{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

chapter 2 lecture notes

chapter 2 lecture notes - Cell and Molecular Biology...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
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. However, the 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 4. complex 5. dominated by large polymers (DNA, proteins, etc.) chains of molecules linked end to end. This is review (not covered in detail in class). Please make sure you understand the different bonds (covalent, ionic, hydrogen, etc). Chemical bonds- 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 chemical means. 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 chemical bonds. 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 the nucleus. Atomic # = # of protons (Hydrogen has 1 proton so atomic # = 1; carbon has 6 protons)
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Each atom has the same number of electrons as protons so overall charge is neutral (the charge carried by the protons is exactly equal and opposite to the charge carried by the electrons). All atoms of a given element have the same atomic # - this # determines the chemical behavior of the element. Atom weight = protons + neutrons (variation in neutrons in an element = isotopes) Ex Carbon 12- stable isotope (6 protons, 6 neutrons), carbon 14 is unstable (6 protons, 8 neutrons) so it decays The mass of atoms or molecules is often measured in daltons. 1 dalton = mass of one H atom. 1 proton or neutron weighs about 1/(6 x 10 23 ) gram, so 1 gram of hydrogen atoms contains 6 x 10 23 atoms. 6 x 10 23 is called Avogadro’s #. Avogadro’s # allows us to relate grams to moles.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern