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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. DNA that is densely packed around histones. The genes in heterochromatin are generally inaccessible to enzymes and are turned off.






2. The pressure in the (theoretical) space between the lung surface and the inner wall of the chest cavity.






3. A prokaryotic enzyme used to twist teh single circular chromosome of prokaryotes upon itself to form supercois. Supercoiling helps to compact prokaryotic DNa and make it sturdier.






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






5. The reduced from (carries electrons) of FAD (flavin adenine dinucleotide). this is the other main electron carrier in cellular respiration (NADH is the most common).






6. The largest artery in teh body; the aorta carries oxygenated blood away from the left ventricle of the heart.






7. The unit of combact bone - also called a Haversian system. Osteons are essentially long cylinders of bone; the hollow center is called the central canal - and is where blood vessels - nervs - and lymphatic vessels are found. Compact bone is laid down






8. A concentrated region of white blood cells found along the vessels of the lympatic system.






9. A network of membranes inside eukarytoic cells invovled in lipid synthesis (steroid in gonads) - detoxification (in liver cells) - and/or Ca2+ storage (muscle cells).






10. The cells of the distal tubule at the juxtaglomerular apparatus. They are receptors that monitor filtrate osmolarity as a means of regulatin filtration rate. If a drop is osmolarity is sensed - the macula densa dilates the afferent arteriole (to incr






11. A peptide hormone produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body - especially the liver and muscle - and allows them to take glucose out of gthe blood (thus lowering blood glucose levels).






12. Also called Leydig cells - these are teh cells within testes that produce and secrete testosteron. They are stimulated by luteinizing hormone (LH).






13. Mendel's seond law. States that genes found on different chromosomes - or genes found very far apart on the same chromosome (i.e. - unlinked genes) sort independently of one another during gamete formation (meiosis).






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






15. The elimination of wastes from the body.






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






17. A nucleotide sequence on DNA that contians three elemtns: a coding sequence for one or more enzymes - *a coding sequence for a regulatory protein - and upstream regulatory sequences where the regulatory proteins can bind. An example is the lac operon






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






19. A long projection on a bacterial surface involved in an attachment - e.g. - the sex pilus attaches F+ and F- bacteria during conjugation.






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






21. Peptidyl - tRNA site; the stie on a ribosome where the growing peptide (attached to a tRNA) is found during translation.






22. The primary androgen (male sex steroid). Testosterone is a steroid hormone produced and secreted by the interstitial cells of the testes. It triggers the development of secondary male sex characteristics during puberty (including spermatogenesis) and






23. A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin - coated pit.






24. A eukaryotic organelle filled with digestive enzymes (acid hydrolases) that is involved in digestion of macromolecules such as worng organelles or material ingested by phagocytosis.






25. The prokaryotic ribosome - binding site on mRNA - found 10 nucleotides 5' to the start codon.






26. 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).






27. Toward the 3' end of an RNA transcript (the 3' end of the DNA coding strand). Stop codons and (in eukaryotes) the pol - A tail are found 'downstream.'






28. 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.






29. A cyoplasmic Ca2+- binding protein. Calmodulin is particularly important in smooth muscle cells - where binding of Ca2+ allows calmodulin to activate myosin light - chian kinase - the first step in smooth muscle cell contraction.






30. The volume of blood pumped out the heart in a single contraction.






31. A fluid - filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.






32. The enzymes that catalyzes the phosphorylation of glucose to form glucose -6- phosphate in the first step of glycolysis. This is one of the ain regulatory steps of this pathway. Hexokinase is feedback - inhibited by glucose -6- P.






33. 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.






34. One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin - hair - nails - and inner linings of the mouth and anus - as well as the entire nervous system.






35. Chemoreceptors on the tongue that respond to chemicals in a food.






36. A method of DNA protection utilized by prokaryotes in which their large circular chromosome is coiled upon itself.






37. Partially digested - semiliquid food mixed with digestive enzymes and acids in the stomach.






38. Formerly called the cardiac sphincter - this sphincter marks the entrance to the stomach. Its function is to prevent reflux of acid stomach contents into the esophagus; note that it does **not regulate entry into the stomach.






39. The maximum amount of air that can be forcibly exhaled from the lungs after filling them to their maximum level - typically about 4500 mL






40. The synapse between a motor neuron and a muscle cell. At the NMJ - the muscle cel lmembrane is invaginated and the axon terminus is elongated so that a greater area of membrane can be depolarized at one time.






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






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. Muscle tissue that is attached to the bones. SKeletal muscle is striated multinucleate - and under voluntary control.






44. The organ that carries out teh command sent along a particular motor neuron






45. A mature - cartilage cell.






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






47. The curled structure in the inner ear that contains the membranes and hair cells that transduce sound waves into action potentials.






48. Arise in blood pH due to hyperventilation (excessive breathing) and a resulting decrease in CO2.






49. The membrane surrounding the DNA in eukaryotic cells made of two lipid bilayers.






50. The small artery that carries blood toward the capillaries of the glomerulus.