First Year M.B.B.S. Examination
February/July-2004-2014
Biochemistry: PAPER- II
Time : 3 Hours] [Total
Marks : 50
SECTION-I
1. State true and false with
justification: (any six) 1x6=6
o
2,3-Bisphosphoglycerate
(BPG) increases affinity of hemoglobin for oxygen.
o
2,3-Bisphosphoglycerate
(BPG) synthesis in RBC is unnecessary wastage of ATPs.
o
2,3-Bisphosphoglycerate
(BPG) synthesis increases at higher altitudes.
o
Alanine
serves as the transport form of ammonia from muscles.
o
Alcohol
consumption leads to Wernicke-Korsakoff Syndrome.
o
All
ketones are not referred as ketone bodies.
o
Allopurinol
is advised in gout patients.
o
Ammonia
is toxic to brain tissue.
o
Amylase
can be used as therapeutic agent.
o
Apolipoprotein-apo
C II inactivates the enzyme lipoprotein lipase.
o
ATP
is a negative modulator of phosphorylase –b.
o
B12
deficiency leads to neurological manifestations.
o
Barbiturates
precipitate an attack of acute intermittent porphyries.
o
Bicarbonate
is known as backbone of buffering system.
o
Bile
salts are not required for digestion and absorption of fats.
o
Bile
salts are required for digestion of proteins.
o
Bilirubin
forms a covalent complex with albumin in plasma.
o
Bilirubin
is conjugated with cysteine and glutathione.
o
Blood
for glucose estimation is collected in fluorinated tubes.
o
Blood
for transfusion should be stored with dextrose.
o
Both
starch and cellulose can be digested in human body.
o
Brain
uses free fatty acids from blood for energy purpose when necessary.
o
Brown
fat is found more in hibernating animals.
o
Calmodulin
is a form of body calcium.
o
Carbohydrates
are the only metabolic substrates that produce ATP under anaerobic conditions.
o
Carnitine
is essential for oxidation of all types of fatty acids.
o
Carnitine
is essential for oxidation of fatty acids.
o
Cataract
develops more commonly in the diabetic patients.
o
Cellular
hypoxia leads to lactic acidosis.
o
Certain
enzymes are activated by selective partial proteolysis.
o
Cyanide
poisoning causes cellular asphyxia.
o
Cyanide
poisoning stops ATP synthesis in ETC between complex I & III.
o
Cytochromes
P-450 are highly inducible.
o
Defect
in galactose metabolism can leads to development of cataract.
o
Deficiency
in G6PD leads to hemolysis.
o
Denaturation
of proteins leads to separation of amino acids from protein.
o
Diarrhea
causes metabolic acidosis.
o
Diet
rich in carbohydrates can reduce the requirement of proteins.
o
Dietary
vegetables and fruits are good for health.
o
DNA
polymerase acts as proof reader.
o
During
starvation, muscle glycogen can be converted to blood glucose.
o
Enzymes
can be used as therapeutic agents.
o
ETC
is located on outer mitochondrial membrane of mitochondria.
o
Ethanol
is given as antidote in methanol poisoning.
o
Extra
proteins consumed in diet can be stored in body for future utilization.
o
Fat
can not be metabolized in the absence of carbohydrates.
o
Fluoride
inhibits glycogenolysis.
o
Gastric
mucosa atrophy leads to vitamin B12 deficiency.
o
Giving
some extradoses of vitamin-A to children is good for health.
o
Gluconeogenesis
from pyruvate is biotin dependent.
o
Gluconeogenesis
is simple reversal of glycolysis.
o
Glucose
can be converted to triacylglycerol in human body.
o
Glucose
can not be completely oxidized in RBC.
o
Glucose
uptake by all tissues is insulin independent.
o
Glucose-6-phosphate
dehydrogenase (G6PD) deficiency leads to drug induced hemolysis.
o
Glucose-6-phosphate
is a branch point compound.
o
Glutathione
is an antioxidant.
o
Glycated
hemoglobin is a marker of uncontrolled diabetes.
o
Glycolysis
in RBC always ends in lactate.
o
Hemoglobin
S leads to sickling of RBC.
o
Hemolysed
blood sample is not suitable for serum potassium estimation.
