Test d'entraînement MCAT

Tous les quiz en Médecine et pharmacie

• Test d'entraînement · 15 questions

  Questions d'entraînement MCAT

• Test d'entraînement · 15 questions

  Entraînement MCAT CARS

• Test d'entraînement · 15 questions

  Questions d'entraînement USMLE Step 1

Tout voir →

Crée le tien

Téléverse ton manuel, tes diapos ou tes notes, ou dis simplement à Bo ce que tu veux réviser. Aucun document n'est nécessaire pour commencer.

Créer mon propre test

Les 15 questions en un coup d'œil

Tu préfères lire avant de jouer ? Toutes les questions de l'échantillon sont listées ci-dessous. Les réponses et les explications restent repliées tant que tu ne les ouvres pas.

1. 1. A person meets the same pathogen for the second time and clears it far faster than the first time. Which feature of the immune system best explains the difference?

   • A. Neutrophils now reach the site of infection sooner than they did before
   • B. The complement system was permanently strengthened by the first exposure
   • C. Memory B and T cells left by the first exposure mount a faster and larger specific response
   • D. Physical barriers such as skin and mucus have adapted to that particular pathogen
   Voir la réponse et l'explication

   Réponse : C. Memory B and T cells left by the first exposure mount a faster and larger specific response

   Innate defenses, meaning barriers, phagocytes and complement, respond the same way every time and keep no record of what they met. The adaptive arm does keep a record, because clonal selection during the first exposure leaves behind long lived memory B and T cells specific to that antigen. On re-exposure those cells expand quickly, so antibody appears sooner and climbs higher, which is the secondary response. That is the effect vaccines are built to produce without the first illness.

2. 2. What is the net yield of glycolysis per molecule of glucose in the cytosol?

   • A. 2 ATP, 2 NADH and 2 pyruvate
   • B. 4 ATP, 2 NADH and 2 pyruvate
   • C. 2 ATP, 2 FADH2 and 2 lactate
   • D. 36 ATP, 2 NADH and 2 pyruvate
   Voir la réponse et l'explication

   Réponse : A. 2 ATP, 2 NADH and 2 pyruvate

   Substrate level phosphorylation makes four ATP in the payoff phase, but two are spent priming the sugar in the investment phase, so the net is two. Glycolysis also reduces two NAD+ to NADH and ends at two pyruvate. None of it needs oxygen, which is why a cell can run glycolysis when the electron transport chain is stalled, as long as it can regenerate NAD+ some other way.

3. 3. Which of the following are true of the tertiary structure of a globular protein?

   Coche toutes les bonnes réponses.

   • A. Hydrophobic side chains tend to cluster in the interior, away from water
   • B. It is determined mainly by hydrogen bonding between backbone amide and carbonyl groups
   • C. Disulfide bridges can form between cysteine residues that are far apart in the sequence
   • D. It refers to the association of two or more separate polypeptide chains
   • E. Salt bridges between oppositely charged side chains help hold the fold together
   Voir la réponse et l'explication

   Réponse : A. Hydrophobic side chains tend to cluster in the interior, away from water, C. Disulfide bridges can form between cysteine residues that are far apart in the sequence, E. Salt bridges between oppositely charged side chains help hold the fold together

   Tertiary structure is the three dimensional fold of one chain, and it is driven by side chain interactions: the hydrophobic effect burying nonpolar residues, disulfide bonds between cysteines, salt bridges, and hydrogen bonds between side chains. Backbone hydrogen bonding is what defines secondary structure, the helices and sheets. Two or more chains coming together is quaternary structure.

4. 4. Complete the sentence.

   In oxidative phosphorylation, electrons passed down the chain are finally handed to _____, and the proton gradient across the inner mitochondrial membrane drives _____.

   Options pour le trou 1 : carbon dioxide, oxygen, NAD+, pyruvate

   Options pour le trou 2 : ATP synthase, the citric acid cycle, glycolysis

   Voir la réponse et l'explication

   Réponse : oxygen, ATP synthase

   Oxygen is the terminal electron acceptor and combines with protons to form water, which is why the whole chain backs up without it. The energy released as electrons fall is used to pump protons out, storing energy as an electrochemical gradient. ATP synthase then lets protons flow back down that gradient and uses the flow to phosphorylate ADP, a coupling known as chemiosmosis.

