1
Q
what are the four classes of biological molecules, and which are polymers
A
Polymers (water soluble)
- proteins
- nucleic acids
- carbohydrates
Non-polymers (water in-soluble)
- lipids
2
Q
what are proteins
A
Linear polymers of L-amino acids that are joined by peptide bonds
3
Q
how many amino acids contribute to peptide formation
A
20
4
Q
how are peptide bonds formed
A
through condensation reaction (dehydration)
- H2O eliminated between COOH of one amino acid and NH2 or the next
5
Q
what makes proteins a highly versatile biomolecule
A
- hormones, growth factors
- transporters (iron, amino acid, glucose)
- enzymes
- actin, myosin, tubulin
- collagen, elastin, keratin, fibroin
6
Q
T/F are all enzymes proteins
A
most, but not all
7
Q
nucleic acids
A
information molecules in the cell
8
Q
what are the two major types of nucleic acids and how are they organized
A
DNA (deoxyribonucleic acid)
- double helix of two strands
- polymers of deoxyribonucleotides
- A, C, T, G
RNA (ribonucleic acid)
- single stranded polymer
- ribonucleotides
- A, G, C, U
9
Q
nucleic acids are polymers of nucleotides joined together by…
A
phosphodiester bonds
10
Q
phosphodiester bond
A
covalent bond between nucleotides in DNA and RNA, catalyzed by DNA or RNA polymerase
11
Q
formation of phosphodiester bond
A
condensation reaction: H2O eliminated between OH of nucleotide and phosphate of the next
12
Q
central dogma
A
DNA (transcription) -> RNA (translation) OR replication -> proteins
13
Q
carbohydrates
A
linear or branched polymers of monosaccharides
14
Q
T/F most sugars are in the cyclic form, not in the open (acrylic) form
A
true
15
Q
sugars
A
monosaccharides and disaccharides (sweet and soluble)
16
Q
disaccharide types
A
lactose (galactose + glucose)
sucrose (fructose + glucose)
maltose (glucose + glucose)
17
Q
polysaccharide types
A
branched glycogen (from animal sources)
starch (plant sources)
unbranched cellulose (plant sources)
18
Q
glycosidic bonds
A
catalyzed by lactose or sucrose synthase or a-amylase
- thousands of different carbs can be linked in chains and form branches by glycogen or starch synthase
19
Q
functions of carbohydrate
A
important fuel source (glucose)
- glycogen in animals
- starch in plants
structural molecules
- cellulose/chitin
signaling molecules
- cell-cell recognition
lubricants
20
Q
lipids
A
water-insoluble molecules that are highly soluble in organic solvents
21
Q
types of lipids
A
- free fatty acids (fuel)
- triacylglycerols (storage form fatty acids)
- phospholipids (membrane)
- glycolipids (membrane components)
- steroids (polycyclic hydrocarbons, signaling)
22
Q
membrane lipids
A
phospholipids
glycolipids
steroids
23
Q
types of fatty acids
A
saturated fatty acids
- single bond
- common in meat
- solid (water in-soluble)
unsaturated fatty acids
- double bond
- common in natural fats
- liquid (water soluble)
- less stable
24
Q
fatty acid
A
simplest form of lipid, long hydrocarbon chain + carboxyl group
25
example of saturated fatty acid
palmitic acid
26
example of unsaturated fatty acid
oleic acid
linoleic acid
27
what is a main source of fuel
fatty acids
28
what is the storage form of fatty acids
triacylglycerols
29
what do fast consist of
glycerol and 3 fatty acids
30
how are fats created
via 3 condensation reactions creating ester linkages that link the fatty acid carboxyl groups to the hydroxyl groups in glycerol
31
T/F esterification=fatty acids
false, no esterification=fatty acids
32
phsopholipids
membrane lipids
- bilayer formation
- similar to triacylglycerols, but only two free fatty acids
33
glycolipids
bound to carbohydrates
- membrane components
34
steroids
cholesterol is a steroid, and they are built from 4 fused hydrocarbon rings
- hydrocarbon tail is connected to steroid at one end, hydroxyl group connected to other end
35
six functions of lipids
- major component of membrane
- long term energy storage
- protection against heat loss
- protection against physical shock
- protection against water loss
- chemical messengers (hormones; steroids)
36
covalent bonds
bonds in which electrons are shared by participating atoms
- peptide bond
- phosphodiester bond
- ester bond
- glycosidic bond
37
peptide bond and enzyme
each amino acid is attached to another amino acid by covalent bond
- enzyme: peptidyltransferase
38
phosphodiester bond
covalent bond in RNA or DNA that holds a polynucleotide chain together by joining
- phosphate group at POSITION 5 in pentose sugar
- hydroxyl group at POSITION 3 in pentose sugar next to molecule
- enzyme: DNA or RNA polymerase
39
ester bonds
triglycerides are lipids consisting of one glycerol molecule bonded with 3 fatty acid molecules
glycerol + 3 fatty acids -> triglyceride + water
monoacylglycerol (MoAG)
diacylglycerol (DAG)
enzyme: acyltransferase
40
glycosidic bond
carbohydrates are made up of monosaccharides linked together into polysaccharide chains
- enzyme: glycogen synthase (depends on end product)
41
four main types of noncovalent bonds and their importance
readily reversible, allowing repeated interactions, essential interaction in the flow of energy and information
- hydrogen bonds
- ionic bonds/electrostatic interactions
- Van der Waals
- hydrophobic bonds
42
how is a water molecule dipolar and cohesive
- uneven distribution of electrons between hydrogen and oxygen
- unequal electron sharing results in dipoles
- forms hydrogen bonds with each other and other polar molecules and acts as a solvent
- water is cohesive by formation
- universal solvent
43
what are the two most common electro negative atoms included in hydrogen bonds
oxygen and nitrogen
44
T/F hydrogen bonds will be disrupted by water, in as much as water itself forms hydrogen bonds with the molecules
true
45
what renders water as a solvent for any charged or polar molecule
the polarity of water and its ability to form hydrogen bonds
46
hydrophilic definition and examples
compounds that dissolve easily in water (polar)
- glucose
- glycine
- aspartate
- lactate
- glycerol
47
hydrophobic definition and examples
non-polar molecules such as lipids; side chains of some amino acids
- typical wax
48
amphipathic definition and examples
molecules have polar or charged regions, as well as non-polar
- phenylalanine
- phsophotidylcholine
49
highest to lowest strength of noncovalent bonds
ionic
hydrogen
hydrophobic
Van der Waals
50
electrostatic interaction
a weak interaction between ions has opposite charges
(ionic bonds or salt bridges)
51
why does water weaken electrostatic interactions
ion dipole interaction
(H + surrounds Cl -)
(O - surrounds Na +)
52
van der Waals interaction
- very weak interaction between nonpolar nor charged molecules
- short range interactions
- depend on transient asymmetry in electric charge induced between closely approaching atoms
