First Exam Flashcards
First Theme of Biology
Organization
Second Theme of Biology
Information
Third Theme of Biology
Energy and matter
Fourth Theme of Biology
Interactions
Fifth Theme of Biology
Evolution
Theme 1: Organization
New properties emerge at successive levels of biological organization. Life is organized into levels. Ex) organelles, cells, ecosystems.
Theme 1: Emergent properties
Novel properties not seen at lower levels of organization
Examples of Emergent Properties:
Water. It is only when combined that hydrogen and oxygen atoms create water.
Theme 1: Structure and Function
At each level of the biological hierarchy, we find a correlation between structure and function. Ex) Flexible branches-shed snow and prevent branches from snapping.
Theme 1: The Cell
Basic unit of structure and function. The cell is the lowest level of organization that can perform all activities required for life.
Theme 2: Life’s processes involve the expression and transmission of genetic information.
Within cells, chromosomes contains genetic material in the form of DNA
Theme 2: Information
Gene expression is the process of converting information from gene to cellular product
Theme 3: Life requires the transfer and transformation of energy and matter
energy flows through an ecosystem, usually entering as light and exiting as heat. The sun is the ultimate source of energy.
Theme 4: Interactions
Interactions between the components of the system ensure smooth integration of all the parts.
Theme 5: Evolution, the core theme of biology
evolution explains the unity and diversity of all life.
Modification with descent: concept that living organisms are modified descendant of common ancestors
Each element consists of just one type
of atom
An atom consists of
protons, neutrons, and electrons
The Nucleus consists of
protons (+) and neutrons (0)
An element is defined by
Its proton number, or its atomic number
Isotopes
atoms of an element with different numbers of neutrons and therefore different atomic mass
Isotopes may be
stable or unstable
Uses of radioactive isotopes (unstable)
used in research and as diagnostic tools in medicine
Why are electrons relevant to life?
electrons allow molecules to interact with each other to form bonds. Theme: Interactions
Typically, in an atom
The number of protons=the number of electrons
What are orbitals
Electron shells
1st electron shell
has up to two electrons
2nd electron shell
has up to eight electrons
3rd electron shell
has up to eight electrons
When are atoms most stable?
when their outer most shell is filled with electrons to the max capacity
Atoms whose outermost shells are not full tend to share, borrow or give away electrons. Why is this?
Sharing, borrowing or giving away electrons creates chemical bonds
Covalent bonds
formed when two atoms share electrons, very stable, both atoms hold onto the electrons
Nonpolar covalent bonds
electrons shared equally
polar covalent bonds
unequal sharing of electrons
Chemical bond
strong force of attraction that holds atoms together resulting from the sharing or transferring of electrons
Ionic bonds
transfer of electrons, positively and negatively charged atoms attract each other forming an ionic bond.
Bonds in order from weakest to strongest:
1) Van der Waals Interactions 2) Hydrogen Bonds 3) Ionic bonds 4) Nonpolar covalent 5) polar covalent
When atoms of different elements form bonds
These compounds have different properties than the atoms from which they are formed. Emergent properties theme.
Hydrogen Bonds
weak chemical bonds
Hydrogen bonds
formed between a hydrogen atom that is covalently bonded to an electronegative atom is attracted to another electronegative atom (bonds between water molecules)
Van der Waals interactions (weak bonds)
nonpolar, electrons are not evenly distributed. Molecule has a transient positive and negative region.
Nonpolar covalent
electrons shared equally, H-H
Polar covalent
H20
Ionic
transfer of positive and negative, NaCl
Hydrogen
weak chemical bonds between water molecules
Van der Waals Interactions
unequal sharing, nonpolar covalent
Chemical reactions
are the making and breaking of chemical bonds
Water’s unique properties come from
its hydrogen bonds
First property of water
cohesion of water molecules
2nd property of water
ability to moderate temperature
third property of water
expansion upon freezing
fourth property of water
versatility as a solvent
First property: Cohesion of water molecules
cohesion and adhesion help the transport of water against gravity in plants
Cohesion
hydrogen bonds cause water molecules to stick to eachother
adhesion
attraction between different substances, for example, between water and plant cell walls
Cohesion example:
surface tension, (measure of how hard it is to break the surface of a liquid)
Second property of water, ability to moderate temperature
water absorbs heat from warmer air and releases stored heat to cooler air
2nd property water’s ability to moderate temperature
water can absorb or release a large amount of heat with only a slight change in its own temperature because water has a high specific heat
2nd property- water’s ability to moderate temperature
water has a high heat of vaporization, as a liquid evaporates, its remaining surface cools, a process called evaporative cooling
3rd property of water- expansion upon freezing
floating of ice on liquid water. ice floats in liquid water because hydrogen bonds are more ordered, making ice less dense then water. If ice sank, all bodies of water would eventually freeze solid, making life impossible on Earth.
Heat of vaporization 2nd water property
the heat a liquid must absorb to be converted into a gas
4th property of water:
water: the solvent of life
solution property four, the solvent of life
a liquid that is a completely homogeneous mixture of substances
Solvent property four the solvent of life
the dissolving agent of a solution
solute property four the solvent of life
the substance that is dissolved
