Exam 2 Flashcards
1
Q
exergonic
A
energy released ΔG<0
2
Q
endergonic
A
energy added ΔG>0
3
Q
Activation energy (Ea) with enzyme
A
lower than Ea without enzyme
4
Q
activation energy (Ea) on a graph looks like
A
arrow from reactants to vertex
5
Q
Free energy (ΔG) on a graph looks like
A
arrow from reactants to products
6
Q
3 ways in which enzymes can lower activation energy
A
- physical strain
- orientation
- chemical change
7
Q
catalyst
A
accelerate reactions without being consumed or permanently changed
8
Q
saturation
A
rate of product formation is maximal.
carrier proteins can be this
9
Q
3 ways to regulate chemical reactions
A
- operate enzymes under optimal conditions (temp, salt concentration, pH)
- inc. # of enzymes
- inhibitor molecules bind to enzyme - dec rate of product formation
- use regulatory molecules to stabilize the conformation and activity of the enzyme in 1 of 2 possible states
10
Q
Irreversible inhibitors
A
Irreversible covalent attachment to enzyme usually at active site
11
Q
Reversible competitive inhibitors
A
reversible noncovalent attachment to enzyme - active site binding
mimics shape of substrate, effects can be reduced by inc concentration of substrate
12
Q
Reversible noncompetitive inhibitors
A
reversible noncovalent attachment to enzyme - non-active site binding
changes structure of enzyme; reduces normal function of enzyme
13
Q
allosteric activator
A
stabilizes enzyme in active conformation
14
Q
allosteric inhibitor
A
stabilizes enzyme in inactive conformation
15
Q
covalent modification - phosphorylation
A
adds a phosphate group
16
Q
feedback inhibition
A
metabolic pathway turned off by an enzyme at the front of pathway binding to end product when there is a lot of end product
stops cycle
17
Q
mmol in a mol
A
1000 mmol = 1 mol
18
Q
c in Π = cRT
A
osmolarity/concentration (mol/L)
19
Q
T in Π = cRT
A
temperature (K)
20
Q
R in Π = cRT
A
gas constant (.0821 L atm/Kmol)
21
Q
Π in Π = cRT
A
osmotic pressure
atm
22
Q
carbohydrates
A
attached to outer surface of proteins or lipids
23
Q
integral membrane protein
A
span entire membrane or partially embedded
24
Q
anchored protein
A
covalently bonded to lipids that are inserted into the membrane
no exposed hydrophobic regions
25
peripheral membrane protein
have polar or charged molecules that interact and noncovalently attached to either membrane surface
26
cholesterol
alters membrane fluidity, little yellow balls inside phospholipid bilayer
soluble in hydrophobic core
inc melting point - less fluid at high temp
interferes w phospholipid aggregation and stiffening - more fluid at low temp
27
outside of cell
carbohydrates stick out into it
28
inside of cell
anchored membrane proteins stick into it
29
diffusion
net movement of molecules from an area of higher to areas of lower concentration (randomness)
30
equilibrium
no net directionality to movement (still always movement)
concentration across membrane equal
31
osmosis
passive movement of water across a membrane to balance different solute concentrations
32
osmotic pressure
pressure that needs to be applied to a solution to prevent the flow of water across a membrane by osmosis
contributed to by presence of charged and large polar molecules
33
osmolarity
total # of solute particles per liter of water (concentration of solute particles)
34
faster diffusion
smaller molecules
hydrophobic, nonpolar molecules
higher temp
greater concentration gradient
larger surface area of membrane
shorter distance to traverse
35
O2
small nonpolar molecules
readily cross cell membrane
36
CO2
small nonpolar molecule
readily cross cell membranes
37
H2O, urea
small polar molecule
can cross cell membrane, permeability lower
37
ion
polar
cannot cross membrane, too hydrophilic
38
Isotonic solution
solution outside. cell has the same concentration as within cell
equilibrium
39
Hypertonic solution
solution outside cell has a higher solute concentration that within the cell
net movement of H2O is out of cell
40
Hypotonic solution
solution outside cell has lower solute concentration than within cell
net movement of H2O into cell
41
charge of magnesium ion (Mg)
+
42
charge of chloride ion (Cl)
-
43
electrons in carbon
6, 4 valence electrons
44
electrons in hydrogen
1
45
why is a bond nonpolar?
