Carbohydrate metabolism involves the different biochemical processes responsible for the formation, breakdown, and interconversion of carbohydrates in living organisms.

1. By Prof. Liwayway Memije-Cruz

3.  Carbohydratemetabolism beginswith digestion in
thesmall intestinewheremonosaccharidesare
absorbed into theblood stream. Blood sugar
concentrationsarecontrolled by threehormones:
insulin, glucagon, and epinephrine. If the
concentration of glucosein theblood istoo high,
insulin issecreted by thepancreas. Insulin stimulates
thetransfer of glucoseinto thecells, especially in the
liver and muscles, although other organsarealso able
to metabolizeglucose.

4.  In theliver and muscles, most of theglucoseis
changed into glycogen by theprocessof
glycogenesis(anabolism). Glycogen isstored in
theliver and musclesuntil needed at somelater
timewhen glucoselevelsarelow. If blood
glucoselevelsarelow, then eqinephrineand
glucogon hormonesaresecreted to stimulatethe
conversion of glycogen to glucose. Thisprocess
iscalled glycogenolysis(catabolism).

5.  If glucoseisneeded immediately upon entering the
cellsto supply energy, it beginsthemetabolic process
called glycolysis(catabolism). Theend productsof
glycolysisarepyruvic acid and ATP.
 sinceglycolysisreleasesrelatively littleATP, further
reactionscontinueto convert pyruvic acid to acetyl
CoA and then citric acid in thecitric acid cycle. The
majority of theATPismadefrom oxidationsin the
citric acid cyclein connection with theelectron
transport chain.
 During strenuousmuscular activity, pyruvic acid is
converted into lactic acid rather thatn acetyl CoA.
Durlng theresting period, thelactic acid isconverted
back to pyruvic acid. Thepyruvic acid in turn is
converted back to glucoseby theprocesscalled

6.  During strenuousmuscular activity, pyruvic acid is
converted into lactic acid rather than acetyl CoA.
During theresting period, thelactic acid isconverted
back to pyruvic acid. Thepyruvic acid in turn is
converted back to glucoseby theprocesscalled
gluconeogenesis(anabolism). If theglucoseisnot
needed at that moment, it isconverted into glycogen
by glycogenesis. You can remember thosetermsif
you think of "genesis" astheformation-beginning.

7. Acetyl-CoA (acetyl coenzyme A)
 a molecule that
participates in many
biochemical reactions in
protein, carbohydrate and
lipid metabolism.
 It’s main function is to
deliver the acetyl group to
the citric acid cycle
(Krebs cycle) to be
oxidized for energy
production.

8. Glycolysis
 thefirst step in the
breakdown of
glucoseto extract
energy for cellular
metabolism.
 consistsof an
energy-requiring
phasefollowed by an
energy-releasing
phase.
 themetabolic
processthat serves
asthefoundation for
both aerobic and
anaerobic cellular
respiration. In
glycolysis, glucoseis
converted into
pyruvate.

9. Glucose: C6H12O6
 Glucosecirculatesin the
blood of animalsasblood
sugar.
 It ismadeduring
photosynthesisfrom water
and carbon dioxide, using
energy from sunlight.
 asix- membered ring
moleculefound in theblood
and isusually aresult of the
breakdown of carbohydrates
into sugars.

11. NADH
 Themoleculeactsasa
shuttlefor electrons
during cellular
respiration. ... Then
NADH, along with
another moleculeflavin
adeninedinucleotide
(FADH2) will
ultimately transport the
electronsto the
mitochondria, where
thecell can harvest
energy stored in the
electrons.

12. Cori Cycle:
 During musclecontractions, ATPisconstantly being
used to supply energy and moreATPisproduced to
replenish supplies. ... At first glycolysisproduces
pyruvic acid which isthen converted into acetyl CoA
and ismetabolized in thecitric acid cycleto makeATP
using theelectron transport chain.

13.  https://study.com/academy/lesson/role-of-
glucose-in-cellular-respiration.html

14.  https://youtu.be/0i9onqGqbo0

15.  They areasourceof instant energy in the
timeswhen oneneedsmorethan thenormal
amount of energy for an activity. For example:
Athletesuseup their ‘Glycogen reserves’
during arace.
 Between mealsor during fasts, thesereserves
help ussurvive.

16.  http://chemistry.elmhurst.edu/vchembook/600glycolysis
.html
 http://www.biologydiscussion.com/metabolism/carbohy
drates-metabolism/metabolism-of-carbohydrates-
catabolism-and-anabolism-with-diagram/17198
 https://study.com/academy/lesson/role-of-glucose-in-
cellular-respiration.html
 https://www.khanacademy.org/science/biology/cellular-
respiration-and-fermentation/glycolysis/a/glycolysis
 https://simplybiotech.wordpress.com/2015/01/28/carboh
ydrate-metabolism-glycogen-metabolism/