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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 connection of a mosin head group to an actin filament during muscle contraction (the sliding filament theory).






2. The muscular femal organ - in which a baby develops during pregnancy.






3. Molecules made from monosaccharides that serve as the primary source of cellular energy -. Carbohydrates can also act as cell surface markers (good thing to remember).






4. A string of several hundred adenine nucletodies added to the 3' end of the eukaryotic mRNA.






5. The movement of a substance from the filtrate (in the renal tuble) bak into the bloodstream. Reabsorption reduces the amount of a substance in the urine.






6. A fibrous protein found on the intracellular side of the plasma membrane (also associated with the Golgi complex) that helps invaginate the membrane. Typically cel surface receptors are associated with clathrin - coated pits at the plasma membrane bi






7. A sensory receptor that responds to hcanges in pressure; for example - there are baroreceptors in the carotid arteries and the aortic ach that monitor blood pressure.






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






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






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






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






12. The formatino of the nervous system during weeks 5-8 of gestation. Neuralation begins when a section of the ectoderm invaginates and pinches off to form the neural groove - which ultimately forms the neural tube - From which the brain and spinal cord






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






14. A lipid bilayer that surrounds the capsid of an animal virus. the envelope is acquired as teh virus buds out through the plasma membrane of its host cell. Not all annimal viruses possess and envelope.






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






16. A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.






17. Extremely small pseudo - cells in the blood - important for clotting. They are not true cells - but are broken - off bits of a larger cell (a megakaryocyte).






18. The theory that mitochondria and chloroplasts originated as independent unicellular organsims living in symbiosis with larger cells






19. (1) In the GI tract - organs that play a role in digestion but not directly part of the alimentary canal. These include the liver - the gallbladder - the pancreas - adn the salivary glands.






20. A method of DNA protection utilized by prokaryotes in which their large circular chromosome is coiled upon itself.






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






22. The primary enzyme in peroxisomes; catalse catalyzes the hydrolysis of hydrogen peroxide (H2O2) into water and oxygen.






23. 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.






24. An organism that lacks a nucleus or any other memrane - bound organelles. All prokaytes belong to the Kingdom Monera (not protista!)






25. Pairing of homologus chromosomes in a diploid cell - as occurs during prophase I of meiosis.






26. The flow of blood from the heart - through the lungs - and back to the heart.






27. The valves in the heart that separte the atria from teh ventricles. The tricuspid valve separates teh right atrium from the right ventricel - and the bicuspid (mitral) valves separates the left atrium from the left ventricle. These valves close at th






28. A protein found in the plasma membrane of all cells in the body that uses the energy of an ATP (hydrolyzes ATP) to move three Na+ ions out of the cell and two K+ ions into the cell - thus establishing concentrations gradients for these ions across th






29. The fourth of meiosis I. Telophase I is identical to mitotic telophase - except that the number of chromosoms is now reduced by half. After this phase the cell is considered to be haploid. Note however - that the chromosomes are still replicated - an






30. The hollow center of an osteon - also known as a Haversian canal. The central canal contains blood vessels - lymphatic vessels - lymphatic vessels - and nerves. Bone is laid down around the central canal in concentric rings called lamellae.






31. The portion of the digestive tract that stores and grinds food. Limited digestion occurs in the somach - and it has the lowest pH in the body (1-2).






32. 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






33. One of several different nutrietns that must be consumed in the diet - and generally not synthesized in the body. Vitamins can be hdyrophobic (fat - solube) or hydrophilic (water - soluble).






34. Also called simply - 'islet cells' these are the endocrine cells of the pancreas. Different cell types wihtin the inslets secrete insulin - glucagon - and somatostatin






35. The loop of the nephron that dips downward into the renal medulla. The loop of Henle sets up a concentration gradient in the kidney such that from the cortex to the renal pelvis osmolarity increases. The descending limb of the loop of Henle is permea






36. 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.






37. A situation in which a heterozygote displays the phenotype associated with each of the alleles - e.g. - human blood type AB.






38. 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).






39. 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






40. The synapse between a motor neuron and a muscle cell. At the NMJ - the muscle cel lmembrane is invaginated and the axon terminus is elongated so that a greater area of membrane can be depolarized at one time.






41. A protein channel in a cell membrane that is specific for a particular ion - such as Na+ or K+. Ion channels may be constitutively open (leak channels) - or regulated (voltage - gated or ligand - gated).






42. A haploid but immature cell resulting from the second meiotic division f spermatogenesis. Spermatids undergo significant physical changes to become mature sperm (spermatozoa).






43. The movement of teh membrane potential of a cell away from rest potential in a more positive direction.






44. 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.






45. A molecule formed by joining many monosaccharides together. POlysaccharides are typically energy- storage molecules (glycogen in animals - starch in plants) or structural molecules (cellulose in plants - chitin in exoskeletons).






46. The clear portion of the tough outer layer of teh eye ball - found over the iris and pupil






47. The portion of the nephron tubule after the loop of Henle - but before teh collecting duct. Selective reabsorption and secretion occur here - most notably regulated reabsorption of water and sodium.






48. The folds of skin that enclose the vaginal and urethral openings of females.






49. A blood pressure cuff






50. 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.)