Textbook Notes (368,794)
Canada (162,165)
Biology (653)
BIO206H5 (60)
Chapter 2

Chapter2.docx

3 Pages
118 Views
Unlock Document

Department
Biology
Course
BIO206H5
Professor
George S Espie
Semester
Fall

Description
CELL BIOLOGY CHAPTER 2  The chemistry of life is based o carbon compounds  It depends on chemical reactions that take place in watery or aqueous solutions and in the relatively narrow range of temperatures experienced on Earth  It is enormously complex and is dominated and coordinated by a collection of enormous polymeric molecules whose unique properties enable organisms to grow and reproduce  The polymeric molecules form from chains of chemical subunits linked end- to-end  It is tightly regulated; cells deploy a variety of mechanisms to make sure that all their chemical reactions occur at the proper place and time CHEMICAL BONDS  Matter is made of combinations of elements  Elements are substances that cannot be broken down or converted into other substances by chemical means.  The smallest particle of an element that still retains its distinctive properties is an atom  The characteristic of substances other than pure elements depends on the atoms they contain and the way these atoms are linked together in groups to form molecules  Living cells are made up of a limited number of elements , four of which H, C, N, O make uo 96.5% of their mass CELLS ARE MADE OF RELATIVELY FEW TYPES OF ATOMS  Each atoms has at its center a dense, positively charged nucleus which is surrounds at some distance by a cloud of negatively charged electrons held in an orbit by electrostatic attraction to the nucleus  The nucleus consists of two kinds of subatomic particles: 1) Protons; which are positively charged 2) Neutrons; which are electrically neutral  The number of protons present in an atomic nucleus determines its atomic number  The electrical charge carried by each proton is exactly equal and opposite to the charge carried by a single electron.  Number of protons = number of electrons  All atoms of a given element have the same atomic number  Neutrons are uncharged subatomic particles with essentially the same mass as the protons  Neutrons contribute to the structural stability of the nucleus; if there are too many or two few the nucleus may disintegrate by radioactive decay  Neutrons do not alter the chemical properties of the atom  An element can exist in several physically distinguishable but chemically identical forms called isotopes, each having a different number of neutrons but the same number of protons  The atomic weight of an atom or the molecular weight of a molecule is its mass relative to that of a hydrogen atom, this is essentially equal to the number of protons plus the number of neutrons that the atom or the molecule contains  The mass of an atom or a molecule is generally specified in Daltons  6 x 10 is called Avogadro’s number, it is the key scale factor describing the relationship between everyday quantities and
More Less

Related notes for BIO206H5

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit