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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. The movement of a particle (the solute) in a solution from its region of high concentration to its region of low concentration ( or down it concentration gradient).






2. Chemoreceptors in the upper nasal cavity that respond to odo chemicals.






3. 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






4. A method of DNA protection utilized by prokaryotes in which their large circular chromosome is coiled upon itself.






5. A type of syanpse in which the cells are connected by gap junctions - allowing ions (and therefore an action potential) to spread easily from cell to cell - usually in smooth and cardiac muscle. - compared to chemical synapse.






6. DNA that is densely packed around histones. The genes in heterochromatin are generally inaccessible to enzymes and are turned off.






7. A nucleotide sequence that intervenes between protein - coding sequences. In DNA - these intervening sequences typically contain **regulatory sequences - however - in RNA they are simply spliced out to form the mature (translated) transcript.






8. A tRNA with an amino acid attached. This is made by an animoacyl - tRNA synthetase specific to the amino acid being attache.d






9. A fibrous protein found on the intracellular side of the plasma membrane (also associated with the Golgi complex) that helps invaginate the membrane. Typically cel surface receptors are associated with clathrin - coated pits at the plasma membrane bi






10. 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






11. Identical copies of a chromosome - produced during DNA replication and held together at the centromere Sister chromatids are separated during anaphase of mitosis.






12. The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens - thus if the live pathogen is encountered in the future






13. An X- linked recessive disorder in Which blood fails to clot properly - leading to excessive bleeding if injured.






14. A specialized region at the ends of eukaryotic chromosmes that contains several repeats of a particular DNA sequence. These ends are maintained (in some cells) with the help of a special DNA poymerase called telomerase. In cells that lack telomerase






15. 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






16. The reduction of pyruvate to either ethanol or lactate in order to regenerate NAD+ from NADH. Fermentation occurs in the absence of oxygen - and allow glycolysis to continue under those conditions.






17. A hormone tha tcontrols the release of another hormone.






18. 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.






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






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






21. A mass of lymphatic tissue at the befenning of the large intestine that helps trap ingested pathogens.






22. A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.






23. Cells found in gastric glands that secrete hydrochloric acid (for hydrolysis of ingested food) and gastric intrinsic factor (for absorption of vitamin B-12).






24. The fertilization of an oocyte by more than one sperm. This occurs in some animals - but in humans - blocks to polyspermy exist (the fast block and the slow block) so that only a single sperm can penetrate the oocyte.






25. The portion of the nephron where water reabsorption is regulated via antidiuretic hormone (ADH). Several nephrons empty into each collecting duct - and this is the final region through which urine must passon its way to the ureter.






26. 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.






27. 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.






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






29. A cell produced when a B cell is activated by antigen. Memory cells do not actively fight the current infection - but patrol the body in case of future infection with the same antigen. If the antigen should appear again the future - memory cells are






30. Physical structures in two different organisms that have structural similarity due to a common ancestor - but may have different functions. Homologous structures arise from divergent evolution.






31. A hormone secreted by the small intestine (duodenum) in response to low pH (e.g. - from stomach acid). It promotes the release of bicarbonate from the pancreas to act as a buffer.






32. The nervous system of the gastrointestinal tract. It controls secretion and motility within teh Gi tract - and is linked to the central nervous system.






33. (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






34. A fibrous - connective - tissue protein taht has the ability to recoil to its original shape after being stretche.d Elastin is found in great amounts in lung tissue - arterial tissue - skin - and the epiglottis.






35. A blood vessel that carries blood toward the heart chambers. Veins do not have muscular walls - have valves to ensure that blood flows in one direction only - and are typically low - pressure vessels.






36. The curled structure in the inner ear that contains the membranes and hair cells that transduce sound waves into action potentials.






37. The darkly pigmented middle layer of the eyeball - found between teh sclera (outer layer) and the retina (inner layer).






38. A hormone made of amino acids (in some cases just a single - modified amino acid). Peptide hormones are generally hydrophilic and cannot cross the plasma membranes of cells - thus receptor for peptide hormones must be found on the cell surface. An ex






39. Very small tube or channel - such as is found between lacunae (connecting them together) in compact bone.






40. An enzyme that phosphorylates something else. Kinases are frequently used in regulatory pathways - phosphorylating other enzymes.






41. 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






42. A gene that has effects on several different characteristics.






43. The mass of cells in the blastocyst that ultimately give rise to the embryo and other embryonic structues (the amion - the umbilical vessels - etc.)






44. 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.






45. The first branches of the trachea. There are two primary bronchi - one for each lung.






46. The phase of the cell cycle during which the replicated genome is divided. Mitosis has four phases (prophase - metaphase - anaphase - telophase) and includes cytokinesis (the physical splitting of the cell into two new cells).






47. The sphincter that separates the final part of the small intestine (the ileum) from the fron part of the large intestine (the cecum). It is typically kept contracted (closed) so that chyme can remain in the small intestine as long as possible. The il






48. The portion of the hindbrain that controls respiratory and blood pressure - and specialized digestive and respiratory functions such as vomiting - sneezing - and coughing.






49. Cells that form the walls of the seminiferous tubules and help in spermatogenesis Sertoli cells are also called susenacular cells.






50. A sweat gland located in the dermis of the skin. Sweat consists of water and ions (including Na+ and urea) and is secreted with temperatures rise.