5. 5. In E. coli, glucose is plentiful and lactose is absent. What is the lac operon doing?

   • A. The repressor is inactive, so transcription runs at a high rate
   • B. cAMP is high, so CAP binds and strongly activates transcription
   • C. Lactose binds the repressor and pulls it off the operator
   • D. The repressor sits on the operator and transcription is largely off
   Voir la réponse et l'explication

   Réponse : D. The repressor sits on the operator and transcription is largely off

   The lac operon is under negative control by the repressor and positive control by CAP. With no lactose there is no inducer to lift the repressor, so it stays bound to the operator. Plentiful glucose also keeps cAMP low, so CAP does not bind and gives no boost. Both signals point the same way: do not build enzymes for a sugar that is not there.

6. 6. Two aqueous solutions sit either side of a membrane that lets water through but no solute. Solution A is 0.10 molar glucose and solution B is 0.10 molar sodium chloride. What happens?

   • A. Water moves toward the glucose, because glucose is the larger molecule
   • B. Water moves toward the sodium chloride, because it splits into about twice as many particles
   • C. There is no net movement, because the two molarities are equal
   • D. Water moves toward the glucose, because ionic compounds cannot generate osmotic pressure
   Voir la réponse et l'explication

   Réponse : B. Water moves toward the sodium chloride, because it splits into about twice as many particles

   Osmotic pressure is a colligative property, so it counts dissolved particles and ignores what those particles are. Sodium chloride dissociates into two ions per formula unit, which puts 0.10 molar NaCl near 0.20 osmolar while the glucose stays at 0.10. Water moves toward the side that is more concentrated in particle terms, so it moves toward the salt. The same counting explains freezing point depression and boiling point elevation.

7. 7. Two identical 10 ohm resistors are connected in parallel across a battery. What is the resistance of the pair, and how does it compare with one resistor on its own?

   • A. 20 ohms, which is larger than either resistor alone
   • B. 10 ohms, the same as either resistor alone
   • C. 5 ohms, which is smaller than either resistor alone
   • D. 0 ohms, because parallel paths cancel each other
   Voir la réponse et l'explication

   Réponse : C. 5 ohms, which is smaller than either resistor alone

   Parallel resistors add as reciprocals, so one over the total equals one tenth plus one tenth, and the total is 5 ohms. Adding a parallel path always lowers total resistance, because current gains another route to take. Series resistors do the opposite and simply add. The same reasoning is why opening more parallel vascular beds lowers total peripheral resistance.

8. 8. Which statements about a galvanic cell, also called a voltaic cell, are correct?

   Coche toutes les bonnes réponses.

   • A. The standard free energy change of the cell reaction is positive
   • B. Oxidation happens at the anode and reduction happens at the cathode
   • C. An external power supply is needed to drive the reaction forward
   • D. The standard cell potential is positive
   • E. The salt bridge keeps each half cell electrically neutral as the reaction runs
   Voir la réponse et l'explication

   Réponse : B. Oxidation happens at the anode and reduction happens at the cathode, D. The standard cell potential is positive, E. The salt bridge keeps each half cell electrically neutral as the reaction runs

   A galvanic cell runs a redox reaction that is already favorable, so its standard cell potential is positive and its standard free energy change is negative, the two tied together by delta G naught equals minus n F E naught. Oxidation at the anode and reduction at the cathode holds in every electrochemical cell, so that pairing is not what separates the two types. Direction is what separates them, since an electrolytic cell needs an outside supply to push an unfavorable reaction uphill. The salt bridge moves ions between the half cells to cancel the charge buildup that would otherwise halt the reaction within seconds.

9. 9. Complete the sentence.

   A reaction whose enthalpy change is negative and whose entropy change is positive is _____.