53
hydrophobic interactions (hydrophobic effect)
aggregation of non-polar molecules results in an increase in randomness of water molecules
hydrophobic effect: process in which nonpolar molecules in aqueous solutions are driven together because of the resulting increase in entropy of water molecules
54
what is powered through the hydrophobic effect
membrane formation- lipids form a contiguous, closed bilayer, with two hydrophilic outsides and a hydrophobic interior (stabilized by van der Waals)
protein folding- entails the transition from a disordered mixture of unfolded molecules to a comparatively uniform solution of folded proteins (nonpolar amino acids)
55
how do lipids serve as a barrier
dual chemical nature of lipid where part of the molecule is hydrophilic, whereas the other part, made up of one or more hydrocarbon chains, is hydrophobic and cannot dissolve in water
56
T/F phospholipids spontaneously form bilayers due to amphipathic nature
true
57
what is part of a lipid hydrophilic head
choline
phosphate
glycerol
58
ionization of water and water dissociation
water has a small but finite tendency to ionize to give H+ and OH- ions
-water dissociates to the extent that 10^-7 moles of H+ and 10^-7 moles of OH- are present in 1L of pure water at 25 C
59
formula for Kw (the ionic product of water)
Kw = [H+][OH-] = (10^-7M)(10^-7M) =
10 ^-14M^2
60
pH is the ____________ __________ of the hydrogen ion concentration
negative logarithm
61
formula for calculating pH
pH = log 1/[H+] = -log[H+]
62
what is the pH of a solution that has [H+] of 1.75x10^-5 M
pH = -log10[H+]
= -log10(1.75x10^-5)
=-(-4.76)
=4.76
63
what is the [H+] or [OH-] of a solution whose pH is 3.82
pH=-log10[H+]
3.82=-log10[H+]
[H+]=10^-3.82
= 1.5x10^-4 M
64
T/F strong acids and bases completely dissociate in solution
true
65
what happens when strong base is added to weak acid
as OH- is added, more HA dissociates to restore the Ka (get back to eq)
66
what happens when strong acid is added to weak acid
as more H+ is added, more A- is converted to HA to restore the Ka (get back to eq)
67
buffers
-aqueous solutions that resist changes in pH as acid or as base
- mixture of a weak acid (proton donor) and its conjugate base (proton acceptor) or a weak base and its conjugate acid
- buffer capacity is generally best within +/- 1 pH unit of pKa
- buffering maintains cellular pH and pH of body fluids
68
when does buffer work best
pH=pKa which happens when [HA]=[A-]
69
Henderson-Hasselbalch equation
pH= pKa+ log ([A-]/[HA])
70
what is often used as a buffer in biochemical experiments
amino acid glycine (R-NH3+)
71
titration curve for ammonia buffer and the importance
pKa=9.25
(NH4+) = (H+) + (NH3)
important for maintaining urinary pH during acidosis
72
titration curve for phosphate buffer and the importance
pKa=6.86
(H2PO4-) = (H+) + (HPO4-)
important for maintaining intracellular pH
73
titration curve or acetate buffer and the importance
(CH3COOH) = (H+) + (CH3COO-)
used as a lab buffer
74
what is the purpose of a side chain (R)
- protein folding
- binding to ligands
- interaction with environment
75
T/F the side chain is the same for each amino acid
false, the side chain is distinctive for each amino acid
76
what is common to all a-amino acids of proteins
amino group (NH3+)
carboxyl group (COOH)
*the a-carbon is always between
77
peptidyl transferase
enzyme responsible for peptide bond formation
78
what are the two types of peptide bonds and what makes them different
trans peptide
- most in nature
- rigid and planar
- uncharged but polar
cis peptide
78
what amino acids have nonpolar R groups
hydrophobic amino acids (side chain hydrophobic)
79
T/F all amino acids are water soluble
true
80
what amino acids have neutral R groups but the charge is not evenly distributed
polar amino acids
81
what amino acids have R groups that have a positive charge and physiological pH (7.4)
positively charged amino acids
82
what amino acids have R groups that are negatively charged at physiological pH (7.4)
negatively charged amino acids
83
what does it mean that a hydrophobic amino acid is nonpolar
they have an even distribution of electrons, but does not gain or lose protons or participate in hydrogen/ionic bonds
84
what 9 amino acids promote hydrophobic interactions and prefer to remain inside of protein molecules
glycine
alanine
valine
leucine
isoleucine
phenylalanine
tryptophan
methionine
proline
85
what is the simplest amino acid
glycine
86
the amino acids having side chains consisting only of hydrogen and carbon are _______
hydrophobic
87
what two amino acids are ambivalent, meaning they can inside or outside the protein molecule
alanine
glycine
88
hydrophobicity increases as the number of carbon atoms on the _________ ________
hydrocarbon chain increases
89
what three amino acids increase hydrophobicity off of each other
isoleucine -> leucine -> valine
90
what two amino acids have aromatic side chains
phenylalanine (phenol ring)
tryptophan (indole ring)
91
the hydrophobic amino acids, particularly the larger aliphatic (open chain) and aromatic one (ring), tend to ______ _______ inside the protein away from aqueous environment of ce
cluster together
92
what is a nonpolar thioether group
(-S-) attached to a molecule
93
what amino acid has a side chain bonded to the a-carbon and the nitrogen atom which
-limits the rotation
-reduces the structural flexibility of polypeptide regions
proline
94
what amino acid has a thioether group attached
methionine
95
what two amino acids share the same molecules, but the bond of the first molecule determines the amino acid
methionine and proline
96
_________ amino acids cluster in the __________ of soluble proteins
nonpolar; interior
97
_________ amino acids cluster on the _______ of membrane proteins
nonpolar; surface
98
_______ amino acids cluster on the ______ of soluble proteins
polar; surface
99
polar amino acids have side chains that contain an ___________ atom (_____) and what are they
electronegative atom (oxygen)
- hydroxyl groups (-OH)
- -OH, -NH2 participate in hydrogen bonds
- phosphate group can be added to the -OH (phosphorylation)
100
what polar amino acids have an oxygen electronegative atom side chain
serine, threonine, tyrosine
101
what is a thiol bond and what amino acid contains one
can form weak hydrogen bonds; at slightly basic pH, thiol group can be oxidized to form disulfide bond
- cysteine
102
disulfide bond
covalent bond that is IMPORTANT for protein folding
103
what two amino acids contain a carboxamide
asparagine, glutamine
104
carboxamide
sugar can be added to the amide in glycoproteins
105
________ charged amino acids are hydrophilic (nitrogen)
positively charged
106
what amino acids are hydrophilic
lysine (amino group)
arginine (guanidinium group)
