AP Biology Discussion Notes
Monday (or Tuesday) 1/5/2015
WELCOME
BACK!
You may choose your seat
Semester 2 AP BIOLOGY
• DNA Structure & Function
– DNA replication, Protein synthesis
• Gene Activity & Biotechnology
– (Genetics & Inheritance)
• Diversity & Organisms
• Anatomy/Development
• Ecology
– Animal behavior, community & population
Ecology
Things to think about:
1. Look over material before the next class
–
Write down thoughts, connections or questions
2. Read the chapter
– even when not “assigned”
3. Watch Videos about topics
– even when not assigned
4. Start reviewing topics from last semester
– Tie them to topics this semester and write
down connections or questions
5. ASK QUESTIONS
PANIC now
and avoid the
rush!
AP BIO TEST
th
May 11
Goals for Today
• Be able to name the scientists that helped
build our knowledge of DNA and be able
to describe their contributions
• Be able to discuss how scientific
understanding is built
• Be able to list or understand the
contributions of less known scientists
• Be name the 3 basic components of DNA
Question of the Day
• Each day in class I will put up a
question of the day.
• Students will be responsible for writing
the question & their best answer.
• After each student has answered the
question on their own we will discuss it
as a class
• QODs will be collected before each test
for points!!!
Question of the Day 1/(5)
• What is DNA? Write your thoughts
down, and what you know about it, you
don’t have to be sure you are correct!
How long have we known what
was the genetic material? (What
molecules allow us to inherit
similarities and characteristics
from our parents?)
3 likely candidates
• DNA
• RNA
• Protein
What do we know about the
relationship between DNA &
Protein?
• DNA
• RNA
• Protein
Griffith’s Experiments (1928 – publication)
Griffith discovered that harmless bacteria could turn
virulent when mixed with bacteria that cause disease.
A bacteria that is virulent is able to cause disease.
Griffith had discovered what is now called
transformation, a change in genotype
caused when cells take up foreign genetic
material.
Oswald Avery’s Experiments (1930 – 1944)
•Series of experiments showed that the activity of the material
responsible for transformation is not affected by proteindestroying enzymes.
•The activity is stopped, however, by a DNA-destroying
enzyme.
•Thus, almost 100 years after Mendel’s experiments,
Oswald Avery and his co-workers demonstrated that
DNA is the material responsible
for transformation NOT protein.
DNA or Proteins?
• Even after Avery’s experiments it
was not widely accepted that DNA
was the genetic material, but this
line of research did spark a race of
sorts to figure out more about the
physical structure of DNA
DNA Nucleotide – a nucleotide is
the three component parts together
Phosphate
Group
N
Sugar
(deoxyribose)
Nitrogenous base
(Adenine,
Guanine,
Cytosine, or
Thymine)
Erwin Chargaff
• Chargaff’s research
analyzed the amount of
each nitrogen base in
different organisms
• Humans Adenine=
30.4%
• E. coli Adenine = 24.7%
Erwin Chargaff
• Chargaff’s research
determined that in DNA
there were always equal
parts
• Adenine = Thymine
As well as equal parts
• Cytosine = Guanine
Erwin Chargaff
• Chargaff’s research
determined that in DNA
there were always equal
parts
• Humans Adenine = 30%
• Humans Thymine = ?
• Humans Guanine = ?
• Humans Cytosine = ?
DNA’s Role Revealed
In 1952, Alfred Hershey and
Martha Chase used the bacteriophage
(__________) to prove that DNA carried
genetic material.
A bacteriophage is a virus that infects
bacteria.
Life Cycle of a virus (bacteriophage)
Hershey & Chase use viruses to
prove DNA is the genetic material
Hershey & Chase use viruses to
prove DNA is the genetic material
Still needed to know the
structure!
• What is the structure of DNA?
• Who discovered the structure of DNA?
DNA is shaped like a double helix (a twisted
ladder)
This shape was discovered by two scientists:
James Watson & Francis Crick
Scientific Knowledge
• Scientific knowledge and discovery is
always built on what we already know,
past discovery & knowledge
• Were Watson & Crick
the only ones
responsible for
discovering the structure
of the DNA molecule?
Who is Rosalind Franklin?
Discovery of DNA’s Structure
• Secret of Photo 51 Video
SPECIES of the Day
Poinsettia - Euphorbia pulcherrima
ASSIGNMENT
DUE TOMORROW
Set 2 goals for the quarter
List 3 ways you can help yourself
to achieve each goal