CARBOHYDRATES Flashcards
Considered as the most
abundant molecules on earth
and is the simplest among
other types of organic
compounds.
CARBOHYDRATES (CHO)
Empirical Formula of carbs
CH2O
Referred to as saccharides,
meaning “sugars”
CARBOHYDRATES
FUNCTIONS OF CARBOHYDRATES (give at least 4)
- Main source of energy for our body.
- Protein-sparing function
- Necessary for normal fat metabolism
- Cellulose stimulate peristaltic movement of our
gastrointestinal tract and adds “bulk” in our stool - Lactose promotes the growth of beneficial bacteria, causing
laxative action. - Glucose is the sole source of energy in our brain and proper
functioning of our tissues. - Certain products of carbohydrate metabolism act as catalyst
• A covalent bond that
is formed between a
carbohydrate
molecule and another
molecule such as
between two
monosaccharides.
GLYCOSIDIC BOND
Occurs in the tissues
such as the conversion
of galactose in the
liver to glucose. The
conversion is
catalysed by an
enzyme epimerase.
EPIMERIZATION
• Sugars with aldehyde function
or an acetal equivalent
• The monosaccharide is an
aldehyde if the carbonyl group
is at the end of the carbon
chain.
Aldose
Sugars having a ketone
function or an acetal
equivalent
• The monosaccharide is a
ketone if the carbonyl group is
at any other position.
Ketose
example of an aldose
glyceraldehyde
example of a ketose
dihyroxyacetone.
Sugars oxidized by
Tollens’ or Benedict’s or
Fehling’s reagents.
REDUCING
Sugars not oxidized by
Tollens’ or other reagents.
NON-REDUCING
• Consist of a single
polyhydroxy
aldehyde or ketone
unit
• Smallest
carbohydrates with
3-7 (5-6)carbon
MONOSACCHARIDES “Simple Sugars”
• Most common
monosaccharide
• Formula: C6H12O6
GLUCOSE
• Sweetest of simple
sugar that are
found in sucrose,
honey, fruits, and
vegetables.
• Formula: C6H12O6
FRUCTOSE
• A part of lactose
or a product of
lactose
breakdown.
• Formula: C6H12O6
GALACTOSE
• Composed of
short chains of
monosaccharides
that are joined together
OLIGOSACCHARIDES
• Are the most
abundant with two
monosaccharide
units that are joined
together through
dehydration
synthesis.
DISACCHARIDES (di-”two”)
•This sugar is formed
when a monomer of
glucose bonds to a
monomer of fructose.
A. SUCROSE
• Consist of
monomers of
glucose and
galactose
LACTOSE
Formed from
bonds of two
glucose
monomers.
MALTOSE
Composed of many
molecules of simple
sugar
POLYSACCHARIDES (Poly-”many”)
• Made up the cell wall of
plants
• Helps in lowering the glucose
level in the blood of people
with diabetes.
• It is also essential in
manufacturing numerous
products, including paper,
textiles and pharmaceuticals.
CELLULOSE
• These complex carbs have
the same structures and
functions.
• They supply energy for
longer period
• Since they are not
water-soluble, they need
digestive enzyme known as
“amylase” to break them apart
STARCH AND GLYCOGEN
• Formed from the
breakdown of starch, is obtained from
starch by the
application of heat or
acids.
• They are mainly used as
adhesives and
thickening agents.
Dextrin
• Sources from fruits
and are often used as
a base for jellies.
PECTIN
• Indigestible sugar that
is found in agar, pectin,
woody fibres, leaves, stems
HEMICELLULOSE
• Important in
medicine and nursing
as it provides test for
renal function.
• It is considered as a
“prebiotic fibre” as
it is fermented by
bacteria that
normalise our colon.
INULIN
The sum of all
chemical reactions
required for the
nutritional and
functional activities of the cell
METABOLISM
FOUR SPECIFIC OBJECTIVES OF METABOLISM:
- To extract chemical energy from the environment such as
from organic nutrients or from the sunlight. - To convert exogenous nutrients to building blocks or
precursors of macromolecular components of the cell. - To assemble building blocks into CHO, CHON, LIPIDS,
NUCLEIC ACIDS and another characteristic cell compound - To form (anabolism) and degrade (catabolism) these
biomolecules needed for the specialised functions of the cell.
