What is Biology?

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Chapter 1 Concepts in Biology
What is Biology?
-the study of life
Unifying themes in biology
Organization
atoms
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Chapter 1 Concepts in Biology
Unifying themes in biology
Cells - basic unit
The cell theory all living things consist of
cells
17th century
Robert Hooke Anton van Leeuwenhoek
19th century
Matthias Schleiden and Theodore Schwann
cell theory
Two main cell types
All cells are membrane bound, and contain DNA
Two categories of cells prokaryotic
eukaryotic
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Chapter 1 Concepts in Biology
Unifying themes in biology
Continuity of life due to heritable information
(DNA)
Double helix Four building blocks Complex
arrangement
Inheritance depends on copying DNA and passing
info
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Chapter 1 Concepts in Biology
The process of science
Science is a process of inquiry that includes
repeatable observation and testable hypotheses
Science latin to know
Two categories
1. discovery science 2.
hypothetico-deductive science
Discovery science verifiable observations and
measurement conclusions based on inductive
reasoning generalization that summarizes many
observations
Hypothetico-deductive science asking questions
and seeking explanations formal process of
inquiry follows a series of steps
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Chapter 1 Concepts in Biology
The process of science
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Chapter 2 Chemical context of life
Chemical elements and compounds
matter element
compound
Life requires about 25 elements carbon (C)
oxygen (O) hydrogen (H)
nitrogen (N)
Atoms and molecules
atom molecule
Subatomic particles neutrons protons
electrons
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Chapter 2 Chemical context of life
Atoms and molecules
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He
2
Atomic number
Mass number
The energy levels of electrons
electrons vary in energy
Energy Potential energy
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Chapter 2 Chemical context of life
Energy levels of electrons
electrons exist at fixed levels
potential energy due to position
more distant greater potential energy
Electron configuration and chemical properties
chemical behavior due to electrons
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Chapter 2 Chemical context of life
Atoms combine by chemical bonding to form
molecules
Chemical behavior depends on valence electrons
Atoms with incomplete valence shells can
interact with other atoms
Covalent bond
Examples
Covalent bond
Double Covalent bond
molecule
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Chapter 2 Chemical context of life
Atoms combine by chemical bonding to form
molecules
Another example
Compound
electronegativity
nonpolar covalent bond polar covalent bond
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Chapter 2 Chemical context of life
Atoms combine by chemical bonding to form
molecules
ionic bonds
ion cation anion
ionic compounds or salts
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Chapter 2 Chemical context of life
Atoms combine by chemical bonding to form
molecules
bonding between molecules
Hydrogen bonds
Chemical reactions
reactions can not create or destroy matter but
can only rearrange it
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Chapter 3 Properties of water
Water whats the big deal?
Polarity of water
Hydrogen bonding
Cohesion
adhesion
Moderates temperatures on Earth
Heat Temperature
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Chapter 3 Properties of water
Water moderates temperatures on Earth
unit of heat calorie
specific heat
Specific heat of water 1 calorie per gram per
degree C 1 cal/g/C
water resists changing its temperature!
heat of vaporization
evaporative cooling
Ice floats
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Chapter 3 Properties of water
Water is the solvent of life
solution solvent solute
aqueous solution
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Chapter 3 Properties of water
Hydrophilic and hydrophobic substances
hydrophilic
hydrophobic
The dissociation of water molecules
Acids and bases
acid base
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Chapter 3 Properties of water
The pH scale
In any aqueous solution HOH- 10-14
In a neutral solution H 10-7 and OH-
10-7 10-7 x 10-7 10-14
If enough acid were added to increase H to
10-5, then OH- must be 10-9
Due to variations in concentrations adopted a
logarithmic scale
pH -log H or H 10-pH
Buffers