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BIOCHEMISTRY EXERCISES
The following exercises are based on the different topics (metabolism of Proteins, Carbohydrates, Lipids,
Nucleic acids, Hormones & Vitamins)
...
If any query, please do not hesitate to contact the lecturer
...
Differentiate the following biochemical terms and explain their physiological importance in
the functioning of the human body by giving at least 1 example of each term:
Anabolism and Catabolism
2
...

- Catabolic process of Hb in different organs of the human body (final products)
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a) Explain the process of digestion of the food protein
b) With your own food proteinic biomolecule (with 12 peptide bonds) in the human digestive
tract, explain precisely and in details the enzymatic catabolic processes of the food
proteins
...
Metabolism of amino acids: explain the mechanism of the following reactions and (by giving
at least 2 own examples of your own choice) explain their physiological importance in the
functioning of the human body: Transamination, deamination, decarboxylation
...
a) Differentiate the terms essential amino acids and non-essential amino acids by giving
examples for the human beings
...

6
...

a
...
Transamination


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A + Glyoxylate Transamination
c
...
+ ………………………


...
……………… Deamination

pyruvate+
...
E Decarboxylation
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F Decarboxylation
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Explain the way of synthesis and physiological importance of gluthation & creatin
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Explain how the metabolic diseases known as phenylketonuria, alcaptonuria & scorbut can
occur in the human body using the catabolic processes of F & Y
...
Explain in details the cause of appearance of the following metabolic disorders (diseases)
(link them with the corresponding enzymes and the reacion this enzyme should normaly
1

catalyse): phenylketonuria, alcaptonuria, scorbut, albinism using the metabolism of aminoacids
in the human body
...

10
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Explain how G & Q are involved in the processes of detoxication of the human body
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Explain precisely and in details the triple physiological importance of Y in the human body
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Detoxification of the human body: explain how ammonia (product of deamination of amino
acids) is transformed into urea cycle (one ways of elimination of toxic ammonia)
...
In the cases of malnutrition or undernutrition, the human body can make the arrangements
(in the term of his needs) for converting the proteins into carbohydrates or into lipids, the
carbohydrates into lipids and vice versa
...

15
...

16
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(1/2 page)
...
Metabolism of amino acids: explain the mechanism of the following reactions and (by giving
your own two examples of your choice) explain their physiological importance in the
functioning of the human body: Transamination, deamination, decarboxylation
...
Name at least 6 proteinic hormones (hormone<60 aminoacids) and explain their
physiological importance
...
Explain in details the cause of appearance of the following metabolic disorders (diseases)
(link them with the corresponding enzymes and the reacion this enzyme should normaly
3

catalyse): phenylketonuria, alcaptonuria, scorbut, albinism using the metabolism of aminoacids
in the human body
...
a) Read and understand the chemical structure of following food carbohydrates
...
(1 page)
...
The human body has involved one molecule of glucose in the cellurar aerobic respiration to
produce the maximum amount of energy (38 ATPs) needed in various cellular activities:
Explain and show how these energetic molecules are produced by indicating the precise steps
on which these ATPs are synthetized
...
(4 marks)
S/N Step

No
...
Explain the process of conversion of galactose into glucose
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23
...
This conversion occurs through a series of steps
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24
...
The human body has involved one molecule of glucose in the cellurar aerobic respiration to
produce the maximum amount of energy (38 ATPs) needed in various cellular activities:
Explain and show how these energetic molecules are produced by indicating the precise steps
on which these ATPs are synthetized
...
Explain briefly the following biochemical processes and explain their physiological
importance in the functioning of the human body: aerobic cellular respiration (= Glycolysis +
Krebs cycle)
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Explain lactic and alcoholic fermentations
...
Fill in the blanks accordingly:
a
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glycogenolysis glycogen (n–1 residues) +
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Glucose-6-phosphate the complete oxidative phase of PPPW
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The biochemical process facilitating the temporally storage of the dietary
monosaccharides not immediately used by the body is …………………………………
d
...

