Kaplan Biochem Contd. Flashcards
..: unit of DNA that encodes a specific protein or RNA molecule
gene
mRNA is synthesized in the … to … direction and is complementary and antiparallel to the DNA .. strand
5’; 3’; template
DNA template for transcription is the … to … strand
DNA … strand is the .. to … strand = identical to the mRNA transcript, except for the fact that DNA has thymine and RNA has uracil
3’; 5’
coding; 5’; 3’
ribosome translates mRNA in the … to … direction, synthesizing the protein from the … to … terminus
5’; 3’; N; C
…: only RNA that contains info translated into protein
transcribed from DNA by ..
mRNA; RNA polymerase
mRNA in eukaryotes is … –> one mRNA = one protein
mRNA in prokaryotes can be … –> one mRNA can code for several different proteins –> this can be achieved by having translation … in the mRNA to yield different proteins
monocistronic
polycistronic; start at different locations
transfer RNA (tRNA) contains a … and a … which recognizes and pairs with the appropriate codon on an mRNA transcript in the ribosome
folded strand of RNA: 3-nucleotide anticodon
transfer RNA:
activated/charged when …
mature tRNA are in the …
bonded to an amino acid
cytoplasm
transfer RNA
activated by …, which attaches amino acids to the 3’ end of the correct tRNA at the CCA nucleotide sequence –> activation requires … high E bonds from ATP, which implies that the bond between tRNA and aa is … (breaking it would release energy)
aminoacyl-tRNA synthetases
two
energy rich
the high energy aminoacyl-tRNA bond supplies energy needed to .. during translation
create peptide bonds
… is the primary component of ribosomes and is synthesized in the nucleolus
ribosomal RNA
rRNA can also function as … –> enzymes made of RNA
rRNA helps catalyze formation of … bonds and plays a role in … in the nucleus
ribozymes
peptide;
splicing out its own introns
there are … codons and the code is … –> one codon codes for only one amino acids
codons are written in .. to … direction
64; unambiguous
5’; 3’
61 codons code for one of the 20 amino acids and 3 code for …
termination of translation
the anticodon and codon are … to one another
antiparallel
every protein begins with …, so … is considered the start codon for translation
methionine; AUG
the way the anticodons stop termination is through the fact that there are no … that …, so it results in the ribosome releasing the protein
tRNAs; recognize them
stop codons: …, …, … –> mnemonics: …, …, …
UGA –> U Go Away
UAA –> U Are Annoying
UAG –> U Are Gone
genetic code is … because more than codon codes for the same amino acid. all amino acids except for … and … are encoded by more than one codon
degenerate; methionine; tryptophan
degenerate genetic code:
… bases are usually the same, and the … is variable –> this position is the … position, which helps protect against harmful mutations –> mutations in this position tend to be …/.. (having no effect)
first two; third
wobble
silent; degenerate
…: mutation that affects one of the nucleotides in a codon
… mutations
… mutation: one amino acid substitutes another
… mutation: early termination, aka … mutation
point mutation
silent
missense
nonsense; truncation
… mutations: insertions/deletions that change the reading frame –> more serious than point mutations
frameshift
translation occurs in the
cytoplasm
(transcription) DNA is unwound by … and … so that RNA polymerase has access to the sequence
template strand = …/… strand
coding strand = … strand
helicase; topoisomerase
antisense; missense
sense
(transcription) RNA polymerase locates the gene by … sequences –> in eukaryotes, this is the …
… help it locate and bind to these sequences
promoter; TATA box
transcription factors
RNA polymerase does not require …
primers
3 types of RNA polymerases in eukaryotes:
… –> in nucleolus, synthesizes rRNA
… –> in nucleus, synthesizes hnRNA (…) and some small nuclear RNA
… –> in nucleus, synthesizes tRNA and some rRNA
RNA polymerase I
RNA polymerase II: pre-mRNA
RNA polymerase III
RNA polymerase doesn’t ..
proofread
numbering system identifies location of important bases in the DNA strand in the vicinity of the gene –>
… is the first base transcribed, bases to the left of this (…, toward … end) are given … numbers and those the right (…, toward … end) are given … numbers
no nucleotide is assigned 0
TATA box is usually around …
\+1 upstream; 5' negative downstream; 3' positive -25
transcription continues until RNA polymerase reaches a …/.. –> results in …, called …, from which mRNA is derived after processing
termination sequence; stop signal
primary transcript; heterogenous nuclear RNA
introns, or non-coding sequences, are spliced out of the pre-mRNA using .., which consists of … coupled with proteins known as … (…)
spliceosome; small nuclear RNA; small nuclear ribonucleoproteins; snRNPs
snRNPs recognize both the 5’ and 3’ ends of the introns and cuts it out in the form of a … (…-shape) and subsequently … it
introns may be important for … regulation and maintaining …
lariat; lasso; degrades
gene expression; genome size
introns may allow for rapid
protein evolution
at 5’ end of hnRNA, a modified … (7-methylguanylate triphosphate cap) is added. this cap is added during … and is recognized by the ribosome as the …
protects mRNA from … in the cytoplasm
guanine
transcription
binding site
degradation
at 3’ end of hnRNA, a … (…) tail is added to protect against … in the cytoplasm
polyadenosyl; poly-A
degradation
longer poly-A tail = … mRNA will be able to survive before being degraded in the cytoplasm
poly A tail also helps facilitate … of mRNA from the …
more time
exit; nucleus
when the mRNA exits, there are still … (UTRs) that exist at both the 5’ and 3’ ends of the transcript, as the ribosome will start at the …and stop at a …
untranslated regions
start codon; termination sequencing
…: primary transcript of hnRNA can be spliced together in different ways to produce multiple variants of proteins encoded by the same original gene –> amplifies amount of proteins that can be made from a single gene, plays a role in regulation of …, and generates ..
alternative splicing
gene expression
protein diversity
mRNA transcript exits nucleus through …
nuclear pores
ribosome has … and … subunits that bind together during protein synthesis
large; small
ribosome has three binding sites for tRNA:
… site (…)
… site (…)
… site (…)
A; aminoacyl
P; peptidyl
E; exit
eukaryotic ribosomes have 4 strands of rRNA –> …, …, …, and …
28S; 18S; 5.8S; 5S
RNA polymerase I transcribes the …, …, and … rRNA as a single unit. this … unit sis processed such that the … rRNA becomes part of the .. small ribosomal subunit and the … and … rRNAs become part of the … large ribosomal subunit
28S; 18S; 5.8S
45S; 18S; 40S;
28S; 5.8S; 60S
RNA polymerase II transcribes … rRNA, which is also in the large subunit
5S
when the 60S and 40S subunits come together during translation, it forms an overall … ribosome
80S
prokaryotic ribosome has a … large subunit, a … small, and altogether it is …
50S; 30S; 70S
numbers of each subunit and each rRNA are not additive because they are based on … and …
size; shape
(initiation of translation)
… ribosomal subunit binds to the mRNA
in prokaryotes, binds to the … sequence
in eukaryotes, binds to the ..
