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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. '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.






2. An organelle bounded by a double membrane (double lipid bilayer) called the nuclear envelope. The nucleus contains the genome and is the site of replication and transcription.






3. The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that secrete renin upon sensing a decrease in blood pressure.






4. Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.






5. A pigmented membrane found just in from the lens of the eye. In the center of iris is the pupil - a hole through which light enters the eyeball. The iris regulates the diameter of the pupil in response to the brightness of light.






6. 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.






7. A small cell with extremely little cytoplasm that results from the unequal cytoplasmic divsion of the primary (produces the first polar body) and the secondary (produces the second polary body) oocytes during meiosis (oogenesis). The polar bodies deg






8. One of several vessels that carry oxygenated blood from the lungs to the left atrium of the heart.






9. The ball of capillaries at the beginning of the nephron where blood filtration takes place.






10. A toxin that secreted by a bacterium into its surrounding medium that help the bacterium compete with other species. Some exotoxins cause serious disease in humans (botulism - tetanus - diptheria - toxic shock syndrome).






11. The first substrate in teh Krebs cycle - produced primarily from the oxidation of pyruvate by the pyruvate dehydrogenase complex - however acetyl - CoA is also produced during fatty acid oxidation and protein catabolism.






12. The relationship of muscle length to its ability to generate strong contractions. Maximum tension (contraction strength) is achieved at sarcomere lengths between 2.0 and 2.2 microns. Tension decreases outside of this range <-- remember.






13. The fourth (and final) phase of mitosis. During telophase the nuclear envelope reforms - chromosomes decondense - and the mitotic spindle is disassembled.






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






15. An intracellular chemical signal (such as cAMP ) that relays instructions from the cell surface to enzymes in the cytosol.






16. The stoppage of bleeding; blood clotting.






17. A receptor that responds to light






18. A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.






19. The return of membrane potential to normal resting values after a depolarization of hyperpolarization.






20. The attachment of an amino acid to a tRNA (not that this a specific interaction). tRNa loading requires two high - energy phosphate bonds.






21. The reduced form of NAD+ (nicotinamide adenine dinucleotide). This is the most common electron carrier in cellular respiration.






22. A hair - like structure on teh cell surface composed of microtubules ina '9+2' arrangement (nine pairs of microtubles surrounding 2 single microtubules in the center). Teh microtubules are conneted with a contractile protien called dynein. Cilia beat






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






24. The flexible membrane in teh chochlea that supports the organ of Corti (structure which contains the hearing receptors). The fibers of the basilar membrane are short and stiff near the oval windown and long and fleaxible near the apex of the cochlea.






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






26. 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






27. A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS).






28. The amount of blood returned to heart by the vena cavae.






29. The portion of the nephron after the glomerulus and apsule; the region of the nephron where the filtrate is modified along its path to becoming urine.






30. The division between neighboring cardiac muscle cells. Intercalcated discs include gap junctions - which allow the cells to function as a unit.






31. The largest artery in teh body; the aorta carries oxygenated blood away from the left ventricle of the heart.






32. The collection of fluid in the alveoli - particularly dangerous because it impedes gas exchange. Common causes of pulmonary edema are increased pulmonary blood pressure or infection of the respiratory system.






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






34. A molecule composed of two monosaccharides. Common disaccharides include maltose - sucrose - and lactose.






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






36. 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.






37. The main duct of the pancreas. The pancreatic duct carries the exocrine secretions of the pancreas (enzymes and bicarbonate) to the small intestine (dueodenum).






38. The ends of a saromere.






39. The 'blind spot' of the eye - this is where the axons of the ganglion cells exist the retinal to form the optic nerve. There are no photoreceptors in the optic disk.






40. A period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation. (usually because Na+ channel closed whle K+ efflux)






41. The 3' end of a tRNA molecule that binds an amino acid. The nucleotide sequence at this end is CCA






42. A pair of similar chromosomes that have the same genes in the same order - but may have different versions (alleles) of those genes. One of the pair of chromosomes came from Mom in an ovum - and the other came from Dad in a sperm. Humans have 23 pair






43. The cells of the distal tubule at the juxtaglomerular apparatus. They are receptors that monitor filtrate osmolarity as a means of regulatin filtration rate. If a drop is osmolarity is sensed - the macula densa dilates the afferent arteriole (to incr






44. A long projection off the cell body of a neruon down which an action potential can be propagated.






45. Steroid hormones secreted from the adrenal cortex. The two major classes are teh mineralocorticoids and glucocorticoids. Aldosterone is the principal mineralocorticoid - and cortisol is the principal glucorcorticoid.






46. The pressure measured in the arteries while the ventricles are relaxed (during diastole).






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






48. DNA that is loosely packed around histones. This DNA is more accessible to enzymes and the genes in euchromatin can be activated if needed.






49. The plasma membrane of a muscle cell.






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