histidine (imidazole group)
107
what amino acid is often fund in the active sites of enzymes, where the imidazole ring can bind and release protons in the course of enzymatic reactions
histidine
108
_______ charged amino acids have acidic side chains
negative
109
what negatively charged amino acids have acidic side chains and what are the ionic forms
aspartic acid - aspartate
glutamic acid - glutamate
110
what makes an amino acid acidic and hydrophilic
- second carboxylic acid group on side chain is deprotonated at neutral pH
- ability of aspartic acid and glutamic acid side chains to donate protons can be important in enzyme catalysts
111
sickle cell disease
group of inherited red blood cell disorders (become hard and sticky c-shaped)
- caused by a mutation of the b-globin gene that results in the substitution of a VALINE for a GLUTAMATE residue at the 6TH position of the b-globin chain of hemoglobin
112
how can glutamate replace valine in sickle cell disease
glutamate - carries a negative charge on its side chain physiological, can engage in ionic or hydrogen bonds with water or other side chains
valine - hydrophobic amino acid, tends to interact with other hydrophobic side chains to exclude water
113
what are the 4 structures of proteins
primary - amino acid residues (sequence of a chain of amino acids)
secondary - a-helix (local folding of the polypeptide chain into helices or sheets H-bonds)
tertiary - polypeptide chain (three D-folding pattern of a protein due to side chain interaction)
quaternary - assembled subunits (protein consisting of more than one amino acid side chain
114
direction of a peptide sequence from N terminal to C terminal
+NH3 - Lys - Lys - Gly - Gly - Leu - Val - Ala - His - COO-
115
secondary structure of protein - a-helix
- structural motif in proteins that forms the inner part of a right-handed helix
- side chains extend outwards
- helix stabilized by intrachain hydrogen bonds between amino and carboxyl groups of main chain
- hydrogen bonds, between AA's not next to each BUT 4 AA's apart
116
T/F in an a-helix, hydrogen bonding between amino acids can happen in the molecules right next to each other
false, cannot be neighboring
117
what amino acid can disrupt an a-helix
proline (helix breaker)
118
what makes proline a helix breaker
attaches to molecule and the N-Ca rotation is not possible, and no hydrogen bond formation is possible
119
what large numbers of charged amino acids can break an a-helix
serine, aspartate, and asparagine
120
what amino acids with bulky side chains or with branched side-chain amino acids can break an a-helix
bulky - tryptophan
branch - valine, isoleucine
aliphatic amino acids
121
secondary structure of protein b-sheet
2 polypeptides
- structural motif in proteins in which a number more than one of B-strands are associated as stacks of chains
- stabilized by interchain hydrogen bonds
- running in same or opposite directions form an antiparallel sheet
122
what do the a-helix and B-sheet structures provide
maximal hydrogen bonding for peptide bond components within the interior of polypeptides
123
what is the driving force of a tertiary structure protein
hydrophobic interaction/effect
124
T/F covalent and other noncovalent interactions between side chains also contribute to the 3-D structure of proteins
true
125
what are the steps to form a tertiary structure of a protein
1- hydrophobic interactions and van der Waals interactions (side chain folding)
2- hydrogen bond
3- ionic bond
4- disulfide bond (covalent) formation folding structure
126
quaternary structure of proteins
refers to the association of individual polypeptide chain subunits (nonpolar side chains; hydrogen bonds; ionic bonds)
127
human hemoglobin consists of what two subunits of one type ____ and two subunits of another type _______
alpha and beta
128
globular proteins
MAJORITY
- soluble and compact
- cytoplasmic secreted from cells (hemo and myo)
- hydrophobic residues inside
129
fibrous proteins
STRUCTURE
- insoluble, fiber like, long strands or sheet repeating unit of 2-D structure
- similar polypeptides tightly packed strong and structural proteins (collagen, keratin)
- will not be a B-strand
130
membrane proteins
OUTSIDE
- embedded in membranes
- hydrophobic residues
131
what is the specific folding pathway of proteins
denatured -> 2-D structure formation -> molten globule -> native (spontaneous) -> unfolded/denatured (primary structure) -> folded/native conformation (tertiary structure)
132
protein denaturation
disrupts the weak forces responsible for 3-D structure, leading to loss of structure and protein function
- COVALENT BONDS NOT AFFECTED
133
denaturation by heat
affects weak interactions (hydrogen bonds)
- characteristic melting temperature of a protein (50-50 unfolded/folded)
134
denaturation by low and high pH
hydrochloric acid (gastric)
- acids and bases disrupt salt bridges held together by ionic bonds
135
why are most proteins denatured by an acid or base
electrostatic repulsion - between side chains if no more neutralization by opposite charges
136
why is urea a reversible denaturing agent
1- form H-bonds to NH and C=O in peptide bonds, blocks intramolecular H-bonding
2- interferes with the hydrophobic interactions that normally stabilize the protein
3- "dissolves out" the peptide chain
4- reversible: dialyze away urea, get refolding
137
what is the reducing reagent used to break down a disulfide bond
Beta-Mercaptoethanol
138
Amyloidosis
protein misfolding and disease
- mutation in the protein itself
- some defect in post-translational "processing" of the protein
- result of a formation of protein aggregates or tangles (amyloid fibrils or plaques)
- adopts B-sheet
139
hydrolases
cleave their substrates by the addition of a molecule of water (hydrolysis reaction)
140
proteases
proteins -> amino acids
141
a-amylase
carbohydrates (poly/oligosaccharides) -> monosaccharides (glucose fructose, galactose)
142
lipases
lipids (TAG) -> fatty acids+glycerol
143
TAG stands for
triacylglycerol
144
nucleases
nucleic acid -> nucleotides (purines and pyrimidines
145
Name the bond associated with the enzyme:
protease -
a-amylase -
lipase -
nucleases -
protease - peptide bonds
a-amylase - glycosidic bonds
lipase - ester bonds
nucleases - phosphodiester bonds
146
T/F when monomeric units in proteins, carbohydrates, and nucleic acids are joined, the elements of H2O are joined as well
false, the elements of H2O are eliminated
147
steps of protein digestion
1- stomach enzyme secretion
enzymatic (pepsin) and hydrochloric acid break down in the stomach
2- pancreas enzyme secretion
protein digesting enzymes are released by pancreas into small intestine
3- protein digestion
small intestine MAJOR site
4- small amount of dietary protein lost