small
Shine-Dalgarno
5’ cap
(initiation of translation)
initiator tRNA binds the start codon in the … site of the ribosome
initial amino acid in prokaryotes is …
in eukaryotes initial amino acid is …
P
N-formylmethionine
methionine
(initiation of translation)
… binds to the small subunit, assisted by …
large subunit; initiation factors
(elongation of translation)
3 step cycle repeated until termination
A site holds incoming … –> next amino acid being added to the growing chain
P site holds tRNA carrying the … –> peptide bond is formed as the polypeptide is passed from the tRNA in the p site to that in the A site –> facilitated by …, which is part of the large subunit, and … for energy
aminoacyl-tRNA
growing polypeptide chain
peptidyl transferase; GTP
(elongation of translation)
E site: where the … tRNA pauses temporarily before exiting the ribosome
… assist by locating and recruiting aminoacyl-tRNA along with …, while helping to remove … once energy has been used
inactivated
elongation factors
GTP
GDP
(elongation of translation) some eukaryotic proteins contain …, which designate a particular destination for the protein –> these are added …
signal sequences;
during translation
(elongation of translation) proteins being secreted will have signal sequences that direct the ribosome to move to the … so that it can be translated into the … and subsequently moved to … to be secreted in a vesicle
ER; lumen; Golgi
(elongation of translation) signal sequences can direct proteins to the …, …, or …
nucleus; lysosomes; cell membrane
(termination of translation)
when one of the stop codons moves into the A site, a protein called … binds to the codon, causing addition of a .. which allows … and … to hydrolyze the completed polypeptide chain from the final tRNA
polypeptide chain is released and ribosome dissociates
release factor
water molecule
peptidyl transferase; termination factors
after translation, proteins must .. and are assisted by …
fold; chaperone proteins
proteins can be modified by …
cleavage events
in peptides with quarternary structure, after translation, the subunits must
come together
other posttranslational processing:
…: addition of a phosphate group to activate/deactivate proteins –> common with …, …, and …
phosphorylation
serine; threonine; tyrosine
other posttranslational processing:
…: addition of carboxylic acid groups, usually to serve as calcium binding sites
…: addition of oligosaccharides as proteins pass through the ER and Golgi to determine cellular destination
…: addition of lipids to certain membrane-bound enzymes
carboxylation
glycosylation
prenylation
…: cluster of genes transcribed as a single mRNA –> prokaryotes
operon
Jacob Monod Model describes … and … of operons
structure; function
Jacob Monod Model:
…: codes for protein of interest
…: nontranscribable region of DNA where repressor protein binds; upstream of structural gene
…: upstream of operator site; provides a place for RNA polymerase to bind
…: furthest upstream, codes for the repressor protein
structural gene
operator site
promoter site
regulator gene
…: repressor is bonded tightly to the operator system to prevent gene expression
inducible systems
(inducible systems) ..: binding of a protein reduces transcriptional activity
an inducer can bind to the .. such that transcription will occur
negative control mechanisms
repressor
(inducible systems) higher conc of inducer means that more … of that gene will occur
transcription
(inducible systems) lac operon - present in E. Coli
E. coli can use lactose as food, but it is more energetically expensive than glucose digestion
When lactose concs are high and glucose is low, the lac operon is “turned on” such that.. can be generated
Assisted by binding of …which is a transcriptional activator used when glucose levels are low. Low glucose concs increases conc of cAMP, which binds to CAP and induces a conformational change that allows CAP to bind to the … to increase transcription of that agene
lactase; catabolite activator protein;
promoter of lac operon
(inducible systems) …: when binding of a molecule increases transcriptional activity
positive control mechanisms
…: allow constant production of a protein product
repressible systems
(repressible systems)
repressor made by the regulator gene is inactive until it binds to a … which facilitates its binding to the operator site
corepressor
(repressible systems) can function as … –> final product often acts as the corepressor, so that, as its levels increase, further transcription of that gene is inhibited
… operon: when tryptophan is present in the enviro in high concs, it acts as a … to prevent the cell from synthesizing its own tryptophan, which is energetically expensive
negative feedback;
Trp;
corepressor
…: transcription-activating proteins that have a DNA-binding domain and an activation domain
transcription factors
…: binds to a specific nucleotide sequence in the protomer region or to a response element to help recruit transcriptional machinery
DNA-binding domain
…: sequence of DNA that binds only to specific transcription factors
response element
…: allows for binding of several transcription factors and other regulatory proteins like polymerase and histone acetylases
activation domain
…: function in remodeling of chromatin structure
histone acetylases
genes have a basal level of transcription but expression can be amplified in response to certain signals –> accomplished through … and …
enhancers; gene duplication
…: several response elements grouped together to allow for control of gene expression
enhancer
enhancer:
signal molecules bind to receptors which are … that bind to their response elements within the enhancer
signal molecules: cAMP, cortisol, estrogen, etc
receptors: CREB, cortisol receptor, estrogen receptor
transcription factors
enhancer:
large distance between enhancer and promoter means that DNA must bend into a … to bring these elements together
enhancer region can be up to … bp away from the gene and can be in an intron
hairpin loop
1000
promoters must be within … of the start of a gene
25 bases
…: increase in gene expression by duplicating a gene
can be duplicated … to yield many copies in a row of the same genetic info
can be duplicated … by opening the gene with helicases and allowing for replication of just that gene, replicating until hundreds of copies of the gene exist … on the same chromosome
gene duplication
in series
in parallel
in parallel
… acetylatelysine residues in the amino terminal tail regions of histone proteins, which decreases the … on lysine and weakens interaction of histone with DNA –> opens chromatin such that it can be transcribed
histone acetylases; positive charge
histone deacetylases remove … groups from histones and are therefore components of …
acetyl; gene silencing
DNA … add methyl groups to .. and … –> linked with gene silencing
… much more heavily methylated
methylases; cytosine; adenine;
heterochromatin
carbs associated with membrane-bound proteins create a …
glycoprotein coat
the cell walls of plants, fungi, and bacteria, have higher levels of
carbs
… protect the internal enviro of the cell, control what enters and exits the cell, and plays a role in inter and intracellular communication
cell membranes
phospholipids move rapidly in the plane of the membrane through
simple diffusion
…; collections of similar lipids with/without associated proteins that serve as attachment points for other biomolecules –> often play roles in …
travel in the … of the membrane as well, but more slowly
lipid rafts
signaling
plane
lipids can flip between the membrane layers, but this is unfavorable bc the polar head would have to pass through the hydrophobic region –> facilitated by …
flippases
cells can … or … the number of cellular receptors in the cell membrane to meet cellular needs
up; downregulate
cell membrane has very few .. and contains …, … and … to maintain structural integrity
… provide membrane stability
free fatty acids; steroids; cholesterol; waxes
waxes
humans can only synthesize a few of the … and must consume the rest in their diets, which are then reabsorbed as chylomicrons in the small intestine
essential fatty acids: … and …
unsaturated fatty acids
alpha-linolenic acid; linoleic acid
saturated fatty acids … overall membrane fluidity where unsaturated fatty acids … it
decreae; increase
micelles are … vesicles whereas liposomes are …
monolayer; bilayered
… can produce a hydrophilic surface layer on …, which are proteins that transport lipids in the bloodstream
e.g. very-low-density lipoprotein
glycerophospholipids
lipoproteins
phospholipids can act as … in signal transduction
second messengers
phosphate group on phospholipids can act as a point of attachment for … such as choline
water soluble groups
… are also important constituents of cell membrane
sphingolipids
… essential for synthesis of all steroids
cholesterol
cholesterol … phospholipids but also occupies space between them –> contributes to its ability to regulate membrane fluidity
cholesterol prevents formation of … structures in membrane which increases fluidity at low temps
stabilizes
crystal
cholesterol is about 20% of cell membrane by … and about 50% by …
mass; mole fraction
waxes rarely found in cell membranes of .., but sometimes found in …
animals plants
waxes:
long chain … and long chain … –> have high melting pts
can provide … and … within nonpolar region of cell membrane
can have extracellular function of …/…
fatty acid; alcohol
stability; rigidity
protection; waterproofing
… proteins; pass completely through membrane
transporters, channels, receptors
transmembrane
…: only in the hydrophobic region of membrane
embedded proteins
…: transmembrane and embedded proteins –> association with interior usually assisted by … that are partially hydrophobic
integral proteins; membrane-associated domains
… (…) proteins may be bound through electrostatic interactions with lipid bilayer, esp at lipid rafts, or can be bound to transmembrane/embedded proteins
membrane-associated peripheral
bc carbs are hydrophilic, interactions between glycoproteins and water can form a … around the cell
coat
carbs on cell membrane can act as … and … molecules (e.g. ABO blodo types)
signaling; recognition
membrane receptors are typically …, but there are some carb and lipid ones, esp in viruses
proteins
… provide direct pathways of communication between cells or between cells and the extracellular matrix
comprised of … molecules, which enable recognition of cells and contribute to cell … and ..
cell-cell junctions
cell adhesion;
differentiation; development
… (…): found in small bunches together, formed by alignment and interaction of pores composed of six molecules of connexin
permit movement of … and some … between cells –> not really for protein transport between cells
gap junctions; connexons
water; solutes
…: prevent solutes from leaking into space between cells via .. route
found in epithelial cells and act as a … link between the cells as they form a single layer of tissue
limit permeability which can allow for a … based on differing concs of ions on either side of the epithelium
tight junctions;
paracellular;
physical;
transepithelial voltage difference
…: bind adjacent cells by anchoring to their cytoskeletons
desmosomes
desmosomes formed by interactions between … proteins associated with … inside adjacent cells
primarily found at interface between two layers of …
transmembrane proteins; intermediate filaments;
epithelial tissue
…: main function is to attach epithelial cells to underlying structures, esp the basement membrane
hemidesmosomes
desmosomes have more of an … purpose whereas tight junctions are aimed more at … from going in space …
attachment; preventing material; outside the cells
…, …, and … generally increase in rate as temp increases
diffusion; facilitated diffusion; osmosis
active transport may or may not increase in rate as temp increases –> depends on … of the process
enthalpy
primary thermodynamic motivator in most passive transport is … increase
entropy
…: substances move down their conc gradient directly across the membrane –> for molecules for which the membrane is permeable
… in a conc gradient is released during this process
simple diffusion;
potential energy
…: molecules move from a high water conc (dilute solution) to low water conc (conc solutoin) in an attempt to bring solute concentrations to …
osmosis
equimolarity
osmosis:
…: has less solute than cell
…: has more solute than cell
…: has equal solute as cell –> does not prevent movement altogether, but prevents net movement of particles across the membrane
hypotonic solution
hypertonic solution
isotonic solution
driving force behind osmosis can be quantified through …, a colligative property
osmotic pressure
….: physical property of solutions that is dependent on conc of dissolved particles but not on chemical identity of the dissolved particles
other examples: vapor pressure depression (Raoult’s Law), boiling point elevation, freezing point depression
colligative property
when osmosis is occurring across a semipermeable membrane that is impermeable to the solute, the concentrations of the solute in the two compartments …
Instead, water level will rise to the pt at which it exerts a sufficient pressure to counterbalance the tendency of water to …
can never be equal; flow across the membrane
osmotic pressure is defined by:
…
π=iMRT
M: molarity, R: ideal gas constant, T: absolute temp in K
i = van’t Hoff factor
i in osmotic pressure: van’t Hoff factor –> number of … obtained from the molecule when in solution
particles
in cells, … is maintained agains the cell membrane. so if osmotic pressure is too high for membrane to sustain, the cell will …
osmotic pressure
lyse
facilitated diffusion can involve carrier or channel proteins:
…: open only to one side of the cell membrane at any given point. binding of the substrate induces a conformational change, and for a brief period the carrier is … (not open to either side)
…: can be in a closed or open state. in their open conformation, they are exposed to both sides of the membrane
carriers; occluded
channels
…: uses ATP to directly power movement of a molecule across the membrane –> typically involves transmembrane …
used by neurons
primary active transport
ATPase
…/…: no direct coupling to ATP hydrolysis; powered by harnessing energy of one molecule moving down its gradient to drive a different molecule up its gradient
secondary active transport/coupled transport
coupled transport:
…: transport of both particles in the same direction
…: transport of the particles in opposite directions
used by .., typically driven by sodium, to reabsorb and secrete solutes into/out of filtrate
symport
antiport
kidneys
endocytosis:
…: endocytosis of fluids and dissolved particles
…: ingestion of large solids like bacteria
..: used to carry out endocytosis when substrates bind to specific receptors (a notable one of these is clathrin)
pinocytosis;
phagocytosis;
vesicle-coating proteins;
…: secretory vesicles fuse with membrane to release material from inside cell to extracellular enviro
exocytosis
…, Vm: difference in electrical potential across cell membranes
membrane potential
maintaining membrane potential requires energy bc ions may passively diffuse through the cell membrane over time using …
ion transporter or pump like … regulates conc of intracellular and extracellular sodium and potassium ions
… also participates in establishing membrane potential
leak channels
Na+/K+ ATPase
chloride
for goldman equation, chloride is inverted relative to the other ions bc it
carries a negative charge
sodium potassium ATPase aims to maintain … conc of sodium ions and … conc of potassium by pumping … out of the cell for every … that enters the cell –> remove … from intracellular space fo the cell, maintaining resting potential
low; high;
3 Na+; 2K+
one positive chare
cell membranes are more permeable to K+ at rest because there are ..
