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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. 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.






2. The perio dof tim ein a woman's life when ovulation and menstruation cease. Menopause typically begins in the late 40s.






3. The first portion of the nephron tubuel after the glomerulus. THe PCT is the site of most reabsorption; all filtered nutrients are reabsorbed here as well as most of the filtered water.






4. A region within the nucleus where rRNA is transribed and ribosomes are partially assembled.






5. A protein embedded in the lipid bilayer of a cell. These are typicallly cell surface receptors - channels - or pumps.






6. 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






7. The portion of the hindbrain that controls respiratory and blood pressure - and specialized digestive and respiratory functions such as vomiting - sneezing - and coughing.






8. A chemical released by the axon of a neuron in response to an action potential that binds to receptors on a postsynaptic cell and causes that cell to either depolarize slightlly (EPSP) or hyperpolarize slightly (IPSP). Examples are acetylcholine - no






9. A cell characterized by the presence of a nucleus and other membrane - bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi - plants and animals).






10. Large conglomerations of proteins - fats - and cholesterol that transport lipids in the bloodstream. (chylomicrons are a type of lipoprotein).






11. A structure composed of a ring of nine microtube triplets - found in pairs in the MTOC (microtubule organizing center) of a cell. The centrioles duplicate during the cell division - and serve as the organizing center for the mitotic spindle.






12. In skeletal and cardiac muscle tissue - a filament composed of bundles of myosin molecules. The myosin head groups attach to the thick filaments and pull the toward the center of the sarcomere during muscle contraction.






13. 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






14. A region of specialized cardiac muscle cells in the right atrium of the heart that initiate the impules of heart contraction; for this reason the SA node is knownas the 'pacemaker' of the heart.






15. An organism that has only a single copy of its genome in each of its cells. Haploid organisms possess no homolous chromosomes.






16. An enzyme that cuts one or both strands of DNa to relieve the excess tension caused by the unwinding of the helix by helicase during replication.






17. A strong band of connective tissue that connets bones to one another.






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






19. One of the main pancreatic proteases; it is activated (from chymotrypsinogen) by trypsin.






20. 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.






21. The second most common of the five classes of leukocytes. Lymphocytes are involved in specific immunity and include two cell types - B- cells and T cells. B- cells produce and secrete antibodies and T- cells are invovled in cellular immunity.






22. A blood pressure cuff






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






24. A smooth sustained muscle contraction - such as occurs in skeletal muscle when stimulation frequency is high enough (this is the normal type of contraction exhibited by skeletal muscle).






25. One of the two peripheral nervous system supporting (glial) cells. Schwann cells from he myelin sheath on axons of peripheral neurons.






26. A subset of a species consisting of members that mate and reproduce with one another.






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






28. 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).






29. An organism that makes its own - typically using CO2 as a carbon source.






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






31. A long - whip - like filament that helps in cell motility. Many bacteria are flagellated - and sperm are flagellated.






32. An ion channel that is constitutively open - allowing the movement of teh ion across the plasma membrane according to its concentration gradient.






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






34. 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.






35. Cells that make up exocrine galnds - adn that secrete their products into ducts. For example - in the pancreas - acinar cells secrete digestive enzyme; in the salivary glands - acinar cells secrete saliva.






36. 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.






37. Specialized tissue with a lot of space that can fill with blood upon proper stimulation - causing teh tissue to become firm. Erectile tissue is found in the penis - the clitoris - the labia - and the nipples.






38. A globular protein that ssociated with tropomyosin as part of the thin filament of the sarcomere. Troponin binds Ca2+ - which causes the conformaiton change in tropomyosin required to expose the myosin - binding sites on actin and initiate muscle con






39. A physiological catalyst. Enzymes are usually proteins - although some RNAs have catalytic activity.






40. A short sequence of amino aids - usually found at the N- terminus of a protein being translated - that directs the ribosome and its associated mRNa to the membranes of the rough ER where trasnlation will be completed. Signal sequences are found on me






41. The inner layer of smooth muscle in the wall of the digestive tract. When the circular muscle contracts - the tube diameter is reduced. Certain areas of the circular muscle are thickened to act as valves (sphincters).






42. The layer of epithelial tissue that lines body cavities in contact with the outside environment (respiratory - digestive - urinary - and reproductive tracts).






43. A general cell junction - used primarily for adhesion.






44. Mal sex hormones. Testosteron is the primary androgen.






45. A hormone released by the anterior pituitary that targets all cells in the body. Growth hormone stimulates whole body growth in children and adolescents - adn increases cell turnover rate in adults.






46. The space between the inner and outer cell membranes in Gram - negative bactera. The peptidoglycan cell wall is found in the periplasmic space - and this space sometimes contains enzymes to degrade antibiotics.






47. The ends of a saromere.






48. An enzyme secreted by the juxtaglomerular cells when blood pressure decreases. Renin onverts angiotensinogen to angiotensin I.






49. The physical characterisitcs resulting from the genotype. Phenotypes are usually described as dominant or recessive.






50. The valve that controls the release of urine from the bladder. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).