Human Physiology: An Integrated Approach 5th Ed. - Ch. 2

23 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences

Chapter 2 Notes Chemistry Review Atoms: the building blocks of all matter o Composed of 3 smaller particles: Protons: +vely chged Electrons: -vely chged Neutrons: unchged o Protons and neutrons account for most of the atoms mass Clustered in the center of the atom in the nucleus, a dense body o Lightweight es rapidly move around the nucleus, which accounts for almost all of the atoms vol Most of an atoms vol is empty space Atomic number: # of atoms protons in its nucleus o determines the element, which is the simplest type of matter 3 elements oxygen, carbon, and hydrogen make up more than 90% of the bodys mass 8 additional elements N, P, Na, K, Ca, Mg, S, and Cl make up the list of major essential elements of the body in addition, the body also needs trace amts of other elements (like selenium, chromium, etc.) called trace elements or minor essential elements Atomic mass: total mass of the protons and neutrons in the atom o Expressed in atomic mass units (amu); 1 amu = 1.6605x10 -27kg p s and n s have about the same mass of roughly 1 amu (es are much much smaller) 1 Da (Dalton) = 1 amu # of neutrons may vary in an atom o atoms of an element that have diff numbers of neutrons = isotopes of the element o all isotopes of an element have the same chemical properties b/cuz - these properties are determined by the e configuration of the atom and not by the # of neutrons o some isotopes (radioisotopes) are unstable and emit energy called radiation often used in medicine Electrons are arranged around an atom in a series of E levels, or shells o Shell E increases as shell distance away from nucleus increases o arrangement of es in the outermost shell determines its ability to bind w/ other atoms - es play 4 important roles in physiology: a. covalent bonds: strong bonds formed by the sharing of es to form - molecules b. ions: electrically chged atom; formed through the addition or removal of es i. -vely chged atom = anion; formed through the addition of electrons ii. +vely chged atom = cation; formed through the removal of electrons c. high-energy electrons: the es in certain atoms can capture E from their environment and transfer it to other atoms, so that the E can be used for synthesis, movement, and other life processes. The released E may also be emitted as radiation d. free radicals: atoms that are converted (via radiation) into UNSTABLE free radicals have their electron distribution altered i. all free radicals have at least ONE unpaired e - - ii. free radicals try to steal an e from another molecule, which in turn does the same thing, and this process continues indefinitely disrupts normal cell function iii. anitoxidents are substances that prevent cell damage by giving up electrons w/o becoming free radicals Molecular Bonds and Shapes molecules: formed when 2 or more atoms link together by sharing es - o compounds: molecules made up of more than one element C6H 12=6compound; O comp2und Bonds are formed through the transfer of electrons from one atom to another, or through the sharing of electrons by 2 atoms o Covalent and ionic bonds are strong bonds o Hydrogen bonds and Van der Waals forces are weak bonds contribute to molecular interactions Covalent Bonds - - Covalent bond: formed when two atoms share a pair of es, one e from ea. atom o Strong bond o Reqs input of E to break Atoms are likely to form molecules by sharing their unpaired electrons w/ other atoms that have unpaired electrons o Ea. shared e pair represents a single covalent bond Double bond: bond formed by sharing TWO pairs of electrons Polar molecules: molecules that have regions of partial +ve and partial ve - regions because of an uneven sharing of es Nonpolar molecules: molecules that DONT have regions of partial +ve and partial ve chged due to evenly distributed and shared electrons Polar molecules = hydrophilic; they dissolve easily in water Nonpolar molecules = hydrophobic; they DONT dissolve well in water Ionic Bonds If an atom completely loses or gains electrons, it becomes an ion o Ionic bond: formed when one atom takes one or more electrons from another atom, and as a result is attracted and bonds with that atom H-Bonds and Van der Waals Forces Hydrogen bond: a weak attractive force b/w an H atom and an O, N, or F atom that is nearby o Responsible for the surface tension of water Van der Waals forces: weak, nonspecific attractions b/w the nucleus of any atom and the electrons of nearby electrons Molecular Shape and Function Both covalent bonds and weak bonds play an important role in determining molecular shape o A molecules shape is closely related to its function Biomolecules Human physiology deals a lot with the elements C, H, and O, as well as P and N which are found in many biological molecules Organic molecules: molecules that contain carbon o Biomolecules: organic molecules associated w/ living organisms 4 major types of biomolecules: o carbohydrates o lipids o proteins o nucleotides o many of these are polymers large molecules made up of repeating units functional gps: combinations of atoms
More Less

Related notes for BIOD27H3

Log In


Don't have an account?

Join OneClass

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

Sign up

Join to view


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.