more K+ leak channels
…: highly permeable, completely surrounds inner mitochondrial membrane, with presence of intermembrane space between the two layers
outer mitochondrial membrane
…: more restricted permeability, has foldings known as cristae
o Encloses the mitochondrial …
o Contains very high level of … and does not contain …
Inner mitochondrial membrane;
matrix;
cardiolipid; cholesterol
normal blood glucose concentrations is … mM (range: … - … mM)
5.6; 4; 6
four glucose transporters, … through …
GLUT 1; GLUT 4
GLUT 2: low affinity transporter in … and … cells
captures … for storage
when glucose conc is below Km for GLUT 2, glucose bypasses … and enters …
hepatocytes; pancreatic
excess glucose
liver; peripheral circulation
GLUT 2:
liver will pick up glucose in proportion to its conc in the blood –> …
… uses GLUT 2 and glucokinase to act as a sensor for .. release
1st order kinetics;
beta islet cells of pancreas;
insulin
GLUT 4:
in … tissue and … and respond to blood glucose concs
rate of glucose transport is increased by …, which stimulates movement of additional GLUT 4 transporters to membrane by …
adipose; muscle
insulin
exocytosis
GLUT 4:
transporter is saturated when blood glucose levels are a bit … than normal
transporters follow … kinetics, so the only way for GLUT 4 to increase glucose intake is for there to be ….
higher
zero-order kinetics
more GLUT4 on the cell surface
GLUT 4:
muscle stores excess glucose as …
adipose tissue requires glucose to form …which is converted to glycerol phosphate to store fatty acids as triacylglycerols
glycogen
dihydroxyacetone phosphate
..: cytoplasmic pathway that converts glucose into two pyruvates, releasing some energy
can feed into … pathway to produce more energy
if mitochondria or oxygen is lacking, can occur …
provides … for other pathways such as fatty acid synthesis
glycolysis
aerobic respiration
anaerobically
intermediates
… adds a phosphoryl group to glucose once it enters the cytoplasm to generate … this makes the glucose more reactive and also prevents it from exiting the cell, since the GLUT transporters don’t recognize … glucose
hexokinase; glucose-6-phosphate;
phosphorylated
hexokinase is inhibited by …
…, which is specific to glucose, is found in liver cells and beta islet – unlike hexokinase, has a high Km (acts on glucose proportionally to its … ). This enzyme is induced by … in hepatocytes
G6P
glucokinase; conc; insulin
… is the rate limiting enzyme of glycolysis and catalyzes the conversion of … into … using ATP
phosphofructokinase-1
fructose-6-phosphate
fructose 1,6-bisphosphate
phosphofructokinase-1
inhibited by … and … and activated by … –> cell turns off glycolysis when there’s enough energy and turns it on when it needs energy; … is intermediate of citric acid cycle, so high concs indicate that sufficient energy is being generated
ATP; citrate; AMP; citrate
Phosphofructokinase-1 contd:
insulin indirectly stimulates PFK1 by activating … which converts a tiny amount of fructose 6-phosphate into … which activates PFK 1
… has the opposite effect
PFK2; fructose 2,6-bisphosphate;
glucagon
Phosphofructokinase-1 contd:
PFK 2 is mostly in the ..
this indirect activation/inhibition by insulin allows hepatocytes to override inhibition caused by … so that glycolysis can continue and its metabolites can be used for …, …, and other storage molecules’ production
liver; ATP; glycogen; fatty acids
… catalyzes an oxidation and addition of Pi to glyceraldehyde-3-phosphate to produce a high energy intermediate, …, and to reduce … to … –> this reduced product can be oxidized by the e- transport chain to provide more ATP
glyceraldehyde-3-phosphate dehydrogenase;
1,3-bisphosphoglycerate;
NAD+; NADH
… transfers high energy phosphate from 1,3-bisphosphoglycerate to ADP to form ATP and … –> ….: not dependent on oxygen and is consequently the only means of ATP production in anaerobic tissue
3-phosphoglycerate kinase; 3-phosphoglycerate;
substrate-level phosphorylation
… catalyzes substrate level phosphorylation of ADP using high energy …
activated by fructose 1,6-bisphosphate –> … activation
pyruvate kinase; phosphoenolpyruvate;
feed-forward
fermentation occurs in anaerobic conditions:
… oxidizes NADH to NAD+ to replenish the coenzyme for … –> prevents glycolysis from stopping under anaerobic conditions
in yeast, fermentation is the conversion of pyruvate to … and …, but the ultimate goal of replenishing … remains the same
lactate dehydrogenase; glyceraldehyde 3-phosphate dehydrogenase
ethanol; CO2; NAD+
(important glycolytic intermediates) ..: used in hepatic and adipose tissue for triacylglycerol synthesis
dihydroxyacetone phosphate
(important glycolytic intermediates) dihydroxyacetone phosphate formed when … is cleaved to … and …
can be isomerized to … which can be converted to …
fructose 1,6-bisphosphate; glyceraldehyde; DHAP
glycerol 3-phosphate; glycerol
(important glycolytic intermediates) … and … are the only intermediates through which ATP is gained by way of substrate level phosphorylation
1,3-bisphosphoglcyerate; phosphoenolpyrvuate
irreversible enzymes of glycolysis:
…
…
…
glucokinase/hexokinase
PFK-1
pyruvate kinase
since erythrocytes lack mitochondria, … is the only way they gain ATP
anaerobic glycolysis
glycolysis has a net gain of … ATP per glucose
2
RBCS have … which produces 2,3-bisphosphoglycerate from 1,3-BPG. 2,3-BPG binds allosterically to … of HbA and …
bisphosphoglycerate mutase;
beta chains;
decreases its affinity for oxygen
RBCs and 2,3-BPG activity:
facilitates … in tissues, but still allows for complete hemoglobin saturation in the lungs
2,3-BPG doesn’t bind well to fetal hemoglobin, which allows fetal hemoglobin to have … than maternal hemoglobin
oxygen unloading;
higher affinity for oxygen
… and … can also feed into glycolysis
galactose; fructose
… is an important dietary source of galactose –> hydrolyzed to galactose and glucose using … (brush border enzyme in duodenum
lactose; lactase
galactose reaches liver through … and can then be phosphorylated by … to form …, which can be converted to … by … and an epimerase
hepatic portal vein;
galactokinase;
galactose 1-phosphate;
glucose 1-phosphate; galactose-1-phosphate uridyltransferase
…: catalyze conversion of one epimer to another
epimerase
sucrose can be hydrolyzed by brush border enzyme … to yield … and …., which are then absorbed through hepatic portal vein. liver phosphorylates fructose using … to yield …, which is cleaved into … and … by …
sucrase; glucose; fructose;
fructokinase; fructose 1-phosphate;
glyceraldehyde; DHAP; aldolase B
pyruvate enters mito where it can be converted to … for entry into the citric acid cycle or for fatty acid synthesis –> catalyzed by …
acetyl-CoA
pyruvate dehydrogenase
pyruvate dehydrogenase complex rxn is …
irreversible
pyruvate dehydrogenase in liver is activated by …, but in the nervous system, it is not responsive to hormones
… levels signal to the liver that glucose is not needed (bc there is enough in bloodstream), and that there should be a shift towards … and … of fatty acids rather than oxidation
insulin;
high insulin;
production; storage
pyruvate can have 3 different fates:
conversion to … by …
conversion to … by …
conversion to … by …
acetyl CoA; pyruvate dehydrogenase
lactate; lactate dehydrogenase
oxaloacetate; pyruvate carboxylase
pyruvate dehydrogenase complex requires multiple cofactors and coenzymes: .... ... ... ... ...
thiamine pyrophosphate lipoic acid CoA FAD NAD+
pyruvate dehydrogenase is inhibited by … –> buildup of this leads to shift in metabolism in that pyruvate is no longer converted into … to enter citric acid cycle but instead is converted into … for …
acetyl-CoA;
acetyl CoA;
oxaloacetate
gluconeogenesis
glycogen is a storage form of glucose and is stored in cytoplasm as …
synthesis and degradation occur primarily in … and ….
