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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 rapid from of action potential conduction along the axon of a neuron in which the action potential appears to jump from nodde of Ranvier to node of Ranvier.






2. The exchange of DNA between paired homologus chromosomes (tetrads) during prophase I of meiosis.






3. A poysaccharide found in the cell walls of fungi and in the exoskeletons of insects.






4. An enzyme that connects two fragments of DNA to make a single fragment; also called DNA ligase. This enzyme is usedd during DNA replication and is also used in recombinant DNA research.






5. The opening to the uterus The ervix is typically plugged with a sticky acidic mucus during non - fertile times (to form a barrier against the entry of pathogens) - however during ovulation the mucus becomes more watery and alkaline to facilitate sper






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






7. 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.






8. 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






9. 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






10. A long - whip - like filament that helps in cell motility. Many bacteria are flagellated - and sperm are flagellated.






11. 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






12. Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.






13. An amphipathic molecule secreted by cells in the alveoli (type 2 alveolar cells) tha reducs surface tension on the inside of the alveolar walls. This prevents the alveoli from collapsing upon exhale and sticking together - thus reducing the effort re






14. A protein - digesting enzyme secreted by the chief cells of the gastric glands. Pepsin is secreted in its inactive form (pepsinogen) and is activated by gastric acid. It is unusual in that its pH optimum is around 1-2; most of these enzymes in the bo






15. 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






16. Specialized tissue with a lot of space that can fill with blood upon proper stimulation - causing teh tissue to become firm. Erectile tissue is found in the penis - the clitoris - the labia - and the nipples.






17. A kinase in smooth muscle cells activated by calmodulin the presence of Ca2+. As its name implies - this kinase phosphorylates myosin - activating it so that muscle contraction can occur.






18. Also called DNA pol - this is the enzyme that replicates DNA. Eukaryotes have a single version of the enzyme - simply called DNA pol (not need to know much detail); prokaryotes have three versions - called DNA pol I - DNA pol II - and DNA pol III.






19. '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.






20. A sensory receptor that responds to hcanges in pressure; for example - there are baroreceptors in the carotid arteries and the aortic ach that monitor blood pressure.






21. The first part of the large intestine.






22. The non - specific uptake of solid material by a cell accomplished by englufing the particle with plasma membrane and drawing it into the cell.






23. 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.






24. A methylated guanine nucleotide added to the 5' end of eukaryotic mRNA. The cap is necessary to initiate translation of mRNA


25. 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).






26. A function in the reproductive system - controlled by the parasympathetic nervous system - that includes erection (via dilation of erectile arteries) and lubrication.






27. Haploid cells resulting from the first meiotic division of spermatogenesis. Secondary spermatocytes are ready to enter meiosis II.






28. A string of sarcomeres with a skeletal muscle cell (hence smaller than myofiber). Each muscle cell contains hundreds of myofibirils.






29. The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at teh AV node - allowing the ventricles to contract just after the atria contract.






30. The regino of the sarcomere made up only of thin filaments. The I band is bisected by a Z line. I bands alternate with A bands to give skeletal and cardiac muscle a striated appearance. I bands get shorter (and may disappear completely) during muscle






31. A sensory receptor that responds to mechanical disturbances - such as shape changes (being squashed - bent - pulled - etc.). Mechanoreceptors include touch receptors in the skin - hair cells - in the ear - muscle spindles - and others.






32. The tubes that carry urine from the kindeys to the bladder.






33. 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.






34. The final portion of the large intestine.






35. The entropy (disorder) of the universe (or system) tends to increase.






36. The movement of water (the solvent) from its region of high concentration to its region of low concentration. NOte that the water concnetration gradient is opposite to the solute concentration gradient - since where solutes are concentrated - water i






37. 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.






38. A contractile protein connecting microtubules in the '9+2- arrangement of cilia and eukaryotic flagella. The contraction of dynein produces the characteristic movement of these structures.






39. 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.






40. A smooth sustained muscle contraction - such as occurs in skeletal muscle when stimulation frequency is high enough (this is the normal type of contraction exhibited by skeletal muscle).






41. A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS).






42. The specific molecule that binds to a receptor.






43. The largest organ in the abdominal cavity. The liver has many roles - including procesing of carbohydrates and fats - synthesis of urea - production of blood proteins - production of bile - recycling heme - and storage of vitamins.






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






45. The final phase of the digestive tract - also called the colon. The primary funcion of the large intestine is to reabsorb water and to store the feces.






46. An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).






47. The structure in the cochlea of the inner ear made up of the basilar membrane - the auditory hair cells - and the tectorial membrane. The Organ of Corti is the site where auditory sensation is detected and transduced to action potentials.






48. Movement that is directed by chemical gradients - such as nutrients or toxins. (seen in some bacteria)






49. A large - non - sepcific - phagocytic cell of the immune syste. Macrophages frequently leave the bloodstream to crawl around in the tissues and perform 'clean up' duties - such as ingesting dead cells or cellular debris at an injury site - or pathoge






50. The specialized cells of the heart that spontaneously initiate action potentials and transmit them to the cardiac muscle cells. The cells of the conduction system are essentially cardiac muscle cells - but lack the contractile fibers of the muscle ce