Biology 181 Lab
TA: Heidi Ma
heidima@email.arizona.edu
Section 55
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…
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…
Name
 Year in School
 Major
 How much music on your iPod is illegally
downloaded

Course Homepage
 http://blc.arizona.edu/courses/181lab

or

http://www.mcb.arizona.edu/courses/181
lab
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 Software

Bio181L_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 Roberts
Asya handles absences- not me
 If you know in advance you will miss a
lab, see her IMMEDIATELY
 BSE Room 109, Mon-Fri: 800AM200PM 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
HOMEWORK
 Online
assignments due by
10:00 PM the night before lab
 CARE NOW!!!! Not at the end
of the semester……
Weekly Quizzes
 Quiz
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 Account
Homepage
 Left Column- MCB 181L Homework
Account

55

Enroll in your section

Create 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 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 shellbased off a mathematical model
 This fact is what characterizes how
atoms will BOND with other
atoms….creating a MOLECULE (many
atoms)

Review
The 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
gas
Every 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
Bonding
Covalent
 Ionic
 Hydrogen interactions
 These are discussed in GREAT DETAIL
in your homework- this review will be
BRIEF

Covalent Bonding
The SHARING of electrons
 If an atom needs more electrons to
reach the desired eight, it BONDS to
another atom

Example
Polar vs. Nonpolar Covalent

This is a VERY essential concept to
being successful in this course and
understanding today’s exercise
Polar
The 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 ELECTRONS
 This occurs most regularly in
molecules with a lot of C – H bonds
 Carbon and hydrogen have the same
electronegativity- no partial sharing

Example:
Nonpolar interactions
There are none. There is no partial
charge to be attracted to anything
 Nonpolar substances don’t care about
anyone
 Oils are common examples

Ionic Bonding
Arises 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
HYDROGEN
 Is 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 UP
This is your responsibility, not the
prep staff’s
 Please return everything at your
station back to normal
 Bio 181L homepage- bottom right link
says “weekly cleanup”- follow that

Homework for next week
Signed plagiarism contract
 Assessor: “181 Lab Intro”
 Assessor: “Molecular World Tutorial”
 “Atoms and Molecules”
◦ Crosswords OR OR OR VocabuWary

◦ VIA BIO181_ GO package
For Homework
You 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 Quiz
Next week’s quiz will include
Concepts from today
Atom colors
Deducing partial charges (from
tutorial)