granules
liver; skeletal muscle
glycogen granules have central protein core with … chains radiating outward to form a sphere
granules that have all linear chains have the highest density of glucose near the … whereas those that have branched chains will have the highest glucose density at the … of the granule –> … chains allow for more rapid glucose release
polyglucose chains
core
periphery
branched
glycogen in the liver acts as a source of glucose for when … is low and is quickly mobilized whereas glycogen in skeletal muscle is stored as …
blood sugar;
energy reserve for contraction
plants store excess glucose in … linked chains of glucose called …
alpha; starch
… is synthesis of glycogen granules –> begins with core protein …
glycogenesis;
glycogenin
glycogenesis
glucose begins as G6P and is converted to …, which is activated by coupling it to a molecule of …
G1P
uridine diphosphate
glycogenesis:
UDP permits glucose’s integration into the glycogen chain by …
glucose 1-phosphate is activated by interacting with … to form .. and …
glycogen synthase;
uridine triphosphate; UDP-glucose; pyrophasphate
glycogenesis:
…: rate-limiting enzyme of glycogen synthesis, forms the alpha 1,4 glycosidic bond in linear chains of glucose
stimulated by … and …
glycogen synthease;
G6P; insulin
glycogenesis
glycogen synthase inhibited by … and …, which causes a protein kinase cascade that phopshorylates and inactivates the enzyme –> these hormones indicate that glucose is needed in the bloodstream and therefore should not be incorporated into glycogen
epinephrine; glucagon
… introduces alpha 1,6-linked branches into glycogen granule as it grows:
the enzyme hydrolyzes one of the … bonds to release a block of … which is then moved and added in a slightly different location. the enzyme then forms an … bond to create a branch –> … will subsequently extend both the original and the new branch
branching enzyme alpha 1,4 oligoglucose alpha 1,6 bond glycogen synthase
…: process of breaking down glycogen
glycogenolysis
(glycogenolysis) Rate limiting enzyme is … (phosphorylases break bonds using an inorganic phosphate instead of water)
breaks … bonds to release … from periphery of granule
glycogen phosphorylase;
alpha 1,4-glycosidic bonds;
glucose 1-phosphate
(glycogenolysis) glycogen phosphorylase:
cannot break … bonds
activated by … in liver and … and … in skeletal muscle
inhibited by
alpha 1,6
glucagon; AMP; epinephrine;
ATP
(glycogenolysis) …: two enzyme complex that deconstructs branches in glycogen that have been exposed to glycogen phosphorylase
debranching enzyme
(glycogenolysis) debranching enzyme:
breaks an … bond adjacent to the branch point and moves the small … chain that is released to the exposed end of the other chain and forms a new … bond. it then hydrolyzes the … bond to release the single residue at the branch point as … –> this is the only … produced directly in glycogenolysis
alpha 1,4 bond; oligoglucose; alpha 1,4; alpha-1,6; free glucose; free glucose
(glycogenolysis) G1P is converted by a mutase to … and then converted to … via …
G6P; glucose; glucose 6-phosphatase
….: slightly different versions of the same protein
isoforms
clinical features of a metabolic glycogen defect (glycogen storage diseases) depend on:
which … is affected
the degree to which that … is …
which … of the … is affected
enzyme;
enzyme’s activity; decreased;
isoform; enzyme
glycogen storage diseases are all characterized by … or … of glycogen in one or more tissues
accumulation/lack
gluconeogenesis is promoted by … and … and inhibited by …
glucagon; epinephrine; insulin
important gluconeogenesis substrates:
… (from stored fats in adipose tissue)
… (from anaerobic glycolysis)
… (from muscle proteins) –> amino acids that can be converted into intermediates that feed into gluconeogenesis (all except … and …)
glycerol 3-phosphate
lactate
glucogenic amino acids;
leucine; lysine
…: can be converted into ketone bodies which can be used as alternative fuel esp during prolonged starvation
ketogenic amino acids
acetyl-CoA cannot be converted back to … and since most fatty acids are metabolized only to acetyl-CoA, they are not a major …
fatty acids with odd number of C atoms, though, yield a small amount of ….
glucose; glucose source;
glucogenic propionyl-CoA
lactate is converted to pyruvate by …
lactate dehydrogenase
alanine is converted to pyruvate by
alanine aminotransferase
glycerol 3-phosphate is converted to … by …
dihydroxyacetone phosphate; glycerol-3-phosphate dehydrogenase
most steps in gluconeogenesis are a reversal of glycolysis. however, there are some different steps that are necessary to circumvent the … steps of glycolysis in the liver
irreversible
(gluconeogenesis) ..: mitochondrial enzyme activated by acetyl-CoA; yield oxaloacetate
pyruvate carboxylase
(gluconeogenesis) oxaloacetate cannot leave mitochondrion so it has to be reduced to … which can exit via … it is then oxidized to oxaloacetate in the cytosol
malate; malate-aspartate shuttle
(gluconeogenesis) pyruvate carboxylase and oxaloacetate being transported via malate-aspartate shuttle:
in this case, acetyl-CoA is derived from … –> to produce glucose in the liver during gluconeogenesis, … must be burned to provide energy, stop forward flow of …, and produce a lot of …
fatty acids; fatty acids; citric acid cycle; oxaloacetate
(gluconeogenesis) …: induced by … and …
converts oxaloacetate to .., using …
phosphoenolpyruvate carboxykinase;
glucagon; cortisol;
phosphoenolpyruvate; GTP
(gluconeogenesis) PEP carboxykinase:
PEP is converted to …
pyruvate carboxylase and PEPCK circumvent action of … by converting pyruvate back into PEP
fructose 1,6-bisphosphate
pyruvate kinase
(gluconeogenesis) …; key control pt of gluconeogenesis –> rate-limiting step of the process
fructose 1,6-bisphosphatase
(gluconeogenesis) fructose-1,6-bisphosphatase
reverses action of … by removing phosphate from fructose 1,6-bisphosphate to produce …
phosphofructokinase-1; fructose 6-phosphate
(gluconeogenesis) fructose-1,6-bisphosphatase:
activated by … and inhibited by … and … –> … will lower F26BP and stimulate … and … has opposite effected
ATP; AMP: fructose 2,6-bisphosphate;
glucagon; gluconeogenesis;
insulin
(gluconeogenesis)
…: only in lumen of ER in liver cells
glucose-6-phosphate transported into … and free glucose is subsequently transported out via …
glucose-6-phosphatase;
ER; GLUT
(gluconeogenesis) glucose-6-phosphatase:
the fact that there is no glucose 6 phosphatase in skeletal muscle indicates that muscle glycogen cannot be used to supply …. –> it is only for use within the muscle
this enzyme circumvents …/…
glucose to the bloodstream;
glucokinase/hexokinase
glucogenic amino acids are converted to … intermediates, and then to …, and then from there to …
citric acid cycle; malate; glucose
glucose produced by gluconeogenesis in the liver is not an … for the liver –> gluconeogenesis requires input of energy which is provided by …
energy source; oxidation of fatty acids
acetyl-CoA from fatty acids can be converted into … as alternative fuel for cells
ketone bodies
…/… –> produces NADPH and serves as a source of … for nucleotide synthesis
pentose phosphate pathway; hexose monophosphate shunt
(pentose phosphate pathway) first part of pathway begins with … and is irreversible; yields … –. produces … and involves rate-limiting enzyme … which is induced by … and by …
glucose 6 phosphate; ribulose 5-phosphate;
NADPH; glucose-6-phosphate dehydrogenase; insulin; NADP+
(pentose phosphate pathway) second part of the pathway begins with … and represents a series of reversible rxns that produce an equiibrated pool of sugars for biosynthesis, including …
ribulose 5-phosphate
ribose 5-phosphate
(pentose phosphate pathway) second part of pathway:
… and … are among the sugars produced —> PPP can feed into glycolysis
pentoses can be made from glycolytic intermediates without going through G6PD –> interconvert by enzymes … and …
fructose 6-phosphate; glyceraldehyde phosphate;
transketolase; transaldolase
… acts as a high energy electron acceptor; potent oxidizing agent –> typically participates in … processes
NAD+; catabolic
…. primarily acts as an electron donor; potent reducing agent –> typically participates in .. processes
NADPH; anabolic
NADPH is mainly used for:
biosynthesis, mainly of … and …
assisting in … in WBCs, contributing to bactericidal activity
fatty acids; cholesterol;
cellular bleach production
NADPH is mainly used for:
maintenance of supply of reduced … to protect against reactive oxygen species:
protects from damage caused by … –> … produced as a byproduct of aerobic metabolism and can break to form free radicals that attack lipids, including the lipids of the cell membrane –> causes cell …
glutathione;
peroxides; H2O2;
lysis
NADPH is mainly used for:
protects from damage caused by peroxides contd: esp true in … which have high levels of oxygen and can form the superoxide radical …
free radicals can damage … and cause …
RBCs; O2•; DNA; cancer
… is a reducing agent that can reverse radical formation before it causes damage to the cell
glutathione
pyruvate dehydrogenase is made of 5 enzymes, 3 of which are used for … and two for the …
pyruvate conversion to acetyl-CoA; regulation of PDH
pyruvate dehydrogenase rxn is …
inhibited by an accumulation of … and … that occur if the electron transport chain isn’t functioning or is inhibited
exergonic;
acetyl-CoA; NADH
pyruvate dehydrogenase:
acetyl-CoA formation involves the acetylation of … (…) to form a …
coenzyme A; CoA-SH; thioester
(enzymes of pyruvate dehydrogenase) …: oxidizes pyruvate, releases CO2; the two remaining Cs bind covalently to …, a coenzyme of PDH
… is also a necessary cofactor
pyruvate dehydrogenase;
thiamine pyrophosphate;
Mg2+
(enzymes of pyruvate dehydrogenase)
…: 2 C molecule on TPP is oxidized and bound to …, a coenzyme whose disulfide group acts as an oxidizing agent to create the acetyl group. this enzyme catalyzes the transfer of the … to form …
dihydrolipoyl transacetylase;
lipoic acid; acetyl group; acetyl-CoA
(enzymes of pyruvate dehydrogenase) …: … is a coenzyme used to reoxidize lipoic acid such that it can facilitate future reactions.
