FOUNDATIONS of Biology of Exam 1
6 Characteristics of living organisms
1. Composed of one or more cells
2 &3. Cells contain genetic information for their structure, physiology, and reproduction
4. Are genetically related and have evolved
5. Acquire nutrients from their environment
6. Regulate their internal environment to achieve homeostasis
7. Respond to changes in their exterior environment both biotic and abiotic
What determines how atoms interact to form molecules?
number of electrons which contributes to bonding patters, molecular geometry, and most
energetically stable distribution of electrons is favored.
The octet rule
atoms with 8 electrons in their outer shell are most stable
2 types of bonding
1. Covalent
2. Ionic
Covalent bonds
sharing of one or more electrons between two atoms
Ionic bonds
involve the transfer of an electron from one atom to another atom and the subsequent
attraction between the two ions of the opposite charge
Electronegativity
the attractive force that an atomic nucleus exerts on shared elections
What does the electronegativity depend on?
the number of protons and the distance between electrons and the nucleus
Polar covalent bond
unequal sharing of electrons
When can a Complete Transfer of electrons occur and what is the result?
,1. when one atom is much more electronegative
2. two oppositely charged ions with a full outer electron shell
Two types of ions and charge of each
1. Cations: positive
2. Anions: negative
Ionic compound
the electrical attraction and subsequent binding of cations and anions
What type of bonding is very important within cells?
Hydrogen bonding
Hydrophobic
water hating, non polar, will not interact well with water.
Hydrophilic
water loving, polar, will interact well with water.
Important rules to remember with chemical reactions
1. matter and energy is neither created or destroyed
2. the number of atoms in the products and reactants of a reaction must balance
3. amount of energy in the products and reactants differs but the total amount of energy is
conserved.
What gives water its unique properties?
its structure
Water's structure and what it allows it to do
-polar molecule
-tetrahedral
-form hydrogen bonds with water and other polar ionic compounds
Hydrogen boding in 1.liquid and 2.solid water makes water
1. cohesive
2. less dense than liquid water, i.e. it floats
The greater the number of hydrogen bonds in water
, the higher the specific heat
What makes water the best solvent? Why?
1. polar covalent bonds
2. polar and ionic compounds dissolve easily
Water ______ in cells
ionizes
Water acts as a weak ______ and ______
acid, base
Acids
give up H+ ions
Bases
accept H+ ions
Cellular pH
close to that of water, around 7
Calculating pH
pH=-log10[H+]
Carbon based organic molecules
1. have four valence electrons
2. can form four covalent bonds with other carbon atoms or other atoms usually (H,N,O)
3. can form single, double, or covalent bonds
What forms the biological skeleton for most molecules?
1. Carbon chains
Structural isomers
chains of atoms that can be straight, branched, or rings
What can optimize the structural and functional diversity of structural isomers
1. Cis-trans
2. Optical isomers
6 Characteristics of living organisms
1. Composed of one or more cells
2 &3. Cells contain genetic information for their structure, physiology, and reproduction
4. Are genetically related and have evolved
5. Acquire nutrients from their environment
6. Regulate their internal environment to achieve homeostasis
7. Respond to changes in their exterior environment both biotic and abiotic
What determines how atoms interact to form molecules?
number of electrons which contributes to bonding patters, molecular geometry, and most
energetically stable distribution of electrons is favored.
The octet rule
atoms with 8 electrons in their outer shell are most stable
2 types of bonding
1. Covalent
2. Ionic
Covalent bonds
sharing of one or more electrons between two atoms
Ionic bonds
involve the transfer of an electron from one atom to another atom and the subsequent
attraction between the two ions of the opposite charge
Electronegativity
the attractive force that an atomic nucleus exerts on shared elections
What does the electronegativity depend on?
the number of protons and the distance between electrons and the nucleus
Polar covalent bond
unequal sharing of electrons
When can a Complete Transfer of electrons occur and what is the result?
,1. when one atom is much more electronegative
2. two oppositely charged ions with a full outer electron shell
Two types of ions and charge of each
1. Cations: positive
2. Anions: negative
Ionic compound
the electrical attraction and subsequent binding of cations and anions
What type of bonding is very important within cells?
Hydrogen bonding
Hydrophobic
water hating, non polar, will not interact well with water.
Hydrophilic
water loving, polar, will interact well with water.
Important rules to remember with chemical reactions
1. matter and energy is neither created or destroyed
2. the number of atoms in the products and reactants of a reaction must balance
3. amount of energy in the products and reactants differs but the total amount of energy is
conserved.
What gives water its unique properties?
its structure
Water's structure and what it allows it to do
-polar molecule
-tetrahedral
-form hydrogen bonds with water and other polar ionic compounds
Hydrogen boding in 1.liquid and 2.solid water makes water
1. cohesive
2. less dense than liquid water, i.e. it floats
The greater the number of hydrogen bonds in water
, the higher the specific heat
What makes water the best solvent? Why?
1. polar covalent bonds
2. polar and ionic compounds dissolve easily
Water ______ in cells
ionizes
Water acts as a weak ______ and ______
acid, base
Acids
give up H+ ions
Bases
accept H+ ions
Cellular pH
close to that of water, around 7
Calculating pH
pH=-log10[H+]
Carbon based organic molecules
1. have four valence electrons
2. can form four covalent bonds with other carbon atoms or other atoms usually (H,N,O)
3. can form single, double, or covalent bonds
What forms the biological skeleton for most molecules?
1. Carbon chains
Structural isomers
chains of atoms that can be straight, branched, or rings
What can optimize the structural and functional diversity of structural isomers
1. Cis-trans
2. Optical isomers
