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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. Also called immunoblobins - the antibodies are protiens secreted by B- cells upon activation that bind in a highly specific manner to foreign proteins (such as those found of the surface of pathogens or transplanted tissues). The foreign proteins are






2. Ribosomal RNA; the type of RNA that associates with ribosomal proteins to make a functional ribosome. It is thought that the rRNA has the peptidyl transferase activity.






3. The specific site on an antigenic molecule that binds to a T cell receptor or to an antibody.






4. Also called transverse tubules - these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.






5. A point mutation in which a pyrimidine is substitued for a purine - or vice versa.






6. 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






7. The removal ( and usually the activation) of a viral genome from its host's genome.






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






9. The portion of the digestive tract that stores and grinds food. Limited digestion occurs in the somach - and it has the lowest pH in the body (1-2).






10. A type of lymphocyte that can recognize (bind to) an antigen adn secrete an antibody specific for that antigen. When activated by binding an antigen - B cells mature into plasma cells (that secreted antibody) and memory cells (that patrol the body fo






11. The first (approximately 5%) of the small intestinte.






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






13. A normal component of the outer membrane of Gram - negative bacteria. Endotoxins produce extreme immune reactions (septic shock) - particularly when many of them enter the circulation at once.






14. The percentage of wholeblood made up of erythrocytes The typical hematocrit value is between 40-45%.






15. The female primary sex organ. The ovary produces female gametes (ova) and secretes estrogen and progesterone.






16. The period of exponential growth of bacterial population.






17. 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.






18. Pepsinogen - secreting cells foudn at teh bottom of the gastric glands






19. A structure composed of a ring of nine microtube triplets - found in pairs in the MTOC (microtubule organizing center) of a cell. The centrioles duplicate during the cell division - and serve as the organizing center for the mitotic spindle.






20. The first generation of offspring from a given genetic cross.






21. 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.






22. 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'.






23. The specific location on a DNa strand where replication begins.. Prokaryotes typically have a single origin of replication - while eukaryotes have several per chromosome.






24. '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.






25. The third phase of the ovarian cycle - during which a corpus luteum is formed from the remnants of the follicle that has ovulated its oocyte. The corpus luteum secretes progestrone and estrogen during this time period - which typically lasts from day






26. 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






27. A protein that is associated with the plasma membrane of a cell - but that is not embedded in the lipid bilayer. Peripheral proteins typically associate with embedded proteins through hydrogen bonding or electrostatic interactions.






28. The phase of the cell cycle during which the genome is replicated.






29. A ductless gland that secretes a hormone into the blood






30. Chemoreceptors on the tongue that respond to chemicals in a food.






31. The sum of all genetic material in a population.






32. A neuron found completely within the central nervous system. Interneous typically connect sensory and motor neurons - especially in reflex arcs.






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






34. An organelle surrounded by a double=membrane (two lipid bilayers) where ATP production takes place. The interior (matrix) is where PDC and the Krebs cycle occur - and the inner membrane contains the enzymes of the electron trasport chain and ATP synt






35. A receptor that responds to changes in temperature.






36. 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






37. 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.






38. Something that increases the rate of a chemical reaction by reducing the activation energy for that reaction. The free energy of reaction remains unchanged.






39. 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






40. The first encounter with an antigen - resuling in activated B cells (antibody secretion) and T cells (cellular lysis and lymphocyte proliferation). The primary immune response takes approximately ten days - which long enough for symptoms of the infec






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






42. An **organic molecuel taht associates non - covalently with an enzyme - and that is required for the proper functioning of the enzyme.






43. Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision.






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






45. The specific molecule that binds to a receptor.






46. The main protease secreted by the pancreas; trypsin is activated (from trypsinogen) by enterokinase - and subsequently activates other pancreatic enzymes.






47. Earlier embryonic ducts that can develop into femal internal genitalia in the absence of testosteron.






48. The volume of air inhaled and exhaled in a normla - resting breath - typically about 500 mL.






49. A triat determined by a gen on either the X or Y chromosomes (the sex chromosomes).






50. A thin - watery fluid found in teh anterior segment of the eye (between the lens and the cornea). THe aqueous humor is constantly produced and drained - adn helps to bring nutrients to the lesn and corena - as well as to remove metabolic wastes