… is formed.
dihydrolipoyl dehydrogenase; FAD;
FADH2
(enzymes of pyruvate dehydrogenase)
… and … are the regulating enzymes of this complex
pyruvate dehydrogenase kinase; pyruvate dehydrogenase phosphatase
fatty acid (beta) oxidation: activation forms a … between carboxyl groups of fatty acids and …
thioester bond; coenzyme A
fatty acid (beta) oxidation: fatty acyl-CoA cannot cross inner mitochondrial membrane, so the acyl group is transferred to ... via ...
carnitine; transesterification
fatty acid (beta) oxidation: acyl-carnitine crosses the inner mitochondrial membrane and transfers the acyl group to a .., forming ... in the matrix. from here, beta oxidation can occur, which removes two C fragments from the carboxyl end
mitochondrial coenzyme A; acyl-CoA;
amino acid catabolism: amino acids lose their … group via … and their carbon skeletons form … which can be converted to …
amino; transamination; ketone bodies; acetyl-CoA
acetyl-CoA can be used to form … when … is inhibited. the reverse yields …
ketones; pyruvate dehydrogenase complex; acetyl-CoA
… and … convert alcohol to acetyl-CoA, but this is accompanied by … buildup which inhibits the Krebs cycle –> this method is used primarily to synthesize …
alcohol dehydrogenase; acetaldehyde dehydrogenase; NADH; fatty acids
citric acid cycle begins with condensation of … and … to form … Parts of the molecule are oxidized to CO2 and the process produces … and energy carriers … and …
oxaloacetate; acetyl-CoA; citrate; GTP; NADH; FADH2;
citric acid cycle doesn’t require input of .. but won’t occur anaerobically, because NADH and FADH2 must be … via the …, which requires …
O2; reoxidized; electron transport chain; oxygen
If NADH and FADH2 is not oxidized it will build up and
inhibit the Krebs cycle
step 1 of Krebs–… formation: … and … undergo a condensation rxn to form … which is hydrolyzed to form … and …
citrate;
acetyl-CoA; oxaloacetate;
citryl-CoA;
citrate; coenzyme A
step 1 of Krebs –citrate formation:
this step is catalyzed by
citrate synthase
Step 2 of Krebs – citrate isomerization: citrate binds to the enzyme …, and water is lost to yield …
When water is added again, … is formed
aconitase;
isocitrate
Step 3 of Krebs- .. and .. formation: isocitrate is oxidized to .. by …
alpha-ketoglutarate; CO2;
oxalosuccinate; isocitrate dehydrogenase
step 3 of Krebs- alpha-ketoglutarate and CO2 formation:
oxalosuccinate is then decarboxylated to produce … and …
alpha-ketoglutarate; CO2
… is rate-limiting enzyme of Krebs
isocitrate dehydrogenase
Step 3 of Krebs- alpha-ketoglutarate and CO2 formation:
this is the first step in which … from the cycle and also the first where … is produced
Cs are lost; NADH
Step 4 of Krebs - … and … formation: carried out by … complex
succinyl-CoA; CO2;
alpha-ketoglutarate dehydrogenase complex
Step 4 of Krebs- Succinyl-CoA and CO2 formation:
… and … come together to produce CO2 and succinyl-CoA
this is the 2nd and last …
Reducing … produces another …
alpha-ketoglutarate; CoA;
C lost from the cycle;
NAD+; NADH
Step 5–succinate formation: succinyl-CoA is hydrolyzed to yield … and …, a process which is coupled to …
succinate; CoA-SH:
phosphorylation of GDP to GTP
step 5- succinate formation:
this is catalyzed by …
phosphorylation of GDP is driven by the energy released by … here
succinyl-CoA synthetase;
thioester hydrolysis
step 5- succinate formation:
GTP can be converted to ATP via the enzyme …
… do not require energy input to form covalent bonds, but … do
nucleosidediphosphate kinase;
synthases;
synthetases
step 6- … formation: only step of the citric acid cycle that doesn’t occur in the .., but instead occurs on the …
fumarate; matrix; inner membrane
step 6- fumarate formation:
succinate is oxidized to fumarate by …, a …, as it is covalently bound to FAD
succinate dehydrogenase; flavoprotein
step 6- fumarate formation:
succinate dehydrogenase is an integral protein on the …, bc the FAD is reduced to … and then passes its electrons to the …
FAD is electron acceptor here because the reducing power of succinate is not …
inner mitochondrial membrane; FADH2; electron transport chain; sufficient to reduce NAD+
Step 7–… formation: … catalyzes hydrolysis of alkene bond in fumarate to give …
malate; fumarase; L-malate
Step 8– … is reformed: … oxidizes malate to …, producing the third and final … of the Krebs cycle
oxaloacetate; malate dehydrogenase; oxaloacetate; NADH
substrates of citric acid cycle mnemonic: ... --> ... ... ---> ... ... --> ... ... --> ... ... --> ... ... --> ... ... --> ... ... --> ... ... --> ...
Please: pyruvate Can: citrate I: isocitrate Keep: alpha-ketoglutarate Selling: succinyl-CoA Seashells: succinate For: fumarate Money: malate Officer?: oxaloacetate
full statement: Please, Can I Keep Selling Seashells For Money, Officer?
total amount of chemical energy harvested per pyruvate is about … ATP, which is about … ATP per glucose. since glycolysis yields
12.5; 25
Since glycolysis yields … ATP and … NADH, the net yield of ATP for one glucose through oxidative phosphorylation is …-…
2; 2; 30-32
energy products inhibit
energy production processes
pyruvate dehydrogenase complex regulation: phosphorylation of PDH by pyruvate dehydrogenase kinase inhibits … production –> occurs when there are high levels of … in the cell
PDH is reactivated by … when there are high levels of ADP
… also has negative feedback on its production
… inhibits PDH as well
acetyl-CoA; ATP;
pyruvate dehydrogenase phosphatase; acetyl-CoA; NADH
control pts of the citric acid cycle:
…
…
…
citrate synthase
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase complex
control pts of the citric acid cycle:
citrate synthase: … and … are inhibitors, as are … and …
ATP; NADH; citrate; succinyl-CoA
control pts of the citric acid cycle:
isocitrate dehydrogenase: inhibited by … and … and allosterically activated by … and …
ATP; NADH; ADP; NAD+
control pts of the citric acid cycle:
alpha-ketoglutarate dehydrogenase complex: … and … inhibit, as well as …; stimulated by … and …
succinyl-CoA; NADH;
ATP;
ADP; calcium ions
the … and … ratios help determine whether the citric acid cycle will be inhibited/activated
ATP/ADP; NAD+/NADH
in eukaryotes, aerobic components of respiration occur in the …, while the anaerobic components occur in the …
mitochondria; cytosol
inner mitochondrial membrane is essential for generating ATP using … – electrochemical gradient generated by the complexes of the e- transport chain
proton-motive force
the physical property that determines the direction of electron flow is …
molecules with higher are … land those with lower are …
reduction potential;
reduced;
oxidized
oxygen has a … reduction potential, making it a good final acceptor in e- transport chain
high
Complex I: …-…: catalyzes transfer of electrons from … to …
NADH-CoQ oxidoreductase;
NADH; coenzyme Q
complex I:
the complex includes a protein with an … and a … that oxidizes NADH. the flavoprotein has … as a coenzyme
iron-sulfur cluster; flavoprotein; flavin mononucleotide
complex I contd:
NADH transfers electrons to …, which becomes reduced. It is reoxidized when the … is reduced. this subunit then donates its electrons to … (…)
FMN; iron-sulfur subunit; coenzyme Q; ubiquinone
complex I contd:
… are moved to the intermembrane space during this process
4 protons
complex II (…-…): receives electrons from …
succinate-CoQ oxidoreductase; succinate
complex II: … from succinate reduces an … protein which transfers its electrons to … –> … is part of complex II
no H+ pumping occurs here!
succinate-CoQ oxidoreductase;
iron-sulfur;
ubiquinone;
succinate dehydrogenase
complex III (…-…): facilitates transfer of electrons from … to …
CoQH2-cytochrome c oxidoreductase;
coenzyme Q; cytochrome c
complex III contd:
…: proteins with heme groups in which iron is reduced to Fe2+ and reoxidized to Fe3+
cytochromes
complex III contd:
both coenzyme Q and cytochrome c aren’t technically part of these complexes. however, bc they are both able to move freely in the inner mitochondrial membrane, they can transfer electrons by … with the next component of the transport chain
physically interacting
complex III contd:
… cytochrome c molecules are needed, bc the iron component of it can transfer only … at a time and coenzyme Q has … to transfer
2; one electron; two electrons
complex III contd:
contributes to proton-motive force via the …., in which two electrons are shuttled from … to a molecule of …. Another two electrons are attached to …, reducing two molecules of … –> displaces …
Q cycle; ubiquinol; ubiquinone; heme moieties; cytochrome c; 4 protons
complex IV (…): transfers electrons from … to …
cytochrome c oxidase; cytochrome c; oxygen
complex IV has subunits …, …, and … ions
cytochrome a, cytochrome a3; Cu2+
complex IV:
cytochrome a and cytochrome a3 make up …, which gets oxidized as … is reduced
… are moved across the membrane here
cytochrome oxidase;
oxygen;
2 protons
when H conc is increased in the intermembrane space, the pH here drops and the voltage difference between the intermembrane space and the matrix … –> electrochemical gradient is formed
this is the … force
increases;
proton-motive
proton-motive force:
… will harness the energy from this gradient to form ATP
this is coupled bc ATP formation is …, but it becomes energetically favorable when it is coupled to this exergonic process
ATP synthase;
endergonic
efficiency of aerobic respiration varies between cells due to the fact that cytosolic NADH cannot …, and must enter via …
directly cross into the mitochondrial matrix; shuttle mechanisms
…: transfers high-energy electrons of NADH to a carrier that can cross the inner mitochondrial membrane
one of these shuttles produces only … ATP while the other produces …l
shuttle mechanism;
1.5; 2.5
…. shuttle: glycerol-3-phosphate dehydrogenase oxidizes cytosolic NADH while forming … from … in the inner mito membrane, another isoform of this enzyme uses … as the oxidizing agent, such that the electrons from NADH are instead picked up by …, generating … ATP
glycerol 3-phopshate; glycerol 3-phosphate; DHAP; FAD; FADH2; 1.5
… shuttle; oxaloacetate from cytosol cannot pass through inner mitochondrial membrane and is instead reduced to malate via malate dehydrogenase. this also allows for the oxidation of … to … Malate moves into the mito where … reverses the rxn to form mitochondrial …, which will produce … ATP as it passes its electrons to the ETC.
