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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 mechanism described by Charles Darwin that drives evolution. Through mutation - some organisms possess genes that make them better adapted to their environment. These organisms survive and reproduce more than those that do not possess the benefic






2. The perio dof tim ein a woman's life when ovulation and menstruation cease. Menopause typically begins in the late 40s.






3. Cells that possess MHC II (B cells and macrophages) and are able to display bits of ingested antigen on their surface in order to activate T cells. See also 'MHC'






4. A tissue in which the cytoplasms of the cells are connected by gap junctions - allowing the cells to function as a unit. Cardiac and smooth muscle tissues are examples of functional synctiums.






5. A receptor that responds to changes in temperature.






6. An enzyme that polymerizes a strand of DNA by reading an RNA template (an RNA dependent DNa polymerase); used by retrovirus in order to integrate their genome with the host cell genome.






7. One of the main pancreatic proteases; it is activated (from chymotrypsinogen) by trypsin.






8. 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.






9. The valve that controls the release of feces from the recturm. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).






10. Paired glands found on the posterior external wall of the bladder in males. Their secretions contain an alkaline mucus and fructose - among other things - and make up approximately 60% of the ejaculate volume.






11. 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.






12. Strong bands of connective tissue that connect skeletal muscle to bone.






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






14. The protective - connective tissue wrapping of the central nervous system (the dura mater - arachnoid mater - and pia mater).






15. A cytoplasmic protein that binds to a stop codon where it appears in the A- site of the ribosome. Release factors modify the peptidyl transferase activity of the ribosome - such that a water molecule is added to the end of the completed protein. This






16. Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.






17. An organism that requires the aid of a host organism to survive - and that harms the host in the process.






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






19. The cell body of a neuron.






20. A gland that secretes a waxy product - found in the external ear canal.






21. The second most common of the five classes of leukocytes. Lymphocytes are involved in specific immunity and include two cell types - B- cells and T cells. B- cells produce and secrete antibodies and T- cells are invovled in cellular immunity.






22. An activated B cell that is secreting antibody.






23. A neuron that arries information (action potentials) to the central nervous system; a sensory neuron.






24. A receptor that responds to changes in body position - such as stretch on a tendon - or contraction of a muscle. These receptor allow us to be consciously aware of the position of our body parts.






25. HCO3-. THis ion results from the dissociation of carbonic acid - together wiht carbonic acid forms the the major blood buffer system. Bicarbonate is also secreted by teh pancreas to neutralize stomach acid in the intestines.






26. The valvecontrolling release of bile and pancreatic juice into the bloodstream.






27. The combination of alleles of an organism carries. In a homozygous genotype - both alleles are the same - whereas in a heterozygous gentorype the alleles are different.






28. The valves in the heart that separte the atria from teh ventricles. The tricuspid valve separates teh right atrium from the right ventricel - and the bicuspid (mitral) valves separates the left atrium from the left ventricle. These valves close at th






29. The site(s) where the parental DNA double helix unwinds during replication.






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






31. 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.






32. All of the cell cycle except for mitosis. Interphase includes G1 - S phase - and G2.






33. 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.






34. 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






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






36. An organ that develops during pregnacy - derived in part from the mother and in part from the zygote. The placenta is the site of exchange of nutrients and gases between the mother's blood and the fetus' blood. The placenta is formed during the first






37. The connection of a mosin head group to an actin filament during muscle contraction (the sliding filament theory).






38. A hormone released by teh G cells of the stomach in the presence of food. Gastrin promotes muscular activity of the stomach as well as secretion of hydrochloric acid - pepsinogen - and mucus.






39. Active transport that relies directly on the hydrolysis of ATP.






40. The third phase of meiosis I. During anaphase I the rplicated homologous chromosomes are separated (the tetrad is split) and pulled to opposite sides of the cell.






41. Paired masses of lymphatic tissue near the back of the throat that help trap inhaled or swallowed pathogens.






42. Cells that form the walls of the seminiferous tubules and help in spermatogenesis Sertoli cells are also called susenacular cells.






43. The movement of molecules through the plasma membrane against their concentration gradients. Active transport requires input of cellular energy - often in the form of ATP. An example is the Na+/K+ ATPase in the plasma membrane of all cells.






44. Also called occluding junctions - tight junctions form a seal between cells that prevents the movement of substances across the cell layer - except by diffusion through the cell membranes themselves. Tight junctions are found between the epithelial c






45. A viral life cycle in which the viral genome is incorporated into the host genome where it can remain dormant for an unspecified period of time. Upon activation - the viral genome is excised from the host genome and typically enters the lytic cycle.






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






47. Pairing of homologus chromosomes in a diploid cell - as occurs during prophase I of meiosis.






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






49. (1) The integration of input (EPSPs and IPSPs) from many presynaptic neruons by a single postsynaptic neuron - either temporaly or spatially. Summation of al input can either stimulate the postsynaptic neuron and possibly lead to an action potential






50. Cranial nerve pair X. The vagus nerves are very large mixed nerves (They carry both sensory input and motor input) that innervate virtually every visceral organ. They are especially important in transmitting parasympathetic input to the heart and dig