o
Hibernating
animals are rich in brown fat.
o
High
density lipoprotein is bad for health.
o
High
LDL is a welcome feature.
o
High
level of HDL cholesterol prevents atherosclerosis.
o
Histamine
is a biogenic amine produced from tyrosine.
o
Histidine
load test is done to rule out pyridoxine deficiency.
o
HMG
CoA reductase is the key enzyme for cholesterol biosynthesis.
o
HMP
shunt pathway operates only in those tissues where NADPH is required.
o
Hydroxylation
of amino acids is post translational modification.
o
Hypercalcemia
leads to tetany.
o
IgE
has a role in anaphylactic response.
o
Immunoglobulin-E
has a role in anaphylactic response.
o
In
a patient of diabetes mellitus, glycated hemoglobin is a better indicator of
long term control than blood glucose level.
o
In
anaerobic glycolysis lactate is produced.
o
In
anaerobic glycolysis pyruvate is produced.
o
In
biliary obstruction there is steatorrhoea.
o
In
ETC P:O ratio is always 3.
o
In
primary structure of DNA in between nucleotides glycosidic bonds are present.
o
In
riboflavin deficiency, erythrocyte transketolase level is decreased.
o
In
starvation, plasma free fatty acids level falls.
o
In
vitamin B12 deficiency there is methyl malonic aciduria.
o
Insulin
and glucagon is antagonistic hormone.
o
Intracellular
buffers play a significant role in acid base balance.
o
Introns
of m-RNA contain genetic code.
o
Km
value of glucokinase is higher than hexokinase.
o
Lactase
deficiency can cause diarrhea on taking milk.
o
Lead
inhibits hemoglobin synthesis.
o
Liver
plays crucial role in metabolism of drugs.
o
Liver
synthesize as well as can utilize ketone bodies for energy purpose.
o
Liver
synthesizes ketone bodies but can not utilize ketone bodies for energy purpose.
o
Metabolic
alkalosis can occur in pulmonary emphysema.
o
Multiple
origin replications are characteristic feature in prokaryotic cell.
o
Muscles
use fatty acids as source of energy during anaerobic exercise.
o
Non
sense codon brings about initiation of protein synthesis.
o
Non-essential
amino acids do not have any significant role in body.
o
Normal
function of endonucleases is to protect bacteria from foreign DNA.
o
Obstruction
to bile flow can cause steatorhoea.
o
Obstructive
jaundice is characterized by increased conjugated bilirubin in blood.
o
Pantothenic
acid has a role in fatty acid biosynthesis.
o
Pasteurized
milk and sterilized milk are different.
o
Patients
of chronic renal failure suffer from osteodystrophy and hypocalcemia.
o
Patients
of diabetes mellitus develop cataract at an early age.
o
pH
– of blood is slightly alkaline while that of urine.
o
Phenylalanine
is essential amino acid.
o
Prion
proteins have normal primary structure.
o
Prolonged
starvation leads to ketoacidosis.
o
Proteins
of rice is incomplete and of poor quality.
o
Pulmonary
airway obstructive diseases produce respiratory alkalosis.
o
Purines
and pyrimidines are dietary non-essential.
o
Radioactive
albumin is used to measure intra vascular fluid volume.
o
Rapaport
leuberung cycle is beneficial to RBC.
o
RBCs
produce lactate.
o
Red
blood cells can use only glucose as a source of energy.
o
Repeated
blood transfusion leads to hemosiderosis.
o
RNA
can act as genetic material.
o
Salvage
pathway is more economical than de-novo synthesis.
o
Sodium
concentration in body is related with retention of total body water.
o
Splicing
take place after translation.
o
Starvation
leads to ketoacidosis.
o
There
is hyperuricemia in patients of Von Gierke’s disease.
o
Transcription
requires RNA primer molecule.
o
Transport
of glucose into cells of skeletal muscles and adipose tissue is not dependent
on insulin.
o
t-RNA
can act as adaptor.
o
TSH
hormone level is low in a patient of primary hypothyroidism.
o
Tumor
markers are chemicals that destroy tumor cells.
o
Tyrosine
is an essential amino acid for patients of phenylketonuria.
o
Unconjugated
Bilirubin can appear in the urine.
o
Urine
of alkaptonuria patients turns black on exposure to air.
o
Vitamin
C deficiency affects collagen.
o
Vitamin
D is a prohormone.
o
Vitamin
D promotes the intestinal absorption of calcium.
o
Vitamin
E protects unsaturated fatty acids.
o
Vitamin
K deficiency rarely seen even if it is not taken in deit.
o
γ-globulins
can act as defense against foreign infections.