28
...
Explain briefly the following biochemical processes and explain their physiological
importance in the functioning of the human body: Glycogenesis & Pentose-Phosphate
Pathway (for PPPW explain at least triple role)
...
Explain briefly the following biochemical processes and explain their physiological
importance in the functioning of the human body: Glyconeogenesis & Glycogenolysis
31
...
Albinism
2
...
Oxytocin
4
...
Glycogenesis
6
...
Taurochalate of sodium
8
...
Glutamine
10
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Is a hypoglycemic process decreasing the level of
glucose in blood
B
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Is a metabolic disorder caused by the deficiency of
tyrosinase in the body
D
...
Participates in digestion of dietary polymers in the
human gastrointestinal tract
F
...
Increases the glucose level in blood by stimulating
glycogenolysis
H
...
produces the molecules of pentose-phosphates which
are essential for the synthesis of nucleotides and
nucleic acids
J
...
The molecules of acetyl-coA produced by β-oxidation can be used by the human body in
different ways for synthesis of biomolecules
...

33
...

34
...

35
...
Define the term avitaminosis
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Explain briefly the process of β-oxidation of fatty acids
...

37
...

38
...
Explain the role of Krebs cycle in the
oxidation of fatty acids and explain the completely oxidation of these two fatty acids
...
Explain in details the process of ketogenesis and explain its physiological importance
...
Explain precisely how acetoacetate can be used by some organs to produce the energy ATP
...
Explain and compare the structures of nucleic acids (DNA, mRNA, rRNA, tRNA) and explain
their main functions in the functioning of the human body
...
In the cases of malnutrition or undernutrition, the human body can make the arrangements
(in the term of his needs) for converting the proteins into carbohydrates or into lipids, the
carbohydrates into lipids and vice versa
...

43
...
Finally, calculate the total number of ATPs gained by the cell
...
Explain the enzymatic digestion of the following food lipids in the human digestive tract (by
indicating exactly the bonds to be broken down): triglyceride, phophatidylcholine
...
Explain the enzymatic digestion of the following food lipids in the human digestive tract (by
indicating exactly the bonds to be broken down): triglyceride, phophatidylcholine
...
List 8 steroid hormones (2 specific only for males, 2 specific only for females, 4 common for
both males & females) synthesized from cholesterol molecules, indicate the site (organ) of
synthesis organs and explain precisely the main physiological role of each hormone in the
functioning of the human body
...
The living cells of the human body use mainly the carbohydrates and lipids (and sometimes
aminoacids) to produce the energy (ATPs) needed in the various cell activities; and it is
known that lipids produce more energy than carbohydrates
...

48
...
Briefly describe the following biochemical terms linked to the structure and physiological
roles of nucleic acids in the functioning of the human body:
S/N
1
2
3
4

Biochemical terms
Transcription
Translation
Complementarity in DNA molecule
Genetic code

Brief description

50
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A cell has completely oxidized one molecule of fructose and one molecule of octadecanoate to
produce the maximum amount of energy: explain and show how the lipids produce more
energy than carbohydrates by indicating the energy yield per carbon atom for lipids and for
carbohydrates
...
Briefly describe the following metabolic processes and explain their main physiological
importance in the functioning of the human body
...
Match the following hormones with their corresponding functions in the functioning of the
human body
...
Antidiuretic Hormone
2
...
Glucagon
4
...
Prolactin
6
...
Insulin
8
...
It stimulates the the growth and development of the
1=
male reproductive organs and promotes an increase in
2=
muscle mass and strength
3=
B
...
It is used to cause contraction of the uterus in order 6=
to start labor or increase the speed of labor, and to
7=
stop bleeding following delivery
8=
D
...
It is needed to conserve body water by reducing the
loss of water in urine
F
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It is needed to decrease the level of glucose in the
bloodstream
H
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Fill in the blanks accordingly:
A
...
…………
B
...