5- final digestion
dipeptides/tripeptides to amino acids in the intestine
6- absorption
amino acids absorbed and entered the blood to travel to the liver
7- regulation
liver regulates distribution of amino acids to the rest of the body
148
what is the path for the breakdown of proteins
dietary protein
- polypeptides and amino acids
- oligopeptides and amino acids
- amino acids
149
HCl (parietal cells) trigger what in the stomach
gastric chief cells to release pepsin
150
what enzymes are involved in the pancreas in protein breakdown (small intestine)
- trypsin
- chymotrypsin
- elastase
- carboxypeptidases
151
what enzymes are involved in brush border which form epithelial cells in protein breakdown
- endopeptidase
- aminopeptidase
- di and tri peptidase
152
what are the roles of HCl in food digestion
1- protein denaturation
- acids and bases disrupt salt bridges held together by ionic charges/bonds (prevent H-bonds)
2- stomach
- pepsinogen is activated by HCl and pepsin (precursor)
153
the roles of secretion and activation of proteases
1- stomach
- pepsin is activated by HCl
- dietary protein -> polypeptides/amino acids
2- small intestine
- pancreatic enzymes are activated by enteropeptidase and protease
3- activation of proteases
- proenzymes (zymogens) -> active enzymes
154
why must the pancreas release inactive form of proteases and cause a cascade
it will breakdown proteins further than supposed to be
155
exopeptidase
carboxypeptidases
- attach on either side of the peptide
156
endopeptidase
serine proteases
- attach within the polymer
- serine, chymotrypsin, elastase
157
transport of amino acids into cells first step
1- from intestinal lumen into epithelial cells
- Na+ dependent transport of amino acid (co-transporter system) (Na+ amino acid supporter)
- Na+ is pumped out on the serosal in exchange for K+ by the Na+, K+-ATPase
158
transport of amino acids into cells second step
2- from epithelial cells into blood
- the amino acid is carried by a facilitated transporter down to its concentration gradient into the blood
159
what cells have common transporter systems for amino acid uptake
- epithelial cells in small intestine
- renal tubular epithelial cells in kidney
160
two diseases associated with amino acids transport
- neutral amino aciduria (Hartnup disease)
- cystinuria
161
neutral amino acid aciduria: Hartnup disease
deficiency of tryptophan
- genetic defect in the transporter genes (SLAC6A19) which is responsible for the ABSORPTION of neutral or nonpolar amino acids
- Loss of amino acids in the body (tryptophan) which can be converted to serotonin, melatonin, and niacin
- Pellagra like symptoms (dermatitis, dementia, diarrhea -- the 3 D's)
162
T/F cysteine and cystine have very different solubility which can be considered medically important
true
163
cystinuria
1 in 7,000 people, the most common genetic error of amino acid transporter (dibasic amino acids)
- aminoaciduria in which large amounts of cystine is found in urine (accumulates in the kidney)
164
cystine vs cysteine
cystine:
- disulfide dimer of cysteine
- insoluble
- precipitation of stones of cystine in the urinary tract
cysteine:
- water soluble
- can form disulfide bond
165
monosaccharides
-single polyhydroxy alcohol or ketone unit
-cyclized
- 6 carbon glucose most abundant in nature
166
oligosaccharides
- short chain of 2-20 monosaccharides
- glycosidic bonds
- disaccharide sucrose = glucose-fructose
- 3 residues are often joined to protein or lipid in glycoconjugates
167
polysaccharides
- chains of 20 to 1000s of monosaccharides in length
- linear: cellulose
- branched: glycogen and starch
- can have very different biological roles
168
digestion of carbohydrates steps
1- mouth
- starts from the mouth by salivary a-amylase
- breaks down the a-1,4-glycosidic bond
2- small intestine
- a-amylase (salivary or pancreatic): only break down a-1,4-glycosidic bonds
169
what can break down a a-1,6-glycosidic bond
a-dextrinase
170
what can break down a a-1,4-glycosidic bond
a-amylase
a-glucosidase
maltase
171
what breaks down maltotriose to glucose
a-glucosidase
172
what breaks down maltose to glucose
maltase
173
what breaks down limit dextrin to maltose
a-destrinase
174
what carbohydrate digestive enzymes are a part of brush border (intestine epithelial cells)
maltase
lactase
sucrase
175
what breaks down maltose to glucose
maltase
176
what breaks down lactose to glucose+galactose
lactase
177
what breaks down sucrose to glucose+fructose
sucrase
178
what is so different about the b-1,4-glycosidic bond (same side plane)
we are unable to digest cellulose carbohydrate of plant origin
- we do not make the enzyme cellulase
179
uptake of monosaccharides
- glucose and galactose (Na+ flowing) through SGLT 1
- fructose through GLUT5
- all three enter enterocyte and travel though GLUT2
- enter capillary
180
lactose intolerance
- reduced levels of lactase due to silencing of lactase gene
- lose production of lactose converting to galactose and glucose leading to build up of lactose
181
what is osmotically active in lactose intolerant people
- lactose
- 2-carbon metabolites
- 3-carbon metabolites
182
T/F lipids are water soluble molecules
false, they are water insoluble
183
enzymes in the stomach
mouth - lingual lipase
stomach - gastric lipase
184
enzymes in the small intestine
pancreatic enzymes:
- lipase
- cholesterol esterase
- phospholipase A2
- lysophospholipase
185
lingual/gastric lipase
acid stable and remove short (lingual) and medium (gastric) chain
186
TAGS and digestion of lipids in the stomach
most active in infants and young children who drink cow's milk
187
TAG in milk
emulsification occurs in the stomach mechanical mixing increasing the surface area of the hydrophobic lipid droplets
188
what hydrolase converts TAGS to fatty acids+glycerol
lipases (ester bonds)
189
emulsification of lipids in the small intestine occur where
duodenum
190
emulsification is accomplished by what two complementary systems
physical: mechanical mixing due to wave-like movement of the intestine
chemical: use of the detergent properties of the bile salts (amphipathic)
191
what amino acids are conjugated bile salts
taurine and glycine (water soluble)
192
what are the end products of lipid digestion
primary products in the lumen:
- free fatty acids (16-18 C)
- 2-monoacylglycerol
- cholesterol
193
where is the long chain fatty acid: 16-18 C most prevalent
TGA in meat
194
micelles
- tiny microdroplets that are emulsified by bile salts, solubilizing lipid
- contain fatty acids and 2-monoacylglycerols, or cholesterols
195
absorption of lipids in the form of micelles steps
-disc shape cluster of amphipathic lipids arranged with their hydrophobic groups on the inside and their hydrophilic groups on the outside
