Chapter 1 - Introduction: Exploring Life

Transcription

Textbook
Summer Assn
GNS AP Biology
Website
NEW AIM: What is Science?
What is
Science
Science is something that you do. It is a verb. It’s the process we use to try and know
something. Remember…its all about making observations and using them to build models,
which are in turn used to make predicts/decisions.
AIM: What is Science?
How do we do
science
?
It’s all about making observations...
Ex. The structure of DNA
The observations:
Phoebus Levene
Russian Organic Chemist
Rockefeller University
1928
One of the first models of DNA
(the tetranucleotide)
The observations:
Levene observed the behavior of polarized light
passing through molecular structures in order to
determine the four nucleotides of DNA and how they
covalently bind to each other.
Phoebus Levene
Russian Organic Chemist
Rockefeller University
1928
One of the first models of DNA
(the tetranucleotide)
The observations:
Erwin Chargaff
Austrian Biochemist
Columbia University
1952
The observations:
Erwin Chargaff
Austrian Biochemist
Columbia University
1952
The observations:
Chargaff took DNA from many
different species, hydrolyzed it down
to nucleotides, and performed
chromatography to separate them
from each other and compare
concentrations.
He observed an A:T ratio of 1:1 and a C:G
ratio of 1:1, but the (A/T):(C/G) ratio
varied, which refuted the
tetranucleotide model.
He did not observe or predict base pairing (That
A hydrogen bonds to T, etc…)
The observations:
Rosalind Franklin
British Chemist/Physicist
King’s College
1953
The observations:
Dr. Franklin used X-rays as a means of
making observations. She purified DNA
is a very special way and then hit the
DNA with Xrays to produce the image
to the right (photo 51)
The observations:
Photo 51 has a particular pattern that
indicates the molecule is a double helix.
Controversy ensued after James
Watson got his eyes on the photo
before being published, which can be
read about here:
http://www.biography.com/people/
rosalind-franklin-9301344#scientificdiscoveries-and-credit-controversy
The observations:
Rosalind Franklin
British Chemist/Physicist
King’s College
1953
Map showing England and the distance between Franklin and
Watson (Cavendish Labs)
The current DNA model:
James Watson (mol. biologist) Francis Crick (biophysicist)
University of Cambridge
1953
Watson and Crick using the following
observation without ever doing a
single experiment to build the
current model of DNA:
1. 
2. 
3. 
Polarized light observations indicating the
four nucleotides and how they are
connected
Chargaffs chromatography observation that
A:T is 1:1 and C:G is 1:1, but vary in ratio to
each other.
The unpublished photo 51 indicating a double
helix
James Watson (mol. biologist) Francis Crick (biophysicist)
University of Cambridge
1953
Where are the control groups in all this science?
How were the foundations of genetics unraveled?
Through careful observations of pea plant matings!
How were the foundations of genetics unraveled?
SCIENCE:
It is all about careful
observation (data collection)…
Followed by building models
that fit the data…
SCIENCE:
Have people figured out
better ways to observe
DNA?
YES! There are a number of
techniques, but none as
amazing as X-ray
crystallography to view the
molecular world!!!
SCIENCE:
h
t
a
m
Fancy
Data (Observation) of where
electrons are located in crystal…
Modern day diffraction image data
(observation) off a crystallized molecule…
Model of the
molecule within
the electron
density data….
SCIENCE:
The most sophisticated scientific instrument?
SCIENCE:
All you do is collect and process data…build and refine models…and
use these models to make predictions constantly…
SCIENCE:
Come up with your own example of you doing science today…
and write it up
We are always doing science!
Because you are always making observations, predictions, etc… When you
walk down the hall you are collected data (visual data with your eyes,
auditory data with your ears, etc…). With this data you generate questions
and make predictions.
For example, you observe someone running at you.
Hypothesis: The person will run into me.
Prediction: If I do not move then I will get hit.
Experiment: Stay put.
Results: The person hit me supporting my hypothesis.
SCIENCE:
We are always doing science. In fact, what you see, the image in
front of you right now, is a scientific model. Explain.
How does the scientific
enterprise actually work?
What is the goal of this
enterprise?
What do scientists do with their findings?
They publish them in scientific journals like Science, Nature, Cell, EMBO, PLOS One, etc…
Tentative and Fallible
The findings of science are based on observation, but the observations
could be misleading. For example, the Earth appears to be flat…
Likewise, people thought Newton’s law of gravity was correct, but Einstein
came along and revised it. This type of thing happens all the time.
In addition, it was originally thought that water was HO. All of the
observations pointed to HO at the time…
The more reliable observations you make, the closer one gets to knowing
the truth…
Theory
1. Very broad in nature (describe many, many different phenomenon).
2. Supported by enormous numbers of observations
3. Examples:
Theory of Evolution
Cell Theory
Law
1. Very concise in nature (describes a very specific phenomenon).
2. Supported by enormous numbers of observations
3. Examples:
Law of Gravity
Laws of thermodynamics
Laws of motion
GOD
and
Science
So is this class really about
science
?
The Course Outline:
The hierarchy of life,
emergent properties, and
the structure -function
relationship
Library / Book Analogy
science
?
Chapter 1
3 - Introduction:
The MoleculesExploring
The
of Cells
Scientific
Life Study of Life
Howdoisorganisms
all life
AIM:
build/break
macromolecules?
AIM:How
What
are
theunited?
major
characteristics
of life?

Chapter 1 - Introduction: Exploring Life

Transcription

Similar documents

MONDAY-FRIDAY

Adventures in Learning – all are welcome! Clases de Computación

EasyPure Genomic DNA Spin Kit

exploring - Banyuwangi

Ramtha - Sound Health Options

Corporate Profile

Publisher Preview

The Masterof

Botany Notebook Pages.htm

DNA Fingerprinting and O.J. Simpson

NCVC Webinar October 2013 - the National Center for Victims of