C
...
The biochemical process by which the molecules of acetyl-CoA which are not immediately
used by the human body are stored is ………………
...
is a congenital metabolic disorder caused by the deficiency of the enzyme
“phosphogalactose uridyl transferase”
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The process of the transfer of genetic information from DNA to mRNA is called …………
54
...
Explain the physiological roles of the water soluble vitamins in the
human body and explain the consequences linked to the deficiencies of those vitamins
...
The monomers for the nucleic acids are called_________
a
...
Sugars
c
...
Nucleotides
56
...
Most RNA usually occurs in the cytoplasm while a very little RNA is found inside
nucleus
b
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RNA contains the genetic information
d
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The two polynucleotidic chains of DNA are linked together by:
a
...
Hydrogen bonds
c
...
Ionic bond
58
...

b
...

d
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The term “metabolism” refers to _______
a
...
the synthesis of big molecules from simpler molecules
...
the breakdown of big molecules into small molecules
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the anabolic and catabolic processes
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Nutritional polysaccharides are ______
a
...
starch and chitin
c
...
starch and glucose
61
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liver and muscles
b
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Muscles and bile
d
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The association between the sugars and proteins makes _______
a
...
glycoproteins
c
...
ganglioside
63
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Glycolysis, β-oxidation, Krebs cycle, Electron transport system
b
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β-oxidation, Glycolysis, Krebs cycle, Electron transport system
d
...
A living cell involves a C26 saturated fatty acid in β-oxidation for getting an amount of ATPs to
use in different cell activities: how many rounds of β-oxidation are needed to convert C26
saturated fatty acid into the molecules of acetyl-CoA and how many molecules of acetyl-CoA
are produced?
a
...
11 rounds and 12 acetyl-CoA
c
...
None of the above
65
...
60
b
...
216
d
...
In the human digestive tract the food glycogen is digested respectively by the following
enzymes:
a
...
α-amylase, maltase, amylo-α-1,4 glycosidase, ,
c
...
α-amylase, amylo-α-1,6 glycosidase, maltase
67
...
the digestion of the food polymers into monomers
b
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the synthesis of big molecules from simpler molecules
...
the breakdown of big molecules into small molecules
...
The highly branched polymer of glucose molecules is ______________
a
...
Starch
c
...
amylose
11

69
...
Pepsin
b
...
Invertase
d
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Nutritional polysaccharides for the human beings are ______
a
...
starch and chitin
c
...
None of the above
71
...
Alcoholic fermentation
b
...
Krebs cycle
d
...
In the human body the essential aminocids are always provided by ____________
a
...
Glucogenic aminoacids
c
...
None of the above
73
...
Glycolysis
b
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Glycogenesis
d
...
Glucogenic aminoacids are_______________
a
...
aminoacids that can be used to convert the proteins to carbohydrates
c
...
Both A and B are correct
75
...
liver and pancreas
b
...
liver and muscles
d
...
The main function of Hb in the human body is ___________
a
...
to carry CO2 molecules from the tissue cells to the lungs
c
...
Both A and B are correct
77
...
spleen, liver, small intestine
b
...
blood, liver, kidney
d
...
Which of the following compunds is involved in the catabolism of Hb in he human body?
a
...
Glucuronic acid
c
...
Gluconic acid
79
...
Glyconeogenesis
b
...
Glycogenesis
d
...
In microorganisms the process of anaerobic glycolysis is followed by_____________
a
...
Krebs cycle
c
...
Alcoholic fermentation
81
...
breakdown the food proteins to monomers
b
...
synthesize the needed energy
d
...
In the human digestive tract the food glycogen is digested respectively by the following
enzymes:
a
...
α-amylase, maltase, amylo-α-1,4 glycosidase, ,
c
...
Lactase, invertase, α-amylase, amylo-α-1,6 glycosidase, maltase
83
...
α-ketoacid
b
...
γ-aminobutyrate
d
...
The dephosphorylation of Glc-6-P in the liver functions to allow the glucose molecules _______
a
...
to enter different pathways inside the hepatocytes
c
...
None of the above
85
...
2 α chains and 2 γ chains
b
...
2 β chains and 2 γ chains
d
...
The association between the sugars and proteins makes _______
a
...
galactosides
c
...
ganglioside
87
...
Testosterone
b
...
Progesterone
d
...
Which of the following is a nucleic acid involved in the transfer of genetic information from
the nucleus to the cytoplasm of an eukaryotic cell?
a
...
RNAm
c
...
RNAt
89
...
Vitamin B6
b
...
Vitamin B12
d
...
Which of the following fatty acids is essential for the human beings_______
a
...
Palmitic acid
c
...
Linoleic acid
91
...
Transcription
b
...
RNA polymerase
d
...
Translation is a process of transferring the genetic information from RNAm to RNAt is
called_________
a
...
RNAt to RNAr
c
...
DNA to RNAm
93
...
Globin
b
...
Stercobilin
d
...
Which of the following is NOT a ketone body?
a
...
Acetyl-CoA
c
...
Β-hydroxybuturate
95
...
Glycolipide
b
...
PAF acether
d
...
It is a lipidic compound that acts as the myelin sheath in the nervous system:
a
...
Glyceride
c
...
Leukotriene
97
...
DNA usually occurs inside nucleus and some cell organelles
b
...
Purine and Pyrimidine bases of DNA are in equal number
d
...
The equation C6H12O6+6O6
6CO2+6H2O+energy (ATP) refers to _______
a
...
Aerobic glycolysis, Pentose phosphate pathway and Krebs cycle
c
...
Cellular aerobic respiration

