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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 layer of cells surroudning the granulosa cells of the follicles in an ovary. Thecal cells help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle.






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






3. Cells that form the walls of the seminiferous tubules and help in spermatogenesis Sertoli cells are also called susenacular cells.






4. Receptors in the central nervous system that monitor the pH of cerebrospinal luid to help regulate ventilation rate.






5. Physical structures in two different organism that have funcitonal similarity due to their evoluntion in a common environment - but have different underlying structure. Analogous structures arise from convergent evolution.






6. The layer of connective tissue directly under the mucosa of an open body cavity.






7. 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.






8. 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






9. A short period of time **prior to exponential growth of a bacterial population during which no - or very limited - cell division occurs.






10. An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).






11. All parts of the nervous system except for the brain and spinal cord.






12. Lacking a blood supply; cartialge is an example of this






13. 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.






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






15. The three small bones found in the middle ear (the malleus - the incus - and the stapes) that help to amplify the vibrations from sound waves. The malleus is atached to the tympanic membrane and the stapes is attached to the oval window of the cochle






16. A passageway leading from behind the nasal cavity to the trachea. The pharynx is divided into three regions - named for their location. The nasopharynx is behind the nasal cavity - the oropharynx is behind the oral cavity - and the laryngopharynx is






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






18. A chemical derived from vitamin A found in the pigment proteins of the rod photoreceptors of the retina. Retinal changes conformation when it absorbs light - triggering a series of reactions that ultimately result in an action potential being sent to






19. A hole in the center of the iris of the eye that allows light to enter the eyeball. The diameter of pupil is controlled by the iris in response to the brightness of the light.






20. An insulating layer of membranes wrapped around the axons of almost all neurons in the body. Myelin is essentially the plasma membranes of specialized cells; Schwann cells in the peripheral nervous system - and oligodendrocytes in the central nervous






21. Aromatic bases found in DNA and RNA that are derived from purine. They have a double rightn structure and include adenine and guanine.






22. A blood protein produced by the liver. Albumin helps to mantain blood osmotic pressure (oncotic pressure)






23. A fluid - filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.






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






25. A mutation caused by an insertion or deletion of base pairs in a gene sequence in DNA such that the reading frame of the gene (and thus teh amino acid sequence of the protein) is altered.






26. The osmotic pressure in the blood vessels due only to plasma proteins (primarily albumin) --> causes water to rush back into capillaries at end.






27. A band of carilage (hyaline) found between the diaphysis and epiphyses of long bones during childhood and adolescence. Cell proliferation in the middle of the eiphyseal plate essentially forces teh diaphysis and epiphyses further apart - while the ol






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






29. A sequence of three nucleotides (found int he anticodon loop of tRNA) that is complementary to a specific codon in mRNA. The codon to which the anticodon is complementary specifies the amino acid that is carried by that tRNA.






30. A large - ring shaped lipid found in cell membranes. Cholesterol is the precursor for steroid hormones - and is used to manufacture bile salts.






31. A contractile protein connecting microtubules in the '9+2- arrangement of cilia and eukaryotic flagella. The contraction of dynein produces the characteristic movement of these structures.






32. A region at the head of a sperm cell that contains digestive enzyems which - when released during the acrosome reaction - can facilitate penetration of the corona radiata of the egg - and subsequently - fertilization






33. The smallest (and final) fibers in the cardiac conduction system. The Purkinje fibers transmit the cardiac impulse to the ventricular muscle.






34. The region at the center of an A band of a sarcomere that is made up of myosin only. The H zone gets shorter (and may disappear) during muscle contraction.






35. The third phase of the uterin (endometrial) cycle - during which the rebuilt endometrium is enhanced with glycogen and lipid stores. The secretory phase is primarily under the controll of progestone and estrogen (secreted from the copus luteum during






36. High frequency of recombination bacterium An F+ bacterium that has the fertility factor integrated into its chromosome. When conjugation takes place - it is able to transfer not only the F factor - but also its genomic DNA.






37. The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at teh AV node - allowing the ventricles to contract just after the atria contract.






38. An amphipathic molecule secreted by cells in the alveoli (type 2 alveolar cells) tha reducs surface tension on the inside of the alveolar walls. This prevents the alveoli from collapsing upon exhale and sticking together - thus reducing the effort re






39. The membranes that line the surface of the lungs (visceral pleura) and the inside wall of the chest cavity (parietal pleura).






40. 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).






41. A hormone produced and secreted by teh adrenal medulla that prolongs and increases teh effects of the sympathetic nervous system.






42. A skeletal muscle cell - also known as a muscle fiber. Skeletal muscle cells are formed from the fusion of many smaller cells (during development) consequently they are very long and are multinucleate.






43. A small gland encircling the male urethra just inferior to the bladder (only reproductive structure not paired). Its secretion contain nutrients and enzymes and account for approximately 35% of the ejaculate volume.






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






45. The location on a chromosome where transcription begins.






46. A prokaryotic enzyme used to twist teh single circular chromosome of prokaryotes upon itself to form supercois. Supercoiling helps to compact prokaryotic DNa and make it sturdier.






47. Messenger RNA; the type of RNa that is read by a ribosome to synthesize protein.






48. Small paired gland found inferior to the prostate in males and at the posterior end of the penile urethra. They secrete an alkaline mucus on sexual arousal that helps toneutralize any traces of acidic urine the urethra that might be harmful to sperm.






49. A type of synapse at which a chemical (a neurotransmitter) is released from teh axon of a neuron into the ysnaptic cleft where it binds to receptors on the next structure in sequence - either another neuron or an organ.






50. A nucleotide sequence in RNA that contains protein - coding information. Exons are typically separated by introns (intervening sequences) that are spliced out prior to translation.