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المركز الوطني للتقويم واالمتحانات
والتوجيه
االمتحان الوطني الموحد للبكالوريا
المسالك الدولية – خيار أنجليزية
الدورة العادية 2018
-الموضوع- NS34E
علوم الحياة واألرض
شعبة العلوم التجريبية : مسلك العلوم الفيزيائية – خيار أنجليزية
المادة
الشعبة أو المسلك
مدة اإلنجاز
المعامل
5
3
Candidates may use non-programmable calculators
Section I : Knowledge Retrieval (5 pts)
I. Define the following notions: - Alcohol fermentation. - Oxidative phosphorylation. (1 pt)
II. For each of the following propositions numbered from 1 to 4, there is only one correct suggestion in each
set. Copy down these pairs (1; ..), (2; ..), (3; ..), (4; ..), and match each number with its corresponding
letter. (2 pts)
1- The transformation of a glucose molecule into
tow molecules of pyruvic acid at the level of
hyaloplasm is accompanied by a/an:
a. reduction of 2 NADH,H+ and production of 4 ATP.
b. oxidation of 2 NADH,H+ and production of 4 ATP.
c. oxidation of 2 NAD and production of 2 ATP.
d. reduction of 2 NAD and production of 2 ATP.
2. The activity of the respiratory chain leads
to a/an:
a. increase in proton concentration in the matrix.
b. decrease in proton concentration in the matrix.
c. increase in proton concentration in the
intermembrane space.
d. decrease in proton concentration in the
intermembrane space.
3- The steps of muscle contraction are :
1- the fixation of ATP on the myosin heads;
2- hydrolysis of ATP ;
3- rotation of myosin heads ;
4- release of Ca2+ ;
5- formation of actomyosin complex ;
6- sliding of actin filaments towards the centre of the
sarcomere.
The correct chronological sequence is:
a. 3 → 6 → 4 → 1 → 2→ 5
b. 6 → 4 → 1 → 5→ 2 → 3
c. 4 → 5 → 2→ 3 → 6 →1
d. 1→ 2 → 3 → 6 → 4 → 5.
4- During phosphorylation of ADP, the
proton gradient created by the respiratory
chain is used by :
a. the proton channels of the mitochondrial
inner membrane.
b. the ATP synthase of the mitochondrial inner
membrane.
c. the electron carriers of the mitochondrial
inner membrane.
d. the coenzymes of the mitochondrial inner
membrane.
III. Copy down on your exam sheet the number corresponding to each proposition and write whether
the statement is “true” or “false”. (1 pt)
1. In the muscle cell, the renewal of ATP from phosphocreatine is due to the intervention of ATP synthase.
2. In the matrix, the oxidation of NADH,H+ is due to the intervention of the dehydrogenases.
3. In the hyaloplasm, alcohol fermentation produces an organic residue and releases CO2.
4. In the mitochondria, pyruvic acid is converted to acetyl CoA.
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االمتحان الوطني الموحد للبكالوريا - الدورة العادية 2018 – الموضوع
- مادة: علوم الحياة واألرض – شعبة العلوم التجريبية مسلك العلوم الفيزيائية – خيار أنجليزية
NS34E
Glucose concentration
in blood (mmol/L)
Glucokinase activity
in the liver (A U)
Document 2
1.00
0.75
0.50
50.5
0
0.25
50.5
0 5 10 15 20 25
Healthy
individual
Individual affected by
Mody-2
IV. Match each recorded myogram (Group 1) to the corresponding state of stimulations applied on the
muscles (Group 2). Copy down these pairs (1; ..), (2; ..), (3; ..), (4; ..), and match each number to its
corresponding letter. (1 pt)
Mody-2 diabetes (Maturity Onset Diabetes of the Young) affects some people before the age of 20.
People with this disease suffer from permanent hyperglycemia.
In order to highlight the genetic origin of this disease, we suggest the following data:
The glucose is stored in the liver as glycogen (glycogenesis) by the intervention of a set of enzymes.
