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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. An enzyme whose transcription can be stimulated by an abundance of its substrate (as opposed to repressible enzyme). Usually in catabolism.






2. A set of veins that connect a capillary bed in the hypothalamus (the primary capillary plexus) with a capillary bed in the anterior pituitary gland (the secondary capillary bed). Releasing and inhibiting factors from the hypothalamus travel along the






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






4. A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.






5. A dense grwoth of bacteria that covers the surface of a petri dish.






6. A layer of connective tissue underneath the epidermis of the skin. The dermis contains blood vessels - lymphatic vessels - nerves - sensory receptors - and glands.






7. Fingerlike projection of the uterin (fallopian) tubes that drape over the ovary.






8. 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.






9. 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






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






11. An organism that makes its own - typically using CO2 as a carbon source.






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






13. The resistance to blood flow in the systemic circulation. Peripheral resistance increases if arteries constrict (diameter decreases) - and an increase in peripheral resistance leads t o an increase in blood pressure.






14. The return of membrane potential to normal resting values after a depolarization of hyperpolarization.






15. A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin - coated pit.






16. The pressure measured in the arteries while the ventricles are relaxed (during diastole).






17. 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.'






18. The environment in which or upon Which bacteria grow. It typically contains a sugar source and any other nutrients that bacteria may require. 'Minimal medium' contain nothing but glucose.






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






20. The second phase of meiosis II. Metaphase II is identical to mitotic metaphase - except that the number of chromosomes was reduced by half during meiosis I.






21. The period of human development from implantation through 8 weeks of gestation. Gastrulation - neurulation - and organogenesis occur during this time period. The developing baby is known as embryo during this time period.






22. A chemical secreted by a T cell (usually the helper Ts) that stimulates activation and proliferation of other immune system cells.






23. The liquid portion of blood; plasma contains water - ions - buffers - sugars - proteins - etc. Anything that dissolves in blood dissolves in the plasma portion.






24. DNA that is loosely packed around histones. This DNA is more accessible to enzymes and the genes in euchromatin can be activated if needed.






25. An intracellular chemical signal (such as cAMP ) that relays instructions from the cell surface to enzymes in the cytosol.






26. The ability of tissues to regulate their own blood flow in the absence of neural stiulation. THis is generally accomplished via metabolic wastes (such as CO2) that act as vasodilators.






27. 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






28. 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






29. A four - carbon molecule that binds with the two - carbon acetyl unit of acetyl - CoA to form citric acid in the first step of the Krebs cycle.






30. Formerly called the cardiac sphincter - this sphincter marks the entrance to the stomach. Its function is to prevent reflux of acid stomach contents into the esophagus; note that it does **not regulate entry into the stomach.






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






32. The division of the inner cell mass of a blastocyst (developing embryo) into the three primary germ layers. Gastrulation occurs during weeks 2-4 of gestation.






33. An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.






34. A protein channel in the nuclear envelope that llows the free passage of molecules smaller than 60 kD.






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






36. The regino of the digestive tract where virtually al digestion and absorption occur. It is subdivided into three regions: the duodenum - the jejunum - and the ileum.






37. DNA replication in which each of the parental strands is read to make a complementary daughter strand - ethus each new DNa molecule is composed of half the parental molecule paired with a newly synthesized strand.






38. An enzyme that digests starch into disaccharides. Amylase is secreted by salivary glands and by the pancreas.






39. 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.






40. A structure composed of two coils of DNA wrapped around an octet of histone proteins. The nucleosome is the primary form of packagin of eukaryotic DNA.






41. A virus with an RNA genome (e.g. HIV) that undergoes a lysogenic life cycle in a host with a double stranded DNA genome. In order to integrate its genome with the host cell genome - the virus must first reverse trasncribe its RNA genome to DNA.






42. 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.






43. The specialization of cell types - especially during the embryonic and fetal development.






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






45. A structure made of two protein subunits and rRNA; this is the site of protein synthessis (translation) in a cell. Prokaryotic ribosomes (also known as 70S ribosomes) are smaller than eukaryotic ribosome (80S ribosomes). The S value refers to the sed






46. Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.






47. The membrane that separates the middle ear from the inner ear.






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






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






50. 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.