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MCAT Prep Biology

Subjects : mcat, science
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. The inner layer of smooth muscle in the wall of the digestive tract. When the circular muscle contracts - the tube diameter is reduced. Certain areas of the circular muscle are thickened to act as valves (sphincters).






2. The secretion of a cellular product to the extracellular medium through a secretory vesicle.






3. The membrane that separates the middle ear from the inner ear.






4. A sac filled with fluid (aminotic fluid) that surroudns and protects a developing embryo.






5. Globular protein that assist in DNA packaging in eukaryotes. Histones form octamers around which DNA is wound to form a nucleosome.






6. One of two large vessels (superior and inferior) that return deoxygenated blood to the right atrium of the heart.






7. The fertilization of an oocyte by more than one sperm. This occurs in some animals - but in humans - blocks to polyspermy exist (the fast block and the slow block) so that only a single sperm can penetrate the oocyte.






8. The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at teh AV node - allowing the ventricles to contract just after the atria contract.






9. The first (approximately 5%) of the small intestinte.






10. The process of reading a strand of mRNA to synthesize protein. Protein translation takes place on a ribosome.






11. The physical characterisitcs resulting from the genotype. Phenotypes are usually described as dominant or recessive.






12. A large - non - sepcific - phagocytic cell of the immune syste. Macrophages frequently leave the bloodstream to crawl around in the tissues and perform 'clean up' duties - such as ingesting dead cells or cellular debris at an injury site - or pathoge






13. A type of lipoprotein; the form in which absorbed fats from the intestines are transported to the circulatory system.






14. A large - mature - ovarian follicel with a well - developed antrum and a secondary oocyte. Ovulation of the oocyte occurs from this type of follicle.






15. A nucleotide sequence that intervenes between protein - coding sequences. In DNA - these intervening sequences typically contain **regulatory sequences - however - in RNA they are simply spliced out to form the mature (translated) transcript.






16. The largest bundle of white matter (axons) connecting th two cerebral hemispheres.






17. A cytoplasmic protein that recognizes the signal sequences of proteins destined to be translated at the rough ER. It binds first to the ribosome translating the protein with the signal sequence then to an SRP receptor on the rough ER>






18. A portion of DNA that codes for some product - usually a protein - including all regulatory sequences. Some genes code for rRNA and tRNA - which are not translated.






19. The movement of air out of the respiratory tract. Expiration can be passive (caused by relaxation of the diaphragm and elastic recoil of the lungs) or active (caused by contraction of the abdominal muscles - which increases intraabdominal pressure an






20. A hormone tha tcontrols the release of another hormone.






21. The division of the autonomic nervous system known as the 'resting and digesting' system. It causes a general decrease in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to the GI tract and d






22. The site(s) where the parental DNA double helix unwinds during replication.






23. Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).






24. 'Yellow body.' The remnants of an ovarian follicle after ovulation has occurred. The cells enlarge and begin secreting progesterone - the dominant female hormone during the second half of the menstrual cycle. Some estrogen is also secreted.






25. Connective tissue with large amounts of either collagen fibers (making them strong) or elastic fibers - or both. Dense tissues are typically strong (e.g. bone - cartilage - tendons - etc.)






26. A point mutation in which a codon that specifies an amino acid is mutated into a new codon that specifies the same amion acid.






27. An energy storage molecule used by muscle tissue. The phosphate from creatine phosphate can be removed and attached to an ADP to generate ATP quickly.






28. An RNA polymerase that creates a primer (made of RNA) initiate DNa replication. DNA pol binds to the primer and elongates it.






29. The process of breaking down large molecules into smaller precursors - e.g. digesion of starch into glucose.






30. The small artery that carries blood away from the capillaries of the glomerulus.






31. In skeleta and cardiac muscle tissue - a filament composed of actin - tropomyosin - and troponin. Thin filaments are attached to teh Z lines of the sarcomers and slide over thick filaments during muscle contraction.






32. A precursor cell that undergoes mitosis during fetal development to produce more oogonium. These cells are then activated to produce primary oocytes - which remain dormant until stimulated to undergo meiosis I during some future menstrual cycle.






33. An integral membrane protein that undergoes a conformational change to move a molecule from one side of the membrane to another. See also 'uniporter' - 'antiporter' - and 'symporter'.






34. The smooth ER of a muscle cell - enlarged and specialized to act as a Ca2+ reservoir. The SR winds around each myofibril in the muscle cell.






35. Identical copies of a chromosome - produced during DNA replication and held together at the centromere Sister chromatids are separated during anaphase of mitosis.






36. A carrier protein that transports a single molecule across the plasma membrane.






37. A contact point between the afferent arteriole of the glomerulus and the distal convoluted tubule of the nephron. It is involved in regulating blood pressure.






38. A kinase in smooth muscle cells activated by calmodulin the presence of Ca2+. As its name implies - this kinase phosphorylates myosin - activating it so that muscle contraction can occur.






39. A form of genetic recombination in bacteria in which plasmid and/or genomic DNA is transferred from one bacterium to the toher through a conjugation bridge.






40. The stage of human development during which the organs are formed. Organogenesis begins after gastrulation and is completed by the eight week of gestation.






41. An enzyme that cuts one or both strands of DNa to relieve the excess tension caused by the unwinding of the helix by helicase during replication.






42. A carrier protein that transports two molecules across the plasma membrane in the same direction. For example - the Na+- glucose cotransporter in intestinal cells is a symporter.






43. A eukaryotic organelle filled with digestive enzymes (acid hydrolases) that is involved in digestion of macromolecules such as worng organelles or material ingested by phagocytosis.






44. The second step in viral infection - the injection of the viral genome into the host cell.






45. A thick - gelatinous fluid found in the posterior segment of the eye (between the lens and the retina). The vireous humor is only produced during fetal development and helps maintain intraocular pressure (the pressure inside the eyeball).






46. An enzyme whose transcription can be stimulated by an abundance of its substrate (as opposed to repressible enzyme). Usually in catabolism.






47. Enzymes that degrade various macromolecules and that require an acidic pH to function properly. Acid hydrolases are found within the lysosomes of cells.






48. The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens - thus if the live pathogen is encountered in the future






49. The tendency of certain factors to stablize the hemoglobin in the tense conformation - thus reducing its affinity for oxygen and enhancing the relase of oxygen to the tissues. The factors include increased PCO2 - increase temperature - increased bisp






50. Integration by a postsynaptic neuron of inputs (EPSPs and IPSPs) from multiple sources.