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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. Myelinated axons






2. A type of lymphocyte. The major subtypes of T cells are the helper T cells (CD4) and the killer T cells (CD8 - or cytotoxic T cells). Helper T cells secrete chemicals that help killer Ts and B cells proliferate. Killer T cells destroy abnormal self -






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






4. A hormone secreted by the small intestine (duodenum) in response to the presence of food. It decreases the rate at which chyme leaves the stomach and enters the small intestine.






5. Summation by a postsynaptic cell of input (EPSPs or IPSPs) from a single source over time.






6. Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).






7. An ion channel specific for potassium found in the plasma membrane of all cells in the body. Leak channels are constitutively open and allow their specifi ion to move across the membrane according to its gadient. Potassium leak channels allow potassi






8. The portion of the nephron after the glomerulus and apsule; the region of the nephron where the filtrate is modified along its path to becoming urine.






9. The movement of air out of the respiratory tract. Expiration can be passive (caused by relaxation of the diaphragm and elastic recoil of the lungs) or active (caused by contraction of the abdominal muscles - which increases intraabdominal pressure an






10. The pressure measured in the arteries during contraction of the ventricles (during systole).






11. 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






12. 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.






13. The shaft of a long bone. The diaphysis is hollow and is made entirely from compact bone.






14. The inner layer of smooth muscle in the wall of the digestive tract. When the circular muscle contracts - the tube diameter is reduced. Certain areas of the circular muscle are thickened to act as valves (sphincters).






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






16. A regulatory protein that binds DNA at a specific nucleotide sequence (sometimes known as the operator) to prevent transcription of downstream genes.






17. A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.






18. The period of time following an action potential when it is possible - but difficult - for the neuron to fire a second action potential due to the fact that membrane is further from theshold potential (hyperpolarized).






19. The period of time during which the ventricles of the heart are contracted.






20. A form of symbiosis in Which both organisms involved benefit from the association.






21. The phase of mitosis during which the cell physically splits into two daugter cells. Cytokinesis begins near the end of anaphase - and is completed during telophase.






22. A neuron - to - neuron - neuron - to - organ - or muscle to cell - to - muscle cell junction.






23. Mal sex hormones. Testosteron is the primary androgen.






24. Something that works together with another thing to augment the the second thing's activity. For example - a uscle that assists another muslce is said to be a syngergist. An enzyme that helps another enzyme is a synergist.






25. Also called vasopressin - this hormone is produced in the hypothalamus and secreted by teh posterior pituitary gland. It tartes teh kidney tubules - increasing their permeability to water - adn thus increasing water retention by the body. Also raises






26. 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.






27. 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.






28. An organism that lacks a nucleus or any other memrane - bound organelles. All prokaytes belong to the Kingdom Monera (not protista!)






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






30. The movement of air into the respiratory tract. Inspiration is an active process - requiring contraction of the diaphragm.






31. The specific molecule that binds to a receptor.






32. The tube that connects the middle ear acity with the pharynx; also known as the Eustachian tube. Its fucntion is to equalize midle ear pressure with atmospheric pressure so that pressure on boths sides of the tympanic membrane is the same.






33. The release of a secondary oocyte (along with some granulosa cells) from the ovary at the approximate midpoint of the menstrual cycle (typically around day 14). Ovulation is triggered by a surge in LH.






34. MRna that codes for several different proteins by utliizing different reading frames - nested genets - etc. Polycistronic mRNa is a characteristic of prokaryotes.






35. The process by which neighboring cells can influence the determination (and subsequent differentiation) of a cell.






36. Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.






37. An embryonic structure particularly important in egg - laying animals because it contains the yolk - the only source of nutrients for the embryo developing inside the egg. In humans - the yolk sac is very small (since mammals get their nutrients via






38. The majority of the cells surrouding an oocyte in a follicle. Granulosa cells secrete estrogen during the follicular phase of the ovarian cycle (before ovulation).






39. The primary female sex hormone. Estrogen stimulates the development of female secondary sex characteristics during puberty - maintains those characteristics during adulthood - stimulates the development of a new uterine lining after menstruation - an






40. The outer layer of an organ - e.g. the renal cortex - the ovarian cortex - the adrenal cortex - etc.






41. A globular protein found in muscle tissue that has the ability to bind oxygen. Myoglobin helps to store oxygen in the muscle for use in aerobic respiration (it does not move - just stays there). Muscles that participate in endurance activities (inclu






42. A subsequent immune response to previously encountered antigen that results in antibody production and T cell activation. The secondary immune response is mediated by memory cells (produced during the primary immune respone) and is much faster and st






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






44. The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage the organs formed in the embryonic stage grow and mature. The developing baby is known as a fetus during this time






45. Transfer RNA; the type of RNA that carries an amino acid from the cytoplasm to the ribosome for incorporation into a growing protein.






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






47. Steroid hormones secreted from the adrenal cortex. The two major classes are teh mineralocorticoids and glucocorticoids. Aldosterone is the principal mineralocorticoid - and cortisol is the principal glucorcorticoid.






48. 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






49. The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.






50. The largest of the cytoplasmic filaments. Microtubules are composed of two types of protein - alpha tubulin and beta tubulin. They are dynamic fibers - constantly being built up and broken down - according to cellular needs. Microtubules form the mit