Food particles do not
become part of our body
tissues but are oxidised to produce energy
Exogenous
Food particles become
part of our body tissues.
Endogenous
containing
carbohydrate-splitting enzymes that is
released in the small intestine
Pancreatic juice
absorbed into
the mucosa cells of the intestine.
Monosaccharides
As glycogen in liver and
muscles, when these
reserves are filled, it is
converted to _______ and
deposited in ______
triglyceride, adipose tissue
If blood glucose
exceeds renal
threshold
(____mg/dL), it will
be excreted in urine
180mg/dl
CONCENTRATION
OF BLOOD SUGAR
Fasting blood
glucose (8-12
hours after the
last meal) is 70-110 mg/dL
SOURCES OF
BLOOD GLUCOSE
▪ Dietary
carbohydrates
▪ Glycogenolysis
▪ Gluconeogenesis
A sequence of
chemical
reactions
undergone by a
compound or class
of compound in a living organism
METABOLIC PATHWAYS
The process of oxidizing food molecules,
like glucose, to carbon dioxide and water
CELLULAR RESPIRATION
The process by which a cell
uses O2 to “burn” molecules
and release energy.
AEROBIC CELLULAR
RESPIRATION
This process allows
organisms to convert energy
for their use without the
presence of oxygen.
ANAEROBIC CELLULAR
RESPIRATION
Access of glucose to the
cell can be regulated
using the __________ proteins that
transport glucose.
glucose transporter
▪ From Greek word
“glykys”, meaning
“sweet” and “lysis”
which means “breaking”
▪ Initially explained by
Gustav Embden and Otto
Meyerhof
▪ The process of converting
glucose into energy.
GLYCOLYSIS
in the process of glycolysis, The enzyme
_________
phosphorylates glucose
in the cell’s cytoplasm.
In the process, a
phosphate group from
ATP is transferred to
glucose producing
glucose 6-phosphate.
hexokinase
in the process of glycolysis, The enzyme ____________converts glucose-6-
phosphate into its isomer,
fructose-6-phosphate.
phospholglucoisomerase
in the process of glycolysis, Phosphorylation of
fructose-6-phosphate.
Another ATP molecule is
used by the enzyme
_____________ to
transfer a phosphate group
to fructose-6-phosphate,
forming fructose-1, 6-
biphosphate.
phosphofructokinase
in the process of glycolysis, The newly high-energy
phosphates further destabilize
fructose-1, 6-biphosphate. The
enzyme __________splits fructose 1,
6-biphosphate into two sugars
that are isomers to each other.
aldolase
Net result for steps 4 and 5 in glycolysis
Fructose 1, 6-bisphosphate and 2 molecules of glyceraldehyde-3-
phosphate
in the second half of glycolysis, Glyceraldehyde-3-
phosphate is converted into
________ and the formation
of _____ ATP molecules and ____ NADH molecules.
pyruvate, two, two
in the second half of glycolysis, The enzyme _______ transfers a P from 1,3-
bisphosphoglycerate to a
molecule of ADP to form ATP.
phosphoglycerate
kinase
in the second half of glycolysis, The enzyme __________
relocates the P from 3-
phosphoglycerate from the
third carbon to the second
carbon, forming 2-
phosphoglycerate (an isomer
of 3-phosphoglycerate).
phosphoglyceromutase
in the second half of glycolysis, The enzyme ________
removes a molecule of water
from 2-phosphoglycerate,
forming phosphoenolpyruvate
(PEP). This happens for each
molecule of 2-
phosphoglycerate
enolase
The last step in glycolysis.
The enzyme _________
transfers a P from PEP to ADP,
forming pyruvate and ATP. This
happens for each molecule of
phosphoenolpyruvate. This
reaction yields 2 molecules of
pyruvate and 2 ATP molecules.
pyruvate kinase
OUTCOME OF GLYCOLYSIS
2 molecules of pyruvate
2 molecules of ATP
2 molecules of NADH
2 molecules of water
THE OXIDATION OF PYRUVATE TO
FORM ACETYL COA FOR ENTRY INTO THE KREBS CYCLE
TRANSITION REACTION
▪ This serves as a bridge
connecting glycolysis with
the Krebs cycle
▪ Takes place in the matrix of
the mitochondrion.
▪ The acetyl coenzyme A is
the high energy molecule
that enters the Krebs cycle.
