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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. Myelinated axons






2. 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.






3. 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






4. The region of teh brain that coordinates and smooth skeletal muscle activity.






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






6. The division of the periperal nervsous system that innervates and cotnrols the visceral organs (everything but the skeletal muscles). It is also knowns as the involuntary nervous system and an be subdivided into the sympathetic and parasympathetic di






7. 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






8. The maintenance of relatively constant internal conditions (such as temperature - pressure - ion balance - pH - etc.) regardless of external conditions.






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






10. A point mutation in which a codon that specifies an amino acid is mutated into a new codon that specifies the same amion acid.






11. The intracellular process triggered by the binding of a ligand to its receptor on the cell surface. Typically this activates seond messenger pathways.






12. 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.






13. 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






14. 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






15. The product of glycolysis; 2 pyruvic acid (pyruvate) molecules are produced from a single glucose molecule. In the absence of oxygen - pyruvic acid undergoes fermentation and is reduced to either lactic acid or ethanol; in the presence of oxygen - py






16. The tube that carries urine from the bladder to the to outside of the body. In males it also carries semen and sperm during ejaculation.






17. The relationship of muscle length to its ability to generate strong contractions. Maximum tension (contraction strength) is achieved at sarcomere lengths between 2.0 and 2.2 microns. Tension decreases outside of this range <-- remember.






18. A version of a gene. For example - the gene may be for eye color - and the allels include those for brown eyes - those for blu e eyes - those green eyes - etc. At most - dploid organsims can posses only two alleles for a given gene - one on each of t






19. The maximal volume of air that the lungs can contain. Total lung capacity is the sum of the vital capacity and the residual volume - and is typically about 6000 mL (6L).






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






21. A group of blood proteins that bind non - specifically to the surface proteins of foreign cells (such as bacteria) - ultimately leading to the destruction of the foreign cell - part of the innate immunity.






22. The fusion of a sperm with an ovum during sexual reproduction. Fertilization typically occurs in the uterine tubes and requires capacitation of the sperm and relase of the acrosomal enzymes. Fertilization is a species - specific process - requiring b






23. The white portion of teh tough outer layer of the eyeball






24. The movement of a substance across a membane via pressure. In the kidney - filtration refers specifically to the movement of plasma across the capillary walls fo the glomerulus - into the capsule and tubule of the neprhon. Filtration at teh glomerulu






25. The third phase of mitosis. During anaphase - replicated chromosmes are split apart at their centromeres (the sister chromatids are separated from each other) and moved to opposite sides of the cell.






26. A nonliving - intracellular parasite. Viruses are typically just pieces of nucleic aid surrounded by a protein coat.






27. The process of bulidng complex structures out of simpler precursors - e.g. synthesizing protiens from amino acids.






28. A protein channel in a cell membrane that is specific for a particular ion - such as Na+ or K+. Ion channels may be constitutively open (leak channels) - or regulated (voltage - gated or ligand - gated).






29. Sperm production; occurs in human males on a daily basis from puberty until death. Spermatogenesis results in the production of four mature gametes (sperm) from a single precursor cell (spermatogonium). For maximum sperm viability - spermatogenesis r






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






31. A region within the nucleus where rRNA is transribed and ribosomes are partially assembled.






32. 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






33. A type of white blood cell; leukocytes are either B or T cells and are involved in disease defense.






34. '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.






35. A nucleotide sequence on DNA that contians three elemtns: a coding sequence for one or more enzymes - *a coding sequence for a regulatory protein - and upstream regulatory sequences where the regulatory proteins can bind. An example is the lac operon






36. Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.






37. A globular protein that ssociated with tropomyosin as part of the thin filament of the sarcomere. Troponin binds Ca2+ - which causes the conformaiton change in tropomyosin required to expose the myosin - binding sites on actin and initiate muscle con






38. The central structure of the diencephalon of the brain. the thalamus acts as a relay station and major integrating area for sensory impulses.






39. 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






40. An embryonic structure particularly important in egg - laying animals because it contains the yolk - the only source of nutrients for the embryo developing inside the egg. In humans - the yolk sac is very small (since mammals get their nutrients via






41. An activated B cell that is secreting antibody.






42. Cranial nerve pair X. The vagus nerves are very large mixed nerves (They carry both sensory input and motor input) that innervate virtually every visceral organ. They are especially important in transmitting parasympathetic input to the heart and dig






43. A thick muscular tube that connects the epididymis of the testes to the urethra. Muscular contractions of the vas deferns during ejaculation ehp propel the sperm outward. Severing of the vas deferens (vasectomy) results in sterility of the male.






44. A situation in which a heterozygote displays the phenotype associated with each of the alleles - e.g. - human blood type AB.






45. An integral membrane protein that undergoes a conformational change to move a molecule from one side of the membrane to another. See also 'uniporter' - 'antiporter' - and 'symporter'.






46. The basic functional and structural unit of the nervous system. The neuron is a highly specialized cell - designed to transmit action potentials.






47. 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.






48. The pituitary gland.






49. A vein connecting the capillary bed of the intestines with the capillary bed of the liver. This allows amino acids and gluocse absorbed from the intestines to be delivered first to the liver for processing before being transported throughout the circ






50. The characteristics of amolecule that has both polar (hydrophilic) and non - polar hydrophobic) regions - e.g. phospholipids - bile - etc.