   Options pour le trou 1 : never spontaneous, spontaneous only at high temperature, spontaneous at every temperature, spontaneous only at low temperature

   Voir la réponse et l'explication

   Réponse : spontaneous at every temperature

   Gibbs free energy change equals enthalpy change minus temperature times entropy change. A negative enthalpy term and a positive entropy term both push that value negative, and absolute temperature is always positive, so the sign never flips. Spontaneous says nothing about speed, though. A reaction can be thermodynamically favorable and still sit untouched for years behind a large activation barrier.

10. 10. Students are told a hard test measures ability in an area where their group is stereotyped as weaker. They score lower than an otherwise identical group told the same test is a problem-solving exercise. This result is usually explained as:

    • A. social loafing
    • B. the bystander effect
    • C. deindividuation
    • D. stereotype threat
    Voir la réponse et l'explication

    Réponse : D. stereotype threat

    Stereotype threat is the drop in performance that appears when someone is reminded of a negative stereotype about a group they belong to, because the resulting worry and self-monitoring consume the working memory the task needs. Nothing about ability changed between the two groups here, only the framing of the task, which is why the instructions alone moved the scores. Social loafing, the bystander effect and deindividuation are all effects of being in a group, and none of them turn on how a task is described to an individual.

11. 11. Which of the following are true of classical conditioning?

    Coche toutes les bonnes réponses.

    • A. A previously neutral stimulus comes to produce a response on its own
    • B. The response is voluntary and is shaped by the consequences that follow it
    • C. Presenting the conditioned stimulus repeatedly without the unconditioned stimulus leads to extinction
    • D. After extinction, the conditioned response can reappear later with no new training
    • E. Learning requires the learner to watch a model being rewarded
    Voir la réponse et l'explication

    Réponse : A. A previously neutral stimulus comes to produce a response on its own, C. Presenting the conditioned stimulus repeatedly without the unconditioned stimulus leads to extinction, D. After extinction, the conditioned response can reappear later with no new training

    Classical conditioning pairs a neutral stimulus with one that already produces a reflexive response until the neutral stimulus produces it alone. Break the pairing and the response fades, which is extinction, and it can come back on its own later, which is spontaneous recovery. Behavior shaped by its consequences is operant conditioning, and learning by watching a model is observational learning.

12. 12. Complete the sentence.

    The system that holds a few items for a matter of seconds while you actively work on them is _____. Recalling a fact more easily in the room where you first learned it is an example of _____.

    Options pour le trou 1 : working memory, sensory memory, procedural memory

    Options pour le trou 2 : proactive interference, the serial position effect, context dependent retrieval

    Voir la réponse et l'explication

    Réponse : working memory, context dependent retrieval

    Sensory memory holds a raw impression for well under a second, working memory holds a small handful of items while you manipulate them, and long term memory has no known practical ceiling. Retrieval is a separate problem from storage, since a memory can be stored perfectly well and still be hard to reach without the right cue. Context dependent retrieval is one of those cues, where the surroundings present at encoding are reinstated at recall, and state dependent retrieval does the same with internal state.

13. 13. Read the excerpt, then answer the question. The catalogue is the quiet argument of a museum. Curators speak of hanging a room, of letting one canvas answer another, and visitors read the sequence as though it were natural. It is not. Every wall states a claim about what belongs beside what, and about which century explains which. A visitor who walks the rooms in order absorbs a thesis she was never asked to accept, and rarely notices that a thesis was offered at all. Which of the following best states the main idea of the passage?

    • A. Museums ought to display their collections in strict chronological order
    • B. The arrangement of a museum makes an argument that most visitors take as given
    • C. Curators disagree sharply with one another about which paintings matter most
    • D. Visitors would learn more from reading a catalogue than from walking the galleries
    Voir la réponse et l'explication

    Réponse : B. The arrangement of a museum makes an argument that most visitors take as given

    The passage says every wall states a claim and that visitors absorb the resulting thesis without noticing it, which is the one idea that covers the whole excerpt. Main idea questions reward the choice that spans the passage, not a detail lifted from one line. The option about chronological order and the one about catalogues both recommend something the author never recommends, and the option about curators disagreeing introduces a conflict the passage never mentions.