TRANSITION REACTION
▪ Oxidation of pyruvate.
▪ AKA as CITRIC ACID
CYCLE
• Occurs in the matrix of
mitochondria.
• Goal: take pyruvate and
produce NADH
and FADH2.
THE KREBS CYCLE
in the Krebs cycle, OXIDATION AND DECARBOXYLATION OF ISOCITRATE is catalyzed
by the enzyme _________
, where
isocitrate is oxidized,
generating a five-carbon
molecule, α-
ketoglutarate, together
with CO2 molecule and two
electrons that reduce
NAD+ to NADH.
isocitrate dehydroenase
in the Krebs cycle, OXIDATION OF SUCCINATE TO FUMARATE is catalyzed
by the enzyme _________, in which
succinate is converted into fumarate
succinate
dehydrogenase
in the Krebs cycle, HYDRATION OF FUMARATE TO PRODUCE
MALATE is catalyzed by the
enzyme ________. The
fumarate is hydrated, producing malate
fumarase
in the Krebs cycle, This is the final point of
entry to the electron
transport chain. This
reaction generates the
NADH and oxaloacetate
OXIDATION OF MALATE TO OXALOACETATE
PRODUCTS OF KREBS CYCLE
6 NADH are generated (3 per Acetyl CoA that
enters)
2 FADH2 is generated (1 per Acetyl CoA that
enters)
2 ATP are generated (1 per Acetyl CoA that
enters)
4 CO2 are released (2 per Acetyl CoA that enters)
The last component of aerobic
respiration and is the only part of
glucose metabolism that uses
atmospheric oxygen. (Rye, et.al,
2017)
ELECTRON TRANSPORT PHOSPHORYLATION
(CHEMIOSMOSIS)
4 DISTINCT MULTIPROTEIN COMPLEXES IN ELECTRON TRANSPORT PHOSPHORYLATION
o Complex I (NADH-Co Q reductase or NADH dehydrogenase)
o Complex II (succinate-Q-reductase)
o Complex III (cytochrome reductase, cytochrome b-c-1 complex
o Complex IV (cytochrome oxidase) as well as two mobile elements coenzyme Q
and cytochrome C.
It is a multiprotein
complex, having a
Cytochrome b, another Fe-
S protein, and Cytochrome
c 1 component.
Cytochrome
Oxidoreductase
PRODUCTS OF ELECTRON
TRANSPORT CHAIN
- 2 NADH from
glycolysis
= 6 ATP - 2 NADH from
transition reaction
= 6 ATP - 6 NADH from
Krebs cycle
= 18 ATP - 2 FADH2 from
Krebs cycle
= 4 ATP
34 ATP
ENERGY YIELD FROM CELLULAR RESPIRATION:
- Glycolysis: 2 ATP
- Krebs Cycle: 2 ATP
- ETC: 34 ATP
• 2 For NADH Transport
• 36 ATPs
▪ Metabolism without
oxygen, and is the only
way to generate NAD+
▪ Reduce pyruvate; thus,
generating NAD+
ANAEROBIC RESPIRATION
This is a process in which it uses an
organic molecule to regenerate NAD+
from NADH.
FERMENTATION
Occurs in yeasts in many
bacteria, that produces
ethanol, an alcohol.
ALCOHOL FERMENTATION
A fermentation method
utilized by animals, and
certain bacteria. For
example, the bacterium
Lactobacillus ferments
lactose in milk, producing
lactic acid – giving yogurt
its sour taste.
LACTIC ACID FERMENTATION
▪ This is the synthesis of
glucose from amino acids,
pyruvate, lactate, or
glycerol.
▪ It occurs primarily in the
liver when supply of blood
glucose is low such as when
fasting, starvation, or low
carbohydrate diet.
GLUCONEOGENESIS
▪ The synthesis of
glycogen from glucose.
▪ Glucose is modified and
gains the ability to be
stored in long chains –
glycogen.
