100+ Free Bac Sciences Expérimentales Algeria Practice Questions

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2026 Statistics

Key Facts: Bac Sciences Expérimentales Algeria Exam

3 science papers

Natural sciences, physics-chemistry, and mathematics

Ministry of National Education timetable

Final-year 3AS

School-candidate level

Ministry registration directive

1,500 DZD

Standard registration fee for enrolled school candidates

Official Ministry Fee Directive

7–11 June 2026

Official national written examination session dates

ONEC National Exam Timetable

English-language 100-question MCQ study bank for Algeria's final-year 3AS Baccalauréat Sciences Expérimentales. The official examination is a five-day paper-based constructed-response session held 7–11 June 2026; this bank is not an official translation or format simulation.

Sample Bac Sciences Expérimentales Algeria Practice Questions

Try these sample questions to test your Bac Sciences Expérimentales Algeria exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1During transcription of genetic information in eukaryotic cells, which enzyme is directly responsible for synthesizing pre-mRNA by polymerizing ribonucleotides complementary to the template DNA strand?

A.RNA polymerase II

B.DNA polymerase III

C.DNA ligase

D.Reverse transcriptase

Explanation: RNA polymerase II is the primary eukaryotic enzyme responsible for transcribing protein-coding genes into precursor messenger RNA (pre-mRNA). It reads the DNA template strand in the 3' to 5' direction and synthesizes the RNA transcript in the 5' to 3' direction using ribonucleoside triphosphates.

2Which sequence of molecular modifications converts eukaryotic precursor mRNA (pre-mRNA) into mature mRNA capable of being exported from the nucleus to the cytoplasm?

A.Removal of exons, addition of a 3' inverted guanosine cap, and circularization of the transcript

B.Addition of a 5' 7-methylguanosine cap, addition of a 3' poly-A tail, and splicing out of non-coding introns

C.Cleavage of the promoter region, phosphorylation of adenine residues, and methylation of all uracil bases

D.Binding to the small ribosomal subunit, translation of leader sequences, and exon ligation

Explanation: In eukaryotic post-transcriptional processing, primary pre-mRNA undergoes 5' capping with 7-methylguanosine (protecting the 5' end and facilitating translation initiation), 3' polyadenylation with a poly-A tail (providing nuclear export and stability), and spliceosome-mediated splicing to excise non-coding introns and join coding exons.

3An mRNA codon changes from GAA to GAG, but the translated amino acid remains glutamate. Which property of the genetic code explains this result?

A.A single codon can specify multiple distinct amino acids depending on cellular conditions

B.Codons overlap along the mRNA strand so that adjacent nucleotides participate in two codons

C.Multiple distinct codons can code for the same amino acid

D.Stop codons mutate spontaneously into initiation codons during stressful conditions

Explanation: Both GAA and GAG specify glutamate. The existence of multiple codons for the same amino acid is called degeneracy or redundancy. The code remains unambiguous because each individual codon specifies only one amino acid.

4During amino acid activation (aminoacylation) prior to translation, what specific biochemical event occurs to couple the amino acid to its cognate tRNA?

A.GTP hydrolysis forms a peptide bond between the amino acid carboxyl group and the tRNA anticodon loop

B.The amino acid is phosphorylated at its amino group and spontaneously binds the 5' triphosphate end of tRNA

C.Peptidyl transferase creates an amide linkage between the tRNA D-loop and the amino acid side chain

D.Aminoacyl-tRNA synthetase uses ATP to form an ester bond between the amino acid carboxyl group and the 3'-CCA hydroxyl end of tRNA

Explanation: Aminoacyl-tRNA synthetase enzymes ensure fidelity by activating each amino acid using ATP to form an aminoacyl-AMP intermediate, then transferring the amino acid to the 2' or 3' hydroxyl group of the adenosine nucleotide at the conserved 3'-CCA terminus of the cognate tRNA, producing an energetic ester bond.

5Which event marks the successful initiation phase of translation in eukaryotic protein synthesis?

A.Release of the completed polypeptide chain by eukaryotic release factors (eRF)

B.Binding of the small ribosomal subunit and initiator tRNA to the 5' AUG codon, followed by recruitment of the large ribosomal subunit

C.Formation of a covalent disulfide bond between the first two incoming amino acids in the E site

D.Translocation of the uncharged tRNA directly from the A site to the extracellular matrix

Explanation: Translation initiation begins when the small (40S) ribosomal subunit, preloaded with initiator Met-tRNA, binds to the 5' cap of mRNA, scans for the start codon (AUG), and forms base pairs. The large (60S) subunit then joins, positioning the initiator tRNA in the P site and creating a functional 80S initiation complex.

6During the elongation phase of translation, which ribosomal component catalyzes the formation of the peptide bond between the amino acid in the A site and the growing polypeptide chain in the P site?