14. 14. Read the excerpt, then answer the question. Economists once treated household labor as a residual, a thing done in the hours left over after real work. The convention was convenient. Unpaid hours resisted measurement, and what resists measurement tends to fall out of the model. When time use surveys finally arrived, they did not so much discover housework as make it countable, and the finding was greeted less as news than as an accounting problem. The hours had always been there. Only the ledger had changed. The author's remark that the surveys did not so much discover housework as make it countable most nearly implies that:

    • A. the work in question was new to the period the surveys covered
    • B. economists had deliberately concealed the existence of unpaid labor
    • C. the surveys changed what could be measured rather than what was happening
    • D. time use surveys were less accurate than the methods that came before them
    Voir la réponse et l'explication

    Réponse : C. the surveys changed what could be measured rather than what was happening

    The last two sentences say the hours had always been there and only the ledger changed, so the shift was in measurement and not in behavior. Reasoning questions want the smallest step past what the text supports. Deliberate concealment is far stronger than anything the author claims, since he calls the old convention convenient rather than dishonest, and the passage never compares the accuracy of one method with another.

15. 15. Read the excerpt, then answer the question. Defenders of the classics rarely argue that old books are useful. They argue instead that usefulness is the wrong test, and that a culture which asks only what a thing is for will end by keeping nothing it cannot spend. The claim has force, and it also has a convenient shape, since any objection can be dismissed as proof of the very narrowness complained of. An argument that cannot lose is not thereby strong. It has only stopped being an argument. Which best describes the author's attitude toward the defense he describes?

    • A. Sympathetic but critical, since he grants the defense force and then objects to its shape
    • B. Full agreement, since he says outright that the claim has force
    • C. Dismissive, since he holds that old books have no practical use
    • D. Neutral, since he only reports what defenders of the classics say
    Voir la réponse et l'explication

    Réponse : A. Sympathetic but critical, since he grants the defense force and then objects to its shape

    The author concedes that the claim has force, which rules out dismissal, and then complains that a defense treating every objection as evidence for itself has stopped being an argument. That is criticism of the reasoning, not of old books, so he never takes the dismissive position either. Attitude questions on this section usually land on a mixed answer whenever a passage contains both a concession and a complaint.

Ce qu'est le MCAT et comment il est noté

Le MCAT est rédigé et administré par l'Association of American Medical Colleges, aux États-Unis. Il compte quatre sections notées : Chemical and Physical Foundations of Biological Systems, Critical Analysis and Reasoning Skills, Biological and Biochemical Foundations of Living Systems, et Psychological, Social, and Biological Foundations of Behavior. Chaque section est notée sur une échelle de 118 à 132, le total va donc de 472 à 528, et 500 se situe au milieu de cette échelle. Il n'y a pas de note de passage. L'AAMC publie les rangs centiles de chaque note, et chaque faculté de médecine décide elle-même de ce qu'elle veut voir, le seul repère utile est donc le profil de notes des facultés où tu comptes candidater.

StudyPDF n'est pas affilié à l'AAMC, et rien sur cette page n'est un produit officiel de l'AAMC. Chaque question et chaque explication ont été rédigées par l'équipe StudyPDF à partir des catégories de contenu que l'AAMC publie, et les extraits de lecture des trois dernières questions ont eux aussi été écrits par nous. Aucun item de l'AAMC, ni d'aucun autre concepteur de tests, n'a été reproduit sur cette page. Cela va dans les deux sens. Comme les questions sont les nôtres, elles ne peuvent qu'approcher la vraie chose, alors sers-t'en pour repérer tes lacunes et utilise le matériel d'entraînement officiel de l'AAMC quand tu veux une idée fiable de ton niveau réel.