▪ Key enzyme of
glycogenesis is glycogen
synthase
GLYCOGENESIS
This is the process in which
glycogen molecule is broken
down into glucose – a simple
sugar used by our cells in
producing energy
GLYCOGENOLYSIS
Key enzyme of glycogenolysis is _________
glycogen phosphorylase
▪ Forms 8-10% of the wet weight
of the liver
▪ Maintains blood glucose
(especially between meals)
▪ Liver glycogen is depleted after
12-18 hours fasting
LIVER GLYCOGEN
▪ Forms 2% of the wet weight of
muscle
▪ Supplies glucose within muscles
during contraction
▪ Muscle glycogen is only depleted
after prolonged exercise
MUSCLE GLYCOGEN
It controls the rate of
glucose absorption
GASTROINTESTINAL TRACT
The maximum rate of
glucose absorption is _____
gm/kg body weight/ hour
1
▪ The main blood glucose state.
▪ Maintains blood glucose level
within normal
LIVER
If blood glucose level increases, the liver controls this elevation and
decreases it through what processes?
• oxidation of glucose
• Glycogenesis
• Lipogenesis
If blood glucose level decreases, the liver controls this drop and increases it through what processes?
• Glycogenolysis
• Gluconeogenesis
All glucose in blood is filtered
through the _______, it then
completely returns to the blood
by tubular reabsorption.
kidneys
If blood glucose exceeds a
certain limit (called renal
threshold), it will pass in
urine, causing ________
glucosuria
• the only hypoglycemic hormone):
• Facilitates the uptake of glucose
in our cells – thus, maintaining
normal glucose levels.
INSULIN
ANTI-INSULIN HORMONES
(hyperglycemic hormones)
▪ Growth Hormone:
- Gluconeogenesis
▪ Thyroxine:
- Increase absorption of glucose in
intestines
- Gluconeogenesis and
glycogenolysis
▪ Epinephrine (adrenaline):
- Glycogenolysis in both liver and
muscles
▪ Glucagon:
- Glycogenolysis in liver ONLY
It is an abnormal
increase in blood
glucose concentration
due to decrease insulin
secretion and/or
hypersecretion of anti-
insulin hormones.
HYPERGLYCEMIA
Previously known as Insulin-
Dependent Diabetes Mellitus
(IDDM) and usually develops
among people younger than
age 20.
Type 1 Diabetes Mellitus
This occurs when the person’s
immune system attacks the
beta cells of the pancreas,
resulting to little or no insulin
produced by the pancreas.
Type 1 Diabetes Mellitus
Previously known as Non-
Insulin-Dependent
Diabetes Mellitus
(NIDDM), and much more
common than type 1.
Diabetes Mellitus 2
It often occurs among
obese people who are over
age 35
Diabetes Mellitus 2
Low blood glucose level, due to
excess insulin that stimulates
too much uptake of our body
cells of glucose.
HYPOGLYCEMIA
the balance of Insulin
and Glucagon to
maintain blood glucose
Glucose homeostasis
a potentially life-threatening complication
of diabetes mellitus
Diabetic ketoacidosis
Signs and symptoms may include vomiting, abdominal pain, deep
gasping breathing, increased urination, weakness, confusion and
occasionally loss of consciousness.
Diabetic ketoacidosis
a condition where the person’s breath may develop a specific “fruity” smell.
Diabetic ketoacidosis
develops
during pregnancy in
individuals that otherwise
have never been diagnosed
with diabetes in the past. It
typically resolves after the
woman gives birth
Gestational
Diabetes
it increases her
risk of developing type 2
diabetes mellitus later in
life.
Gestational
Diabetes
Gestational Diabetes Complications
- Large for gestational age infant
- early (preterm) birth
- hypoglycemia
- stillbirth
increased urination
polyuria
increased thirst
polydipsia
increased apetite
polyphagia
the general product formed when starch is hydrolyzed is _____-
GLUCOSE
is a sugar alcohol that can be used to test for asthma, to reduce intracranial and
intraocular pressure, to measure glomerular filtration rate, and to manage pulmonary symptoms
associated with cystic fibrosis
MANNITOL IVF
the scale to measure how fast or slow carbohydrates are turned into blood
glucose to guide the patient’s diet
GLYCEMC INDEX
sugars unsuited for parenteral feeding due to caloric restriction and toxic side-effects
GALACTOSE
the sweetest sugar
FRUCTOSE
excessive sweating
Diaphoresis
excessive eating
Diaphoresis
Most abundant
polysaccharide in
nature
starch and cellulose
blood glucose above a desirable level 1 or 2 h after a
person has eaten.
Postprandial hyperglycemia
the opposite of photosynthesis
CELLULAR RESPIRATION
the opposite of photosynthesis
CELLULAR RESPIRATION