- micelles travel through layer of water to microvilli on surface of intestinal epithelial cells
- fatty acids, 2-monoacylglycerols, and other lipids are absorbed
- bile salts left behind in lumen
196
T/F short or medium chain fatty acids do not require bile salts for absorption
true
197
where are chylomicrons assembled
inside Golgi
198
(chylomicrons)
newly synthesized TG and cholesterol ester are packaged as lipid droplets surrounded by a thin layer of __________
- apolipoprotein B-48
- phospholipids
- free cholesterol
199
secretion of chylomicrons
exocytosis into lymphatic vessels around villi of small intestine then enter systemic circulation
200
ApoE is recognized by ________
hepatic receptors
201
nascent chylomicron
particle released by intestinal mucosal cell that is functionally incomplete
-ApoB is primary organizer
202
ApoCII
necessary for the activation of lipoprotein lipase, the enzyme that degrades the triacylglycerol contained in the chylomicron
203
lipid malapsorbtion
poor digestion
- mechanical block in biliary tract or by intrahepatic lesions, lack of bile salts
- chronic pancreatitis, cystic fibrosis
- CF mutations in the CFTR cause decreased hydration and thickened secretions and the pancreatic enzymes are unable to reach the intestine
malabsorption
- IBD causing decreased absorption
204
what is the presence of excess fat in feces due to poor digestion and malabsorption
stearrohea
205
release of the hormone CCK is stimulated by
1- the polypeptide products of pepsin digestion
2- digested lipid products
206
Cholecystokinin (CCK) is secreted by specialized intestinal cells and causes the secretion of
- bile salts from the gall bladder
- digestive enzymes from the pancreas
- enteropeptides from intestinal epithelial cells
207
steps of digestion of nucleic acids
1- denature of DNA or RNA in the stomach (low pH)
2- DNA or RNA in oligonucleotides by ribo/deoxyribo nucleases (pancreat8ic enzymes)
3- oligonucleotides into mononucleotides by phosphodiesterase (pancreatic enzymes)
4- in intestinal mucosal cells, nucleotidases removes the phosphate groups, releasing nucleosides
5- nucleosides into pyrimidine and purine by nucleosidases
6- purine is degraded into uric acid and excreted in urine, pyrimidine enter circulation and can be reused
208
secretin stimulates... in hormonal digestion
bicarbonate secretion from the pancreas which neutralizes the stomach acid
209
in the hormonal control of digestion, the low pH od the food stimulates...
the cells of the small intestine to release hormone secretion
210
digestion of nucleic acids step
1- denature of DNA or RNA in the stomach (low pH)
2- DNA or RNA into oligonucleotides by ribo/deoxyribo nucleases (pancreatic enzymes)
3- oligonucleotides into mononucleotides by phosphodiesterase (pancreatic enzymes)
4- in the intestinal mucosal cells, nucleotidases removes the phosphate groups, releasing nucleosides
5- nucleosides into pyrimidine and purine by nucleosidases
6- purine is degraded into uric acid and excreted in urine. pyrimidines enter the circulation and can be reused
211
what is the major site of amino acid degradation in humans
the liver
212
transamination
removal of nitrogen for amino acids
- re-use for biosynthesis AA, nucleotides and biological amides
213
what happens after the r4emoval of nitrogen from amino acids with oxidative deamination
waste, urea cycle
214
transamination: the transfer of the _________ of an amino acid to ___________
a-amino group; a-keto acid
215
what are the end products of transamination
a-keto acid and amino acid
216
what is the enzyme and coenzyme involved in transamination
enzyme: aminotransferases - cytosolic proteins in liver, kidney, intestine, muscle
coenzyme: pyridoxal phosphate - (PLP, derivative of B12) is the Co-Factor
- PLP is also co-factor for reactions in deamination, decarboxylation, and gluconeogenesis
217
Alanine Aminotransferase (ALT)
alanine <-> pyruvate
a-ketoglutarate <-> glutamate
predominately in the liver, more specific indicator of liver damage
218
Aspartate Aminotransferases (AST)
aspartate <-> oxaloacetate
a-ketoglutarate <-> glutamate
in the liver, heart, skeletal muscle, kidneys brain, and red blood cells
219
where does oxidative deamination take place
liver and kidney mitochondria
220
what is the enzyme for oxidative deaminarion
glutamate dehydrogenase
221
T/F ammonia is toxic to the cell so, it is released as urea
true
222
the ammonium ion is converted into urea from what. where do the nitrogen's come from?
first N in urea (aspartate)
second n in urea (free form of ammonia)
223
where is urea produced and excreted
produced in the liver, excreted in the kidney
224
what is the first step of the urea cycle
formation of carbamoyl phosphate (use 2 ATP)
- occurs in the mitochondria
- CPS 1 mediator (2 ATP -> 2 ADP)
- cannot be reversed
- FIRST N IN UREA FROM FREE AMMONIA
225
what is the second step in the urea cycle
formation of citrulline
- occurs in the mitochondria
- OTC (ornithine transcarbamoylase) mediator
- ornithine -> citrulline
226
what is the third step of the urea cycle
formation of arginosuccinate
- occurs in the cytosol
- arginosuccinate synthetase mediator
- SECOND N IN UREA FROM ASPARTATE
227
what is the fourth step of the urea cycle
cleavage of arginosuccinate
- occurs in the cytosol
228
what is the fifth step of the urea cycle
cleavage of arginine to ornithine and urea
- occurs in the cytosol
229
what makes synthesis of urea an irreversible process
4 high-energy phosphates are consumed
230
where does the urea in the body travle
most transported from the liver through blood to kidney and excreted in urine, BUT some diffuses into the intestine
231
BUN test
blood urea nitrogen test
7-21 mg/dL
higher = more urea
232
T/F in hibernating bears, there is no carbon or water intake, and no release of urine or digestive matter
true
233
how do hibernating bear excrete urea
- the use of fat stores to keep the basal metabolism functioning, with ketone bodies serving as fuel for the brain
- protein turnover continues to take place in tissues
234
steps of nitrogen metabolism in bears
1- nitrogen is still salvaged to produce urea, passed to the bladder
2- urea absorbed into blood and r4eleased into intestine by a special transporter
3- bacteria in the intestine hydrolyze urea, generating NH4+, used to synthesize amino acids and proteins
4- use the hydrolysis of urea to generate an electrochemical gradient that is used to synthesize ATP
ENZYME = UREASE
NEED degradation of body protein to retrieve an AA to start the cycle
235
what are the metabolic intermediate from protein to urea
protein -> amino acids -> carbon skeletons -> NH4+ -> Urea and NH4+
236
what are carbon skeletons important for
- energy
- synthesis of other compounds
(pyruvate, acetyl CoA, a-ketoglutarate, etc.)