Le format est long. Chacune des trois sections scientifiques te donne 59 questions en 95 minutes, et la section de raisonnement te donne 53 questions en 90 minutes, ce qui porte le temps total sur place à environ sept heures et demie une fois les pauses et l'enregistrement comptés. La plupart des questions s'accrochent à un texte, avec un plus petit ensemble de questions isolées, présentes uniquement dans les sections scientifiques. Rien n'est retiré pour une mauvaise réponse, laisser une case vide est donc toujours pire que deviner. Les règles du jour de l'examen, la structure des pauses, la prise de rendez-vous et les aides sur les frais changent, alors vérifie les détails à jour sur students-residents.aamc.org plutôt que de te fier à un chiffre lu sur un forum.

Comment utiliser cet échantillon

Les 15 questions ci-dessous reprennent en miniature l'équilibre de l'examen. Cinq viennent des fondements biologiques et biochimiques, quatre des fondements chimiques et physiques, trois des fondements psychologiques et sociaux du comportement, et trois sont des questions de la section CARS. Chaque question CARS porte son propre court extrait, écrit par nous dans le registre qu'utilise cette section, tu peux donc travailler la compétence sans avoir à chercher un texte d'abord. Le vrai examen n'utilise que des questions à choix multiple à réponse unique, les questions à réponses multiples et les textes à trous que tu vois ici sont donc un outil de révision et pas un aperçu du format. Ils sont dans le lot parce que devoir valider chaque partie d'une réponse révèle des lacunes que quatre choix bien rangés peuvent cacher. Aucune de ces questions n'est une vraie question d'examen, et aucune n'est un conseil médical. C'est de l'entraînement à l'examen, rien de plus.

Fais-le d'une traite, sans notes, puis lis l'explication de chaque question, y compris celles que tu as réussies. Au MCAT, une bonne réponse trouvée par chance et une réponse raisonnée se ressemblent sur le relevé de notes et n'ont rien à voir dans ta tête, c'est donc dans la relecture que l'apprentissage se fait. Traite une erreur comme un thème, pas comme un fait isolé. Si tu as raté la question sur la pression osmotique et celle sur la thermodynamique, le problème vient sans doute de ce que tu mémorises des équations au lieu de lire ce que chaque variable représente vraiment.

Ensuite, répartis honnêtement ton temps de révision. La révision du contenu comble les lacunes, mais la progression du score vient surtout des tests complets chronométrés et de leur relecture lente. La section de raisonnement fait exception, puisqu'elle récompense la lecture quotidienne et régulière de textes argumentatifs denses plus que n'importe quelle liste de contenus. Le timing est une compétence en soi. Quatre-vingt-quinze minutes pour 59 questions te laissent un peu plus d'une minute et demie par question, et la plupart des gens perdent des points à la fin d'une section plutôt qu'au début, alors une fois le contenu solide, entraîne-toi contre la montre plutôt que sans limite de temps. Les deux quiz frères liés plus bas creusent les sections scientifiques et le raisonnement, fais donc les trois et vois lequel fait mal.

Comment StudyPDF crée des tests complets à partir de tes propres documents

Quinze questions peuvent te montrer où tu es fragile. Elles ne peuvent pas te rendre prêt à elles seules, et une banque générique correspond rarement aux priorités du livre de préparation, du cours ou des notes de cours sur lesquels tu travailles vraiment.

StudyPDF part plutôt de ton matériel. Tu importes tes livres de préparation au MCAT, tes diapos de cours de biochimie ou de psychologie, ou les résumés de chapitres que tu as écrits toi-même, et Bo, l'agent de révision, crée des tests d'entraînement complets à partir de ces pages précises. Chaque question est ancrée dans ton matériel, et chaque explication indique d'où vient la réponse, donc quand quelque chose te semble faux tu peux aller droit à la source et vérifier. Tu peux générer de nouveaux tests aussi souvent que tu veux, les restreindre à un seul domaine comme les acides aminés, les circuits ou les méthodes de recherche, et suivre les concepts qui reviennent sans arrêt en erreur.

Tu n'as pas besoin d'importer quoi que ce soit pour commencer. Si tu n'as aucun fichier sous la main, nomme plutôt un thème, par exemple la chimie acide-base, la physiologie musculaire ou la stratification sociale, et Bo écrit un test d'entraînement dessus. Commencer est gratuit.