A.DNA helicase situated in the ribosomal exit channel

B.Aminoacyl-tRNA synthetase associated with the 40S subunit

C.Peptidyl transferase, an RNA enzyme (ribozyme) catalytic center of the large ribosomal subunit

D.Elongation factor G acting exclusively as a proteolytic cleavage enzyme

Explanation: Peptidyl transferase activity is intrinsic to the 28S ribosomal RNA (in eukaryotes) of the large ribosomal subunit, demonstrating that the ribosome is a ribozyme. It catalyzes the nucleophilic attack of the amino group of the aminoacyl-tRNA in the A site on the ester carbon of the peptidyl-tRNA in the P site.

7Under electron microscopy, a polyribosome (polysome) appears as an mRNA strand associated with several ribosomes simultaneously. What is the functional significance of this structure?

A.It enables rapid and simultaneous synthesis of multiple identical copies of the same polypeptide from a single mRNA molecule

B.It allows each attached ribosome to produce a completely different protein with unrelated amino acid sequences

C.It prevents mRNA degradation by completely halting translation until environmental stress passes

D.It facilitates the reverse transcription of mRNA back into nuclear genomic DNA

Explanation: As soon as the first ribosome moves past the start codon, another ribosome can assemble and initiate translation on the same mRNA. A polysome allows a cell to amplify translation efficiency, synthesizing many identical polypeptide chains concurrently from a single transcript before it is degraded.

8A single nucleotide substitution in an exon changes the codon UAC (tyrosine) into UAA. What type of mutation is this, and what is its expected phenotypic consequence?

A.Silent mutation; the protein retains full length and wild-type enzymatic activity

B.Frameshift mutation; the reading frame shifts downstream, altering all subsequent amino acids

C.Missense mutation; a single nonpolar amino acid replaces tyrosine without truncating the chain

D.Nonsense mutation; UAA acts as a stop codon, causing premature termination and yielding a truncated, usually nonfunctional protein

Explanation: UAA is one of three termination codons (along with UAG and UGA). A point mutation that converts an amino acid codon into a stop codon is a nonsense mutation. Translation halts prematurely at this position, producing a truncated polypeptide that typically lacks functional activity and is rapidly degraded.

9The biological activity of a globular enzyme depends on its specific tertiary conformation. Which types of chemical interactions are primarily responsible for stabilizing this three-dimensional folding?

A.Continuous covalent peptide bonds linking adjacent alpha-carbons along the backbone only

B.Phosphodiester linkages and glycosidic bonds formed between lipid side chains

C.Hydrophobic interactions, hydrogen bonds, ionic bonds, and covalent disulfide bridges between cysteine R-groups

D.Magnetic interactions between iron ions and nuclear histone complexes

Explanation: Tertiary structure arises from interactions between the variable side chains (R-groups) of amino acids. Non-covalent forces (hydrophobic collapse in the protein core, hydrogen bonding, and electrostatic salt bridges) alongside strong covalent disulfide bonds (-S-S-) between oxidized cysteine residues stabilize the functional native conformation.

10An amino acid with an uncharged, non-ionizable side chain (such as alanine) is placed in an aqueous solution where the pH equals its isoelectric point (pI). What is the predominant ionic state and net charge of this amino acid?

A.Zwitterion (dipolar ion) with a protonated amino group (-NH3+) and a deprotonated carboxyl group (-COO-), giving a net charge of 0

B.Cation with a protonated amino group (-NH3+) and a neutral carboxyl group (-COOH), giving a net charge of +1

C.Anion with a neutral amino group (-NH2) and a deprotonated carboxyl group (-COO-), giving a net charge of -1

D.Fully uncharged molecule with neutral -NH2 and neutral -COOH groups, giving a net charge of 0

Explanation: At its isoelectric point (pI), an amino acid exists predominantly as a zwitterion (dipolar ion). The alpha-carboxyl group is deprotonated (-COO-, pKa ~ 2.3) while the alpha-amino group is protonated (-NH3+, pKa ~ 9.7). The equal and opposite charges cancel out, resulting in a net electrical charge of zero and zero electrophoretic mobility.

About the Bac Sciences Expérimentales Algeria Exam

The Algerian Baccalauréat Série Sciences Expérimentales is the national secondary-school-leaving examination for final-year 3AS (Terminale) lycée students in the experimental sciences stream. Governed by the Ministry of National Education and administered by ONEC, its official five-day session includes natural and life sciences, physics-chemistry, mathematics, and compulsory language and humanities papers. This collection is an English-language four-option MCQ study adaptation for the official 3AS curriculum; it is neither an official translation nor a format simulation of the constructed-response exam.

Assessment

Five-day national written session administered by ONEC from 7–11 June 2026. The official timetable includes natural and life sciences, physics-chemistry, mathematics, Arabic, French, English, philosophy, history-geography, Islamic sciences, and Tamazight where applicable; paper durations vary by subject. This bank is an English-language MCQ study adaptation, not an official translation or format simulation.

Time Limit

5-day national written examination session held 7–11 June 2026; paper durations vary by subject.

Passing Score

No current pass mark was published in the official 2026 sources reviewed.

