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Biology 181 LabBiology 181 LabTA: Heidi Ma
Office Hours: Tuesday 9:30-10:30 AM Koffler 422
Office Hours
I’m only in my office hours if you ask me to be
I am more than willing to meet personally with you on another day if you need
A Little About Me…A Little About Me…
I’m an undergraduate just like you.
I’m a Biology Major with a minor in Ecology and Evolutionary Biology.
I’m from Tempe, AZ.
A Little About You…A Little About You…NameYear in SchoolMajorHow much music on your iPod is
illegally downloaded
Course Homepage
http://blc.arizona.edu/courses/181labor
http://www.mcb.arizona.edu/courses/181lab
Important Tabs
Course homepage◦Instructor Tab◦Section 55 under my picture◦Access to class calendar and links to assignments
Course Software
ADOBE SHOCKWAVE PLAYER◦Course Homepage◦Software Tab◦Left Column under “General” Find “Get Shockwave” link and
download program
Course SoftwareBio181L_GO
◦Is a folder that contains all the programs you will need for homework
◦Course Homepage Software Links for “MAC” and “WIN” at top of page
◦DOWNLOAD AND KEEP!!!!◦This is how you will access your
homework
Course Software
Bio181L_Go package◦Has various homework assignments◦The most important one is
ASSESSOR This contains the majority of your online
tutorials
Syllabus
Course homepage- link is in right column
READ for next week◦Questions from syllabus included on next week’s quiz and this week’s homework
Asya RobertsAsya handles absences- not meIf you know in advance you will
miss a lab, see her IMMEDIATELY BSE Room 109, Mon-Fri: 800AM-
200PM is her general schedule
Plagiarism Contract
Page xiii of Lab Manual◦Sign and return to me by beginning of lab next week
◦Having a signed syllabus will be 10 points of your first quiz
HOMEWORKOnline assignments due by 10:00 PM the night before lab
CARE NOW!!!! Not at the end of the semester……
Weekly QuizzesQuiz in the first ten minutes of class every week
Used as late penalty Material covers current day’s lab and concepts you need to complete the lab
READ lab manual….it will save time
Create 181L AccountHomepageLeft Column- MCB 181L
Homework Account
Enroll in your section 55Create a password and WRITE IT
DOWN- this is what you will use the rest of the course
LAB 1: MOLECULAR TAO
The World is made of Atoms Made up of protons, neutrons,
and electrons
Review of Terminology
Nucleus (the center)= protons (+ charge) and neutrons (neutral charge)
Electrons (- charge) - rotate AROUND the nucleus
Coloring Your WorldColoring Your World
Periodic Table of Elements (0-1 Lab Manual)The number below the elemental symbol refers to the amount of PROTONS in the nucleus◦This EQUALS THE NUMBER OF ELECTRONS rotating about the nucleus
◦This is meant to BALANCE THE CHARGE
BUT
Atoms “prefer” to have EIGHT electrons in their outermost shell- based off a mathematical model
This fact is what characterizes how atoms will BOND with other atoms….creating a MOLECULE (many atoms)
ReviewThe rings around the atoms are a
way to depict “orbitals” or the “electron shell” – which is the space where electrons reside
Atoms like to have EIGHT electrons in their OUTERMOST orbital or electron shell (EXCEPT HYDROGEN AND HELIUM)
Electronegativity
A characteristic that describes how BADLY an atom wants an electron
This property determines how the atom will bond and HOW MANY bonds it will make
The GENERAL trend
How badly do atoms want electrons?
The CLOSER an atom is to having the full eight electrons in the outer shell, the MORE they want electrons= the more electronegative they are
Elements are organized into columns on the PTE to denote how many electrons are still needed
Everyone wants to be a noble gasEvery atom seeks to be like the
gases in the right hand column of the periodic table
These elements already have eight electrons in the outer shell
The column number indicates how many more electrons the element needs to have eight total
How many bonds?However many electrons are
missing from the outer shell is how many bonds the atom will make
EX: Nitrogen- in column 5, meaning it needs 3 more electrons, meaning it will bond 3 times
NH3 Ammonia
Example: Ammonia
BondingCovalent IonicHydrogen interactions These are discussed in GREAT
DETAIL in your homework- this review will be BRIEF
Covalent Bonding
The SHARING of electronsIf an atom needs more electrons
to reach the desired eight, it BONDS to another atom
Example
Polar vs. Nonpolar CovalentThis is a VERY essential concept
to being successful in this course and understanding today’s exercise
PolarThe electrons shared in the
covalent bond spend MORE TIME ROTATING ABOUT THE MORE ELECTRONEGATIVE ATOM
UNEQUAL SHARING OF ELECTRONS BETWEEN ATOMS
Results in partial charges on each atom
THE Example: Water
What creates the charge?How many protons does oxygen
have?How many electrons does oxygen
have?How many does it have if the two
electrons from water is rotating around it? Is this a charge balance?
Polar Interactions
Molecules with polar covalent bonding tend to be attracted to OTHER molecules with polar covalent bonding
Why? Because charges attract each other
Nonpolar
EQUAL SHARING OF ELECTRONSThis occurs most regularly in
molecules with a lot of C – H bonds
Carbon and hydrogen have the same electronegativity- no partial sharing
Example:
Nonpolar interactionsThere are none. There is no
partial charge to be attracted to anything
Nonpolar substances don’t care about anyone
Oils are common examples
Ionic BondingArises due to the attraction of
opposite charges One atom steals the electron= has
total ownership over electron
Hydrogen “Interactions” Happens BETWEEN molecules Does NOT MEAN A BOND WITH
HYDROGENIs the INTERACTION of hydrogen
with an electronegative atom, such as oxygen, nitrogen, or fluorine
Example: Network of water molecules
Today’s Lab Activity
Computer desktops- Lab 1 Tao Stack Exercise
Work in groups of 3-4
Discussion Points
Why did water “bead up” on wax paper?
Why did adding salt to the alcohol mixtures create a layer for the propanol mixture?
Why did the pepper flakes “flee” the toothpick dipped in detergent?
CLEAN UPThis is your responsibility, not the
prep staff’sPlease return everything at your
station back to normal Bio 181L homepage- bottom right
link says “weekly cleanup”- follow that
Homework for next weekSigned plagiarism contractAssessor: “181 Lab Intro”Assessor: “Molecular World
Tutorial” “Atoms and Molecules”
◦Crosswords OR OR OR VocabuWary
◦VIA BIO181_ GO package
For HomeworkYou must download the
BIO181_GO package and access the homework there
OR access it via the Software tab on the website, but downloading the package works better
The website is less secure, it functions slower than the BIO181L_GO package
Next Week’s QuizNext Week’s Quiz
Next week’s quiz will includeConcepts from today
Atom colorsDeducing partial charges (from
tutorial)