Glucokinase is one of such enzymes. Document 1 shows the level of intervention of glucokinase in the
chain of reactions of glycogenesis.
The measurement of glucokinase activity in the liver
in a healthy individual and in another individual affected
by Mody-2 has given the results presented in document 2.
1. Based on documents 1and 2:
a- Describe the glucokinase activity variations in the
healthy individual and in the individual affected by
Mody-2. (0.5 pt)
b- Explain the permanent hyperglycemia in the
individual affected by Mody-2. (0.5 pt)
Section II : Scientific reasoning and communication in graphic and written modes (15 pts)
Exercise 1 (2.5 pts)
Group 1: Recorded myogram. Group 2 : Application of 2 effective stimulations on
the muscle.
1- Complete fusion of two muscle
twitches.
a- The second stimulation is applied after completion of the
first muscle twitch.
2- Incomplete fusion of two muscle
twitches.
b- The second stimulation is applied during the latent period
of the first muscle twitch.
3- Two isolated muscle twitches. c- The second stimulation is applied during the contraction
period of the first muscle twitch.
4- One isolated muscle twitch.
d- The second stimulation is applied during the relaxation
period of the first muscle twitch.
Glucose Glucose-6P Glucose-1P UDP-Glucose Glycogen
Glucokinase Enzyme 1 Enzyme 2 Enzyme 3
Document 1
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االمتحان الوطني الموحد للبكالوريا - الدورة العادية 2018 – الموضوع
- مادة: علوم الحياة واألرض – شعبة العلوم التجريبية مسلك العلوم الفيزيائية – خيار أنجليزية
NS34E
To know the origin of this disease, we suggest documents 3 and 4.
Document 3 presents part of a transcribed strand of the gene coding for glucokinase in a healthy individual
and in another individual affected by Mody-2, and document 4 gives an extract of the genetic code.
2 . Based on documents 3 and 4, determine the amino acid sequence corresponding to each part of the
gene coding for glucokinase in a healthy individual and in an individual affected by Mody-2. (0,5 pt)
3. Based on your previous answers, explain the genetic origin of Mody-2 disease. (1 pt)
In order to study the mode of transmission of the two hereditary characteristics (traits) in rabbits,
we suggest the exploitation of the results of the two following crosses:
- First cross between two pure lineages of rabbits: one lineage has long hair (angora) and a uniform
colour, and the other has short hair and variegated white colour.
The first generation obtained (F1) is composed of individuals with short hair and variegated white colour.
- Second cross between females of F1 and males with long hair (angora) and uniform colour.
This cross has given a generation F’2 composed of:
- 338 rabbits with short hair and variegated white colour;
- 341 rabbits with long hair and uniform colour;
- 12 rabbits with long hair and variegated white colour;
- 9 rabbits with short hair and uniform colour.
1 . Based on the results of the two crosses, determine the mode of transmission of the two hereditary
traits studied. (0.75 pt)
2. Interpret and use Punnett square to explain the results obtained in the second cross. (0.75 pt)
NB. Use the symbols L and l for ‘hair length’ trait and the symbols P and p for ‘hair colour’ trait.
3. Determine the phenomenon responsible for the appearance of rabbits with long hair and variegated
white colour and rabbits with short hair and uniform colour in generation F’2. Explain this phenomenon
by drawing a scheme. (1 pt)
Glu Met Val Stop Lys Ser Asp Gly Ala Amino acids
GCU
GCA
GCC
GCG
GGU
GGC
GGA
GGG
GAU
GAC
AGU
AGC
UCU
UCC
AAA
AAG
UAG
UAA
UGA
GUG
GUA
GUC
GUU
AUG GAA
GAG Codons
Document 4
Reading direction
277 278 279 280 281 282
Healthy individual : ...CAC CTG CTC TCG AGA CGT...
Individual affected by Mody-2 : ...CAC CTG ATC TCG AGA CGT...
Number of nucleotide triplets :
Document 3
Exercise 2 (2.5 pts)
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