chapters 2-6 Flashcards
(116 cards)
1
Q
Why does Rutherford experiment use gold foil?
A
to scatter a-particles by hitting the atomic nucleus
2
Q
atoms are electrically neutral:
A
protons = #electrons = atomic number
3
Q
Element
A
any substance that can’t be broken down by chemical means
4
Q
mass is the amount of substance
A
and it is the same on earth or moon
5
Q
weight is different on earth than on moon
A
is the force gravity exerts on a substance
6
Q
mass of proton =
A
mass of neutron = 1 dalton. 1 gram = 6.02 x 1023 daltons
7
Q
a cation has more protons than electrons
A
Anion has more electrons than protons
8
Q
Isotopes
A
are atoms of the same element with different numbers of neutrons: C12, C13, etc.
9
Q
Radioactive isotopes
A
are unstable and decay at a constant rate measured as half-life
10
Q
The chemical nature of an atom is dictated by
A
electrons in the outermost orbital (valence orbital)
11
Q
electrons occupy discrete energy levels
A
K, L.. inside orbitals, each orbital with 2 electrons max
12
Q
electronegativity is the affinity of an atom for electrons.
A
O = 3.5, N = 3.0, C = 2.5, H = 2.1
13
Q
What does electronegativity make?
A
H2O is a polar molecule with oxygen being partially negative
14
Q
Because of water’s polarity
A
hydrogen bonding is favored with O-acceptors and H-donors
15
Q
Cohesion
A
when water molecules stick to each other at the surface
16
Q
Adhesion
A
when water molecules stick to other polar molecules, such as glass
17
Q
What does water cause hydrophobic molecules to do?
A
to aggregate or assume shapes like monolayers of micelles
18
Q
Water is almost neutral: 1 molecule in 10
A
1 molecule in 10,000,000 ionizes
19
Q
. strong acids dissociate completely in water
A
weak acids partially dissociate in water
20
Q
. a buffer is a mixture of a weak acid + its salt that resists changes of pH
A
such as acetic acid + Na acetate
21
Q
. the buffering comprises 1 pH unit above and 1 pH unit below the pKa of the acid
A
22
Q
. primary functional groups are hydroxyl
A
carbonyl
23
Q
. secondary functional groups are ester &thioester
A
ether & thioether
24
Q
. structural isomers differ in structure of carbon skeleton
A
25
. stereoisomers differ in how groups attached. Enantiomers are chiral and mirror image
26
. polymers such as carbohydrates
nucleic acids & proteins are made of monomers
27
. macromolecules
including polymers
28
. monosaccharides: simple sugars with 3 – 9 carbons
have a carbonyl and hydroxyl groups
29
. oligo- and polysaccharides are also called glycans. Linear D-glucose has 4 stereocenters
30
. When D-glucose cyclize forms one more stereocenter with 2 orientations and
31
. D-glucose and D-fructose are structural isomers. D-galactose is a stereoisomer of D-glucose
32
. D-glucose + D-fructose makes sucrose. D-glucose + D-glucose makes maltose
33
. starch
a polymer of glucose
34
. cellulose is a linear polymer of D-glucose
35
. a nucleotide has a sugar + nitrogenous base + phosphates
36
. DNA has deoxyribose
RNA has ribose
37
. nucleic bases are purines (adenine & guanine) and pyrimidines (cytosine
thymine and uracil)
38
. purines are present in both RNA and DNA as well as cytosine. DNA has thymine
RNA has uracil
39
. DNA encodes information for protein synthesis
has double helix with H-bonding: A:T and C:G
40
. RNA uses information in DNA to specify sequence of amino acids in proteins. RNA is single strand
41
. ATP is the primary energy currency of the cell; NAD+ and FAD are electron carriers
42
. there are 20 amino acids that DNA codes in protein synthesis. All amino acids are L
43
. there are four levels of protein structure: 1a is the sequence
2a can be -helix or -sheet mainly
44
. the 3a structure is the final shape of a globular or fibrous protein; 4a has 2 or more 3a structures
45
. hydrogen bonding
disulfide bridge
46
. motif is a folding pattern; domain is a unit of the protein that has a function
such as catalysis
47
. the functional form of a protein is called native state. Folding a protein requires chaperones
48
. the primary structure of a protein determines its tertiary structure
49
. fats
oils
50
. triglycerides are esters of glycerol with 3 fatty acids. Fatty acids are acids with 12 to 20 carbons
51
. animal unsaturated fatty acids are cis. Phospholipids have glycerol + 2 fatty acids + phosphate
52
. phospholipids are amphiphilic (surfactants
soaps) with a polar head and non-polar tail
53
. cells are the basic unit of an organism
arise from previous cells; most are less than 50 m
54
. Robert Hooke in 1665
was the first to observe cells using a microscope
55
. microscopes are: light (resolve structures 200nm) and electronic (resolve structures 0.2 nm apart)
56
. light microscopes have 2 magnifying lenses (compound) and are limited to lights’ wavelengths
57
. electronic
beam of electrons and can be transmission (through sample) or scanning (on the surface)
58
. basic structures of all cells: nucleoid or nucleus
cytoplasm
59
. prokaryotes
the simplest organisms
60
. in archaea domain walls have sugars/protein
in bacteria domain walls have peptidoglycans
61
. some prokaryotes have organelles and infoldings in plasma membrane for chemical reactions
