Biology MDCAT MCQs

Cell biology, genetics & physiology MCQs

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Showing 305 MCQs in Biology
Biology
A. Measure gene expression
B. Predict offspring genotypes
C. Count chromosomes
D. Analyze DNA sequences
Answer: Punnett squares predict the probability of offspring genotypes from parental crosses.
Biology
A. Golgi apparatus
B. Lysosome
C. Mitochondria
D. Smooth ER
Answer: Mitochondria have their own circular DNA, supporting the endosymbiotic theory of evolution.
Biology
A. Flagella
B. Pili
C. Capsule
D. Nucleoid
Answer: Pili (fimbriae) are hair-like appendages that help bacteria attach to surfaces and other cells.
Biology
A. 500
B. 2,000
C. 20,000-25,000
D. 100,000
Answer: The Human Genome Project estimated approximately 20,000-25,000 protein-coding genes.
Biology
A. Respiration
B. Transpiration
C. Photosynthesis
D. Fermentation
Answer: Photosynthesis uses light energy, CO2, and water to produce glucose and oxygen.
Biology
A. Xanthophyll
B. Chlorophyll
C. Carotene
D. Anthocyanin
Answer: Chlorophyll absorbs primarily red and blue light, reflecting green light.
Biology
A. Neutrophil
B. Erythrocyte
C. Lymphocyte
D. Monocyte
Answer: Erythrocytes are red blood cells, not white blood cells.
Biology
A. Root pressure
B. Cohesion-tension theory
C. Translocation
D. Imbibition
Answer: The cohesion-tension theory explains that water is pulled up by transpiration and held together by cohesion.
Biology
A. Antibiotic resistance in bacteria
B. Dog breeding
C. Industrial melanism
D. Darwin\'s finches
Answer: Dog breeding is human-directed artificial selection for desired traits.
Biology
A. Tallness in pea plants
B. ABO blood group
C. Color blindness
D. Sickle cell anemia
Answer: In ABO blood groups, both A and B alleles are equally expressed in type AB individuals.
Biology
A. Mitosis
B. Asexual reproduction
C. Meiosis
D. Cloning
Answer: Meiosis introduces variation through crossing over and independent assortment of chromosomes.
Biology
A. Mutation
B. Natural selection
C. Genetic drift
D. All of the above
Answer: Hardy-Weinberg equilibrium is maintained only in the absence of all evolutionary forces.
Biology
A. Gregor Mendel
B. Charles Darwin
C. Louis Pasteur
D. Watson and Crick
Answer: Charles Darwin proposed natural selection as the mechanism of evolution in On the Origin of Species.
Biology
A. Nucleic acids
B. Proteins
C. Cell wall
D. Cell membrane
Answer: Penicillin inhibits transpeptidase, preventing cross-linking of peptidoglycan in bacterial cell walls.
Biology
A. Genetic drift
B. Mutation
C. Natural selection
D. Gene flow
Answer: Natural selection favors individuals with traits that improve survival and reproduction.
Biology
A. Yeast
B. Amoeba
C. E. coli
D. Paramecium
Answer: E. coli is a bacterium, which is a prokaryote lacking a membrane-bound nucleus.
Biology
A. Convergent evolution
B. Divergent evolution
C. Parallel evolution
D. Coevolution
Answer: Homologous structures indicate common ancestry and divergent evolution from a shared ancestor.
Biology
A. Suture
B. Hinge joint
C. Ball and socket joint
D. Pivot joint
Answer: Ball and socket joints (like the shoulder and hip) allow movement in all directions.
Biology
A. Plasma
B. White blood cells
C. Platelets
D. Hemoglobin in red blood cells
Answer: Hemoglobin in RBCs binds oxygen in the lungs and releases it at the tissues.
Biology
A. Chromosome 1
B. Chromosome 21
C. X chromosome
D. Autosome
Answer: Most sex-linked traits are carried on the X chromosome, which is why they affect males more.
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