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Midterm

BIOL 1201 Study Guide - Midterm Guide: Hydrolysis, Pyrimidine, Chlorine


Department
Biological Sciences
Course Code
BIOL 1201
Professor
Wischusen
Study Guide
Midterm

Page:
of 27
Biology Exam 1 Notes
What is science?
A body of knowledge
An approach to understanding nature
A process with an outcome of a body of knowledge
What do scientists do?
Make observations
Attempt to discern patterns from the observations
Assume that the future is like the past
oThis assumption creates a problem – not 100% sure (can’t guarantee)
oScience is not about the truth or being sure about things – it’s about getting to the
best model or general understanding
Science is about creating really good models – the best models that are
available at the moment
Scientific Method
The scientific method tells a lot about how we understand science
Steps of the Scientific Method:
oObservations
oGeneralization or Model
oPredictions or Hypothesis
oTest
Tests generate new set of observations  circular process
Science has a limit of observing phenomenon
oScience has limits  Example: cannot observe ghost (outside the realm of science)
What is the outcome of this process?
oBetter model or generalization
New observations confirm that you are in agreement with model – so
model is better
New observations disagree with model so you have to form new model
**Model improves either way
o*Science is not about truth but about getting the best model*
Terminology
Hypothesis: an explanation for something that hasn’t been tested
oCarries with it no weight of validity
Theory: hypothesis that has been tested many times and has always been supported
oWith term comes some weight of evidence that says the theory is pretty accurate
Has some weight of validity to it
oVery misused word in public speaking
Law: theory that has been tested even more and always supported
oNever violated
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What is biology?
Biology: the study of life
What is life?
Really hard to answer – not a set definition
Defined as a set of characteristics
Characteristics of Living Systems
Organization*
oLiving things are highly organized (molecular level to ecosystem level)
Energy Use*
oLife requires a huge amount of energy to keep you organized
Development
oOrganisms change during lifetime
Reproduction*
oLiving things can reproduce by themselves
Side note: viruses cannot reproduce by themselves – must be put in a
living cell
Evolve
oChanges that occur between generations
Respond to the Environment* (* means covered in 1201)
oReaction to surroundings
All living things respond to environment in one form or another
**Living things must do all of these things
oNone of these characteristics by themselves define what it means to be alive
Cannot just have one or two of these characteristics and “be alive”
oBeing alive means that you have to be able to do all of these things
simultaneously
oVirus – not considered alive
Don’t use energy
Cannot reproduce on own – can only reproduce if put in living cell
Viruses are halfway to alive – can do all of the other characteristics
Scale of Nature
What scales are biologists interested in?
oAtomic Scale – 10-8 meters (lowest level)
oCommunity/Ecosystem – 106 meters
Scale has range of 14 orders of magnitude
Approaches to Biology
Two competing approaches
oReductionist Approach
Take system apart and reduce it down to smallest parts then study those
parts (study the small pieces)
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Once you understand the parts, you start putting the system back together
oWholist Approach
Study the whole thing intact
Some say you can only understand when it is whole
To really understand biology, you must take both approaches
oMust study parts to understand whole, but also must study whole to understand
whole
oIn this course, we will start will the reductionist approach and move to a wholist
approach
What determines solubility?
Whether a compound goes into a solution in water is really important—it determines a lot
of things
Compounds that are soluble in water behave differently than molecules that are not
soluble in water
oWhich molecules can move through cell membrane and which can’t?
Determined by solubility
Simple version of solubility – like dissolves like (different than opposites attract)
oLike is in terms of polarity
Polar molecules are soluble (dissolve) in polar solvents
Water is a polar solvent
Nonpolar molecules are soluble (dissolve) in nonpolar solvents
Cell membrane is nonpolar
oIf you look at a molecule, how do you know if its polar or nonpolar?
If it is ionic, it is polar (One side has a + charge, one side has a – charge)
Compounds held together with a pure covalent bond have no polarity
(purely nonpolar molecules)
Carbon and Oxygen form a polar covalent bond  not such a strong bond
but still has polarity
All carbons: nonpolar
Carbons and hydrogens: nonpolar (their electronegativities are almost the
same)
What determines polarity?
Cannot understand polarity without understanding valence
oPolarity is very important biologically so need to understand valence
Polarity of a molecule is determined by the types of bonds within that molecule
Atoms
Definition:
oSmallest unit of matter separable by normal chemical means
oSmallest unit of an element that retains all of the properties of that element
oFundamental unit of an element
Why is the atomic structure biologically important?
oAtoms make up elements – elements make up life
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