final exam Flashcards
salivary a-amylase hydrolyzes which bonds
1,4 glycosidic bonds
T/f, digestion of amylose and amylopectin occurs in the stomach
false
which enzyme resumes the digestion of dextrins in duodenum/SI
pancreatic a-amylase
what are the four brush border enzymes
maltase, isomaltase, sucrase, lactase
function of maltase
cleave α1-4 bonds of maltose
and maltotriose to glucose
function of isomaltase
cleaves the
α1-6 bond of limit dextrins
function of sucrase
cleaves α1-2 bonds of sucrose
to produce fructose and glucose
function of lactose
cleaves the β1-4 bond between
galactose and glucose in lactose
the enzyme in the mouth that digests fats
lingual lipase
the enzyme in the stomach that digests fats
gastric lipase
phospholipids/phosphotidylcholine is hydrolyzed by
pancreatic enzyme __________
Phospholipase A2
Phospholipase A2 hydrolyzes phosphotidylcholine to produce _______
lysophosphatidylcholine
removes the FAs that
form the cholesterol fraction in the pancreas
cholesterol esterase
which transporter absorbs lipids into enterocytes when there is a low concentration
Fatty acid transporter 4 (FATP4) or
FAT/CD36
how do lipids get absorbed into enterocytes if there is large concentration?
passive diffusion
absorbed lipid molecules in enterocytes get converted into
TAG, PLs, and cholesterol esters
Chylomicrons are
synthesized at the
___________ and __________ in enterocytes
endoplasmic reticulum and
golgi
which enzyme digests proteins in the stomach
pepsin
which enzymes digest proteins in the SI
Trypsin, chymotrypsin, elastase, carboxypeptidases
glucose and galactose get absorbed by _______ in enterocytes
SGLT1
fructose is taken up by _______ into the enterocyte
glute5
galactose, glucose, and fructose all exit the enterocyte through this transporter
glute2
glute 5 and glute 2 are _________ diffusion
facilitated
lipids enter enterocytes through the _________ side and leave through the ______________ side
luminal; basal lateral membrane
Phospholipase A2 cleaves off ….
fatty acids at position 2
hormone that causes bicarbonate to be released from the pancreas
secretin
hormone that causes the release of bile from the gallbladder
CCK
activated trypsinogen to form trypsin
enteropeptidase
T/F, glycolysis is on in a fed state
true
major hormone present in a fed state
insulin
T/F, insulin works as a dephosphorylater
true
activates fatty acids by adding coA
Acyl-coa synthetase
pathways on in a fed state for lipids
triglyceride synthesis
phospholipid syn
cholesterol synthesis
fatty acid activation takes how many atps
2
AMPK _________phorylates GPAT1 which turns it _______
phosphorylate; off
HMG CoA reductase is _______phorylated by AMPK turning it off
phosphorylated
HMG CoA reductase is activated/dephorylated by ________
PP2a
the main lipoprotein circulating in a fed state
chylomicrons
primary lipoprotein in a fasted state
VLDLs
in a fed state, TSC complex is ________ which allows rheb to turn ________ MTORR
off; on
If TSC complex is active, _______ is blocked and then mTORR is inactive
RHEB
_______ phosphorylates mTORC1, turning it _________
AMPK, off
which HK is found in all mammalian tissues
HK I
when glucokinase is bound to GKRP, it is __________
inactive
glucokinase is induced by _______ & _________
glucose and insulin
this molecule stimulates the binding of GK to GKRP if there is excess
fructose-6-phosphate
what are the five enzyme that phosphorylate and turn off glycogen synthase
-glycogen synthase kinase
-glycogen phosphorylase kinase a -protein kinase A
-calmodulin kinase
-AMP kinase
positive allosteric regulator of the inactive form of glycogen synthase
glucose 6 phosphate
glycogen synthase gets dephosphorylated/activated by
pp1
in glycolysis, glucose from glycogen nets _____ ATP instead of 2
3
products of anaerobic glycolysis
2 lactate, 2 atp, 0 nadh
products of aerobic glycolysis
2 nadh, a pyruvate, 2 atp
rate-limiting enzyme of glycolysis
phosphofructokinase 1
what allosterically activates PFK1
AMP, ADP, F2,6BP
what allosterically inhibits PFK1
ATP, citrate
F2, 6BP is produced by
PFK2