237
what are the two fates of the carbon skeletons of amino acids
A- amino acids whose catabolism yields pyruvate or one of the intermediates of the TCA cycle
B- amino acids whose catabolism yields either acetoacetate or acetyl CoA or acetoacetyl CoA
238
what amino acids form pyruvate
- serine
- cysteine
- alanine
- glycine
- threonine
- tryptophan
239
__________ -> alanine -> pyruvate
tryptophan
240
___________ -> serine -> pyruvate
glycine
241
amino acids that form oxaloacetate
aspartate
242
amino acids that form a-ketoglutarate
- glutamate
- glutamine
- proline
- histidine
- arginine
243
T/F glutamate to a-ketoglutarate is an irreversible process
false
244
FIGLU test
urine test, an indicator of Vitamin B12 or folic acid deficiency, or liver disease
245
degradation of histidine
with histidase to form urocanate
246
amino acids that form flumarate
- phenylalanine
- tyrosine
247
tyrosine can later be converted to _________
BH4 (tetrahydrobioprotein)
248
PKU disease
phenylketonuria
- deficiency of phenylalanine hydroxylase
- accumulation of phenylalanine, to transamination of ketones
- mousy odor in urine
249
amino acids that form succinyl CoA
branched chain amino acids
- valine
- isoleucine
- leucine
- methionine
- threonine
250
branched chain amino acids must go through transamination and oxidative decarboxylation for amino acid degradation. what are the co-factors
transamination: a-amino acid aminotransferase
oxidative: branched chain a-keto acid dehydrogenase
251
MSUD
maple syrup urine disease
- defect in branched chain a-keto acid dehydrogenase
- will not convert
252
for methionine to degrade down to homocysteine, what is the intermediate step
SAM (S-adenosylmethionine)
- major methyl-group donor in one carbon metabolism
253
two major disposal pathways for homocysteine
1) synthesis of cysteine and succinyl CoA
2) resynthesis of methionine
254
what does the formation of cysteine require
PLP (B6) - trans-sulfuration process
255
what is the mediator for the transition of L-homocysteine to L-methionine with N5-methyl-THF to THF
methylcobalamin (methyl B12)
256
what are two reactions using B12
1- resynthesis of methionine from homocysteine
2- synthesis of succinyl CoA
257
what is the reaction for resynthesis of methionine from homocysteine using vitamin B12
L-homocysteine -> (methylcobalamin, Methyl B12) -> L-methionine
258
what is the reaction for synthesis of succinyl CoA using B12
L-methylmalonyl CoA -> (deoxyadenosylcobalamin, deoxyadenosyl-B12) -> succinyl CoA
259
T/F the conversion of a methylmalonyl CoA into succinyl CoA is a vitamin B-12 dependent reaction, accumulation of methylmalonic acid is a clinic indicator of a possible vitamin B12 deficiency
true
260
amino acids that form acetyl CoA or acetoacetyl CoA
phenylalanine
MSUD
isoleucine
leucine
tryptophan
lysine
tyrosine
261
how many essential and nonessential amino acids are there and what are there
essential - 9: cannot be synthesized de novo by the body
nonessential - 11: can be synthesized in sufficient amounts from intermediates
262
what are the steps for the biosynthesis of nonessential amino acids
1) form intermediates of TCA
2) form intermediates of glycolysis
3) form essential amino acids
conditionally essential AA: tyrosine under PKU
263
ammonia fixation
the use of ammonia in the net synthesis of nitrogen containing molecules
- N2 comes from the air but needs to be converted to use
264
what are the steps for nitrogen fixation
1) a-ketoglutarate -> glutamate
2) glutamate -> glutamine
3) NH4+HCO3- -> carbamoyl phosphate
265
nitrogen fixation
N2 in the atmosphere is converted into ammonia by some soil microorganism
266
nitrogenase
1- the reductase provides high-energy electrons, in the form of ferredoxin, for reducing power (Fe protein)
2- the nitrogenase uses the electrons to reduce N2 to NH3 (MoFe protein)
267
what are the two nitrogenous bases
purine (A, G)
pyrimidine (C, T/U)
268
nucleoside
- nitrogenous base
- pentose sugar
269
nucleotide
- nitrogenous base
- pentose sugar
- one, two, or three phosphate groups
(NMP, NDP, NTP)
270
nucleoside examples
adenosine, guanosine, cytidine, thymidine, uridine
271
what is the specific nucleotide for DNA
deoxyribose (OH - H) instead of two hydroxyls
(dNMP, dNDP, dNTP)
272
de non synthesis
the base itself is synthesized from simple starting materials, including amino acids
(start from scratch)
273
salvage pathways
preformed bases are recovered and attached to an activated ribose
274
what is the active form of ribose called
PRPP
275
first step of synthesis of a purine nucleotide
synthesis of 5-phosphoribosyl-1-pyrophosphate (PRPP)
- mediated by PRPP synthetase
276
what makes a ribose activated
high energy stored in the pyrophosphate
277
second step of the synthesis of a purine nucleotide
synthesis of 5'-phosphoybosylamine
278
third step of the synthesis of a purine nucleotide
synthesis of inosine monophosphate (IMP)
- first intermediate nucleotide
279
regulation of purine synthesis PRPP synthetase
negative feedback regulation by purine nucleotides
280
what are the end products of purine synthesis
GTP and ATP - negative feedback and reused
281
what are the synthetic inhibitors of purine synthesis
1- PRPP synthetase
2- Azathioprine
3- Mycophenolic acid
lose DNA synthesis and undergo necrosis
282
azathioprine (purine analogues)
purine synthesis synthetic inhibitor
- immunosuppressive and cancer drug
-highly proliferative
283
mycophenolic acid
purine synthesis synthetic inhibitor
- drug id reversible, uncompetitive inhibitor of inosine monophosphate dehydrogenase
- drug deprives rapidly proliferating T and B cells of key components of nucleic acids
- used to prevent graft rejeciton
284
tetrahydrofolate
active form of folic acid (B9)
- THF, FH4
- essential active form for many derivatives
285
methotrexate
inhibit reductase ability in purine synthesis
286
salvage pathways for purines (90%)
turnover of cellular nucleic acids and nucleic acids from diet
287
what are the reactions involved in the salvage pathway for purines with hypoxanthine-guanine phosphorisbosyltranferase (HGPRT) as a mediator
hypoxanthine -> IMP
guanine -> GMP
288
