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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 'language' of a molecular biology that specifies which amino acid corresponds to which three - nucleotide group (codon).






2. Movement across the membrane of a cell that does not require energy input from the cell. Passive transport relies on concentration gradients to provie the driving force for movement - and includes both simple and facilitated diffusion.






3. A bacterium that cannon survive on minimal medium (glucose alone) because it lacks the ability to syntheisze a molecule it needs to live (typically an amino acid). Auxotrphs must ave the needed substance (the auxiliary trophic substance) added to the






4. Also called DNA pol - this is the enzyme that replicates DNA. Eukaryotes have a single version of the enzyme - simply called DNA pol (not need to know much detail); prokaryotes have three versions - called DNA pol I - DNA pol II - and DNA pol III.






5. One type of eukaryotic mRNA processing in which introns are removed from the primary transcript and exons are ligated together. SPlicing of transcripts can be different in different tissues.






6. Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.






7. (1) The secretion of useful substances from a cell - either into the blood (endocrine secretin) or into a cavity or onto the body surface (exocrine secretion). (2) in the nephron - the movement of substances from the blood to the filtrate along the t






8. The three small bones found in the middle ear (the malleus - the incus - and the stapes) that help to amplify the vibrations from sound waves. The malleus is atached to the tympanic membrane and the stapes is attached to the oval window of the cochle






9. A protein complex foudn in the inner membrane of the mitochondira. It is essentially a channel that llows H+ ions to flow from teh intermembrane space to the matrix (down teh gradeint produced by the enyzmes complexes of the electron transport chain)






10. A sweat gland located in the dermis of the skin. Sweat consists of water and ions (including Na+ and urea) and is secreted with temperatures rise.






11. The main duct of the pancreas. The pancreatic duct carries the exocrine secretions of the pancreas (enzymes and bicarbonate) to the small intestine (dueodenum).






12. Also known as the adenohypophysis - the anterior pituitary is made of gland tissue and makes and secretes six different homrones: FSH - LH - ACTH - prolactin - TSH - and growth hormone. The anterior pituitary is controlled b yreleasing and inhibiting






13. The fraction of teh end - diastolic volume ejected from the ventricles in a single contraction of teh heart. THe ejection fraction is normally around 60% of the end diastolic volume.






14. DNA replication in prokaryotes - so named because as replication proceeds around the single - circular chromosome - it takes on the appearnce of the Greek letter theta.






15. An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.






16. The second phase of the uterine (endometrial) cycle - during which the endometrium (shed off during menstration is rebuilt). This phase of the cycle is under the control of estrogen - secreted from the follicle developing in the ovary during this tim






17. The allele in a heterozygous genotype that is expressed; the phenotype resulting from either a heterozygous genotype or a homozygous dominant genotype.






18. A string of sarcomeres with a skeletal muscle cell (hence smaller than myofiber). Each muscle cell contains hundreds of myofibirils.






19. A microscopic space between the axon of one neuron and the cell body or dendrites of a secon neruon - or between the axon of a neuron and an organ.






20. Small convoluted tubules in the testes where spermatogenesis takes place.






21. 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.






22. The exchange of DNA between paired homologus chromosomes (tetrads) during prophase I of meiosis.






23. A region of specialized cardiac muscle cells in the right atrium of the heart that initiate the impules of heart contraction; for this reason the SA node is knownas the 'pacemaker' of the heart.






24. The first step in viral infection. Attachemen of a virus to its host is very specific and is also known as adsorption.






25. A form of evolution in which different organisms are placed into the same environment and exposed to teh same selection pressures. This causes the organisms to evolve along similar lines. As a result - they may share functional - but not structural s






26. The ball of capillaries at the beginning of the nephron where blood filtration takes place.






27. Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.






28. The primary male sex organ. The testes are suspended outside the body cavity in the scrotum and have two functions (1) produce sperm - and (2) secrete testosterone.






29. (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






30. A non - protein - but organic - molecule (such as vitamin) that is covalently bound to an enzyme as part of the active site.






31. A hormone tha tcontrols the release of another hormone.






32. The first substrate in teh Krebs cycle - produced primarily from the oxidation of pyruvate by the pyruvate dehydrogenase complex - however acetyl - CoA is also produced during fatty acid oxidation and protein catabolism.






33. Small organelles that contain the hydrogen peroxide produced as a byproduct of lipid metabolism. Peroxisomes convert hydrogen peroxide to water and oxygen by way of the enzyme catalase.






34. The volume of air remaining in the lungs after a maximal forced exhalation - typically about 1200 mL.






35. 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.






36. The location on a chromosome where transcription begins.






37. Movement of a hydrophilic molecuel across the plasma membrane of a cell - down its concentration gradient - through a channel - pore - or carrier molecule in the membrane. Because the hydrophilic nature of the molecule - it requires a special path th






38. 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






39. The characteristics of amolecule that has both polar (hydrophilic) and non - polar hydrophobic) regions - e.g. phospholipids - bile - etc.






40. Small fragments of DNa produced on the lagging strand during DNa replication - joined later by DNA ligase to form a complete strand.






41. 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).






42. The nerve extending from the back of teh eyeball to teh brain that carries visual information. The ptic nerve is made up of the axons of the ganglion cells of the retina.






43. One of the four basic tissue types in the body (epithelial - connective - muscle - and nervous). Epithelial tissue is a lining and covering tissue (e.g. skin - the lining of the stomach and intestines - the lining of the urinary tract - etc. ) or a g






44. 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.






45. A lubricating - nourishing fluid found in joint capsules.






46. The collection of fluid in the alveoli - particularly dangerous because it impedes gas exchange. Common causes of pulmonary edema are increased pulmonary blood pressure or infection of the respiratory system.






47. 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.






48. The regino of the sarcomere made up only of thin filaments. The I band is bisected by a Z line. I bands alternate with A bands to give skeletal and cardiac muscle a striated appearance. I bands get shorter (and may disappear completely) during muscle






49. (1) In the GI tract - organs that play a role in digestion but not directly part of the alimentary canal. These include the liver - the gallbladder - the pancreas - adn the salivary glands.






50. An organism that has two copies of its genome it each cell. The paired genomes are said to be homologous.