99
...
spleen, liver, small intestine
b
...
blood, liver, kidney
d
...

a
...

c
...


In the adult humans one molecule of Hb contains normally __________
2 α chains and 2 γ chains
2 α chains and 2 β chains
2 β chains and 2 γ chains
None of the above

101
...
A-G-C-T-A-T-C-G
...
A-G-C-A-T-A-C-C
b
...
T-C-G-A-T-A-G-C
d
...
Metabolism of aminoacids: α-ketoglutarate is a predominant amino-acceptor in the
transamination reactions where it replaces its ketone group by amino group and becomes:
a
...
α-ketoacid
c
...
glutamate
103
...
synthesize the non-essential amino acids
16

b
...
synthesize the needed energy
d
...
The dephosphorylation of Glc-6-P in the liver functions to allow the glucose molecules _______
a
...
to enter different pathways inside the hepatocytes
c
...
None of the above
105
...
Urea cycle nitrogen
b
...
Uric acid nitrogen
d
...
The process in which the genetic information is transferred from DNA to RNA is called ______
a
...
transcription
c
...
translation
107
...
replication
b
...
translation
d
...
Which of the following biochemical processes is NOT hypoglycemic?
a
...
Pentose phosphate pathway
c
...
Glycogenesis
109
...
to carry O2 molecules from the lungs to the tissue cells
b
...
to carry blood from the heart to the tissue cells and lungs
d
...
Which of the following biocompunds is involved in the catabolism of Hb in the human body?
a
...
Triglyceride
c
...
Glucuronic acid
111
...

2
...

4
...
Prevention of oxidative damage
B
...
Vision
D
...
The term “metabolism” refers to _______
a
...
the anabolic and catabolic processes
c
...

d
...

