BIS 103 MT 2 Exam Test Questions with 100% correct answers |Verified |Rated A+
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BIS 103 MT 2
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BIS 103 MT 2
lactate fermentation mechanism - lactate dehydrogenase - ANSWERwhat are the unique reactions of GNG? - ANSWER-GNG is glycolysis in reverse, but in glycolysis there are
three irreversible steps; we have enzymes to bypass these irreversible steps
Inside the mitochondria,
these enzyme can bypass PY...
BIS 103 MT 2 Exam Test Questions with 100%
correct answers |Verified |Rated A+
lactate fermentation mechanism - lactate dehydrogenase - ANSWER-
what are the unique reactions of GNG? - ANSWER-GNG is glycolysis in reverse, but in glycolysis there are
three irreversible steps; we have enzymes to bypass these irreversible steps
Inside the mitochondria,
these enzyme can bypass PYR ---> PEP
1) PC enzyme (pyruvate carboxylase)
PYR ---(ATP/biotin-->ADP)---> OAA
2) PEPCK enzyme
OAA-->(CO2)--> PEP
-NEED TO USE 2 PYR (or 2 LAC) to generate GLC because PYR is 3C and GLC is 6C
irreversible enzyme:
1. F-1,6-bisP
---FRUCTOSE BISPHOSPHATASE --(cleave off HPO4^2-) --> F6P <--> GLC-6-P
2. GLC-6-P --(glucose-6-phosphatase/H2O)---> GLC
which is ONLY active in the LIVER
how is glycerol converted to glucose? - ANSWER-In the liver,
glycerol is phosphorylated ---> glycerol-3-P---(NAD+ oxidized)--> DHAP
2 glycerol (C3) needed to convert to GLC (C6)
,describe the cori cycle - ANSWER-muscle performs glycolysis and lactate fermentation, lactate leaves
muscle --> blood --> liver.
Liver recycles LAC --(GNG)--> GLC, GLC --> reenters blood ---> back to muscle for another round of
glycolysis and lactate fermentation
what else can GLC-6-P from GNG be used for? (Other than going back to glycolysis) - ANSWER-can be
used to make glycogen (storage of CHO in animals)
can be used in PPP
possible substrates for GNG - ANSWER-pyruvate
lactate
Fatty Acids (for plants)
Glycerol
what is invested when converting PYR to OAA? - ANSWER-1 ATP
biotin
what is the pathway and "complication" when ALA is used in the mitochondria to make PYR for GNG? -
ANSWER-It needs to be shuttled to cytosol from the mitochondria to the cytosol.
ALA-->PYR-->Malate (all in mitochondria)--> shuttled to cytosol--> malate converted back to OAA -->
PEP, but no cofactor balance (buildup of NADH)
how else can OAA leave the mitochondria (if not by conversion to PEP or Malate)? - ANSWER-OAA -->
Asp, leave the mitochondria, then Asp can go back to OAA in the cytosol
what organs rely solely on carbohydrates (glucose) for energy? - ANSWER-the brain
why does GNG occur in humans? In what organ does GNG occur most highly in humans? - ANSWER-
Some organs rely solely on glucose for energy (like the brain)
,GNG occurs in the liver
What cofactor does pyruvate carboxylase (PC) require? - ANSWER-Biotin, 1 ATP, and bicarbonate
in what human organ does lactate get converted to GLC - ANSWER-liver
what are the substrates to produce glycogen? what is the essential enzyme name? - ANSWER-UDP-GLC
and glycogen residues (makes a-1,4 linkages)
to make a-1,6 linkages, it uses branching enzyme
how is UDP GLC made? - ANSWER-G-6-P can either come from GLC or GNG ---> GLC-1-P + UTP ---> UDP-
GLC
what type of intermediate is used in synthesizing di, oligo, and poly saccharides? - ANSWER-A C1
(anomeric) carbocation, to which the nonreducing end's OH group from starch or glycogen attacks
UDP-GLC is used to make these polysaccharide
what roles do the liver, brain, and muscle have in supplying blood glucose and in supplying GLC and
energy for their own energy needs? - ANSWER-Liver - GNG ---> GLC --> blood ---> bodily organs/tissues;
Brain and muscle - no G6Pase activity, no blood glucose produced from GNG
muscle contributed GNG
GLC-->PYR--->LAC (in anaerobic conditions) --> liver GNG: LAC --> GLC-6-P ---> GLC---> used in the body
(perhaps back to the muscle)
what is the principle of forming glycosidic linkages? - ANSWER-using activated sugars and nucleotide
sugars (like UDP-GLC) for synthesis
, how can OAA be transferred from mitochondria to cytosol? - ANSWER-In the mito: OAA ---> Asp, -->
cytosol: Asp ---> OAA
In the mito: OAA -(reduced NADH)--> Malate ---> cytosol ---> Malate --(oxidized NAD+)->OAA
how is sucrose synthesized? - ANSWER-UDPGLC + F6P --(UDP Leaves)--> sucrose phosphate ---(H2O--
>HPO4^2-)--> sucrose
what are the roles of the PPP in the cell? - ANSWER-1) it is the major source of NADPH (a biosynthetic
reducing agent--esp for reducing glutathione)
2) biosynthetic pathway for making ribose-5-P (precursor for nucleotide synthesis)
3) it is the cell's pathway for the catabolism of 4 and 5 C sugars; 5 C sugars can be converted into
glycolytic intermediates for energy
4) maintaining enzyme activity
what are the two ways ribose 5 P can be made via PPP? - ANSWER-1) Reverse phase 3 and reverse phase
2
from F6P and G3P (starting with phase three of PPP) OR
2) starting with GLC 6 P (from phase 1 of PPP) only need one GLC-6-P but there will be build up of
NADPH
which part(s) of PPP is physiologically reversible? which part(s) is not? What is the irreversible enzyme
named? - ANSWER-reversible: phases 2 and 3
irreversible: phase 1. Glc-6-dehydrogenase
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