---------------------------------------------------------------------------------------------------------------------------
2. (a) Read the
following case report and answer the questions : 1x5=5
A
12 years old boy was admitted in emergency ward in comatose condition. He was a
known patient of diabetes mellitus. His blood glucose was 485 mg/dl. Urine
ketone bodies was +++ and serum bicarbonate was below normal during admission.
The case was diagnosed as diabetic coma with ketoacidosis. Immediately insulin,
glucose drip and bicarbonate were prescribed in the line of treatment along
with serum potassium estimation every hourly was also instructed by the
physician.
Questions:
- Why
ketone body synthesis increased in this condition?
- Diabetic
ketoacidosis is which type of acidosis?
- What
is the normal range of fasting blood glucose value?
- For
diagnosis of diabetes mellitus by WHO criteria how much should be minimum
fasting blood glucose value?
- Why
every hourly serum potassium estimation was instructed by the physician?
A
40 years old male patient having type 2 diabetes mellitus came to hospital with
complaints of impaired vision and feeling of tiredness. The patient was
referred to ophthalmologist. Report from ophthalmologist showed cataract in
both eyes.
His
biochemical reports were:
Fasting
plasma glucose 300 mg/dl, Urine glucose +++, Glycated hemoglobin- 12 mg%
(normal:4-6%).
1.
How
much is the renal threshold for glucose?
2.
Why
cataract develops more commonly in diabetes mellitus patients?
3.
What
is the significance of estimating glycated Hb?
4.
Mention
other late complications of diabetes mellitus besides cataract.
5.
Why
type 2 diabetes mellitus patients are less prone to develop ketoacidosis?
A
40 years old male patient of known Non insulin dependent diabetes mellitus came
to O.P.D. hospital with impaired vision and feeling of tiredness. The patient
was referred to ophthalmologist. Report from ophthalmologist showed cataract in
both eyes.
His
biochemical findings were:
Fasting
plasma glucose 300 mg/dl, Urine glucose +++, Glycated hemoglobin- 12 mg%
(normal:4-6%).
1.
How
much is the renal threshold for glucose?
2.
Why
cataract develops more commonly in diabetes mellitus patients?
3.
What
is the significance of estimating glycated Hb?
4.
Mention
any other late complications of diabetes mellitus besides cataract.
5.
Why
Non insulin dependent diabetes mellitus patients are less prone to develop
ketoacidosis?
A 12 year old
girl was brought to hospital with complaints of weakness, increased thirst,
weight loss in spite of good appetite and increased frequency of
micturation.biochemical tests showed presence of reducing sugar in urine and
blood glucose level=290 mg/dl.
1.
What
is the diagnosis? Is it necessary to perform oral glucose tolerance test in
this patient to confirm the diagnosis?
2.
State
the biochemical basis of symptoms of this patient.
3.
Differentiate
between type 1 and type 2 diabetes mellitus.
4.
At
the time of admission, what do you expect the patient’s tissue glycogen level
to be and why?
5.
What
are the various complications she may develop, about which you would like to
caution her before discharge?
A 40 years old
male was admitted in emergency ward for left sided chest pain. His serum CK-MB
enzyme level was double than normal. There was family history of heart attack
below 40 years of age. His serum total cholesterol was 300 mg/dl and LDL
cholesterol was 200 mg/dl. The patient was shifted to ICCU with provisional
diagnosis of myocardial infarction.
1.
What
are isoenzymes?
2.
What
are the different isoenzymes of creatinine phosphokinase (CK)
3.
Name
a disease where a predominant increase in CK-MM occurs?
4.
What
are the other serum enzymes increases in myocardial infarction?
5.
Why
LDL cholesterol is considered bad cholesterol?
