Test your basic knowledge |

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






2. An immune organ located near the heart. THe thymus is the site of T cell maturation and is larger in children and adolescents.






3. A membrane lipid consisting of a glycerol molecule esteried to two fatty acid chains and a sugar molecule.






4. The first part of the large intestine.






5. One of the four basic tissue types in the body (epithelial - connective - muscle - and nervous). Connective tissue is a supportive tissue consisting of a relatively few cells scattered among a great deal of extracellular material (matrix) - and inclu






6. A structure near the middle of eukaryotic chromosomes to which the fibers of the mitotic spindle attach during cell division.






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






8. In skeleta and cardiac muscle tissue - a filament composed of actin - tropomyosin - and troponin. Thin filaments are attached to teh Z lines of the sarcomers and slide over thick filaments during muscle contraction.






9. A portion of DNA that codes for some product - usually a protein - including all regulatory sequences. Some genes code for rRNA and tRNA - which are not translated.






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






11. An enzyme inhibitor that binds at a site other than the active sit of an enzyme (binds at an allosteric site). THis changes the three - dimensional shape of the enzyme such that it can no longer catalyze the reaction






12. A viral enzyme that makes a strand of RNA by reading a strand of RNa . All prokaryotic and eukaryotic RNa polymerases are DNa dependent; they make a strand of RNa by reading a strand of DNA.






13. Muscle tissue found in the walls of hollow organs - e.g. - blood vessels - the digestive tract - the uterus - etc. Smooth muscle is non - striated - uninucleate - and under involuntary control (controlled by the autonomic nervous system).






14. The movement of a particle (the solute) in a solution from its region of high concentration to its region of low concentration ( or down it concentration gradient).






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






16. A point mutation in which a pyrimidine is susbstituted for a pyrimidine - or a purine is substituted for a purine.






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






18. '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.






19. The capillaries that surround the tubules of the nephron. The vasa recta reclaims reabsorbed substances - such as water and sodium ions.






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






21. 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.






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






23. A function the reproductive system (conrolled by the sympathetic nervous system) that returns the body to its normal resting state after sexual arousal and orgasm.






24. The failure of two separate genes to boey the Law of Independent Assortment - as might occur if the genes were found close together on the same chromosome.






25. A localized change in a neruon's or musce cell's membrane potential that can propogate itself away from its point of origin. Action potentials are an all - or - none process mediated by the opening of voltage - gated Na+ and K+ channels when the memb






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






27. 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.






28. An organism that can survive in the presence of oxygen (oxygen is not toxic) - but that does not use oxygen during metabolism (anaerobic metabolism only).






29. The location on a chromosome where transcription begins.






30. A protein found in the plasma membrane of all cells in the body that uses the energy of an ATP (hydrolyzes ATP) to move three Na+ ions out of the cell and two K+ ions into the cell - thus establishing concentrations gradients for these ions across th






31. A strong band of connective tissue that connets bones to one another.






32. 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.






33. 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.






34. 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






35. A substance secreted by embryonic testes that causes the regression of the Mullerian ducts.






36. One of the four aromatic bases found in DNA and RNA. Guanine is a purine; it pairs with cytosine.






37. 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






38. A molecule (usually a protein) capable of initiating an immune repsonse (antibody production).






39. The middle (approximtely 40%) of the small intestine.






40. 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






41. 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.






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






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






44. 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'.






45. The fourth of meiosis I. Telophase I is identical to mitotic telophase - except that the number of chromosoms is now reduced by half. After this phase the cell is considered to be haploid. Note however - that the chromosomes are still replicated - an






46. The current understanding of membrane structure - in which teh membrane iscomposed of a mix o lipids and proteins (a mosaic) that are free to move fluidly among themselves.






47. A pair of similar chromosomes that have the same genes in the same order - but may have different versions (alleles) of those genes. One of the pair of chromosomes came from Mom in an ovum - and the other came from Dad in a sperm. Humans have 23 pair






48. The product of glycolysis; 2 pyruvic acid (pyruvate) molecules are produced from a single glucose molecule. In the absence of oxygen - pyruvic acid undergoes fermentation and is reduced to either lactic acid or ethanol; in the presence of oxygen - py






49. 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






50. 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.