advanced placement biology mr. jim sullivan boston university

Advanced Placement Biology

Mr. Jim SullivanBoston University

Boston University Project STAMP

• STAMP– Sciecne, Technology, And Math

Partnerships

Undergraduate- Boston CollegeStudy of Painted Turtles

Past:Undergraduate- Boston College

Study of Painted Turtles

Past:Graduate- University College

DublinNutrient Cycling

Graduate- University College Dublin

Nutrient Cycling

Past:‘Radio’-pharmaceuticals

• Using ‘radioactive’ chemicals to create therapeutic medicines

• Designed to fight cancer

Present:

• Boston University– Ecology – Molecular Biology– Environmental

Chemistry

• You!– Working with you

guys.– Exploring and

understanding biology from the molecular to the organismal level

Nematostella vectensis

Time for the flashlight!

• Before going into Genetics, we need to review basic chemistry

Time for the flashlight!

• Before going into Genetics, we need to review basic chemistry

• Why is Chemistry important for understanding biology?

The Building Block of Life-The Atom

What are atoms comprised of?

What are atoms comprised of?

• Neutrons, Protons, and Electrons

• Neutrons– Electrically neutral– Found in nucleus– Have mass

• Protons– Positively charged– Found in nucleus– Have mass

• Electrons– Negatively charged– Encircle the nucleus– Do not have mass

Contains protons and protons

Define Mass

Define Mass

• Mass is an important unit of measurement which will come up often throughout the year.

• Mass is a measure of ‘matter.’

• It is a function of both the density and the size of the object in question.

• Are mass and weight identical?

How do we describe atoms?

• We define different atoms based upon the number of each of their three components.

• What are the three parts of an atom again?

How do we describe atoms?

• We define different atoms based upon the number of each of their three components.

– Neutrons, Protons, and Electrons

• Each atom has a unique number of protons.

• Atoms are (usually) electrically neutral, so the number of electrons equals the number of protons.

• The atomic mass describes the sum of protons and neutrons

How Do We Differentiate Between Atoms?

• Tell me how many neutrons, protons, and electrons are in the following elements

612C

714N

15 30P

816O

16 32S

11H



612C

714N

15 30P

816O

16 32S

11H

•16 protons, 16 neutrons, 16 e-



612C

714N

15 30P

816O

16 32S

11H





612C

714N

15 30P

816O

16 32S

11H






•1 proton, 0 neutrons, 1 e-



612 C

714 N

15 30 P

816 O

16 32 S

11 H

•These 6 elements, which you can remember as ‘SPONCH’ make up 97.6% of your body, by mass

Sulfur

Phosphorous

Oxygen

Nitrogen

Carbon

Hydrogen



612 C

714 N

15 30 P

816 O

16 32 S

11 H

•Two other essential elements areCalcium (Ca) and Iron (Fe), which you remember as ‘CaFE.’•Using your Periodic Table, tell me howneutrons, protons, and electrons are present in atoms of these elements

Bonds

• What is a bond?

Bonds

• What is a bond?– A bond between atoms is the result of

interactions bringing atoms closer together

• Name different types of bonds

Types of Bonds

• There are four types of bonds that will be important to us throughout the year:– Ionic Bonds– Covalent Bonds– Hydrogen Bonds– van der Waals Interactions

• For now, you should understand Ionic and Covalent bonds, we’ll cover the others later

Ionic and Covalent Bonds

• These bonds are interactions between atoms in which each of the atoms involved attempts to fill its valence shell with eight electrons

• In ionic bonds, there is taking and giving of electrons

• In covalent bonds, there is a sharing of electrons

Ionic Bonds- The Bully

• Look for the ‘electronegativity (δ)’ section of your periodic table.

• This number indicates how strongly electrons are drawn to the nucleus of that particular atom; the higher the

number, the greater the affinity

• If the difference of electronegativities (δ) of atoms which share a bond is ≥ 1.5, then the bond is ionic

• The more electronegative atom involved ‘takes’ the electrons from the less electronegative

Covalent Bonds- Friendly Atoms

• If the difference between electronegativities (δ) of atoms sharing a bond is < 1.5, then the atoms in the bond are sharing the electrons– These are Covalent Bonds

Just to confuse you…

• There are two types of covalent bonds– Non-polar– Polar



• In Non-polar Covalent bonds, the electrons are shared almost completely equally– CH4 is an example

– The difference in terms

of δ between C and H is

2.6 - 2.2 = 0.4C

H

H

H

H



•In Polar Covalent Bonds, the electrons are still shared… but not as equally. H2O is an example

•The difference in electronegativities (δ) between O (3.4)and H (2.2) is 3.4 – 2.2 =1.2 •This is still a covalent bond, but one in which electrons are not evenly shared

•The polar nature of water gives it unique properties!

Ionic or Covalent?NaCl

Ionic or Covalent?NaCl- Ionic (3.2 - 0.9 = 2.3) Table Salt

N2


N2- Covalent (3.0 – 3.0 = 0) Dinitrogen gas, makes up ~78% of the air we breathe

CH4



CH4- Covalent (2.6 – 2.2 =0.4) Methane, aka Natural Gas

HF



CH4- Covalent (2.6 – 2.2 =0.4) Methane, aka Natural Gas

HF- Ionic (4.0 – 2.2 = 1.8) Hydrogen flouride

Review

• What are the three components of an atom?

Review


• How can we interpret the periodic table.– Write down the number of protons, electrons,

and neutrons for five elements. Write down the electronegativity of each also.

Review


• How can we interpret the periodic table.– Write down the number of protons, electrons,

and neutrons for five elements. Write down the electronegativity of each also.

• What is a bond?– Name four types of bonds

Review

• What are the three components of an atom?• How can we interpret the periodic table.

– Write down the number of protons, electrons, and neutrons for five elements. Write down the electronegativity of each also.


• What is the difference between an ionic and a covalent bond?

Review

• What are the three components of an atom?• How can we interpret the periodic table.

– Write down the number of protons, electrons, and neutrons for five elements. Write down the electronegativity of each also.


• What is the difference between an ionic and a covalent bond?

• What are the two types of covalent bonds?

Back to the Future!

• Next class we will cover Chapter 3.– This will be a discussion of the unique

properties of water, thanks to the polar covalent bonds H2O forms.

• We will also introduce some of the concepts from Chapter 5

• After that, we will begin our discussion of Unit 3: Genetics

Homework for next Teusday

• Review the handouts from this class

• Read Chapter 3.

• Read pages 52-54.

• Skim Chapter 5. Look at all of the figures and read the figure legends. Don’t worry about the details.

advanced placement biology mr. jim sullivan boston university

Documents

mass slide

e slide

atom slide

cancer slide

mass protons

s 11h11h slide

electrons neutrons

basic chemistry slide