid oils so that they can withstand
better in food production process and provide a better
shelf life.
As a result of hydrogenation, trans fatty acids are
formed.
Trans fatty acids are found in many commercially
packaged foods, commercially fried food such as French
Fries from some fast food chains, other packaged snacks
such as microwaved popcorn as well as in vegetable
shortening and hard stick margarine.
Good Fat
•Monounsaturated Fats
Have just one double bond.
Monounsaturated fats lower total cholesterol and LDL
cholesterol (the bad cholesterol) and increase the HDL
cholesterol (the good cholesterol).
Nut, canola and olive oils are high in monounsaturated
fats.
Good Fat 2
•Polyunsaturated Fats
Have two or more double bonds.
Polyunsaturated fats also lower total cholesterol and LDL
cholesterol.
Seafood like salmon and fish oil, as well as corn, soy,
safflower and sunflower oils are high in polyunsaturated
fats.
Omega 3 fatty acids belong to this group.
02_18_Fatty acids.jpg
02_19_fatty side chains.jpg
02_20_lipid membranes.jpg
02_21_Alanine.jpg
02_22_peptide bonds.jpg
Nucleotides
DNA and RNA are the two nucleic acids that come to mind first
However, there are many other uses for these important
compounds….
ATP - Adenosine Triphosphate - made of ribose sugar
This is the most important molecule for ready energy storage - it can
be considered to be the cells’ battery
02_23_ATP.jpg
02_24_energy carrier.jpg
02_25_nucleotide residues.jpg
By weight 25% of total bacterial cell contents are macromolecules.
They are essential in dictating the character of the cell type, ie.
E.coli, Salmonella, heart cells, liver cells, brain cells, etc.
Irrespective of the type of biological macromolecule being made
they have a common construction theme:
A subunit is added one at a time by a repetitive enzymatic process
02_27_monomeric subunits.jpg
However, unlike a bottle factory, where the same robot performs the
identical function, with these biological systems the subunits have to
be added in a set sequence because we have more than one flavour!
4 subunits in NA; 20 subunits in P’; many many in polysaccarides
Revision Question - What is this process called?
02_28_adding subunits.jpg
By design, macromolecule construction occurs by the addition of the
incoming subunit to just one end of the growing molecule, ie. DNA
growth only takes place at the 3’OH end of an existing DNA strand.
These processes are common to the construction of all these
macromolecules. YOU MUST REMEMBER THEM!
WOW!
Due to these differencing subunits there is the potential to
make many many alternative polymers. Consider:
• Proteins
• A protein of just 200 amino acids
• We have 20 amino acids to choose from each time
• There are then possible 20200 possible combinations!
• DNA
• 10,000 base DNA molecule
• We have just 4 different base types to choose from
• There are then possible 410000 possible combinations
More molecular interactions
We learnt that there are 3 types of atomic interactions between
atoms. ACTUALLY there are other forces too;
van der Waals attractions weaker than hydrogen bonds
attraction between closely located atoms
Hydrophobic interactions weakest of all
3 dimensional structure of water forces hydrophobic
groups together
Oil in water
Most P’s and RNA molecules have a stable confirmation
which they adopt readily and it is dictated by their primary
sequence.
02_32_Noncovalent bonds.jpg
E.g. immunoglobulins (Abs). Heavy chain and
light chain are made in various locations and
combine readily together.
02_33_macro complexes.jpg
Study Requirements
At the end of each chapter there are two resources:
• Essential Concepts
• You are required to learn each of these facts
for every chapter that we cover (These
concepts are essential!)
• Key Terms
• You are required to know the definition of
each of these regardless of the fact that they
did or did not appear on my PowerPoint slides
(one needs to be familiar with these terms for
subsequent courses)