113
...
Transamination
b
...
Taken food
d
...
Metabolism of aminoacids: transamination reactions can be used by the living cells to _______
a
...
synthesize the non-essential amino acids
c
...
Both B and C are correct
115
...
to carry O2 molecules from the lungs to the tissue cells
b
...
to carry blood from the heart to the tissue cells and lungs
d
...
Metabolism of aminoacids: α-ketoglutarate is a predominant amino-acceptor in the
transamination reactions where it replaces its ketone group by amino group and becomes:
a
...
α-ketoacid
c
...
γ-aminobutyrate
117
...
2 α chains and 2 γ chains
b
...
2 β chains and 2 γ chains
e
...
Which of the following is a lipidic compound that is involved in the process of blood clotting?
a
...
Fatty acid
c
...
PAF acether
119
...
Oleate
b
...
Stearate
d
...
Which of the following is NOT a ketone body?
a
...
Acetate
c
...
β-hydroxybyturate
121
...
precursor to bile salts
b
...
moderator of the membrane fluidity
d
...
Deamination reactions of the aminoacids can be used by the living cells to _______
a
...
convert the proteins to lipids or carbohydrates
c
...
Among the different types of lipids the most commonly occurring lipids are: _______
a
...
fatty acids or ester of fatty acids
c
...
Both a and b are correct
124
...
Creatine
b
...
Sphingosine
d
...
The process of transfer of genetic information from DNA to RNAm is commonly known as
______
a
...
Transcription
c
...
Translation
126
...
Vitamin B12
b
...
Vitamin K
d
...


128
...
it is an antioxidant as it accepts and donates electrons
b
...
it assists in differentiation and maturation of tissues and organs during embryonic growth
d
...
A-C-T-A-G-C-T-C-G-A-C-G
...
T-G-A-T-C-G-T-G-C- T-G-C
b
...
T-G-A-T-C-G-A-G-C-A-G-T
d
...


Which of the followings is the final product of HB degradation in the liver?
a
...
Urobilin
c
...
Bilirubin

130
...
Glycerolipids
b
...
Cholesterol
d
...
In the human body the glycogen molecules are mainly stored in _______
e
...
liver and muscles
g
...
liver and adipose tissues
132
...
to carry O2 from lungs to tissue cells
20

b
...
to carry O2 from lungs to tissue cells and CO2 from tissue cells to the lungs
d
...
Which of the following hormones stimulates the process of preparation of uterus to
implantation and maintenance of endothelium?
a
...
Cortisol
c
...
Progesterone
134
...
Vitamins are organic compounds that are required for the maintenance of normal health
and metabolic integrity
b
...
Vitamins are not catabolized to satisfy part of the energy requirement and are not used for
structural purposes
d
...

Which of the following is involved in the emulsification of lipids in the human
digestive tract?
a
...
Bile salts
c
...
Cholesterol
136
...

b
...

d
...

f
...

h
...


138
...
carbamoylphosphate
b
...
ammonia
21

d
...
The human body completely oxidizes one molecule of 4,7,11-trimethyl-palmitate to get a
sufficient amount of ATPs to be used in different cell activities:
(3 marks)
i
...
8 rounds of β-oxidation
f
...
7 rounds of β-oxidation
h
...
how many molecules of acetyl-CoA are produced?
a
...
5 acetyl-CoA
c
...
6 acetyl-CoA
iii
...
116
b
...
126
d
...
Answer by True (T) or False (F) to the following questions
i
...

ii
...
4
(case of acidosis)
...
The synthesis of fatty acids from acetyl CoA (lipogenesis) takes place in mitochondria
(cytosol), uses reduced coenzyme NADPH2 and requires an acyl carrier protein
...
In the human body the process of lipogenesis is activated by glucagon and lower blood
glucose while β-oxidation is activated by insulin and high blood glucose
...
The proteins that are in the bloodstream, in the cells, and in the spaces surrounding the cells
work together to keep fluids moving across these spaces in the proper quantities to maintain
fluid balance and blood pressure
...
Cholesterol is an important lipidic compound in the functioning of the human body by the
fact that it is a precursor of many physiological substances like bile salts, reproductive
hormones and enzymes
...
The conversion of lipids to proteins and carbohydrates passes always through the reactions
of glyoxylate cycle and Krebs cycle where succinate is the key compound
...
The highly toxic ammonia in the human being is usually neutralized through urea cycle by
converting it to urate (urea) which will finally be excreted to outside the body through urine
...
Enzymes catalyze chemical reactions by lowering the activation energy (energy that is
required for a chemical reaction to occur)
...
At physiologic pH (pH 7
...

xi
...


xii
...


xiii
...


xiv
...


xv
...


xvi
...


23



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