malate-aspartate; cytosolic NADH; NAD+; malate dehydrogenase; NADH; 2.5 ATP;
malate-aspartate shuttle;
malate in mito can then be converted into oxaloacetate, which is … into …, which returns to the cytosol and is reconverted to oxaloacetate, allowing this cycle to continue
transaminated; aspartate;
… is the portion of ATP synthase that spans the membrane –> acts as an …, wherein protons travel down their gradient into the matrix
F0; ion channel
F0 ATP synthase;
… allows chemical energy of H+ gradient to be harnessed to phosphorylate ATP
as the protons flow down their gradient, the … portion of ATP synthase utilizes the energy released to phosphorylate ATP
chemiosmotic coupling;
F1
… suggests that the relationship between the proton gradient and ATP synthesis is indirect:
ATP is released by the synthase resulting from a … caused by the gradient.
in this mechanism, F1 acts as a …, spinning to harness the gradient energy for …l
conformational coupling; conformational change; turbine; chemical bonding
rates of … and the … are closely coordinated
oxidative phosphorylation; citric acid cycle
… and … are key regulators of oxidative phosphorylation
O2; ADP
less O2 = … oxidative phosphorylation and … concs of NADH and FADH2 –> this consequently … the citric acid cycle
less; increasing; inhibits
coordinated regulation of these pathways is known as … –> when there is adequate oxygen, rate of oxidative phosphorylation is dependent on …
respiratory control; availability of ADP
ADP accumulation activates .., increasing rate of Krebs and the production of … and .., which thus leads to increase in rate of ETC and rate of ATP synthesis
isocitrate dehydrogenase; NADH; FADH2;
dietary fat consists mainly of .., with the remainder comprised of …, …, … and …
triacylglycerols; cholesterol; cholesteryl esters; phospholipids; free fatty acids
the pancreas secretes …, …, …, into the small intestine which hydrolyze emulsified lipids to …, …, and …
pancreatic lipase; colipase; cholesterol esterase;
2-monoacylglycerol; free fatty acids; cholesterol
…: the mixing of two normally immiscible liquids
emulsification
…: clusters of amphipathic lipids that are soluble in the aqueous enviro of the intestinal lumen
micelles
at the end of the ileum, … are actively reabsorbed and recycled
bile salts
when digested lipids pass through the brush border of the small intestine, they are absorbed into mucosa and re-esterified to form … and … and packaged with …, …, and other lipids, into …
cholesteryl esters; apoproteins; fat-soluble vitamins; chylomicrons
body is in … state at night, using energy stores instead of food –> in this state … are released from adipose tissue and used for energy
postabsorptive; fatty acids
fall in insulin levels activates … which hydrolyzes triacylglycerols to yield … and …
hormone-sensitive lipase (HSL); fatty acids; glycerol
HSL is also activated by … and …
released glycerol can be transported to the liver for … or …
HSL is active in … cells
epinephrine; cortisol;
glycolysis; gluconeogenesis;
adipose
…: necessary for the metabolism of chylomicrons and very-low-density-lipoproteins –> enzyme that can release … from triacylglycerols in the lipoproteins
lipoprotein lipase; free fatty acids
triacylglycerol and cholesterol are transported in the blood as … – aggregates of … and …
lipoproteins; apolipoproteins; lipids
density of lipoproteins increases in proportion to the percentage of … in the particle
protein
of the lipoproteins … are the least dense –> containing the most …
chylomicrons; fat
… and … primarily carry triacylglycerols; but also contains small amounts of …
chylomicrons; very-low-density-lipoproteins (VLDL); cholesteryl esters
… and … are primarily used for cholesterol transport
low density lipoproteins (LDL);
high density lipoproteins (HDL)
…: highly soluble in lymphatic fluid and blood and transport dietary triacylglycerols, cholesterol, and cholesteryl esters
chylomicrons
…: metabolism is similar to chylomicrons, but these are assembled in … cells. like chylomicrons, they primarily function to transport triacylglycerols to other tissues. they also have … synthesized from excess glucose or retrieved from … remnants
VLDL; liver; fatty acids; chylomicron
… (…): this is a VLDL remnant that forms when … is removed from VLDL. some is absorbed by the liver by … and some is processed further in the bloodstream
IDL; intermediate-density; triacylglycerol; apolipoproteins
IDL can pick up .. from HDL to become …
cholesteryl esters; LDL
IDL is a transition particle between … transport and … transport
triacylglycerol; cholesterol
LDL: majority of cholesterol in blood associated with LDL, whose normal role is to deliver … to … for …
cholesterol; tissues; biosynthesis
HDL: synthesized in the … and …; .,.. and …-rich and contains … used for cholesterol recovery –> it picks up excess … from blood vessels for excretion
liver; intestines; dense; protein-rich; apolipoproteins; cholesterol
HDL also delivers cholesterol to … tissues and transfers apolipoproteins to some of the other lipoproteins
steroidogenic
…/…: form the protein component of lipoproteins – these are receptor molecules and are involved in signaling
apolipoproteins; apoproteins
apolipoproteins:
…: activates LCAT – enzyme that catalyzes cholesterol esterification
…: mediates chylomicron secretion
…: permits uptake of LDL by the liver
…: activates lipoprotein lipase
…: permits uptake of chylomicron remnants and VLDL by liver
apoA-I apoB-48 apoB-100 apoC-II ApoE
most cells derive cholesterol from LDL or HDL but some cholesterol can be synthesized in the liver, a process driven by … and …
acetyl-CoA; ATP
cholesterol synthesis
… carries mitochondrial acetyl-CoA into the cytoplasm
… supplies reducing equivalents
citrate shuttle
NADPH
cholesterol synthesis;
… is synthesized in the smooth ER and and acts as the rate limiting step in cholesterol biosynthesis –> catalyzed by …
mevalonic acid; 30-hydroxy-3-methylglutaryl; CoA
cholesterol synthesis is inhibited by increased levels of cholesterol as a form of …
promoted by …
control over this synthesis is also dependent on regulation of … gene expression
feedback inhibition;
insulin;
HMB-CoA reductase
… is activated by HDL apoproteins and adds a fatty acid to cholesterol to produce soluble … for transport. these can be distributed to other lipoproteins
lecithin-cholesterol acetyltransferase (LCAT); cholesteryl esters
transfer of cholesteryl esters to other lipoproteins, namely from HDL to IDL such that IDL becomes LDL, is catalyzed by …
cholesteryl ester transfer protein (CETP)
fatty acids are long chain … the carboxyl C is … and that adjacent C is the ..
carboxylic acids; C1; alpha-C
for fatty acids, the total number of Cs is given along with the number of double bonds, written as
carbons: double bonds
… and … and their derivatives are essential polyunsaturated fatty acids that are critical to maintaining cell membrane fluidity
alpha-linolenic acid; linoleic acid
… numbering system is used for unsaturated fatty acids –> … designation describes the position of the last double bond relative to the end of the chain and identifies the major …
omega; omega; precursor fatty acid
double bonds in natural fatty acids are typically in the … configuration
cis
excess carbs and proteins acquired from the diet can be converted to … and stored as energy reserves in the form of …
fatty acids; triacylglycerols
lipid and carb synthesis are known as … synthesis processes because they do not rely directly on the …
nontemplate; coding of a nucleic acid
fatty acid biosynthesis occurs in the … and its products are transported to … for storage
liver; adipose tissue
adipose tissue can synthesize
smaller quantities of fatty acids
major enzymes of fatty acid synthesis: … and …
stimulated by …
… (…) is the primary end product of fatty acid synthesis
acetyl-CoA carboxylase; fatty acid synthase;
insulin
palmitic acid; palmitate
… accumulates in matrix after a large meal and is transferred to the cytosol for fatty acid biosynthesis –> acetyl-CoA enters the Krebs cycle to form citrate BUT since … would be slowed at this point (when cell is energetically satisfied), there would be a …
acetyl-CoA; isocitrate dehydrogenase; buildup of citrate
after buildup of citrate:
citrate diffuses across mitochondrial membrane and, in the cytosol, … catalyzes its conversion back into … and … (OAA moves back into mito)
citrate lyase; acetyl-CoA; oxaloacetate
… activates acetyl-CoA for fatty acid synthesis –> rate-limiting enzyme
this enzyme requires … and … to function and adds CO2 to acetyl-CoA to form … –> this Co2 is later removed by … further in this pathway
acetyl-CoA carboxylase;
biotin; ATP;
malonyl-CoA;
fatty acid synthase
acetyl-CoA carboxylase activated by … and …
insulin; citrate
…/.. is a large multienzyme complex in the cytosol that is induced by the liver after a carb-heavy meal due to high levels of insulin
fatty acid synthase; palmitate synthase
fatty acid synthase:
contains an … protein that requires …
… is required to reduce acetyl groups added to the fatty acid
acyl carrier; pantothenic acid;
NADPH
fatty acid synthase contd:
… acetyl-CoA groups are needed to produce … - the only fatty acid that humans can synthesize de novo
fatty acyl-CoA can be elongated and desaturated using enzymes associated with the …
8; palmitate;
smooth ER
fatty acid synthase:
steps include attachment to an …, bond formation between activated .. and the …, reduction of a …, …, and reduction of a … –> these rxns are repeated until palmitate is created
acyl carrier protein; malonyl-CoA; growing chain; carbonyl; dehydration; double bond
… are the storage form of fatty acids and are formed by attaching three fatty acids to …
