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






2. 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.






3. 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






4. The reduced form of NAD+ (nicotinamide adenine dinucleotide). This is the most common electron carrier in cellular respiration.






5. A phagocytic - like bone cell that breaks down bone matrix to release calcium and phosphate into the bloodstream.






6. A form of evolution in which the same organism is placed into different environments with different selection pressures. This causes organisms to evolve differently - to diverge from their common ancestor. The resulting (new) species may share struct






7. The secretion of a cellular product to the extracellular medium through a secretory vesicle.






8. Multiple sites of replication found on large - linear eukaryotic linear eukaryotie chromosomes.






9. The muscuar layer of the uterus. The myometrium is made of smooth muscles that retains its ability to divide in order to accomodate the massive size increases that occur during pregnancy. The myometrium is stimulated to contract during labor by the h






10. The flexible membrane in teh chochlea that supports the organ of Corti (structure which contains the hearing receptors). The fibers of the basilar membrane are short and stiff near the oval windown and long and fleaxible near the apex of the cochlea.






11. 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






12. A pigment produced by melanocytes in teh bottom cell layer of the epidermis. Melanin production is increased on sun exposure and helps prevent cllular damage due to UV radiation.






13. A layer of cells surroudning the granulosa cells of the follicles in an ovary. Thecal cells help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle.






14. Small paired gland found inferior to the prostate in males and at the posterior end of the penile urethra. They secrete an alkaline mucus on sexual arousal that helps toneutralize any traces of acidic urine the urethra that might be harmful to sperm.






15. The layer of granulosa cells taht surround an oocyte after is has been ovulated.






16. Microscopic outward folds of the cells lining the small intestine; microvilli serve to increase the surface area of the small intestine for absorption.






17. Produced in muscle cells from the reduction of pyruvate (under anaerobic conditions) to regenerate NAD+ so that glycolysis can continue. A rise in lactic acid usually accompanies an increase in physical activity.






18. The energy in a system that can be used to drive chemical reactions. If the change in free energy of a reaction (Delta G - the free energy of the products minus the free energy of the energy of the reactants) is negative - the reaction will occur spo






19. Active transport that releies on an established concentration gradient - typically set up by a primary active transporter. Secondary active transport relies on ATP indirectly.






20. A pair of replicated homologous chromosomes. Tetrads form during prophase I of meiosis so that homologous chromosomes can exchange DNA in a process known as 'crossing over.'






21. The first phase of the uterine (endometrial) cycle - during which the endometrium from the previous cycle is shed off. Estrogen and progesterone levels are low during this time period. Menstruation typically lasts from day 1 to day 5 of the cycle.






22. A protein fiber with a unique triple - helix that gives it great strength. Tissues with a lot of collagen fibers are typically very strong - e.g. bone - tendons - ligaments - etc.






23. 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






24. Mendels' first law. The Law of Segregation states that the two alleles of a given gene will be separate from one another during gamete formation (meiosis).






25. 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






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






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






28. The osmotic pressure in the blood vessels due only to plasma proteins (primarily albumin) --> causes water to rush back into capillaries at end.






29. The normal configuration of double - stranded DNA in which the 5' end of oen strand is paired with the 3' end of the other






30. The monomer of a protein; amino acids hae an amio group on one end fo the molecule and a carboxylic acid group on the other - and of the of 2 different side chains.






31. An organism that will use oxygen (aerobic metabolism) if it is available - and that can ferment (anaerobic metabolism) if it is not.






32. A layer of collagen fibers that separates epithelial tissue from connective tisse (example of epithelial cells in digestive tract) - they are actual connective tissue.






33. The ends of a saromere.






34. A fluid - filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.






35. Having the ability to become anything; a zygote is totipotent.






36. The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that secrete renin upon sensing a decrease in blood pressure.






37. 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.






38. 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.






39. A self - initiating action potential that occurs in the conduction system of the heart and triggers action potentials (and thus contraction) in the cardiac muscle cells Tee pacemaker potential is triggered by the regular - spontaneous depolarization






40. A blood clot that forms in an unbrokened blood vessel. Thrombi are dangerous they can break free and begin travelin in the bloodstream (become an embolus). Emboli ultimately become stuck in a small vessel and prevent adequate blood delivery to tissue






41. A cell characterized by the presence of a nucleus and other membrane - bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi - plants and animals).






42. The RF value - the percentage of recombinant offspring resulting from a given genetic cross. The recombination frequency is proportional to the physical distance between genes on a chromosome. If a recombination frequency is low - the genes under con






43. A stack of membranes found near the rough ER in eukaryotic cells that is involved in the secretory pathway. The Golgi is involved in protein glycosylation (and other protein modification) and sorting and packagin proteins.






44. The attachment of an amino acid to a tRNA (not that this a specific interaction). tRNa loading requires two high - energy phosphate bonds.






45. The failure of homologous chromosomes or sister chromatids to separate properly during cell division. This could ocur during anaphase I of meiosis (homologous chromosomes) [--> leaving 2 gametes w/ 2 copies and 2 gametes w/ no copies of chromosome] -






46. A single piece of double - stranded DNA; part of the genome of an organism. Prokaryotes have circular chromosomes and eukaryotes have linear chromosomes.






47. Complementary DNA. DNA produced synthetically by reverse trascribing mRNA. Because of eukaryotic mRNA splicing - cDNA contains no inrons.






48. Molecules made from monosaccharides that serve as the primary source of cellular energy -. Carbohydrates can also act as cell surface markers (good thing to remember).






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






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