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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 principal glucocorticoid secreted from teh adrenal cortex. This steroid hormone is released ruing stress - causing increased blood glucose levels and reducing inflammation. The latter effect has led to a clinical use of cortisol as an anti - infl






2. A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females - FSH stimulates the ovaries to develop follicles (oogenesis) and secrete estrogen; in males - FSH stimulates spermatogenesis.






3. The innermost layer of the eyeball. The retina is made up of a layer of photoreceptors - a layer of bipolar cells - and a layer of ganglion cells.






4. A type of lymphocyte. The major subtypes of T cells are the helper T cells (CD4) and the killer T cells (CD8 - or cytotoxic T cells). Helper T cells secrete chemicals that help killer Ts and B cells proliferate. Killer T cells destroy abnormal self -






5. The contribution of an individual gas to the total ppressure of a mixture of gases. Partial pressures are used to describe the amounts of the various gases carried in the bloodstream.






6. A situation in which the expression of one gene prevents expression of all allelic forms of another gene - e.g. - the gene for male pattern baldness is epistatic to the hair color gene.






7. 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.






8. The central structure of the diencephalon of the brain. the thalamus acts as a relay station and major integrating area for sensory impulses.






9. 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






10. The structure in the cochlea of the inner ear made up of the basilar membrane - the auditory hair cells - and the tectorial membrane. The Organ of Corti is the site where auditory sensation is detected and transduced to action potentials.






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






12. A sequence of amino acids (usually basic) that directs a protein to the nuclear envelope - where it is imported by a specific transport mechanism.






13. Movement that is directed by chemical gradients - such as nutrients or toxins. (seen in some bacteria)






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






15. The valve that regulates the passage of chyme from the stomach into the small intestine.






16. 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.






17. The movement of air into the respiratory tract. Inspiration is an active process - requiring contraction of the diaphragm.






18. One of the four aromatic bases found in DNA. Thymine is a pyrimidine; it pairs with adenine.






19. The synthesis of blood cells (occurs in the red bone marrow)






20. A bacterium having a rod - like shaped (plural = bacilli).






21. The pituitary gland.






22. A bacterium that cannon survive on minimal medium (glucose alone) because it lacks the ability to syntheisze a molecule it needs to live (typically an amino acid). Auxotrphs must ave the needed substance (the auxiliary trophic substance) added to the






23. A network of membranes inside eukarytoic cells invovled in lipid synthesis (steroid in gonads) - detoxification (in liver cells) - and/or Ca2+ storage (muscle cells).






24. A triat determined by a gen on either the X or Y chromosomes (the sex chromosomes).






25. One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin - hair - nails - and inner linings of the mouth and anus - as well as the entire nervous system.






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






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






28. One of the two ends of long bone (pl: eiphyses). The epiphyses have an outer shell made of compact bone and inner core of spongy bone. The spongy bone is filled with red bone marrow - the stie of blood cell formation.






29. 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>






30. A receptor that responds to light






31. The female primary sex organ. The ovary produces female gametes (ova) and secretes estrogen and progesterone.






32. To remove oxygen - to add hydrogen - or to add electrons to a molecule.






33. The outer layer of smooth muscle in the wall of the digestive tract. When the longitudinal muscle contracts the tube shortens.






34. All of the cell cycle except for mitosis. Interphase includes G1 - S phase - and G2.






35. A string of sarcomeres with a skeletal muscle cell (hence smaller than myofiber). Each muscle cell contains hundreds of myofibirils.






36. A cell produced when a B cell is activated by antigen. Memory cells do not actively fight the current infection - but patrol the body in case of future infection with the same antigen. If the antigen should appear again the future - memory cells are






37. The second phase of meiosis II. Metaphase II is identical to mitotic metaphase - except that the number of chromosomes was reduced by half during meiosis I.






38. The primary membrane lipid. Phospholipids consist of a glycerol molecule esterified to two fatty acid chains and a phosphate molecule. Additional - highly hyrohpilic groups are attached to the phosphate - making this molecule extremely amphipathic.






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






40. The membrane surrounding the DNA in eukaryotic cells made of two lipid bilayers.






41. A peptide hormone produced and secreted by the alpha cells - of the pancreas. It tartes primarily the liver - stimulating the breakdown of glycogen - thus increasing blood gluocse level.s






42. The first part of the large intestine.






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






44. The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).






45. A blood pressure cuff






46. The amount of energy required to produce the transition state of a chemical reaction. If the activation energy for a reaction is very high - the reaction occurs very slowly. Enzymes (and other catalysts) increase reaction rates by reducing activation






47. A mass of lymphatic tissue at the befenning of the large intestine that helps trap ingested pathogens.






48. The movement of a substance across a membane via pressure. In the kidney - filtration refers specifically to the movement of plasma across the capillary walls fo the glomerulus - into the capsule and tubule of the neprhon. Filtration at teh glomerulu






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






50. The primary androgen (male sex steroid). Testosterone is a steroid hormone produced and secreted by the interstitial cells of the testes. It triggers the development of secondary male sex characteristics during puberty (including spermatogenesis) and