triacylglycerols; glycerol
triacylglycerol forms from … and … and occurs in the .. and somewhat in the …
fatty acid; glycerol-3-phosphate; liver; adipose tissue
triacylglycerol packaged in the … and sent to .. as … –> only small amount of stored triacylglycerols is left
liver; adipose tissue; VLDL
… in the ER produces dicarboxylic acids
omega-oxidation
insulin indirectly inhibits … while glucagon stimulates it
beta-oxidation (breakdown of fatty acids)
fatty acids are first activated by attachment to … when they are metabolized – catalyzed by …
product is a … or …
CoA; fatty-acyl-CoA-synthetase;
fatty acyl-CoA; acyl-CoA
… fatty acids (..-… Cs) and … fatty acids (…-… Cs) diffuse freely into the mitochondria for oxidation, but … fatty acids (..-… Cs) require transport via a … shuttle
short chain; 2-4; medium chain; 6-12; long-chain; 14-20; carnitine
… is the rate limiting enzyme of fatty acid oxidation
carnitine acyltransferase I
very long fatty acid chains that are over 20 Cs in length
aren’t oxidized in the mito
beta oxidation reverses fatty acid synthesis in that acetyl-CoA is … and …
oxidized; released
beta oxidation:
repetition of four steps, which releases one … and reduces … and …, which can be used in the ETC for ATP production
acetyl-CoA; NAD+; FAD;
beta oxidation:
in muscle and adipose tissue, the acetyl-CoA
enters the Krebs cycle
beta oxidation:
in the liver, acetyl-CoA stimulates … by activating …
in a fasting state, the liver produces more acetyl-CoA from beta-oxidation than is used in the citric acid cycle
gluconeogenesis; pyruvate carboxylase
acetyl-CoA can be used to synthesize … that are released in the bloodstream and transported to other tissues
ketone bodies
four steps of beta-oxidation:
oxidation of fatty acid to form a …
… of the double bond to form a …
… of the hydroxyl to form a… –> …
splitting of the previous molecule into an … and …
double bond
hydration; hydroxyl
oxidation; carbonyl; beta-ketoacid;
acyl-CoA; acetyl-CoA
odd-numbered fatty acids are slightly different in beta oxidation than even numbered fatty acids at the final step:
odd numbered fatty acids produce one … and one … at the final step
acetyl-CoA; propionyl-CoA
odd numbered fatty acids beta oxidation:
propionyl-CoA is converted to … by … which requires …
methylmalonyl-CoA; propionyl-CoA carboxylase; biotin
odd numbered fatty acids beta oxidation:
methylmalonyl-CoA is converted to … by …, which requires … –> this is a citric acid cycle intermediate and can also be converted to … to enter gluconeogenic pathway –> odd numbered fatty acids are exception to the rule that fatty acids cannot be converted to glucose in humans for this reason
succinyl-CoA; methylmalonyl-CoA mutase; cobalamin
in unsaturated fatty acids, two additional enzymes are needed bc the double bonds can disturb the stereochem needed for oxidative enzymes to act on the fatty acid –> these enzymes can have at most … in their active site and it must be located between Cs … and …
one double bond; 2; 3
unsaturated fatty acid beta oxidation:
… rearranges cis double bonds at 3,4 position to … double bonds at … position once enough acetyl-CoA has been cleaved to isolate the double bond within the first three carbons –> this is sufficient in … for oxidation to proceed
enoyl-CoA isomerase; trans; 2,3; monounsaturated fatty acids
unsaturated fatty acid beta oxidation:
in polyunsaturated fatty acids, further reduction is facilitated by … to convert conjugated double bonds to just one double bond at the 3,4 position where it will again be rearranged to the trans 2,3 double bond using enoyl-CoA isomerase
2,4-dienoyl-CoA reductase
in the fasting state, excess acetyl-CoA from beta oxidation is converted by the liver to … and … which can be used for energy
… and …. muscle can metabolize these to acetyl-CoA –> during these fasting periods, muscle metabolizes ketones as rapidly as they are produced such that there is not accumulation in the bloodstream
ketone bodies acetoacetate; 3-hydroxybutyrate;
cardiac and skeletal muscle
after a week of fasting, there’s enough ketones in the bloodstream for the … to begin metabolizing it
brain
…: occurs in mitochondria of liver when excess acetyl-CoA accumulates. HMG-CoA synthase forms HMG-CoA and HMG-CoA lyase breaks down HMG-COA into acetoacetate which can be reduced to …
ketogenesis;
3-hydroxybutyrate
…: acetoacetate picked up from blood is activated in the mitochondria by succinyl-CoA acetyoacetyl-CoA transferase (aka …) –> 3-hydroxybutyrate is oxidized to …
liver does not have this enzyme and thus can’t …
ketolysis;
thiphorase;
acetoacetate;
catabolize ketone bodies
during prolonged fast, brain begins to derive … of its energy from ketone bodies. in the brain, when ketones are metabolized to acetyl-CoA, … is inhibited such that … and … in the brain decreases –> spares protein in the body and allows the brain to indirectly metabolize fatty acids ad ketone bodies
2/3rds;
pyruvate dehydrogenase;
glycolysis; glucose uptake
in order to provide reservoir of amino acids for protein building, proteins must be … and …
digested; absorbed
proteolysis begins in the stomach with .. and continues with pancreatic proteases …, …, and … and … –> all secreted as zymogens
pepsin;
trypsin
chymotrypsin
carboxypeptidases A and B
protein digestion is completed by small intestinal brush-border enzymes … and …
dipeptidase; aminopeptidase
main end products of proteolysis; …, …, and .. –> these are absorbed through the luminal membrane via … linked to …
at basal membrane, … transports aas into the bloodstream
amino acids; dipeptides; tripeptides;
secondary active transport; sodium;
simple and facilitated diffusion
during prolonged fasts/starvation protein can be obtained from … or from the … as energy source –> bodily protein derives from … and …
diet; body; muscle; liver
amino acids released from proteins usually lose amino group through …. or … and the … is used for energy
transamination; deamination; C-skeleton
…: can be converted to glucose through gluconeogenesis
glucogenic amino acids
ketogenic amino acids: ... ... ... ... ... ... ... can be converted into acetyl-CoA and ketone bodies
leucine lysine isoleucine phenylalanine threonine tryptophan tyrosine
removed amino groups from amino acids must be excreted via the …, which occurs in the … and is the primary way of removing excess nitrogen from the body
urea cycle; liver
… of amino acids feed into urea cycle
basic side chains
other side chains (non-basic) of amino acids act like the … and produce energy through … or …
C skeleton; gluconeogenesis; ketone production
biological systems are … systems –> interact with energy and matter in the enviro
…: no exchange of matter with enviro
open; closed
…: sum of all different interactions between and within atoms in a system –> …, …, …, and stored … energies contribute
internal energy;
vibration;
rotation;
linear motion;
chemical
work in thermodynamics = …, constant in most living systems, so the quantity of interest in determining internal energy is …
pressure * change in volume;
heat
… measures overall change in heat of a system during a rxn
at constant pressure and volume, … and … are equal
enthalpy
enthalpy; thermodynamic heat exchange (Q)
… measures degree of disorder or energy dispersion in a system; units of …
entropy; J/K
delta G = ..
definition with enthalpy and entropy
delta H - T*delta S
free energy approaches … as the reaction proceeds to equilibrium and there is no net change in concs of reactants or products
zero
delta G =
delta G naught definition
delta G naught + RTln(Q)
biochemical analysis works well under all standard conditions except for …, which under standard conditions would be 0 - way too … for biological systems
pH; acidic
… adjusts it such that pH is 7 –> indicated by ..
modified standard state; delta G naught’
reactions with more products than reactants tend to have a more .. delta G, while reactions with more reactants than products tend to have a more … delta G
negative; positive
combustion of fat yields … of energy, with only … derived from carbs, proteins, or ketones
9 kcal/g; 4kcal/g
ATP is generated via substrate-level phosphorylation and/or oxidative phosphorylation and is a … energy carrier –> this is important bc ATP cannot get back the “leftover” free energy after a rxn, so its best to use a carrier with a … so less energy is wasted and dissipated as heat
mid-level;
smaller free energy
ATP consumed either through … or the transfer of a …
hydrolysis; phosphate group
…: transfer of a high energy phosphate group from ATP to another molecule
ATP cleavage
to determine the free energy of phosphoryl group transfer to another biological molecule, one could use … and calculate the … between the reactants and products
Hess’s law; difference in free energy
redox rxns can be divided into … that represent the individual reduction and oxidation states to determine how many … are actually being transferred
half reactions; electrons
all of the high energy e- carriers are soluble and include …, …, …, …, …, and …
NADH; NADPH; FADH2; ubiquinone; cytochromes; glutathione
… is a membrane bound electron carrier embedded in the inner mito membrane as part of complex 1 of the ETC –> can also act as … electron carrier
flavin mononucleotide; soluble
… are particularly well suited for electron transport
iron-sulfur clusters
flavoproteins: contain a modified … - …
vitamin B2; riboflavin
flavoproteins:
nucleic acid derivatives – … or …
flavin adenine dinucleotide (FAD); flavin mononucleotide (FMN)
flavoproteins:
can act as …, involved in modification of other B vits to …, … for enzymes in oxidation of …, … of pyruvate, and reduction of ..
