MCAT 练习

The cell is the basic structural and functional unit of life. Atoms and molecules form cells, and organs are made of tissues.

DNA is a polymer of nucleotides, each with a sugar, phosphate, and nitrogenous base. Amino acids form proteins, fatty acids form lipids, and monosaccharides form carbohydrates.

Mitochondria generate ATP through cellular respiration. Ribosomes synthesize proteins, the nucleus stores DNA, and lysosomes break down waste.

Enzymes are usually proteins that catalyze reactions by lowering activation energy. Lipids store energy, carbohydrates provide structure, and nucleic acids store information.

Cellular respiration breaks down glucose to produce ATP. DNA replication, protein synthesis, and cell division are separate processes.

Homeostasis keeps internal conditions such as temperature, pH, and glucose stable. It is not a single movement, temperature spike, or antibody response.

A gene is a DNA segment that encodes RNA or protein. Membrane proteins, lipids, and sugars are not genes.

Mitosis produces two genetically identical somatic cells. Meiosis produces gametes, apoptosis is cell death, and folding is a protein process.

The cell membrane controls transport and maintains separation. ATP production, DNA storage, and protein synthesis happen in organelles.

Hormones are chemical messengers that coordinate physiology. Enzymes catalyze reactions, structural proteins provide support, and glycogen stores glucose.

The immune system recognizes and attacks pathogens. Oxygen transport is red blood cells, digestion is the GI tract, and blood sugar is hormonal.

Glycolysis converts glucose to pyruvate in the cytoplasm. The Krebs cycle and oxidative phosphorylation occur later, and gluconeogenesis builds glucose.

An atom is the smallest unit of an element with its chemical properties. Molecules, proteins, and organelles are larger structures.

Covalent bonds involve shared electrons. Ionic bonds attract opposite charges, hydrogen bonds are intermolecular, and London forces are weak dispersions.

Ions form when atoms gain or lose electrons and become charged. Neutral atoms, bonds, and radioactive particles are different.

pH indicates hydrogen ion concentration and whether a solution is acidic or basic. It does not measure temperature, mass, or pressure.

Stoichiometry uses mole ratios to relate reactants and products. Kinetics studies rates, thermodynamics studies energy, and VSEPR predicts shape.

Enthalpy is heat content at constant pressure. Entropy measures disorder, rate measures speed, and concentration measures amount.

Catalysts lower activation energy and are regenerated. Reactants are consumed, products are formed, and solvents dissolve solutes.

Equilibrium is reached when forward and reverse rates are equal, not when reactants disappear or the reaction stops.

Brønsted-Lowry acids donate protons. Bases accept protons, and electron donors are reducing agents.

Bases accept protons. Acids donate protons, and electron acceptors are oxidizing agents.

Oxidation is the loss of electrons. Reduction is the gain of electrons, and proton or bond changes are separate concepts.

Boyle law says pressure increases as volume decreases when temperature is constant. The product of pressure and volume stays constant.

Classical conditioning pairs stimuli, as in Pavlov experiments. Operant conditioning uses consequences, observational learning uses models, and repetition is rehearsal.

Operant conditioning changes behavior through consequences. Classical conditioning associates stimuli, observational learning watches models, and imprinting is developmental.

Working memory holds and processes current information. Long-term memory stores durable facts, sensory memory is brief, and habits are procedural.

Long-term memory stores information for long periods. Short-term storage lasts seconds, afterimages are sensory, and reflexes are automatic.

Schemas help organize and interpret information. Neurons, receptors, and memory cells are biological structures.

Attribution explains why behavior occurs, such as internal or external causes. Persuasion, encoding, and habit formation are different processes.

Conformity is changing behavior to fit a group. Obedience follows authority, independence resists pressure, and helping is prosocial behavior.

Fight-or-flight prepares the body for threat through sympathetic activation. It is not memory, digestion, or sleep.

Neurotransmitters transmit signals across synapses. Hormones travel in blood, and proteins or sugars are not synaptic messengers.

Reinforcement increases behavior; punishment decreases it. Neutral stimuli and memory cues are different concepts.

Cognitive dissonance occurs when beliefs and actions conflict, motivating consistency. It is not memory loss, learning style, or reinforcement.

Experiments need controls and clearly defined independent and dependent variables. Personal opinion is not an experimental component.

Start by mapping the passage structure and main argument. Memorizing details or skipping reading leads to wrong answers.

The main idea is the author central claim, supported by the passage. It is not one sentence, a detail, or the title alone.

Author purpose explains the goal, such as arguing, explaining, or evaluating. Length, citations, and vocabulary are not purposes.

Inferences go beyond the text but are supported by evidence. Direct statements, outside opinions, and unsupported guesses are not inferences.

Tone reflects the author attitude, such as critical or sympathetic. Structure, length, and formatting are not tone.

Counterarguments present opposing views, which authors often refute. The conclusion, examples, and rhetorical questions are different.

Passage mapping tracks each paragraph job so you can locate evidence quickly. Word counts and highlighting are not mapping.

Evidence supports claims with facts, examples, or reasoning. Opinions, question stems, and transitions are not evidence.

Transitions show contrast, cause, or sequence between ideas. They do not signal endings, question counts, or authorship.

Eliminating wrong choices narrows the answer using passage evidence. Length, guessing, and outside knowledge are not reliable strategies.

Steady pacing prevents losing points on later passages. Rushing or over-investing harms accuracy, and question-first is not always best.

Reviewing reasoning builds transferable skills. Memorizing letters or counting words does not improve understanding.

The MCAT has four sections: Biological and Biochemical Foundations, Chemical and Physical Foundations, Psychological and Social Foundations, and Critical Analysis and Reasoning.

The independent variable is manipulated. The dependent variable is measured, controls are held constant, and the control group receives no treatment.

The dependent variable is the outcome measured. The independent variable is manipulated, constants are fixed, and random error is noise.

Control variables are kept the same to isolate effects. Outcomes, manipulations, and confounds are different.

Confounds threaten validity by providing alternative explanations. Controlled variables are intended constants, and hypotheses or means are not confounds.

Timed, realistic practice plus error review builds endurance and accuracy. Open-book or selective practice hides weaknesses.

Spaced repetition improves retention by scheduling reviews over time. Cramming, single readings, and highlighting are less effective.

Only valid ID and AAMC-approved materials are allowed. Notes, phones, and unauthorized calculators are prohibited.

The MCAT total score ranges from 472 to 528, with each section scored from 118 to 132. Other ranges belong to different exams.

Passage-based questions use information from a passage. Standalone questions do not, and rules or surveys are not MCAT items.

Effective plans combine content, timed practice, and error analysis. Any single method leaves gaps.

The MCAT sections cover living systems, physical principles, human behavior, and reading comprehension.