Cell and Molecular Biology
Chemical components of cells
Today, we will discuss the different molecules of cells and the chemical bonds that hold
these molecules together.
So, today, we’ll be reviewing things that
you should already
have had several times in the past; bonds, carbons, associations with water, etc.
Living organisms are governed by the laws of chemistry and physics.
chemistry of living organisms is special in that it deals with organic compounds or carbon
compounds. This is called organic chemistry.
You should have already taken organic
chemisty prior to this class- or, at the very least, you should be taking it right now.
Chemistry of living organisms
1. organic- carbon compounds
2. reactions take place in aqueous solution
3. reactions take place in a narrow temp range
5. dominated by large polymers (DNA, proteins, etc.) chains of molecules linked end to
This is review (not covered in detail in class). Please make sure you understand the
different bonds (covalent, ionic, hydrogen, etc).
Matter is made of elements- ex, hydrogen, carbon and oxygen (there are 92 naturallly
occuring elements). Elements are substances that may not be broken down or changed by
Living organisms use only a small number of elements: C,O, H, N, S
and P constitute ~99% of the organic molecules/water in living organisms. Living
organisms also contain small (Na, Ca, Mg, K) or trace amounts of other elements (Fe, Zn,
Cl, I , Cr, Cu, Se, Mn).
The smallest particle of an element is an atom. Atoms are made from protons (+),
electrons (-), and neutrons (not charged).
Atoms are linked together to form molecules and the way that they are linked together in
groups determines the characteristics of the molecule.
So, it’s important to understand
Atoms have a dense, centrally located nucleus- positively charged- contains most of the
atom’s mass. This nucleus contains protons and neutrons.
The nucleus is surrounded by a
much less dense cloud of negatively charged electrons. The electrons move rapidly about
Atomic # = # of protons (Hydrogen has 1 proton so atomic # = 1; carbon has 6 protons)