electron carriers; active form; coenzymes; fatty acids; decarboxylation; glutathione
equilibrium … for biological systems –> it’s a fixed state, which prevents … –> … state is preferred
is not favorable; storage of energy; homeostatic s; potential energy
…: physiological tendency toward relatively stable state that is maintained and adjusted, often with expenditure of energy –> allows for storage of …
homeostasis
../…/… state: occurs shortly after eating
postprandial; absorptive; well-fed
postprandial state:
more …, less …
lasts … after eating a meal
anabolism; catabolism;
3-5 hrs
3 major target tissues for insulin: …, …, …
liver; muscle; adipose tissue
liver converts excess glucose to … and …
fatty acids; traicylglycerols
insulin promotes … in adipose tissue and … in muscle, and … into both tissues
triacylgycerol synthesis; protein synthesis; glucose entry
most of the energy needs of the liver are met by the oxidation of … after a meal
excess aminoa cids
… and … are insensitive to insulin
nervous tissue; red blood cells
nervous tissue derives E from …. and … in well-fed and normal fasting states
oxidizing glucose to CO2; water
RBCs use … for all energy needs
glucose anaerobically
postabsorptive state: …, …, …, …, and … oppose action of insulin –> … hormones
glucagon; cortisol; epinephrine; norepinephrine; growth hormone; counterregulatory
postabsorptive state:
hepatic gluconeogenesis is stimulated by … but is slower than …
glucagon; glycogenolysis
postabsorptive state:
release of … from skeletal muscle and … from adipose tissue are both stimulated by decrease in insulin and increase in … –> carried into liver to provide … and … for gluconeogenesis
amino acids; fatty acids; epinephrine; C skeleton; energy
prolonged fasting (…): elevated levels of … and …
starvation; glucagon; epinephrine
starvation:
once glycogen stores are depleted, … activity becomes predominant source of glucose in the body until … “takes over”
gluconeogenic; ketone metabolism
starvation:
shift from glucose to ketones is important bc it reduces the amount of … that must be degraded to support gluconeogenesis, which … for other functions
amino acids; spares proteins
starvation:
cells that have few mitochondria (or none like RBCs) continue to
depend on glucose for energy
metabolism must be regulated …, which is best achieved via …
across the entire organism; hormones
tissues that require insulin for effective uptake of glucose are … and ..
adipose tissue; resting skeletal muscle
tissues in which glucose uptake is not affected by insulin: ... ... ... ... ...
o Nervous tissue o Kidney tubules o Intestinal mucosa o RBCs o Beta cells of the pancreas
tissues that require insulin actively … when it is present in high concs., while the others must still be able to … even when glucose conc is low
store glucose; absorb glucose
for carbs, insulin increases … and increases … in muscle and fat
uptake of glucose; carb metabolism
insulin increases … synthesis in liver by activating … and …, while suppressing activity of enzymes that promote …, namely … and …
glycogen; glucokinase; glycogen synthase; glycogen breakdown; glycogen phosphorylase; glucose-6-phosphatase
insulin increases … uptake by muscle cells, increasing levels of … synthesis and decreasing breakdown of …
amino acid; protein; essential proteins
insulin increases:
… and … uptake by fat cells
… activity, which clears VLDL and chylomicrons from the blood
… synthesis (…) in adipose tissue and the liver from acetyl-CoA
glucose; triacylglycerol;
lipoprotein lipase;
triacylglycerol; lipogenesis;
insulin decreases:
… breakdown (…) in adipose tissue
formation of … by the liver
triacylglycerol; lipolysis;
ketone bodies
for glucose to promote insulin secretion it has to be metabolized in …, increasing intracellular ATP concs. Increased ATP leads to … release which promotes exocytosis of …
beta-cells; calcium release; preformed insulin
glucagon acts through second messengers to cause the following:
increased liver … through activation of … and inactivation of …
glycogenolysis; glycogen phosphorylase; glycogen synthase
glucagon acts through second messengers to cause the following:
increased liver … through promoting conversion of pyruvate to … by … and … Increases conversion of … to … by …
gluconeogenesis; PEP; pyruvate carboxylase; phosphoenolpyruvate carboxykinase; fructose-1,6-bisphosphate; fructose 6-phosphate; fructose-1,6-bisphosphatase
glucagon acts through second messengers to cause the following:
increased liver … and decreased …
ketogenesis; lipogenesis
glucagon acts through second messengers to cause the following:
increased … in the liver. glucagon activates … in liver –> bc action is on the liver and not adipocyte, glucagon is not considered to be a major … hormone
lipolysis; hormone-sensitive lipase; fat-mobilizing
… levels is main regulator of glucagon activity
plasma glucose
…, esp the basic ones, promote secretion of glucagon –> glucagon can thus be secreted in response to ingestion of a meal rich in …
amino acids; protein
enzymes that are phosphorylated by insulin are typically … by glucagon and vice versa –> they are …
dephosphorylated; antagonistic
… from adrenal cortex are responsible for part of the stress response –> glucose must be rapidly mobilized from liver to fuel muscle cells while fatty acids are released from adipocytes
glucocorticoids
glucocorticoids:
e. x. cortisol: steroid that promotes mobilization of energy stores through degradation and increased delivery of … and increased …
amino acids; lipolysis
glucorticoids contd:
cortisol increases blood glucose concs by inhibiting … in most tissues and increasing … by …
glucose uptake; hepatic output of glucose; gluconeogenesis
glucocorticoids contd:
cortisol:
enhances … activity as well as the activity of …
glucagon; catecholamines
adrenal cortex produces … and adrenal medulla produces …
steroid hormones; catecholamines
catecholamines include epinephrine and norepinephrine (adrenaline and noradrenaline):
increase activity of liver and muscle … to promote …
glycogen phosphorylase; glycogenolysis
catecholamines include epinephrine and norepinephrine (adrenaline and noradrenaline):
… also increases in muscle, but muscle lacks G6P, so glucose cannot be released into the bloodstream and is instead metabolized by the muscle tissue itself
acts on adipose tissue to increase … by increasing activity of …
glycogenolysis;
lipolysis; hormone-sensitive lipase
thyroid hormone levels are kept … generally:
increase in metabolic rate is produced by … after a latency of several hours but can last for several days
constant;
thyroxine (T4)
thyroid hormone:
… produces more rapid increase in metabolic rate and has shorter duration of activity
triiodothyronine (T3)
thyroid hormone:
T4 can be precursor to T3 –> converted by …
deiodonases
thyroid hormone:
… requires thyroid hormones to promote significant metabolic effect
epinephrine
major sites of metabolic activity in the body:
…
… and … muscles
… and …
liver;
skeletal; cardiac
brain; adipocyte
… and … do not make major contributions to consumption of E, but epithelial cells are primary … cells so they are involved in regulation of metabolism
connective tissue; epithelial cells;
secretory
2 major roles of liver: maintain constant level of … and synthesize … when excess fatty acids are being oxidized
blood glucose; ketones
fatty acids in liver are converted to … and released into the blood as …
triacylglycerols; VLDL
… from anaerobic metabolism, … from triacylglycerols, and … provide C skeletons for glucose synthesis
lactate; glycerol; aas
insulin triggers fatty acid release from … and … and induces …
fatty acids released from lipoproteins are taken up by … and reesterified to triacylglycerols for storage
VLDL; chylomicrons; lipoprotein lipase;
adipose tissue
during fasting, decreased … and increased … activate hormone-sensitive lipase in fat cells
insulin; epinephrine
major fuels of skeletal muscle are …. and …
in fasting state, resting muscle uses … derived from free fatty acids circulating in the bloodstream. …. may be used in prolonged fasting state
glucose; fatty acids;
fatty acids;
ketone bodies
primary fuel to support muscle contraction depends on magnitude and duration of … and … involved
very short lived source: … which can help form ATP
blood glucose and free fatty acids
anaerobic glycolysis
exercise; major fibers;
creatine phosphate
high intensity continuous exercise relies on … and …
oxidation of glucose and fatty acids
cardiac myocytes prefer … as major fuel, even in well fed state, but … can be used during prolonged fasting
in failing heart … increases and … falls
fatty acids; ketones;
glucose oxidation; beta oxidation
blood glucose tightly regulated to maintain a sufficient glucose supply for the brain, which depends on a continuous glucose supply from the bloodstream:
fatty acids cannot … and are not used at all as an energy source in brain
only during … does brain gain capacity to use ketone bodies for energy, and even then its only 2/3rd of the fuel; the rest is glucose
cross blood-brain barrier;
prolonged fasting
in humans, glucose levels, thyroid hormones and thyroid-stimulating hormone, insulin, glucagon, oxygen, and CO2 can all be measured in the blood and can be indicators of …
metabolic function
respirometry allows accurate measurement of respiratory quotient, which differs depending on fuel being used by the organism
RQ = …/…
RQ for carbs is around … and for lipids around …
CO2 produced/O2 consumed;
1.0; 0.7
RQ is generally … in resting individuals indicating that both fat and glucose are consumed
RQ changes with …, …, and …
0.8;
stress; starvation; exercise
calorimeters can measure basal metabolic rate based on … with the environment
BMR can be estimated based on …, …, … and …
heat exchange; age; weight; height; gender
metabolic controls involved in maintaining body mass:
overall mass of carbs and proteins tends to be stable over time so its not a significant contributor to body mass
… is primary source of frequent minor weight fluctuations bc it is subject to rapid adjustment
…. are primary factor in gradual change of body mass over time
water;
lipids
individual maintaining weight consumes … amount of energy that is spent on average each day:
> E consumed than used –> …
< E consumed than used –> …
same;
accumulation of fat stores;
decrease in weight
caloric excess will cause … until equilibrium is reached between new basal metabolic rate and existing intake
increase in body mass
small adjustments in intake are compensated by changes in … and small increases/decreases in activity are compensated by changes in … –> represents threshold for body mass changes –> changes must exceed these baselines such that … can’t occur
energy expenditure; hunger; compensation
larger changes must be made to … weight than to …
lose; gain
…: secreted by stomach in response to signals of impending meal; increases appetite and stimulates secretion of orexin
ghrelin
…: further increases appetite and is involved in alertness and sleep-wake cycle; stimulated by hypoglycemia as well
orexin
…: secreted by fat cells and decrease appetite by suppressing orexin production –> genetic variations in this hormone and its receptors have been implicated in obesity
leptin
body mass can be measured using body mass index: BMI = …
mass/height^2
normal BMI: between … and …
lower: …
BMI between 25 and 30 is … and over 30 is …
18.5; 25;
underweight;
overweight; obese
