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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 relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus - often without conscious brain involvement.






2. An abdominal organ that is considered part of the immune system. THe spleen has four functions: (1) it filters antigen from the blood (2) it is the site of B cell maturation - (3) it stors blood - and (4) it destroys old red blood cells.






3. The release of milk from the mammary glands via contraction of ducts within the glands. Contraction is stimulated by oxytocin - which is released from the posterior pituitary when the baby begins nursing.






4. Ribosomal RNA; the type of RNA that associates with ribosomal proteins to make a functional ribosome. It is thought that the rRNA has the peptidyl transferase activity.






5. The third phase of meiosis II. During anaphase II the sister chromatids are finally spearated at their centromeres and puled to opposite sides of teh cell. Note that anaphase II is identical to mitotic anaphase - excep the number of chromosmes was re






6. 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






7. A point mutation in which a pyrimidine is substitued for a purine - or vice versa.






8. A non - bony material that fills the hollow spaces inside bones. Red bone marrow is found in regiosn of spongy bone and is the site of blood cell (red and white) production. Yellow bone marrow is found in the diaphysis (shaft) of long bones - is most






9. A bundle of skeletal muscle cells. Fascicles group together to form skeletal muscles.






10. The inner region of the adrenal gland. The adrenal medulla is part of the sympathetic nervous systme - and releases epinephrine (adrenaline) and norepinephrine into the blood when stimuated. These hormones augment and prolon the effects of sympatheti






11. The subdivision of the nervous system consisting of the brain and spinal cord.






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






13. An organism that requires oxygen to survive (aerobic metabolism only).






14. Strong bands of connective tissue that connect skeletal muscle to bone.






15. The division of the autonomic nervous system known as the 'resting and digesting' system. It causes a general decrease in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to the GI tract and d






16. A green fluid made from cholesterol and secreted by teh liver. It is stored and concentrated in the gallbladder. Bile isn an amphipathic molecule that is secreted itno the small intestine when fats are present - adn serves to emulsify the fats for be






17. A hormone secreted by the small intestine (duodenum) in response to the presence of food. It decreases the rate at which chyme leaves the stomach and enters the small intestine.






18. 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.






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






20. 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






21. A dense grwoth of bacteria that covers the surface of a petri dish.






22. A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females LH triggers ovulation and the development of a corpus luteum during the menstrual cycle; in males - LH stimulates the production and release of testosteron.






23. The layer of ciliated - mucus - covered cells in the respiratory tract.The cilia continually beat - sweeping contaminated mucus upward toward the pharynx.






24. The largest organ in the abdominal cavity. The liver has many roles - including procesing of carbohydrates and fats - synthesis of urea - production of blood proteins - production of bile - recycling heme - and storage of vitamins.






25. 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






26. A viral life cycle in which the viral genome is incorporated into the host genome where it can remain dormant for an unspecified period of time. Upon activation - the viral genome is excised from the host genome and typically enters the lytic cycle.






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






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






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






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






31. In the autonomic divison of the PNS - a neuron that has its cell body located in the CNS - and whose axon extends into the PNS to synapse with a second neuron at an autonoic ganglion. (The second neuron's axon synapses with the target axon)






32. Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).






33. (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.






34. The protective - connective tissue wrapping of the central nervous system (the dura mater - arachnoid mater - and pia mater).






35. The exchange of DNA between paired homologus chromosomes (tetrads) during prophase I of meiosis.






36. A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin - coated pit.






37. The set of adult characteristics that develop during puberty under the control of the sex steroids. In males the secondary sex characteristics include enlargement and maturation of the genitalia - growth of facial - body - and pubic hair - increased






38. The cord that connects the embryo of a developing mammal to the placenta in the uterus of the mother. The umbilical cord contains fetal arteries (carry blood toward the placenta) and veins (carry blood away from the placenta). The umbilical vessels d






39. The enzymatic process of reading a strand of DNA to produce a complemenetary strand of RNA






40. The movement of a hydrophobic molecule across the plasma membrane of cell - down its concentration gradient. Since the molecule can esialy interact with the lipid bilayer - no additional help (such as a channel or pore) is required.






41. 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.






42. An organelle surrounded by a double=membrane (two lipid bilayers) where ATP production takes place. The interior (matrix) is where PDC and the Krebs cycle occur - and the inner membrane contains the enzymes of the electron trasport chain and ATP synt






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






44. 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






45. An immune organ located near the heart. THe thymus is the site of T cell maturation and is larger in children and adolescents.






46. Also called negative feedback - the inhibition of an early step in a series of events by the product of a later step in the series. This has the effect of stopping the series of events when the products are plentiful and the series is unnecesseary. F






47. A cytoplasmic protein that binds to a stop codon where it appears in the A- site of the ribosome. Release factors modify the peptidyl transferase activity of the ribosome - such that a water molecule is added to the end of the completed protein. This






48. A lubricating - nourishing fluid found in joint capsules.






49. Fat cell






50. One type of eukaryotic mRNA processing in which introns are removed from the primary transcript and exons are ligated together. SPlicing of transcripts can be different in different tissues.