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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. Receptors in the central nervous system that monitor the pH of cerebrospinal luid to help regulate ventilation rate.






2. The 28 days of the menstrual cycle as they apply to events in the ovary. The ovarian cycle has three subphases: the follicular phase - ovulation - and the luteal phase.






3. Photoreceptors in the retina of the eye that responds to bright light and provide color vision.






4. A protein channel in the nuclear envelope that llows the free passage of molecules smaller than 60 kD.






5. A thin (4 mm) layer of gray matter on the surface of the cerebral hemispheres. The cerebral cortex is the conscious mind - and is functionally divided into four pairs of lobes: the frontal lobes - the parietal lobes - the temporal lobes - and the occ






6. An asexual method of bacterial reproduction that serves only to increase the size of the population; ther is no introduciton of gnetic diversity. THe bacterium simply grows in size until it has doubled its cellular components - then it replicates its






7. An organism that utilizes light as its primary energy source.






8. A green fluid made from cholesterol and secreted by teh liver. It is stored and concentrated in the gallbladder. Bile isn an amphipathic molecule that is secreted itno the small intestine when fats are present - adn serves to emulsify the fats for be






9. 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.






10. A waste product of protein dbreakdown - produced by the liver and relased into the bloodstream to be eliminated by the kidney.






11. A neuron with a single axon and a single dendrite - often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon m






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






13. An immune reaction directed against normal (necessary ) cells.Fo example - diabets melitus (typeI) is an autoimmun reaction directed against teh beta cells of the pancrease (destorying them and preventing insulin secretion) and aginst insulin itself.






14. Messenger RNA; the type of RNa that is read by a ribosome to synthesize protein.






15. The first part of the large intestine.






16. Very small tube or channel - such as is found between lacunae (connecting them together) in compact bone.






17. Haploid cells resulting from the first meiotic division of spermatogenesis. Secondary spermatocytes are ready to enter meiosis II.






18. An organism that cannot make its own food - and thus must ingest other organisms.






19. 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.






20. Small fragments of DNa produced on the lagging strand during DNa replication - joined later by DNA ligase to form a complete strand.






21. An organ that develops during pregnacy - derived in part from the mother and in part from the zygote. The placenta is the site of exchange of nutrients and gases between the mother's blood and the fetus' blood. The placenta is formed during the first






22. A fluid - filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.






23. A non - protein - but organic - molecule (such as vitamin) that is covalently bound to an enzyme as part of the active site.






24. Excitatory postsynaptic potential; a slight depolarization of a postsynaptic cell - bringing the membrane potential of that cell closer to the threshold for an action potential.






25. The entropy (disorder) of the universe (or system) tends to increase.






26. An enzyme inhibitor that binds at a site other than the active sit of an enzyme (binds at an allosteric site). THis changes the three - dimensional shape of the enzyme such that it can no longer catalyze the reaction






27. 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.






28. A statistical rule stating that the probability of two independent events occuring together is the product of their individual probabilities.






29. Genes that are inherited only from the mother - such as mitochondrial genes (all organelles come only from the ovum).






30. A subsequent immune response to previously encountered antigen that results in antibody production and T cell activation. The secondary immune response is mediated by memory cells (produced during the primary immune respone) and is much faster and st






31. The mass of cells in the blastocyst that ultimately give rise to the embryo and other embryonic structues (the amion - the umbilical vessels - etc.)






32. A strong connective tissue with varying degrees of flexibility. (1) Elastic cartilage is the most flexible - forming structures that reuqire support but also need to bend - such as the epiglottis and outer ear. (2) Hyaline cartilage is more rigid tha






33. The first branches of the trachea. There are two primary bronchi - one for each lung.






34. A solid clump of cells resulting from cleavage in the early embryo. Because there is very little growth of these cells during cleavage - the morula is ony about as large as the original zygote.






35. The regino of the sarcomere made up only of thin filaments. The I band is bisected by a Z line. I bands alternate with A bands to give skeletal and cardiac muscle a striated appearance. I bands get shorter (and may disappear completely) during muscle






36. 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.






37. The volume of blood pumped out the heart in a single contraction.






38. Muscles located in between the ribs that play a role in ventilation.






39. The darkly pigmented middle layer of the eyeball - found between teh sclera (outer layer) and the retina (inner layer).






40. The first encounter with an antigen - resuling in activated B cells (antibody secretion) and T cells (cellular lysis and lymphocyte proliferation). The primary immune response takes approximately ten days - which long enough for symptoms of the infec






41. An ion channel that is opened or closed based on the binding of a specific ligand to teh channel. Once opened - the channel allows the ion to cross the plasma membrane according to its concentration gradient. An examples is the acetylcholine receptor






42. The phase of the cell cycle during which the genome is replicated.






43. A gland that secretes its product into a duct - which ultimately carries the product to the surface of the body or into a body cavity. Some examples of exocrine gland and their products are sweat glands (sweat) - gastric glands (acid - mucus - protea






44. A blood clot that forms in an unbrokened blood vessel. Thrombi are dangerous they can break free and begin travelin in the bloodstream (become an embolus). Emboli ultimately become stuck in a small vessel and prevent adequate blood delivery to tissue






45. The division of the autonomic nervous system known as the 'fright or flight' system. It causes a genera increase in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to skeleltal muscle. It cau






46. A neuron - to - neuron - neuron - to - organ - or muscle to cell - to - muscle cell junction.






47. The step in the sliding filament theory during which yosin undergoes a conformaitonal change to its low energy state - in the process dragging the thin filaments (and the attached Z lines) toward the center fo the sarcomere. NOte that power stroke re






48. A protein fiber with a unique triple - helix that gives it great strength. Tissues with a lot of collagen fibers are typically very strong - e.g. bone - tendons - ligaments - etc.






49. A wave of contraction that sweeps along a muscular tube - pushing substances along the tube (e.g. - food through the digestive tract - urine through the ureters - etc.)






50. A genotype in which two different alleles are possessed for a given gene.