62
. bacteria have microcompartments with semipermeable protein shell for metabolic processes
63
. prokaryotes have actin- and tubulin-like structures
but cell shape is given by cell wall
64
. some prokaryotes have pili and flagella that rotate using a proton gradient similar to ATP synthase
65
. the peptidoglycan (sugars + polypeptides) cell walls of bacteria is susceptible to antibiotics
66
. cell wall of archaea has saturated hydrocarbons attached to glycerol that gives them thermal protection
67
. animal and plant cells have in common: plasma membrane
most of the same organelles + cytoskeleton
68
. plant cells have in addition: cell wall
chloroplasts
69
. the eukaryotes nucleus has DNA divided in linear chromosomes that with protein is called chromatin
70
. eukaryotes nucleus has nucleolus for RNA synthesis and 2-phospholipid bilayer membrane with pores
71
. nuclear pores allow the passage of ions and small molecules
control passage of large RNA complexes
72
. largest internal membrane is the endoplasmic reticulum (ER) which divides the lumen from cytoplasm
73
. rough ER (RER) has ribosomes that make proteins for export that can be tagged to form glycoproteins
74
. smooth ER (SER) is a network of tubules and sacs with enzymes to make sugars
steroids and lipids
75
. SER assembles membrane lipids
stores Ca ions and modifies foreign substances for detoxification
76
. Golgi sorts and modifies proteins/ lipids received in cis face from RER/ SER and send those on trans face
77
. lysosomes (organelles buddings from Golgi) have enzymes for degradation of many internal substances
78
. peroxisomes
organelles bud off from ER
79
. vacuoles in plants serve as storage for food or toxins
maintain osmotic pressure via water channels
80
. osmotic pressure is the force required to stop flow from dilute to concentrated side on a membrane
81
. an isotonic solution has equal concentrations on both sides of semipermeable membrane
82
. mitochondria are semiautonomous and have inner-membrane enzymes for oxidative phosphorylation
83
. chloroplasts of plants have two membranes and make sugars using CO2 as the source of carbon
84
. cell cytoskeleton has 3 types of proteins: actin
microtubules and intermediate filaments
85
. centrioles occur in pairs in animal cells and most protist
but not in plants or fungi. They have tubulin
86
. eukaryotic flagella and cilia have 9 microtubule pairs surrounding 2 microtubules used for movement
87
. eukaryotic cell walls have cellulose in plants and protists
and chitin or N-acetyl glucosamine in fungi
88
. instead of cell wall
animals have collagen
89
. cell surface has glycolipids and MHC protein: markers (blood types)
cell recognition (immune system)
90
. Cell connections are: 1) adhesive junctions 2) tight junctions and 3) communicating junctions
91
. plasmodesmata in plants are gaps in cell walls that connect ERs of two cells by a central tube
92
. cellular membranes have: lipids
integral proteins
93
. membrane lipids are glycerophospholipids
sphingolipids and sterols such as cholesterol
94
. saturated fatty acids are present in warm temperatures
unsaturated FA are present in cold
95
. membrane transport can be: passive
facilitated and active which requires energy from ATP
96
. in passive transport
molecules move from high to low concentration with no energy needed
97
. in facilitated diffusion solute move through channel and carrier proteins from high to low concentration
98
. osmosis is the diffusion of water across a membrane toward a higher solute concentration
99
. primary active transport requires ATP and move substances from low to high concentration
100
. 2a active transport uses energy of 1a active transport to move another against concentration gradient
101
. bulk transport can be endocytosis (into the cell) or exocytosis (discharge of materials out of the cell)
102
. endocytosis is: phagocytosis (solids)
pinocytosis (liquids) or receptor mediated
103
. one calorie is the heat required to raise 1oC to 1 gram of water
104
. oxidation is the loss of electrons
reduction is gain of electrons and has higher energy than oxidation
105
. enthalpy (H) is the heat exchange between a system and its surroundings at constant pressure
106
. entropy (S) is the degree of disorder of a system and increases in an isolated system (2nd law)
107
. free energy
G
108
. if G is negative
the products have less free energy than reactants and reaction can be spontaneous
109
. activation energy is the energy required to destabilize bonds to initiate a chemical reaction
110
. the rate of a reaction depends on the activation energy (Ea) required; the lower Ea the faster the rate
111
. a catalyst influences chemical bonds to lower Ea. Enzymes are protein catalysts
but some are RNA
112
. ATP is 1a energy currency of a cell
good for short-term storage. For long energy storage: fats & sugars
113
. the enzyme active site is a pocket or clef for precise fit binding of a substrate
114
. inhibitors can bind enzyme at active site (competitive) or at a different site (allosteric site)
115
. cofactors assist enzymes in function; can be metal ions (Zn
Mn
116
