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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. A statistical rule stating that the probability of either of two indpendent (and mutually exclusive) events ocuring is the sum of their individual probabilities minus the probability of them both occuring together.






2. The portion of the cardiac conduction system between the SA node and the AV node.






3. The resistance to blood flow in the systemic circulation. Peripheral resistance increases if arteries constrict (diameter decreases) - and an increase in peripheral resistance leads t o an increase in blood pressure.






4. A developing oocyte and all of its surrounding (supporting) cells.






5. The middle (approximtely 40%) of the small intestine.






6. Small organelles that contain the hydrogen peroxide produced as a byproduct of lipid metabolism. Peroxisomes convert hydrogen peroxide to water and oxygen by way of the enzyme catalase.






7. 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






8. DNA that is densely packed around histones. The genes in heterochromatin are generally inaccessible to enzymes and are turned off.






9. DNA replication in which each of the parental strands is read to make a complementary daughter strand - ethus each new DNa molecule is composed of half the parental molecule paired with a newly synthesized strand.






10. The unit of combact bone - also called a Haversian system. Osteons are essentially long cylinders of bone; the hollow center is called the central canal - and is where blood vessels - nervs - and lymphatic vessels are found. Compact bone is laid down






11. A hormone secreted by the samll intestine (duodenum) in response to the presence of fats. It promotes release of bile from the gallbladder and pancreatic juice from the pancreas - and reduces stomach motility.






12. A concentrated region of white blood cells found along the vessels of the lympatic system.






13. The portion of the brain responsible for visual and auditory startle reflexes.






14. Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.






15. One of the four aromatic bases found in DNA and RNA. Guanine is a purine; it pairs with cytosine.






16. (singular alveolus.) Tiny sacs - with walls only a single cell layer thick found at the end of the respiratory bronchiole tree. Alveoli are the site of gas exchange in the respiratory system.






17. A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.






18. Amino - acyl tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide.






19. A hormone secreted by the small intestine (duodenum) in response to the presence of food. It decreases the rate at which chyme leaves the stomach and enters the small intestine.






20. A microscopic space between the axon of one neuron and the cell body or dendrites of a secon neruon - or between the axon of a neuron and an organ.






21. The process of bulidng complex structures out of simpler precursors - e.g. synthesizing protiens from amino acids.






22. Also known as the neurohyophysis - the posterior pituitary is made of nervous tisssue and stores and secretes two hormones made by the hypothlamus; oxtytocin and ADH. The posterior pituitary is controlled by action potentials from the hypothalamus.






23. The ability of tissues to regulate their own blood flow in the absence of neural stiulation. THis is generally accomplished via metabolic wastes (such as CO2) that act as vasodilators.






24. The monomer of a protein; amino acids hae an amio group on one end fo the molecule and a carboxylic acid group on the other - and of the of 2 different side chains.






25. A localized change in a neruon's or musce cell's membrane potential that can propogate itself away from its point of origin. Action potentials are an all - or - none process mediated by the opening of voltage - gated Na+ and K+ channels when the memb






26. Oil - forming glands found all over the body - especially on the face and neck. The product (sebum) is released to the skin surface through hair follicles.






27. The portion of theforebrain that includes the thalamus and hypothalamus.






28. The maintenance of relatively constant internal conditions (such as temperature - pressure - ion balance - pH - etc.) regardless of external conditions.






29. The sum of all genetic material in a population.






30. The subdivision of the nervous system consisting of the brain and spinal cord.






31. A form of symbiosis in Which both organisms involved benefit from the association.






32. A form of evolution in which the same organism is placed into different environments with different selection pressures. This causes organisms to evolve differently - to diverge from their common ancestor. The resulting (new) species may share struct






33. The 28 days of the menstrual cycle as they apply to the events in the uterus. The endometrial cycle is also known as the uterine cycle - and has the three subphases: menstruation - the proliferative phase - and the secretory phase.






34. A substance secreted by embryonic testes that causes the regression of the Mullerian ducts.






35. The specialized cells of the heart that spontaneously initiate action potentials and transmit them to the cardiac muscle cells. The cells of the conduction system are essentially cardiac muscle cells - but lack the contractile fibers of the muscle ce






36. The blood vessels taht carry blood to and from cardiac muscle. The coronary arteries branch off teh aorta and carry oxygenated blood to the cardiac tissue. The coronary veins collect deoxygenated blood from teh cardiac tissue - merge to form teh coro






37. A cyclic version of adenosine monophosphate - where the phosphate is esterified to both the 5' and 3' carbons - forming a ring. Cyclic AMP is an important intracellular signaling moelcule - often called the 'second messenger.' It serves to activate c






38. The maximum amount of air that can be forcibly exhaled from the lungs after filling them to their maximum level - typically about 4500 mL






39. The muscuar layer of the uterus. The myometrium is made of smooth muscles that retains its ability to divide in order to accomodate the massive size increases that occur during pregnancy. The myometrium is stimulated to contract during labor by the h






40. 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.






41. The function unit of the kidney. Each kidney has about a million nehprons; this is where blood filtration and subsequent modification of the filtrate occurs. The nephron empties into collecting ducts - which empty into the ureter.






42. A type of mutation in DNa where a single base is substituted for another.






43. A lubricating - nourishing fluid found in joint capsules.






44. A bacterial extrachromosal elent that allows the bacterium to initati conjugation. Bacteria that possess teh F factor are known as F+ 'males'.






45. Connective tissue that lacks great amount of collagen or elastic fibers (hence - loose) - e.g. - adipose tissue and areolar (general connective) tissue.






46. Small convoluted tubules in the testes where spermatogenesis takes place.






47. The third phase of the ovarian cycle - during which a corpus luteum is formed from the remnants of the follicle that has ovulated its oocyte. The corpus luteum secretes progestrone and estrogen during this time period - which typically lasts from day






48. The three glands in the male reproductive system that reproduce semen: the seminal vesicles - the prostate - and the






49. A fibrous - connective - tissue protein taht has the ability to recoil to its original shape after being stretche.d Elastin is found in great amounts in lung tissue - arterial tissue - skin - and the epiglottis.






50. An enzyme inhibitor that competes with substrate for binding at the active site of teh enzyme. When the inhibitor is bound - no product can be made.