very small difference in the electronegativity of carbon and hydrogen
46
potassium (K) charge
+
47
Chlorine (Cl) charge
-
48
passive diffusion
for smaller hydrophobic molecules; simple diffusion
no energy or membrane protein required
CO2, urea
49
facilitated diffusion
membrane proteins (some integral membrane proteins) can aid in transport of polar or charged molecules
moves with concentration gradient
no energy required
specificity
various ions, flucose
50
facilitated diffusion examples
carriers and channels
51
active transport
energy added, against concentration gradient
allows cells to generate and maintain diff concentrations of substance across membrane
various ions
52
cotransport
move more than one substance at a time
passive or active
53
What type of transport is the Na+/K+ ATPase pump
primary active transport
54
# type of pores, specific or nonspecific bidning, what it transports
transport proteins - channels
hydrophilic pores; no specific binding
rapid movement of ions and water
55
# specific or nonspecific binding, speed (+ why), what it transports
transport proteins - carriers
specific binding of solute like an enzyme
requires a conformation change so its slower
glucose transport
56
primary active transport
energy from ATP hydrolysis used to pump solute across a membrane to area of higher concentration
ADP + water --> ADP + phosphate ion
57
primary active cotransport
ATP hydrolysis can provide the energy to actively move 2 solutes
58
symport
cotransport where 2 substances moved to same side of membrane
59
antiport
cotransport where 2 substances moved to different side of membrane
60
uniport
1 substance transported; not cotransport
61
# & what type of protein does it use, what does it transport
secondary active cotransport
energy released from movement of one solute can assist in the movement of another solute again concentration gradient
cotransporter membrane protein
transports sugar and amino acid
62
how is glucose transported against concentration gradient
secondary active transport - uses movement from Na+ in Na+-K+ pump
63
exocytosis
secretion or release of material outside cell
64
phagocytosis
cellular eating
cell extends cytoplasm to engulf material
65
pinocytosis
cellular drinking
bringing fluid and dissolved substances into cell
66
receptor-mediated endocytosis
brings specific molecules into cells
ligands bind to specific receptors
67
clathrin
coating on the vesicle
68
cyanobacteria
contains chlorophyll and therefore an autotroph
69
archaea
lives in extreme conditions and is a seperate group because it resembles both bacteria eukaryotes
70
where are membrane bound organelles found
only eukaryotes
71
3 differences between plant and animal cells
plant cell has cell wall, large central vacuole, chloroplasts (autotrophs)
animals are heterotrophs with irregular shape, numerous small vacuoles, centrosomes, lysosomes
72
what size of surface area-to-volume ratio is favored
larger
73
what type of cells are favored
small cells
74
what does surface area determine in cells
rate at which resources can enter and waste can leave
75
what does volume determine in cells
amount of metabolic activity
76
cytoplasm
everything within a cell membrane excluding nucleus; mostly water
77
cytosol
gel like substance in cytoplasm
78
organella
subcellular compartments in cytoplasm
79
cytoplasmic inclusions
non-membrane bound substances
80
nucleus
contains most of cell's DNA
81
what is the nucleus surrounded by
nuclear envelope
82
what does the nuclear envelope have
nuclear pores
83
nucleolus
region in nucleus where ribosomes are formed
84
Endoplasmic Reticulum (ER)
network of interconnected membranes; high surface area
85
lumen
interior compartment in ER
86
Rough Endoplasmic Reticulums
outer membrane studded w ribosomes that synthesize proteins for secretion
once inside, proteins are chemically modified and transported to other locations
87
smooth Endoplasmic Reticulum
connected to rough ER, lacks ribosomes
lipid synthesis, Ca2+ storage, detoxification of small molecules
88
Golgi Apparatus
processes and packages material for secretion
protein and lipid secretion
89
lysosomes
digestion autophagy (programmed destruction)
holds digestive enzyme and merges with food vacuole
90
mitochondrion
oxidation of carbohydrates, lipids, proteins to produce ATP
91
Chloroplasts
type of plastid
photosynthesis, food production
believed to have arisen from cyanobacteria
92
peroxisomes
accumulate and break down toxic peroxide byproducts
93
glyoxysomes
convert stored lipid to carbohydrates in plants
94
vacuoles
