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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. Also called transverse tubules - these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.






2. The tendency of certain factors to stablize the hemoglobin in the tense conformation - thus reducing its affinity for oxygen and enhancing the relase of oxygen to the tissues. The factors include increased PCO2 - increase temperature - increased bisp






3. The duplication of DNA






4. The final portion of the large intestine.






5. A situation in which a heterozygot displays a blended version of the pheotypes associated with each allele - e.g. pure - breeding white - flowered plants crossed with pure - breeding red - flowered plants produces heterozygous offspring plants with p






6. The three glands in the male reproductive system that reproduce semen: the seminal vesicles - the prostate - and the






7. The valvecontrolling release of bile and pancreatic juice into the bloodstream.






8. One of the four aromatic bases found in DNA and RNA; also a component of ATP - NADH - and FADH2. Adenine is apurine; it pairs with thymine (in DNA) and with uracil (in RNA)






9. The 28 days of the menstrual cycle as they apply to the events in the uterus. The endometrial cycle is also known as the uterine cycle - and has the three subphases: menstruation - the proliferative phase - and the secretory phase.






10. A clear fluid the circulates around through the brain and spinal cord that helps to physially support teh brain and act as a shock absorber - and taht also exchanges nutrients and wastes with teh brain and spinal cord.






11. Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.






12. Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node - thus increasing the speed of conduction (saltatory conduction).






13. 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






14. The mechanism that ensures tehat skeletal muscle contraction does not occur without neural stimulation (excitation). A trest - cytosolic [Calcium] is low - and the troponin - tropomyosin complex covers the myosin - binding sites on actin. When the mu






15. Arise in blood pH due to hyperventilation (excessive breathing) and a resulting decrease in CO2.






16. A protein hormone secreted by sustenacular cells of the testes that acts to inhibit the release of FSH and LH from the anterior pituitary.






17. One of the four aromatic bases found in DNA and RNA. Cytosine is a pyrimidine; it pairs with guanine.






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






19. An ion channel that is oepend or closed based on the electrical potential across the plasma membrane. Once opened - the channel allows ions to cross the membrane according to their concentration gradients. Examples are the Na+ and K+ voltage - gated






20. 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.






21. The first phase of mitosis. During prophase the replicated chromosomes condense - the spindle is formed - and the nuclear envelope breaks apart into vessicles.






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






23. An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.






24. Having the ability to become anything; a zygote is totipotent.






25. The burrowing of a blastocyst (a developing embryo) into the endometrium of the uterus - typically occuring about a week after fertilizaiton.






26. Also known as the adenohypophysis - the anterior pituitary is made of gland tissue and makes and secretes six different homrones: FSH - LH - ACTH - prolactin - TSH - and growth hormone. The anterior pituitary is controlled b yreleasing and inhibiting






27. A globular protein found in muscle tissue that has the ability to bind oxygen. Myoglobin helps to store oxygen in the muscle for use in aerobic respiration (it does not move - just stays there). Muscles that participate in endurance activities (inclu






28. The volume of blood pumped out the heart in a single contraction.






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






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






31. A phase in the cycle between mitosis and S phase (G1) or between S phase and mitosis (G2). During gap phases the cell undergoes normal activity and growth; G1 may include preparation for DNA replication and G2 includes preparation for mitosis. Note t






32. Also known as the cortical reaction - the slow block invovles an increase in intracellular [Ca2+] in the egg - which causes the release of cortical granules near the egg plasma membrane. This results in the hardening of the zona pellucida and its sep






33. Hardy crystals consisting of calcium and phosphate that form the bone matrix.






34. 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.






35. 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






36. The final section (approximately 55%) of the small intestine.






37. A blood protein essential to blood clotting. The conversion of fibrinogen to its active form (fibrin) is among the final steps in clot formation - and is triggered by thrombin.






38. 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.






39. A point mutation in which a pyrimidine is susbstituted for a pyrimidine - or a purine is substituted for a purine.






40. A genotype in which two identical alleles are possessed for a given gene. The allelles can both be dominant (homozygous dominant) or both be recessive (homozygous recessive)






41. An RNA polymerase that creates a primer (made of RNA) initiate DNa replication. DNA pol binds to the primer and elongates it.






42. 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.






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






44. The monomer of a protein; amino acids hae an amio group on one end fo the molecule and a carboxylic acid group on the other - and of the of 2 different side chains.






45. An **organic molecuel taht associates non - covalently with an enzyme - and that is required for the proper functioning of the enzyme.






46. A protein that is associated with the plasma membrane of a cell - but that is not embedded in the lipid bilayer. Peripheral proteins typically associate with embedded proteins through hydrogen bonding or electrostatic interactions.






47. The prokaryotic ribosome - binding site on mRNA - found 10 nucleotides 5' to the start codon.






48. A drop in blood pH due to hypoventilation (too little breathing) and a resulting accumulation of Co2.






49. 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.






50. The largest bundle of white matter (axons) connecting th two cerebral hemispheres.