Chapter 2 Flashcards
1
Q
Five fundamental characteristics of life
A
1) cells
2) replication
3) evolution
4) information (DNA) etc
5) energy
2
Q
Three fundamental theories underly biology
A
1) cell theory
2) theory of evolution
3) chromosome theory of inheritance
3
Q
Definition of theory
A
An explanation for a very general class of phenomena or observations that are supported by a wide body of evidence NOT just a speculation or guess
4
Q
Inductive
A
Observations
5
Q
Deductive
A
Hypothesis testing
6
Q
The chemical basis of life
A
Water and carbon
7
Q
Proton charge
A
+1
8
Q
Electron charge
A
-1
9
Q
Neutron charge
A
Neutral
10
Q
When chemicals come together it is because…
A
Their electrons attract
11
Q
What is found in nucleus?
A
Protons and neutrons
12
Q
Atomic number
A
The number of protons in the nucleus of an atom
13
Q
Mass number
A
Number protons and neutrons
14
Q
Isotope
A
An element with the same number of protons but different weights
15
Q
Electron weight
A
It is so small we ignore it
16
Q
Proton weight
A
1 “ Dalton” (Da)
17
Q
Neutrons weight
A
1 “Dalton” (Da)
18
Q
Orbits
A
- Electrons cruise around specific tracks
- hold up to two electrons
19
Q
Electron shells
A
- Regions where the orbitals are found
- you have to fill all the orbitals in the shell before you go to the next Shell
20
Q
Outermost shell=
A
Valence shell
21
Q
Valence electrons are usually?
A
Unpaired
22
Q
Unpaired electrons are?
A
Very unstable
23
Q
Covalent bond
A
Where atoms share valence electrons, very strong attraction.
Require them to be stuck together
24
Q
Molecule
A
A substance held together by covalent bonds
25
Compound
A thing composed of two or more elements
26
All Compounds are molecules but
All Molecules are not compounds
27
Polar
Unequally shared
28
Non polar
Shared equally
29
# of unpaired electrons=
#Of valence
30
Electronegativity
Atoms that tend to pull shared electrons harder
It has more protons
Its valence Shells are closer to the nucleus
31
Atoms are usually more electronegative if you...
Move right or up the periodic table
32
Most electronegative
Oxygen & Nitrogen
33
Ionic bonds
When electrons are transferred from one atom to another to give both atoms full valence Shells
34
Ion
A molecule that carries a charge
35
Cation
An atom that loses an electron and becomes positively charged
36
Anion
An atom that gains an electron and becomes negatively charged
37
The number of unpaired electrons determines the...
Number of bonds an atom can make
38
Atoms with more than one unpaired electron can...
- Can form multiple single bonds
- double bonds
- triple bonds
39
The geometry of Simple molecules
- A molecule's shape often dictates its behavior
- The shape of a simple molecule is governed by the geometry of its bonds
40
Molecular formulas
Indicate the numbers and types of atoms in molecule
41
Structural formulas
Indicate which atoms are bonded together....single, double or triple
42
Properties of water and the early oceans:
Chemical evolution likely occurred in an aqueous, or water based environment
43
Life is based on water because
Water is an excellent solvent
44
A solute dissolved into a solvent makes a...
Solution
45
What is a solvent?
A substance that dissolves one or many substances into creating a solution
46
What is a solute?
A substance that is dissolved in a solution
47
What is a solution?
A homogenous mixture of one or more solutes dissolved in a solvent
48
Why does ice float?
Because water forms an open lattice when it becomes solid that is not as dense as its liquid form
49
Why is water such an efficient solvent?
- Water is polar
- oxygen atoms have partial negative charge
- hydrogen atoms have partial positive charge
50
Hydrophilic
- "Water-loving" atoms and molecules are ions and polar molecules that stay in solution
- hydration shell
51
Hydrogen bonding
Makes it possible for almost any charged or polar molecule to dissolve in water
52
Hydrophobic
-"water-fearing" molecules are uncharged and nonpolar compounds
- they do not dissolve in water (they don't stick)
- interact with each other
53
Cohesion
Is binding between like molecules which results in surface tension
54
Adhesion
Is binding between unlike molecules
55
Specific heat
Amount of energy needed to raise the temperature of 1 gram of a substance by 1°C (1 cal/g)
56
Heat of vaporization
Energy required to change 1 gram of substance from liquid to gas (540 cal/g)
57
Chemical reactions
Occur when a substance is combined with another or broken down into another substance
58
Acids
Are substances that give up protons during chemical reactions and raise the hydronium ion concentration[H3O+]
59
Bases
Are substances that acquire protons during chemical reactions and lower [H30+]
60
The concentration of substance in a solution is typically expressed as
Molarity(m= per liter)
61
The pH of a solution reveals
Whether it is acidic or basic
62
Acids have a pH of?
Less than 7
63
Bases have a pH of?
Greater than 7
64
Buffers help...
Maintain homeostasis a relatively constant conditions
65
Endothermic
Reactions must absorb thermal energy to proceed
66
Exothermic
Reactions release thermal energy
67
What is energy?
Energy is the capacity to do work or supply heat
68
Potential energy
Stored potential to do work
69
Kinetic energy
Active energy of movement
70
Chemical energy
A molecules potential to form stronger bonds is a type of potential energy
71
Thermal energy
The kinetic energy of a molecular motion
72
Temperature
Is a measure of the thermal energy in a molecule
73
Heat
Is a measure of thermal energy being transferred between two objects
74
The first law of thermodynamics
- energy is conserved
- it cannot be created or destroyed
- it can be transferred or transformed
75
What makes a chemical reaction spontaneous
They proceed without any continuous external influence, no added energy is needed
76
What spontaneous reaction is determined by two factors?
1) products are less ordered than the reactants
2) products have lower potential energy than the reactants
77
The second law of thermodynamics
- Entropy always increases
- chemical reactions result in products with less ordered energy and less usable energy
78
Organic compounds
Are molecules that contain Carbon bonded to other elements
79
Functional groups
Amino, caraboxyl, carbonyl, hydroxyl, phosphate, sulfhydryl
80
Amino groups
Attract a proton and act as a base
81
Caraboxyl groups
Drop a proton and act as acids
82
Carbonyl groups
Have sites that link molecules into more-complex compounds
83
Hydroxyl groups
Act as weak acids
84
Phosphate groups
Have two negative charges
85
Sulfhydryl groups
Link together via disulfide bonds