Exam Fee

1,500 DZD (schooled candidates). Free candidates without prior Bac: 3,000 DZD (attempts 1–2), 5,000 DZD (attempt 3), 10,000 DZD (attempt 4), 20,000 DZD (attempt 5+). Free candidates with prior Bac: 5,000 DZD (attempt 2), 10,000 DZD (attempt 3), 20,000 DZD (attempt 4+). (Office National des Examens et Concours (ONEC), Ministry of National Education)

Bac Sciences Expérimentales Algeria Exam Content Outline

30%

SVT: Molecular & Cellular Biology

Protein synthesis mechanisms (transcription, RNA processing, translation, genetic code), enzyme kinetics, allosteric regulation, cellular respiration, glycolysis, Krebs cycle, electron transport chain, and photosynthetic carbon assimilation.

25%

SVT: Physiology, Immunology & Geology

Neurobiology (resting and action potentials, ion channels, synapse mechanics, reflex arc), immunology (self vs non-self markers, MHC-I/II, humoral antibody response, cytotoxic T lymphocytes, HIV retroviral infection), and plate tectonics (subduction zones, collision orogeny, calc-alkaline magmatism).

25%

Physics & Chemistry

Newton's second law, linear motion with drag, projectile trajectories, Kepler's planetary laws, RC and RL electrical circuits, radioactive half-life and decay laws, mass defect and nuclear binding energy, chemical reaction kinetics, esterification-hydrolysis equilibria, and pH titrations.

10%

Mathematics for Sciences

Natural logarithm and exponential functions, limits, derivatives, integration by parts, first-order differential equations, arithmetic and geometric sequences, and combinatorics / discrete probability.

10%

General Core & Humanities

Arabic language and literary analysis, philosophy of the experimental method (Claude Bernard, scientific determinism, hypothesis testing), French, English, history of Algerian liberation, and world geopolitical geography.

How to Pass the Bac Sciences Expérimentales Algeria Exam

What You Need to Know

Passing score: No current pass mark was published in the official 2026 sources reviewed.
Assessment: Five-day national written session administered by ONEC from 7–11 June 2026. The official timetable includes natural and life sciences, physics-chemistry, mathematics, Arabic, French, English, philosophy, history-geography, Islamic sciences, and Tamazight where applicable; paper durations vary by subject. This bank is an English-language MCQ study adaptation, not an official translation or format simulation.
Time limit: 5-day national written examination session held 7–11 June 2026; paper durations vary by subject.
Exam fee: 1,500 DZD (schooled candidates). Free candidates without prior Bac: 3,000 DZD (attempts 1–2), 5,000 DZD (attempt 3), 10,000 DZD (attempt 4), 20,000 DZD (attempt 5+). Free candidates with prior Bac: 5,000 DZD (attempt 2), 10,000 DZD (attempt 3), 20,000 DZD (attempt 4+).

Keys to Passing

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

Bac Sciences Expérimentales Algeria Study Tips from Top Performers

1Dedicate substantial study time to SVT document analysis: practice formulating structured responses identifying experimental observations, logical deductions, and summary interpretations.

2Consistently verify physical units and algebraic derivations when solving mechanics and circuit problems, especially RC time constants and Newton's second law integrations.

3Work through past official Baccalauréat papers to master the standard French/Arabic scientific terminology and understand recurring exam themes in enzyme kinetics and immunology.

4Review properties of exponential and logarithmic functions thoroughly, focusing on composite limits, asymptotes, and solving first-order differential equations.

Frequently Asked Questions

What is the Algerian Baccalauréat Série Sciences Expérimentales?

It is the national secondary-school-leaving examination for final-year 3AS (Terminale) lycée students enrolled in the experimental sciences stream. Administered by the Office National des Examens et Concours (ONEC), it certifies completion of secondary education and determines admission into higher education programs, most notably medical, pharmaceutical, and scientific faculties.

Is the official Algerian Baccalauréat an MCQ examination?

No. The official Algerian Baccalauréat consists exclusively of paper-based, constructed-response written examinations featuring multi-part scientific problem sets, biological document analyses, and long-form calculations. This 100-question practice bank is an English-language study adaptation created for self-paced review and conceptual reinforcement; it is neither an official translation nor a format simulation.

Which scientific papers appear in the official 2026 Sciences Expérimentales timetable?

The timetable lists natural and life sciences, physics-chemistry, and mathematics, alongside the compulsory language and humanities papers. The official sources reviewed did not publish subject coefficients.

What are the registration fees for the 2026 Baccalauréat?

Under official Ministry directives, registered school candidates pay 1,500 DZD. Free candidates (candidats libres) without a prior Bac pay 3,000 DZD for their 1st and 2nd attempts, 5,000 DZD for their 3rd attempt, 10,000 DZD for their 4th attempt, and 20,000 DZD for attempt 5 and beyond. Free candidates who already hold a Bac pay 5,000 DZD for their 2nd attempt, 10,000 DZD for their 3rd attempt, and 20,000 DZD for attempt 4 and beyond.

What pass mark applies to the 2026 Baccalauréat?

The current official 2026 sources reviewed did not publish a pass mark, so this study page does not state one.