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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 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






2. A duodenal enzyme that activates trypsinogen (from the pancreas) to trypsin.






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






4. The environment in which or upon Which bacteria grow. It typically contains a sugar source and any other nutrients that bacteria may require. 'Minimal medium' contain nothing but glucose.






5. The volume of air inhaled and exhaled in a normla - resting breath - typically about 500 mL.






6. The outermost layer of teh skin. The epidermis is made of epithelial tissue that is constantly dividing at the bottom; teh cells migrate to teh surface (dying along the way) to be sloughed off at the suface.






7. Major Histocompatability complex - a set of proteins found on the plasma membranes of cells that help display antigen to T cells. MHC I is found on all cells and displays bits of proteins from within the cell; this allows T cells to monitor cell cont






8. A type of cell division (in diploid cells) that reduces the number of chromosomes by half. Meiosis usualy produces haploid gametes in organisms that undergo sexual reproduction. It consists of a single interphase (G1 - S - and G2) followed by two set






9. 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.






10. 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.






11. 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.






12. A carrier protein that transports a single molecule across the plasma membrane.






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






14. The newly forming daughter strand of DNA that is replicated in a discontinuous fashion - via Okazaki fragments that will ultimately be ligated together; the daugther strand that is replicated in the opposite direction that parallel DNA is unwinding






15. The sequence of nucleotides on a chromosome that activates RNA polymerase so that transcription can take place. The promoter is found upstream of the start site - the location where transcription actually takes place.






16. A neuron found completely within the central nervous system. Interneous typically connect sensory and motor neurons - especially in reflex arcs.






17. 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.






18. An organism that relies on a chemical source of energy (such as ATP) instead of light (which phototrophs).






19. The tube that connects the middle ear acity with the pharynx; also known as the Eustachian tube. Its fucntion is to equalize midle ear pressure with atmospheric pressure so that pressure on boths sides of the tympanic membrane is the same.






20. The 28 days of the menstrual cycle as they apply to events in the ovary. The ovarian cycle has three subphases: the follicular phase - ovulation - and the luteal phase.






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






22. Salivary amylase






23. All the genetic information in an organism; all of an organism's chromosomes.






24. The bond formed between the carboxyl group of one amino acid and the amino group of another.






25. The second phase of the uterine (endometrial) cycle - during which the endometrium (shed off during menstration is rebuilt). This phase of the cycle is under the control of estrogen - secreted from the follicle developing in the ovary during this tim






26. The stoppage of bleeding; blood clotting.






27. The phase of mitosis during which the cell physically splits into two daugter cells. Cytokinesis begins near the end of anaphase - and is completed during telophase.






28. The enzyme that catalyzes the phosphorylation of fructose -6- phosphate to form fructose -1-6- bisphosphate in the third step of glycolysis. This is the main regulatory step of glycolysis. PFK is feedback - inhibited by ATP.






29. Paired masses of lymphatic tissue near the back of the throat that help trap inhaled or swallowed pathogens.






30. (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.






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






32. The principal mineralocorticoid secreted by teh adrenal cortex. This steroid hormone targets the kidney tubules and increases renal reabsorption of sodium [and excretion of potassium]. (this causes ADH to be secreted & increased water comes out - inc






33. The blood vessels taht carry blood to and from cardiac muscle. The coronary arteries branch off teh aorta and carry oxygenated blood to the cardiac tissue. The coronary veins collect deoxygenated blood from teh cardiac tissue - merge to form teh coro






34. A normal component of the outer membrane of Gram - negative bacteria. Endotoxins produce extreme immune reactions (septic shock) - particularly when many of them enter the circulation at once.






35. A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.






36. 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






37. Diploid cells resulting from the activation of anoogoium; primary oocytes are ready to enter meiosis I. remember: cyte means ready to undergo meiosi






38. 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.






39. The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).






40. Also called occluding junctions - tight junctions form a seal between cells that prevents the movement of substances across the cell layer - except by diffusion through the cell membranes themselves. Tight junctions are found between the epithelial c






41. A gene appearing in a single copy in diploid organisms - e.g. X- linked genes in human males.






42. 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






43. A cytoplasmic protein that recognizes the signal sequences of proteins destined to be translated at the rough ER. It binds first to the ribosome translating the protein with the signal sequence then to an SRP receptor on the rough ER>






44. An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.






45. 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.






46. Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision.






47. The 3D site of an enzyme where substrates (reactants) bind and a chemical reaction is facilitated.






48. The reactants in an enzyme - catalyzed reaction. Substrate binds at the active site of an enzyme.






49. A receptor that responds to changes in temperature.






50. The newly forming daughter strand of DNA that is replicated in a continuous fasion; the daughter strand that is replicated in thes aem direction that parental DNA is unwinding.