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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 person with blood type O-. Because this person's red blood cells possess none of the typical blood suface proteins - they cannot initiate an immune reaction in a recipient.






2. The clear portion of the tough outer layer of teh eye ball - found over the iris and pupil






3. Bacteria that have a thick peptido glycan cell wall - and no outer membrane. They stain very darkly (purple) in Gram stain.






4. A tropic hormone produced by the anterior pituitary gland that targets the thyroid gland - stimulating it to produce and release thyroid hormone.






5. Also called falopian tubes - these tubes extend laterally from their side of the uterus and serve as a passageway for the ocyte to travel from the ovary to the uterus. This is also the normal site of fertilization. Severing of the uterine tubes (tuba






6. (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.






7. A cyclic version of adenosine monophosphate - where the phosphate is esterified to both the 5' and 3' carbons - forming a ring. Cyclic AMP is an important intracellular signaling moelcule - often called the 'second messenger.' It serves to activate c






8. The fourth (and final) phase of mitosis. During telophase the nuclear envelope reforms - chromosomes decondense - and the mitotic spindle is disassembled.






9. A viral life cycle in which the host is turned into a 'virus factory' and ultimately lysed to release the new viral particles.






10. 'Yellow body.' The remnants of an ovarian follicle after ovulation has occurred. The cells enlarge and begin secreting progesterone - the dominant female hormone during the second half of the menstrual cycle. Some estrogen is also secreted.






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






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






13. Excitatory postsynaptic potential; a slight depolarization of a postsynaptic cell - bringing the membrane potential of that cell closer to the threshold for an action potential.






14. A statistical rule stating that the probability of either of two indpendent (and mutually exclusive) events ocuring is the sum of their individual probabilities minus the probability of them both occuring together.






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






16. The capillaries that surround the tubules of the nephron. The vasa recta reclaims reabsorbed substances - such as water and sodium ions.






17. 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






18. A peptide hormone produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body - especially the liver and muscle - and allows them to take glucose out of gthe blood (thus lowering blood glucose levels).






19. 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






20. The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage the organs formed in the embryonic stage grow and mature. The developing baby is known as a fetus during this time






21. An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate - which are delivered to the small intestine via the pancreatic duct. The second is an endocrine role: to secrete insulin an






22. 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.






23. Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.






24. The secon phase of mitosis. During metaphase chromosomes align at the center of the ell (the metaphase plate).






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






26. 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.






27. 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.






28. The middle (approximtely 40%) of the small intestine.






29. The process of breaking down large molecules into smaller precursors - e.g. digesion of starch into glucose.






30. The depolarzation of the motor end plate on a muscle cell.






31. The stage of human development during which the organs are formed. Organogenesis begins after gastrulation and is completed by the eight week of gestation.






32. The period of time during which the ventricles of the heart are contracted.






33. 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






34. One of the two small chambers in the heart that receive blood and pass it on to the ventricles. The right atrium receives deoxygenated blood from teh body through the superior and inferiro vena cavae - adn the left atrium receives oxygenated blood fr






35. 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.






36. 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.






37. (1) The integration of input (EPSPs and IPSPs) from many presynaptic neruons by a single postsynaptic neuron - either temporaly or spatially. Summation of al input can either stimulate the postsynaptic neuron and possibly lead to an action potential






38. A contractile protein. In skeletal and cardiac muscle - actin polymerizes (along with other proteins) to form the thin filaments. Actin is involved in many contractile activities - such as cyotkinesis - pseudopod formation - and muscle contraction.






39. A hormone released by teh G cells of the stomach in the presence of food. Gastrin promotes muscular activity of the stomach as well as secretion of hydrochloric acid - pepsinogen - and mucus.






40. The contribution of an individual gas to the total ppressure of a mixture of gases. Partial pressures are used to describe the amounts of the various gases carried in the bloodstream.






41. One of the three primary (embryonic) germ layers formed during gastrulation. Mesoderm ultimately forms 'middle' structures such as bones - muscles - blood vessels - heart - kindeys - etc.






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






43. Movement across the membrane of a cell that does not require energy input from the cell. Passive transport relies on concentration gradients to provie the driving force for movement - and includes both simple and facilitated diffusion.






44. 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.






45. The duct that carries bile from the gallbladder and liver to the small intestine (duodenum).






46. 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.






47. The percentage of wholeblood made up of erythrocytes The typical hematocrit value is between 40-45%.






48. A microscopic space between the axon of one neuron and the cell body or dendrites of a secon neruon - or between the axon of a neuron and an organ.






49. One of the three primary (embryonic) germ layers formed during gastrulation. Endoderm ultimately forms internal structures - such as the inner lining of the GI tract and glandular organs.






50. A regulatory protein that binds DNA at a specific nucleotide sequence (sometimes known as the operator) to prevent transcription of downstream genes.