what are the reactions involved in the salvage pathway for purines with adenine phosphporibosyltransferase (APRT)
adenine -> AMP
289
Lesch Nyhan syndrome
deficiency of HGPRT
- increased PRPP and decreased IMP and GMP, increased de novo synthesis
- increased breakdown of purine
- excessive production of uric acid (hyperuricemia)
290
adenosine deaminase reactions
adenosine -> (adenosine deaminase) -> inosine -> uric acid
DNA -> deoxyadenosine -> (adenosine deaminase) -> deoxyinosine- > uric acid
291
adenosine deaminase deficiency
accumulated adenosine becomes phosphorylated
deoxyadenosine produces dATP which inhibits ribonucleotide reductase
- inhibition of DNA synthesis, with increased T and B cell apoptosis
- severe combined immunodeficiency (SCID)
292
treatment for sever combine immunodeficiency (SCID)
- bone marrow or cell transplants
- injection of ADA
- gene therapy
293
sources of purine nucleotides
- dietary purine
- tissue nucleic acids
- endogenous purine synthesis
294
gout
high levels of uric acid in the blood due to underexcretion/overproduction of uric acid
- deposition of crystals of sodium urate in kidney and joint, causing pain and inflammation
- increased PRPP, purine nucleotide synthesis overload, increased uric acid
295
what are three reasons as to how someone can get gout
1- abnormal PRPP synthetase activity: higher Vmax and lower Km for ribose 5-phosphate resistant to feedback regulation by nucleotides
2- defect in purine salvage pathway: increased PRPP and enhanced purine synthesis (Lesch Nyhan syndrome)
3- alcohol (beer: purine rich), (wine: dehyradtion)
296
treatment of gout
prevent of the deposition of urate crystals
1) inhibition of inflammation: colchicine - decrease the movement of the granulocytes into the deposition area
2) inhibition of uric acid production: allopurinol - analog of hypoxanthine, inhibitor of xanthine oxidase
297
de novo pyrimidine synthesis
- sources of carbon and nitrogens or pyrimidine rings are bicarbonate (CO2), aspartic acid, and ammonia
- base is synthesized first, then attached to the PRPP
298
first step of de novo pyrimidine synthesis
orotate is the first base synthesized
- done by using CPS II and CAD to form the ring structure
299
second step of de novo pyrimidine synthesis
orotate converted to nucleotide UMP by UMP synthetase
- first nucleotide
300
what enzyme is bifunctional and in what process
uridine monophosphate synthetase in de novo pyrimidine
301
salvage pathways for pyrimidine synthesis
thymine, a product of DNA degradation, is salvaged by first being incorporated into a nucleoside by thymidine phosphate
302
thymidylate synthetase
dUMP to dTMP
303
dihydrofolate reductase
dihydrofolate to tetrahydrofolate
304
drug that inhibits thymidylate synthesis in pyrimidine synthesis
5-fluorouracil -> 5-Fdump (inhibitor)
305
drug that inhibits dihydrofolate reductase in pyrimidine synthesis
methotrexate
306
what are the side effects of DNA synthesis inhibitors as anti-cancer drugs?
prevent highly proliferated cells which can be used for cancer drugs
307
what are the versions of THF in purine and pyrimidine synthesis
purine - N10-formyl-FH4
pyrimidine - N5,N10-methylene-FH4
308
where is THF found in AA metabolism
1- degradation of histidine
2- serine synthesis
3- resynthesis of methionine from homocysteine
309
what is the purpose of a one-carbon carrier
carry and transfer the oxidation state of one carbon unit (methane, methanol, formaldehyde, formic acid)
- will form products after they receive carbon
310
about half of the bodys store of folate is in what form
fully formed THF or FH4 in the liver and is conjugated with seven glutamates
311
folate vs folic acid
folate - directly from food sources
folic acid - manufactured as supplement or synthetic
312
PABA
para-aminobenzoic acid analogs (sulfides)
- competitively inhibit bacterial synthesis of folic acids
- purine synthesis requires THF as coenzyme, the sulfa drugs slow down this pathway
313
T/F humans can synthesize folic acids
false, they must rely on external sources
314
T/F methyl-THF cannot be reoxidized
true
315
what is the most oxidized form of THF
N10-formyl-FH4
316
what is the major carbon source of one-carbon groups in the human body
serine
317
how many high energy bonds does one ATP hold
2
318
what is oxidative phosphorylation
a process for the synthesis of ATP and the major source of ATP in aerobic organism
319
what is the source and the path of oxidative phosphorylation
source: high-energy electrons from NADH or FADH2 (from TCA cycle)
path: through number of electron-transfer reactions
- take place in electron-transport chain in mitochondria
320
what are the results of oxidative phosphorylation
- reduction of oxygen
- generation of proton gradient (proton motive force)
- used to power the synthesis of ATP
321
what is the outer membrane of mitochondria responsible for in oxidative phosphorylation
- permeable to most small ions and molecules because of the channel protein mitochondrial Porin (passive diffusion)
322
what is the inner membrane of the mitochondria responsible for in oxidative phosphorylation
ETC location
- impermeable to most molecules
- site of electron transport and ATP synthesis
323
what is the intermembrane space of the mitochondria responsible for in oxidative phosphorylation
proton gradiet
324
what is the matrix of the mitochondria responsible for in oxidative phosphorylation
the citric acid cycle and fatty acid oxidation
- TCA (source of NADH and FADH2)
- transcription/translation of mitochondrial DNA/RNA
325
how many large protein complexes are there in the inner mitochondrial membrane
four
326
what is the respiratory chain that takes place in the four complexes of the inner mitochondrial membrane
the oxidation-reduction reactions that allow the flow of electrons from NADH and FADH2 to oxygen
327
what is the outcome of the ETC
reduction of oxygen and the generation of proton gradient
328
T/F the electron affinity of the carriers increases as electrons move down the ETC
true
329
flavin mononucleotide (FMN)
electron carrier
- present in complex I and II
- reduction of the isoalloxazine ring
330
iron-sulfur clusters (centers)
