CARBOHYDRATES, PROTEINS, AMINO ACIDS AND LIPID METABOLISM Flashcards
In the catabolism of carbohydrates, glycolysis converts glucose into ____ which is then metabolized into ___
pyruvate
acetyl CoA.
In the catabolism of lipids, fatty acids are
converted into ___ and then cleaved into many acetyl CoA units
thioesters
are usually reassembled into new proteins.
Amino acids
The amino groups (NH2) are converted to ___ which is excreted in __
urea
urine
catalyzes the addition of a -COO- (carboxylate).
Carboxylase
catalyzes the removal of CO2
Decarboxylase
catalyzes the removal of 2 H atoms.
Dehydrogenase
catalyzes the isomerization of one isomer into another.
Isomerase
catalyzes the transfer of a phosphate.
Kinase
is a linear, 10-step anaerobic pathway that converts glucose into two molecules of pyruvate.
Glycolysis
Steps [1] to [5] comprise the ____ where 2 ATP molecules are hydrolyzed.
energy investment phase,
Steps [6] to [10] comprise the _____ , producing 1 NADH and 2 ATPs for each pyruvate formed.
energy-generating phase
Step [1] begins with the
____ of
glucose into glucose 6-
phosphate, using an ATP
and a ___ enzyme.
phosphorylation
hexokinase
Step [2] __ glucose 6-phosphate to
fructose 6-phosphate
with an ___
enzyme.
isomerization,
phosphohexose isomerase
Step [3] is the
___ of
fructose 6-phosphate
into fructose 1,6-
bisphosphate with a
___ enzyme.
phosphorylation,
phosphofructokinase
Step [4] ___ the fructose ring into a dihydroxyacetone phosphate and a gleraldehyde 3-phosphate with enzyme__
cleaves, aldolase
Step [5] ___the dihydroxyacetone phosphate
into another glyceraldehyde 3-phosphate.
isomerizes, triose phosphate isomerase
In step [6] the aldehyde end of the molecule is
___ by a dehydrogenase
enzyme and this produces
___ and ___
oxidized and phosphorylated
1,3-bisphosphoglycerate and NADH
In step [7], the ___ onto
an ADP with a kinase enzyme, forming
3-phosphoglycerate and ATP by enzyme __
phosphate group is transferred
phosphoglycerate kinase
In step [8], the phosphate group is __ to a
new position in 2-phosphoglycerate by enzyme
isomerized
phosphoglycerate mutase
In step [9], ___ form phosphoenolpyruvate by enzyme __
dehydration
enolase
In step [10], the ____ to an
ADP, yielding pyruvate and ATP with a
___ enzyme.
phosphate transfer/
pyruvate kinase
Overall, the energy-generating phase forms
2NADHs and 4 ATPs.
The fate of the 2 pyruvate molecules depends on
__ availability.
O2
The 2 NADHs formed are made in the__
and must be transported to the __ to
join the electron transport chain and make ATP.
cytoplasm
mitochondria
is obtained by the hydrolysis of the
disaccharide sucrose, found in sugar beets and
sugarcane.
Fructose
___ can be converted by muscle or kidney cells into
___ and enter glycolysis at step [3].
fructose/ fructose 6-phosphate
it can be converted by the liver to ___ and enter glycolysis at step [6].
glyceraldehyde
3-phosphate
is obtained by the hydrolysis of the
disaccharide lactose in milk.
Galactose
Galactose is converted into _ and then enters glycolysis in step [2].
glucose 6-phosphate
__ is obtained from polysaccharides in
fruits such as cranberries and currants.
Mannose
Mannose is converted to __
and it enters glycolysis at step [3].
fructose 6-phosphate,
Thus, all the common hexoses enter glycolysis
and are metabolized into ___
pyruvate.
___ can be converted into three possible
products depending on the conditions and the
organism.
Pyruvate
pyruvate three products
under aerobic
conditions
under anaerobic
conditions
in fermentation by
microorganisms
Under __(when O2 is plentiful),
pyruvate is oxidized by in the presence of
coenzyme A to form acetyl CoA.
aerobic conditions
The NADH formed needs ___ to return to so without O2 no additional pyruvate can be
oxidized.
O2
In ___ (when O2 is lacking) there is an abundance of NADH.
anaerobic conditions
The NADH acts as a ____ reducing
pyruvate to ___
reducing agent,
lactate.