A
42 years old shopkeeper, whose brother died of sudden myocardial infarction a
month back, visited the physician for routine examination. Investigations
revealed: S.Glucose-90 mg/dl, S.Urea-20 mg/dl, S.Cholesterol-255 mg/dl,
S.HDL-35 mg/dl, S.triacylglycerol-110 mg/dl, S.LDL-198 mg/dl.
He
was diagnosed as a case of primary hyperlipoproteinemia and was advised life
style modification along with statin group of drugs.
1.
Which type of primary
hyperlipoproteinemia is he likely to be suffering from? Justify.
2.
What
lifestyle and dietary modifications should be advised to this patient?
3.
What will be the fate of LDL cholesterol
if apo B100 receptors are defective?
4.
How statins are helpful in this case?
5.
What biochemical tests other than
lipoproteins and cholesterol are helpful in assessing the risk of
atherosclerosis?
A
young shopkeeper was diagnosed for hypercholesterolemia during routine
laboratory investigations. His total serum cholesterol was 245 mg/dl, S.HDL-33
mg/dl, and S.triacylglycerol-126 mg/dl.
1.
Calculate his LDL cholesterol.
2.
What are the salient features of
lifestyle modification therapy in the case?
After 6 months the laboratory investigations were
repeated.
The laboratory report was as follows:
Total serum cholesterol was 230 mg/dl, S.HDL-30
mg/dl, and S.triacylglycerol-120 mg/dl.
Decision to start a statin was taken.
3.
Explain mechanism of action of statins.
4.
Draw structure of LDL
5.
HMG CoA reductase may affect co-enzyme Q
status in the cell. Explain.
----------------------------------------------------------------------------------------------------------
(b) Discuss the followings: 3+2=5
§ Amino
acids and their derivatives as neurotransmitters
§ Aminoacidurias
§ Antioxidant
enzymes
§ Beta-oxidation
of palmitic acid and calculate its energetic
§ Biosynthesis
of palmitic acid
§ Dehydration
§ Diabetes
mellitus and its complications
§ Disorders
associated with deficiency of B-complex vitamins
§ Disorders
of aromatic amino acids metabolism
§ Dyslipoproteinemias
§ Genetic
code
§ Glycogen
storage diseases
§ Gout
§ Heme
biosynthesis and hyperbilirubinemias
§ Hexose
Mono Phosphate (HMP) shunt and its significance
§ hyperlipoproteinemias
§ Iron
absorption, transport, biochemical functions and deficiency diseases
§ Medical
applications of recombinant DNA technology
§ Metabolic
reactions of glycine
§ Purine
salvage pathway
§ Salvage
pathway
§ Substrate
for gluconeogenesis
§ Synthesis
of important biological substances from aromatic amino acids
§ TCA
cycle
§ Trace
gluconeogenic pathway from alanine
3.
Write short notes: (any three) 3x3=9
· 2,3-bisphosphoglycerate
· Albinism
· Alcohol
metabolism
· Basal
metabolic rate
· Beta
oxidation of fatty acids
· Biochemical
cardiac function tests
· Blood
glucose regulation
· Calcium
and phosphate homeostasis
· Calcium
homeostasis
· Citric acid cycle
· Conjugation
· Diabetes mellitus
· Direct
and indirect vanden bergh reaction
· Fatty
acid synthase
· Fatty
liver
· Folate
trap or methyl trap
· Free
radicals and its hazards
· Functions
of bile salts
· Gluconeogenesis
· Glucose
transportes
· Glycogen
storage diseases
· Glycolysis
· Gout
· GTT
· Hepatic
coma
· Iron
· Iron absorption and transport
· Kidney
function tests
· Lipid digestion and absorption
· Lipid:
digestion, absorption and transport
· Maple
syrup urine disease
· Metabolic
acidosis
· Metabolic
significance of HMP shunt
· Nitrogen
balance
· One
carbon metabolism
· Phenylketonuria
· Protein
digestion
· Regulation
of glycogen metabolism
· Regulation
of glycolysis and gluconeogenesis
· S-Adenosyl
methionine
· Specific
dynamic action
· Trace
elements
· Transcription
· Transdeamination
reaction
· Uncouplers in ETC
· Urea
cycle
· Vitamin D
· Wald’s visual cycle
--------------------------------------------------------------------------------------------
SECTION-II
4. Give
your comments with biochemical justification :(any six) 1x6=6
Ø
Alcoholism leads to fatty liver.