largest plant organelles
store toxic and waste byproducts, contain pigments that attract pollinators, have catabolic enzymes (lysosomes)
95
cytoskeleton
meshwork of protein polymers
maintains cell shape and position of internal constituents, interacts w extracellular structures to anchor cell in place
96
microfilaments
actin protein, actin monomers can be added or removed
in cytoskeleton; maintain overall cell shape and cause localized changes in cell shape
cell movement; pseudopodia, muscle contractions, "pinching" contractions when animal cell divides
97
intermediate filaments
anchor cell structures in place in cytoskeleton
keratin
monomers cannot be aded or removed
98
# what does it do, what's it made of, can monomers be added/removed
mictrotubules
form rigid skeletons for some cells in cytoskeleton
can help move "cargo"
made up of tubulin (a and B) proteins
tubulin monomers can be added/removed
99
cell junctions
cells joined through these
100
tight junctions
prevent substances from moving through spaces btwn cells
epithelium of urinary bladder prevents urine from leaking into adjacent abdomen
101
desmosomes
hold adjacent cells together w stable protein connections
permit some materials to move
mechanical stability for skin and other tissues under movement stress
102
gap junctions
channels that run between membrane pores in adjacent cells
allows ions, small molecules, and electrical signals to pass between cells
heart muscles beat in unison
103
juxtacrine
signaling between adjacent cells w physical contact
signals diffuse between cells through gap junctions and plasmodesmata or a membrane-bound signal binds to membrane receptor
104
panacrine
btwn nearby cells
signals bind to receptors on nearby cell receptors
105
autocrine signaling
signals bind to receptors on the same cell that secretes them
106
Transmembrane protein receptors
(hydrophilic signals): Ligand-Gated Ion Channel
Cell membranes of many cells contain ligand-gated channels for ions like Na+, K+, Ca2+, Cl-.
* These protein channels/receptors
depend on ligand binding
* Ligands can be neurotransmitters (ACh, GABA, glutamate, epinephrine,
dopamine, serotonin, etc.)
107
Transmembrane protein receptors
(hydrophilic signals): G-protein coupled receptor
* Especially important in sensory systems
* coupled with a G-protein
that can bind GDP or GTP
* seven hydrophobic
membrane-spanning regions while G
proteins have three subunits (α, β, γ)
108
Transmembrane protein receptors
(hydrophilic signals): protein kinase receptor
* Abundant and have enzymatic activity
* Changes in receptor conformation on β subunits
from α bonding to insulin (signal)
activates the cytosolic region of the
receptor, which has protein kinase
activity (adds phosphate groups here)
* It adds phosphate group (obtained from ATP) to certain amino acids on proteins
109
endocytosis
important role in feeding for unicellular eukaryotes
110
do prokaryotes undertake endocytosis or exocyotisis
no, they release enzymes extracellularly to break down food
111
endocrine signals
hormones
transported by circulatory system (w a vessel) and bind to receptors on distant cells
112
Covalent Modification - dephosphorylation
removes a phosphate group
113
covalent modification - proteolytic cleavage
amino acids removed (inactive enzyme becomes active)
114
enzyme that adds a phosphate group from ATP to a protein
Protein Kinase
115
What does addition and removal of phosphate groups signify?
addition - activates enzyme
removal - inactivation of enzyme
116
name of enzyme involved in cAMP generation
Adenylyl Cyclase
117
name of the enzyme that ceases the activity of cAMP
phosphodiesterase
(PDE)
118
Intracellular Response
Receptors found in the
cytoplasm or nucleus
* Signal must be primarily
hydrophobic or very
small to diffuse through
the membrane.
119
enzyme that removes a phosphate group from a protein
Protein Phosphatase
120
Concentration of Na+ and K+ in outside in Na+/K+ ATPase pump
high Na+ concentration and low K+ concentration
121
Concentration of Na+ and K+ in inside in Na+/K+ ATPase pump
low Na+ concentration and high Na+ concentration
122
Steps of Na+/K+ ATPase pump
1. 3 NA+ and 1 ATP bind to protein pump from inside of cell
2. hydrolysis of ATP releases ADP and phosphorylates (amino acid) into pump of protein
3. change in shape causes Na+ ions to be released outside cell and 2 K+ to enter + bind to pump
4. 2 K+ binds to pump
5. dephosphorylation of pump releases phosphorylates (pi) causing 2 K+ ions to be released into interior of cell
6. returns pump to original form
7. cycle repeated
