Lecture 3 Flashcards
process of glycolysis
glucose is converted to pyruvate
process of respiration
- pyruvate converted to 3 molecules of CO2
3 pathways involved in cellular respiration
- pyruvate oxidation, CAC, and ETC
process of fermentation
-converts pyruvate into lactic acid or ethyl alcohol
is fermentation aerobic or anaerobic
anaerobic
is cellular respirarion aerobic or anaerobic
aerobic
Waste products in cellular respiration
H20 and CO2
Waste products in fermentation
lactic acid or ethanol and CO2
net energy trapped/glucose in cellular respiration
32 ATP
net energy trapped/glucose in fermentation
2 ATP
Where does glycolysis occur
in the cytosol
what does glycolysis
converts glucose into 2 molecules of pyruvate
end product of glycolysis
2 ATP and 2 NADH
what do steps 1-5 of glycolysis require
ATP; energy investing reactions
what do steps 1-6 of glycolysis yield
NADH and ATP (energy- harvesting rxns)
preparation phase of glycolysis
conversion of glucose to G3P
what is the second phase of glycolysis
G3P converted to pyruvate
When are 2 ATP used in glycolysis
steps 1 and 3
step 6
steps
each glucose molecule yields…
2 pyruvate, 2 NADH, 2H+ and 2 ATP
Where does pyruvate oxidation occur
in the mitochondrial matrix
what are products from pyruvate oxidation
acetate and CO2
how is acetyl coA produced and during which process
when acetate binds to coenzyme A; pyruvate oxidation
pruvate oxidatio is a multistep rxn catalyzed by..
pyruvate dehydrogenase complex
what is glycogen
storage form of glucose, mainly in liver and muscle
when does glycogen release glucose
when energy demands are high
when is glucose polymerized to form glycogen
when the organism has no immediate need for energy from glucose breakdown
release of insulin is anabolic or catabolic
anabolic
release of glucagon is anabolic or catabolic
catabolic
what does glycogen synthase do
control enzyme for synthesis of glucose
what does glycogen phosphorylase do
control enzyme for breakdown of glucose
what is gluconeogenesis
conversion of glucose from pyruvate
what are the 3 irreversibel steps in glycolysis
- phosphoenolpyruvate –> pyruvate + ATP
- fructose-6 phosphae –> fructose- 1,6-bisphosphate
- glucose –> glucose - 6-phosphate
T or F: gluconeogenesis is NOT the exact reversal of glycolysis
true
what is the Cori Cycle
metabolic process and chemical pathway during which lactic acid produced in the muscles is converted to glucose by the liver and moved back to the muscles to be metabolized again.
pentose phosphate pathway is also known as…
hexose monophosphate shunt
PPP is an alternative to what
glycolysis BUT different in several ways
how is PPP different than glycolysis
- five-carbon sugars including ribose are produced from glucose
- oxidizing agent is NADP+ and reduced to NADPH
- begins with two oxidation steps to give ribulose-5-phosphate
what is starting point of CAC
acetyly coA
acetyl group is oxidized to what in CAC
2 molecules of CO2
what is released energy captured by in the CAC
ADP, NAD+, FAD, and GDP
pyruvate oxidation is endergonic or exergonic
exergonic
what happens in pyruvate oxidations
one NAD+ is reduced to NADH
pyruvate oxidation reaction
pyruvate + NAD+ + CoA –> NADH + H+ + CO2
for each molecule of glucose, how many times does CAC occur
2x
what are inputs of CAC
acetyl coA, water, oxidized electron carriers and GDP
what are oxidized electron carriers in CAC
3 NAD+ and FAD
what are outputs in CAC
2 CO2, reduced electron carriers and GTP
what are reduced electron carriers in CAC
3 NADH, 3 H+, and FADH2
What are important steps of CAC
- NAD+ is reduced to NADH + H+ ( steps 3,4,8)
- one GTP is produced (step 5)
- one FADH2 is produced (step 6)
- two CO2 produced (steps 3 and 4)
each acetyl coA yields…
3 NADH + 3H+ + FADH2 + 2 CO2 and ATP
pyruvate oxidation and CAC regulated by?