Ø
Allopurinol is used in the treatment
of gout.
Ø
Alpha-1 antitrypsin deficiency leads
to emphysema.
Ø
Any impairment in fatty acid
oxidation leads to hypoglycemia.
Ø
Arachidonic acid is a dietary
essential fatty acid during linoleic acid deficiency.
Ø
Aspirin is an anti-inflammatory,
anti-platelet agent.
Ø
At high altitude 2,3-BPG
concentration is increased in RBC.
Ø
Bile salts help in lipid absorption.
Ø
Brain cannot utilize free fatty
acids for energy purpose.
Ø
Calcium deficiency leads to
osteomalacia.
Ø
Carbidopa and gamma methyl dopa are
used for the treatment of Parkinson’s disease.
Ø
Carnitine is essential for fatty
acid oxidation.
Ø
Cellulose even though not digested
is dietary essential.
Ø
Cereals are usually mixed with
pulses.
Ø
Chargaff’s rule is applicable in DNA
but not in RNA.
Ø
Cigarette smoking is injurious to
health.
Ø
Citric acid cycle is a common
metabolic pathway.
Ø
Citric acid cycle is an amphibolic
pathway.
Ø
Citric acid cycle plays a pivotal
role in metabolism.
Ø
Copper is an essential component of
oxidases.
Ø
Cytochrome p-450 is considered as
the most versatile biocatalysts.
Ø
Endogenous purines are more
important than exogenous purines.
Ø
Ethanol is used as an antidote for
methanol poisoning.
Ø
Ethyl alcohol is used to treat
methyl alcohol poisoning.
Ø
Excess ammonia interferes with TCA
cycle in brain.
Ø
Exocrine pancreatic insufficiency
causes steatorrhoea.
Ø
Fat burns in the flame of
carbohydrates.
Ø
Fat synthesis does not take place
without NADPH.
Ø
Fructose is utilized in diabetics.
Ø
Galactosemic children tend to
develop premature cataract.
Ø
Glucocorticoids are potent
anti-inflammatory drugs.
Ø
Gluconeogenesis is not a simple
reversal of glycolysis.
Ø
Glucose transporters exhibit tissue
specificity.
Ø
Glucuronic acid is important in
bilirubin detoxification
Ø
Glucuronic acid is important in detoxification
reaction.
Ø
Glycated hemoglobin is a good
indicator of blood sugar control in diabetes mellitus.
Ø
Glycerol can be converted to
glucose.
Ø
Glycine is also called “little
master”.
Ø
Glycogen breakdown and synthesis do
not take place simultaneously.
Ø
Glycogen is the carbohydrate reserve
in animals.
Ø
GOD-POD method estimate true blood
glucose value.
Ø
Gouty attacks may be precipitated by
high purine diet or increased intake of alcohol.
Ø
Hexose monophosphate shunt (HMP)
pathway is useful for lipogenesis and purine biosynthesis.
Ø
Hibernating animals are rich in
brown fat.
Ø
Hyperkaelimia is usually associated
with metabolic acidosis.
Ø
Increased cholesterol in blood above
normal level is harmful.
Ø
Increased level of LDL is harmful
for our body.
Ø
Increased level of plasma HDL is
beneficial for our body.
Ø
Insulin is the treatment for
diabetic keto-acidosis.
Ø
Ketonuria is commonly observed
during prolonged fasting.
Ø
Key enzymes of metabolic pathways
are usually allosteric enzymes.
Ø
Lactate is the end product of
anaerobic glycolysis.
Ø
Lecithin cholesterol acyl
transferase (LCAT) deficiency leads to atherosclerosis.
Ø
Lipids are the concentrated fuel
reserve of human body.
Ø
Lipoprotein lipase (LPL) deficiency
can cause hyperchylomicronemia.
Ø
Lipoproteins help in lipid transport
in blood.
Ø
Liver glycogen can supply glucose to
blood.
Ø
Malnutrition may lead to the
occurrence of certain diseases.
Ø
Muscle glycogen cannot supply
glucose to blood.
Ø
Oxaloacetate plays a catalytic role
in TCA cycle.
