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 steroid hormone produced by the corpus luteum in the ovary during the second half of the menstrual cycle Progesterone maintains and enhances the uterine lining for the possible implantation of a fertilized ovum. It is the primary hormone secreted d






2. An enzyme secreted by the juxtaglomerular cells when blood pressure decreases. Renin onverts angiotensinogen to angiotensin I.






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






4. A mechanism for increasing tension (contractile length) in a muscle by activating more motor units.






5. The amount of energy required to produce the transition state of a chemical reaction. If the activation energy for a reaction is very high - the reaction occurs very slowly. Enzymes (and other catalysts) increase reaction rates by reducing activation






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






7. A cell that produces bone.






8. The tube that carries urine from the bladder to the to outside of the body. In males it also carries semen and sperm during ejaculation.






9. The division of the autonomic nervous system known as the 'fright or flight' system. It causes a genera increase in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to skeleltal muscle. It cau






10. A diploid cell that can undergo mitosis to form more spermatogonium - and can also be triggered to undergo meiosis to form sperm.






11. The contribution of an individual gas to the total ppressure of a mixture of gases. Partial pressures are used to describe the amounts of the various gases carried in the bloodstream.






12. Enzymes that degrade various macromolecules and that require an acidic pH to function properly. Acid hydrolases are found within the lysosomes of cells.






13. Also known as the Bundle of His - this is the first portion of the cardiac conduction system - after the AV node.






14. The relationship of muscle length to its ability to generate strong contractions. Maximum tension (contraction strength) is achieved at sarcomere lengths between 2.0 and 2.2 microns. Tension decreases outside of this range <-- remember.






15. An enzyme that transcribes RNa. Prokaryotes have a single RNA pol - while eukaryotes have three; in eukaryotes - RNA pol I transcribes rRNA - RNA pol II transcribes mRNA - and RNA pol III transcribes tRNA.






16. 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.






17. An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.






18. The outermost layer of teh skin. The epidermis is made of epithelial tissue that is constantly dividing at the bottom; teh cells migrate to teh surface (dying along the way) to be sloughed off at the suface.






19. The duct that carries bile from the gallbladder and liver to the small intestine (duodenum).






20. Sperm production; occurs in human males on a daily basis from puberty until death. Spermatogenesis results in the production of four mature gametes (sperm) from a single precursor cell (spermatogonium). For maximum sperm viability - spermatogenesis r






21. The process of reading a strand of mRNA to synthesize protein. Protein translation takes place on a ribosome.






22. 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.






23. 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.






24. All the genetic information in an organism; all of an organism's chromosomes.






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






26. Specif ic defense of the body by antibodies - secreted into the blood by B- cells.






27. One of the four aromatic bases found in DNA. Thymine is a pyrimidine; it pairs with adenine.






28. A long projection off the cell body of a neruon down which an action potential can be propagated.






29. The elimination of wastes from the body.






30. A genetic cross between an organism displaying a recessive phenotype (homozygous recessive) and an organism displaying a dominant phenotype (for whic the genotype is unknown) - done to determine the unknown genotype.






31. The inner region of an organ - e.g. - the renal medulla - the ovarian medulla - and the adrenal medulla - etc.






32. An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.






33. Aromatic bases found in DNa and RNA that have a single - ring structure. They include cytosine - thymine - and uracil.






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






35. A cyclic version of adenosine monophosphate - where the phosphate is esterified to both the 5' and 3' carbons - forming a ring. Cyclic AMP is an important intracellular signaling moelcule - often called the 'second messenger.' It serves to activate c






36. An alkaline - fructose - rich fluid produced by three different glands in the male reproductive tract and released during ejaculation. Semen is very nourishing for sperm.






37. A bacterium having a spiral shape (plural = spirochetes)






38. The principal glucocorticoid secreted from teh adrenal cortex. This steroid hormone is released ruing stress - causing increased blood glucose levels and reducing inflammation. The latter effect has led to a clinical use of cortisol as an anti - infl






39. A hormone produced and secreted by teh adrenal medulla that prolongs and increases teh effects of the sympathetic nervous system.






40. One of several different nutrietns that must be consumed in the diet - and generally not synthesized in the body. Vitamins can be hdyrophobic (fat - solube) or hydrophilic (water - soluble).






41. A pigment produced by melanocytes in teh bottom cell layer of the epidermis. Melanin production is increased on sun exposure and helps prevent cllular damage due to UV radiation.






42. A version of a gene. For example - the gene may be for eye color - and the allels include those for brown eyes - those for blu e eyes - those green eyes - etc. At most - dploid organsims can posses only two alleles for a given gene - one on each of t






43. The structure in the cochlea of the inner ear made up of the basilar membrane - the auditory hair cells - and the tectorial membrane. The Organ of Corti is the site where auditory sensation is detected and transduced to action potentials.






44. 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






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






46. A strong connective tissue with varying degrees of flexibility. (1) Elastic cartilage is the most flexible - forming structures that reuqire support but also need to bend - such as the epiglottis and outer ear. (2) Hyaline cartilage is more rigid tha






47. Very small tube or channel - such as is found between lacunae (connecting them together) in compact bone.






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






49. A thick - gelatinous fluid found in the posterior segment of the eye (between the lens and the retina). The vireous humor is only produced during fetal development and helps maintain intraocular pressure (the pressure inside the eyeball).






50. 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.