concentrations of starting molecules
what happens if O2 is present during pyruvate oxidation
oxygen accepts electrons and H2O it formed
what forms ATP in pyruvate oxidation
when energy is released by oxidation of electron carriers
What is ETC carried out by
four closely related multusubunit membrane bound complexes and two electron carriers: coenzyme Q and cytochrome c
what are the two electron carriers in the ETC
coenzyme Q and cytochrome C
what is oxygen reduced to in ETC
to water
what is result of protons in ETC
protons are pumped across the inner membrane to the intermembrane space which creates a pH gradient
where is ATP produced during oxidative phosphorylation
in the mitochondrion
what drives ATP production in chemiosmotic coupling
the flow of protons through the pore in the synthase drives ATP production
in conformational coupling, a change in the shape of the synthase causes what
releases bound ATP that has already been formed
P/O ratio
number of moles of Pi condumes in phosphorylation to the numebr of moles of oxygen atoms consumed in oxidation
when is P/O when NADH is oxidize
2.5
what is P/O when FADH2 is oxidized
1.5
phosphorylation process rxn
ADP + Pi –> ATP + H2O
oxidation process rxn
1/2O2 + 2H+ + 2e- –> H2O
what processes does corneal metabolism involve
aerobic oxidation, anaerobic glycolysis, and PPP
the lens mostly depends on what for ATP production
anaerobic metabolism
which processes are limited in the epithelium
aerobic glycolysis and Krebs cycle
under normal conditions, the retina will prefer which process
a high rate of anaerobic glycolysis
Where is PPP particularly active
in phosphoreceptors for rhodopsin regeneration and ribose prodution for nucleotide synthesis
how are lipids transported in the blood stream
through lipoproteins
which biomolecules are packaged into several classes of lipoproteins for transport
cholesterol and its fatty acid esters
how is each lipoprotein classified
by density; protein vs lipid content
function of chylomicrons
made in the intestine and transport dietary TGs from intestine to other tissues
VLDL
made in liver and transport lipids synthesized in the liver to other tissues
LDL
transport cholesterol to cells
when is LDL formed in the blood
when VLDLs lose TG and apoproteins
HDL
transports cholesterol from peripheral tissue to the liver for catabolism and excretion in bile
which cholesterol is considered good
HDL
HDL or LDL: high levels associated with INCREASED risk of heart disease
LDL
what are hormones
intracellular messenher produced in ductless gland of endocrine system
types of hormones
steroids, polypeptides, and amino acid derivativesster
examples of steroids
estrogen and androgen
examples of polypeptides
insulin and glucagon
examples of amino acid derivatives
epinephrine
roles of hormones
maintainance of homeostasis and regulation of growth and development
secondary messengers
hormone binds to receptor site on target cell to initiate series of rxns
binding of secondary messenger to receptor site causes what
triggers production of cAMP from ATP which is catalyzed by adenylate cyclase
ex of secondary messenger
cyclic AMP
what does cAMP do
causes actual changes
what are reactions of cyclic AMP mediated by
stimulatory G protein
G protein is bound to..
plasma membrane
G protein subunits
alpha, beta, and gamma
when is G protein inactive
when GDP is bound to alpha subunit
what activates G protein
binding of the hormone to its receptor which causes a GDP –> GTP exchange
active G protein stimulates ______ which catalyzes what
stimulates adenylate cyclase which catalyzes conversion of ATP to cAMP and pyrophosphate
Receptor tyrosine kinase
spans the membrane of the cell and has a hormone receptor on the outside and a tyrosine kinase portion on the inside
which hormones regulate carb metabolism
epinephrine and glucagon and insulin
epinephrine
- derived from tyrosine
- acts on muscle tissue to raise glucose levels
what is glucagon
polypeptide of 29 amino acid sequences
what allows the release of glucagon
alpha cells of the islets of langerhans
what does glucagon do
binds to specific receptor sites to set off chain of events to make glucose available to organism
hormone amplification
activation of G protein which stimulates adenylate cyclase several times and increases production of cAMP
what kind of hormone is insulin
peptide hormone released by liver
what does insulin do
stimulates anabolic pathway to store fuels
3 functions of glucose
- increase glucose uptake into cells via glucose transporter
- increase glycogen synthesis and decrease breakdown
- increase fatty acid synthesis
what are targets of insulin
muscle, liver, and adipose
diabetes mellitus
insulin either defective or insulin receptor is defective (or reduced in quantity)
transducin
g protein in the rod outer segment discs
what is transducin activated by
light activated rhodophsin (R*)
what does activated transducin do
activated transducin binds, and activates phosphodiesterase
what does phosphodiesterase do
an enzyme that lowers cGMP levels via the rxn cGMP –> GMP
what does cGMP do
controls ion channels of the cell involved in the visual signal