electron carrier
- present in complex I, II, and III
- ferric (oxidized, receives e-)
331
coenzyme Q (Q)
electron carrier
- derived from isoprene, known as ubiquinone
- present at the beginning and end of complex II
- bind protons (QH2) as well as electrons, exist in several oxidation states
- oxidized and reduced Q are present in the inner mitochondrial membrane (Q pool)
332
cytochrome (Cyt)
electron carrier
- present in complex III and IV
- ferrous reduce to ferric oxidized
333
Complex I in ETC
IN: NADH, OUT: QH2
- entry point for NADH
- FMN acts as transducer, picking up pair, but passing them on SINGLY to the Fe-S centers
- electrons passed singly to CoQ to form QH2 (ubiquinol)
- 4 protons simultaneously pumped
- removal of 2 e- contributes to the formation of the proton-motive force
334
Complex II in ETC
IN: FADH2, OUT: QH2
- entry point for FADH2
- succinate dehydrogenase of citric acid cycle is a part of the succinate-Q reductase
-FADH2 passes e- singly to Fe-S centers
Fe-S centers pass them to CoQ (ubiquinone) to form QH2
- NOT A PROTON PUMP (why less ATP is made from FADH2)
335
Complex II in ETC
IN: QH2, OUT: Cyt c1
Q-Cytochrome C Oxidoreductase
- ubiquinol carries two e-, cytochrome c only carries one
- Q cycle (coupling electron transfer from QH2 to cytochrome c)
- four protons pumped
- Cyt. c is soluble and moves between complex III and IV
336
Complex IV in ETC
IN: Cyt C, OUT: water
Cytochrome c Oxidase
- cytochrome c oxidase accepts four electrons for four molecules of cytochrome c in order to catalyze the reduction of O2 to 2 molecules of H2O
- 2 protons pumped from matrix
- O2 is final e- acceptor
337
proton-motive force
the proton gradient generated by the oxidation of NADH and FADH2, which powers the synthesis of ATP
338
what is the chemiosmotic hypothesis by Peter Mitchell
chemiosmosis:
- electron transport and ATP synthesis are couples by a proton gradient across the inner mitochondrial membrane
proton gradient:
- drives the formation of proton-motive force
- the chemical gradient for protons can be represented as a pH gradient
- the charge gradient is created by the positive charge on the unequally distributed protons forming the chemical gradient
PMF = chemical (pH) + charge gradient
339
what is composed of a proton-conducting unit and a catalytic unit
ATP synthetase
340
ATP synthetase components and subunits
Fo component: (hydrophobic) embedded in the inner mitochondrial membrane and contains the proton channel
F1 component contains the catalytic activity and protrudes into the mitochondrial matrix
B subunit: each enzyme had three active sites on the three B-subunits (each one interacts differently with the Y subunit
Y subunit: connects the Fo and F1 components
341
what is the proton flow around the c ring that powers ATP Synthesis
1) subunit a, around the c ring, has TWO channels that reach halfway. one half channel opens to the intermembrane space, the other half to the matrix
2) protons enter the half channel facing the proton-rich INTERMEMBRANRE space, bind to a glutamate residue on one of the subunits of the c ring, then leave the c ring once they rotate around to face the matric half channel
3) the force of the proton gradient powers the rotation of the c ring
4) the rotation of the c ring powers the movement of the Y subunit, which in turn alters the conformation of the B subunits
342
what two amino acids have the ability to donate protons for enzyme catalysis due to their side chains
aspartic acid and glutamic acid
343
what are the three conformations of the catalytic B subunits of the F1 component and what do they do
open form: release
loose form: trap
tight form: synthesis
344
how many protons must flow into the matric for each molecule of ATP formed
3
345
how many molecules of ATP are made through the complete oxidation of glucose and where do they come from
- 26 molecules formed in oxidative phosphorylation
- metabolism of glucose to two molecules of pyruvate in glycolysis yields 2 ATP
- TCA yields 2 ATP
346
T/F the mitochondrial inner matric is permeable to NADH
false
347
glycerol 3-phosphate shuttle
NADH -> FADH2
- in muscle, electrons from cytoplasmic NADH can enter the ETC using this shuttle
- e- are transferred from NADH to FADH2 and subsequently to Q to form QH2
348
malate-aspartate shuttle
NADH -> NADH
- in heart and liver, e- from cytoplasmic NADH are used to generate mitochondrial NADH using this shuttle
- consists of two membrane transporters and four enzymes
349
how many ATP can be generated from 1 glucose?
1 NADH = 2.5 ATP
1 FADH2 = 1.5 ATP
muscle - 30 ATP
heart/liver - 32 ATP
350
how does regulated uncoupling lead to the generation of heat
adrenergic hormones enter the intermembrane space
- nonshivering thermogenesis
- facilitated by uncoupling protein 1 (UCP-1), also called a thermogenin
- uncoupling occurs in the mitochondria in BROWN FAT
- UCP-1 transports protons from the intermembrane space to the matric with the assist of fatty acids
351
how does the inhibition of the ETC inhibit oxidative phosphorylation
inhibiting the formation of the proton-motive force
352
how does the inhibition of ATP synthase inhibit oxidative phosphorylation
inhibiting proton flow prevents electron transport
353
how does the inhibition of uncouplers inhibit oxidative phosphorylation
they cannot carry protons across the inner mitochondrial membrane, ETC will not function, but ATP synthesis does not occur because the proton gradient can never form
354
how does the inhibition of the ATP-ADP translocase inhibit oxidative phosphorylation
just prevents
355
inhibition of ETC molecules in complex !, III, and IV
I- rotenone
III- antimycin A
IV- cyanide, azide, carbon monoxide
356
inhibition of ATP synthase
oligomycin, DCC
- prevents by binding to the carboxylate group of the c subunits
357
inhibition of uncouplers
2,4-dinitrophenol (DNP) - dieting agent, active agent in herbicides
Xanthohumol - shows promise in treatment for obesity
358
inhibition of ATP-ADP translocase
atractyloside (cytoplasmic, plant glycoside)
bongkrekic acid (matric, antibiotic in ferments coconut)
MCB 450
flashcards
Decks in class (6)
# Cards