in the liver, PP1 dephosphorylates ________ turning it ________ which then allosterically activates _______
PFK2; on; PFK1
PKA ______________ PFK2 turning it _______ but only in this organ
phosphorylates; off; liver
in the liver, pyruvate kinase is ______________ to turn it off by __________
phosphorylate; PKA
in glycerol synthesis, G3P has to be made in adipocytes through glycolysis because
they lack the enzyme glycerol kinase, so they can’t just phosphorylate glycerols
when does de novo fatty acid synthesis occur
when there’s excess CHO intake and glycogen stores are full
de novo fatty acid synthesis primarily occurs in these 3 places
adipose tissue, mammary glands, and liver
acetyl-coa is converted to malonyl coa via
acetyl-coa carboxylase
ACC1 is activated by _______ and inhibited by _________
citrate; palmitate
These two kinases phosphorylate and inhibit ACC1
PKA and AMPK
_______ dephosphorylates ACC1, activating it
PP4
products of 1 turn of the TCA cycle
1 GTP, 1 FADH, and 3 NADH
in the TCA cycle, ______ and ______ inhibit citrate synthase
NADH & citrate
isocitrate dehydrogenase is inhibited by ________ & activated by __________
NADH & Ca2+
a-ketoglutarate dehydrogenase complex is inhibited by ________ & _________
NADH & Succinyl coa
a-ketoglutarate dehydrogenase complex is activated by _________
Ca2+
glucose 6-phosphate dehydrogenase is activated by ________ & _________
glucose 6-phosphate & NADP+
glucose 6-phosphate dehydrogenase is inhibited by __________
NADPH
Enzyme that adds O-glcnac in hexosamine biosynthetic pathway
OGT
what activates PDH kinase
-acetyl coa
-NADH
what inhibits PDH kinase
-pyruvate
-NAD+
-coA
-ADP
-calcium
what inhibits PDH phosphatase
acetyl-coa
what stimulates PDH phosphatase
Magnesium and calcium
PDH kinase phosphorylates PDH turning it ______
off
when ACC is phosphorylated, it is __________
inactive
when MCD is phosphorylated it is ______
active
AMPK phosphorylates ACC, turning it ______
off
AMPK phosphorylates MCD, turning it _______
on
fatty acyl coas ________ ACC
inhibit
fatty acyl coa ________ malonyl decarboxylase
activates
in a fed state, protein phosphatases turn ACC ______ and MCD _________
on; off
activator for ACC
citrate
ketogenesis occurs in the ______
liver
glycogen phosphorylase kinase is phosphorylated by ________ making it _________active
PKA; active
glycogen phosphorylase kinase is in its most active form when
its phosphorylated and when Ca2+ is bound
if Arg builds up during the urea cycle, what does that mean about its speed
its going too slow
Arginia ________ the production of NAG by activating __________
increases; N-acetyl glutamate synthase
At 24 hours, proteolysis _________, after 48 hrs, it __________
increases; decreases
when are ketones formed
-uncontrolled diabetes
-very low carb diet
-prolonged fasting
insulin is an ________ hormone
anabolic
T/f, in a fasted state we see glucagon, catecholamines, and cortisol
true
RER is ________ in a fasted state in obese people
lower
RER is _________ in a fed state in obese ppl
higher
those obese have more of this muscle fiber
fast glycolytic
the mitochondria has a positive charge and low pH where
inner membrane space
NADH donation of electrons in ETC pumps out ______ electrons
10
FADH donation of electrons in ETC pumps out ______ electrons
6
it takes _____ equivalent protons to make ATP
4
Initial reaction in the catabolism of BCAA
BCAT
is BCAT highly expressed in liver
no
BCKAD kinase ________ activity of BCKAD
decreases
BCKAD activity increases through BCKAD __________
phosphatase
what products allosterically inhibit BCKAD
isovaleryl coa, a-methylbutyrl coa, isobutyrl coa
in what situations is BCAA metabolism activated
-starvation and prolonged exercise
-increased cortisol
T/f, SODS convert superoxides into hydrogen peroxide
true
the SOD isoform, CuZnSOD, is located where
cytosol
Located in the mitochondria, this SOD isoform is important for ros in the matrix
MnSOD
catalase has a high Kcat meaning
it can reduce hydrogen peroxide into water very quickly
which system handles the removal of hydrogen peroxide and has a low Km
glutathione system