Ø
Polyuria is often observed in
diabetics.
Ø
PRPP synthesis is an important step
in denovo synthesis of purine nucleotides.
Ø
Pyruvate accumulates in tissues of
body in thiamine deficiency.
Ø
Pyruvate acts as a junction point
between various metabolic pathways.
Ø
RBC glycolysis always terminates
into lactate.
Ø
RBC glycolysis is always anaerobic.
Ø
SAM takes part in one carbon
metabolism.
Ø
Significance of
2,3-bisphosphoglycerate formation in RBC.
Ø
The blood levels of some proteins
are increased in inflammatory conditions.
Ø
The cardinal features of diabetes
mellitus are three Ps (Polyuria, polyphagia and polydypsia).
Ø
Tyrosine is an essential amino acid
for patients of phenylketonuria.
Ø
Urine of alkaptonuric patients turns
black on keeping.
5.
Discuss the following: (any two) 5x2=10
µ Acid
base disturbances with compensatory mechanism and laboratory findings
µ Ammonia
detoxification and urea synthesis
µ Biochemical
changes occurs in starvation
µ Biochemistry
of cancer and tumor markers
µ Blood
glucose regulation and metabolic derangement in diabetes mellitus
µ Cholesterol
metabolism
µ Disorders
associated with sulphur containing amino acids
µ Disposition
of ammonia from extra hepatic tissues to liver
µ Dyslipoproteinemia
µ Free
radicals and antioxidants
µ Free
radicals generation and its toxic effects
µ Heme
biosynthesis and its regulation
µ Iron
absorption and transport
µ Lipoproteins-
structure, types, metabolism, associated disorders and clinical significance
µ Mechanisms
for regulation of sodium and water in the body
µ Metabolic
reactions of glycine
µ Metabolism
and disorders associated with sulfur containing amino acids
µ Metabolism
of high density lipoprotein (HDL)
µ Metabolism
of xenobiotics
µ Polymerase
chain reaction and its complications
µ Purine
catabolism and gout
µ Recombinant
DNA technology and its applications
µ Regulation
of cholesterol biosynthesis
µ Regulatory
mechanisms of water and electrolyte balance in our body
µ Renal
regulation of pH
µ Role
of vitamins in preventing anemia
µ Structure
of DNA
µ Synthesis
of important biological substances from aromatic amino acids.
µ Transamination
µ Transamination
reaction and its importance
µ Translation
and post translational modifications
-------------------------------------------------------------------------------------------------------------
6.
Write short notes : (any three)
3x3=9
¬ Abnormal
constituents of urine
¬ Absorption
of amino acids
¬ Antioxidant
enzymes
¬ Body
buffers
¬ Calcium
¬ Carbohydrate
metabolism in RBC
¬ Carcinogenesis
¬ Chimeric
DNA
¬ Cholesterol
metabolism
¬ Chronic
complications of diabetes mellitus
¬ Conjugation
reaction
¬ Creatinine
clearance test
¬ Detoxification
of xenobiotics
¬ Dietary
fibers
¬ Dyslipoproteinemias
¬ Electron
transport chain
¬ ELISA
¬ Fatty
acid synthesis
¬ Free
radicals and antioxidants
¬ Fructose
metabolism
¬ Gene
therapy
¬ Glucose
tolerance test
¬ Glucose
transporters
¬ Glycolysis
¬ Iron
metabolism
¬ Ketogenesis
¬ Ketone
bodies form fuel of preference to brain tissue next to glucose
¬ Ketone
bodies synthesis
¬ Ketone
body formation and breakdown
¬ Lead
poisoning
¬ Lesch
nyhan syndrome
¬ Lipoprotein
lipase
¬ Metabolic
characteristics of liver
¬ Methyl
folate trap
¬ Methyl
malonic aciduria
¬ Milk
as a desirable food
¬ Mutations
¬ Oncogenes
¬ One
carbon group generation and utilization
¬ Oxidative
decarboxylation
¬ Oxidative
phosphorylation
¬ Polymerase
chain reaction and its applications
¬ Protein
calorie malnutrition
¬ Protein
digestion
¬ Protein
energy malnutrition
¬ Trace
elements
¬ Transamination
reaction and its importance
¬ Tumor
markers
